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1
Anisovich, A. G. "Measurement of Steel Structure Elements in the Specialized Module of the IMAGE-SP Image Processing Software." Devices and Methods of Measurements 11, no. 4 (December 17, 2020): 279–88. http://dx.doi.org/10.21122/2220-9506-2020-11-4-279-288.
Повний текст джерелаАнотація:
Grain size is one of the most important characteristics of the microstructure of metals and alloys. Determination of the grain size of steel is regulated by Standart 5639-82 "Steels and alloys. Methods for detection and determination of the grain size". Standart includes determining the grain score by comparison with reference scales, as well as manual measurement methods. The use of image processing software opens up new opportunities for the materials analysis, including for the quantitative metallographic analysis of steels and alloys. The purpose of this work was to test the specialized "Metallography" module to determine the grain score of the image processing software "IMAGE – SP", as well as to check the reliability of the obtained results using the example of ferritic and austenitic steels.In the "Metallography" module, the analysis of standard images of annex No. 3 of Standart 5639-82, as well as real images of the structures of ferritic and austenitic steel, is carried out. It is shown that the results correspond to the definition of the Standart grain score. The divergence in the results is 1 point, which is acceptable.The active development of software products for the quantitative analysis of images in metallography will make it possible to legitimize the methods of computer measurement of parameters of the structures of metals and alloys by creating appropriate standards. Successful testing of the specialized "Metallography" module demonstrates opportunities and prospects for further development of specialized software products for measuring quantitative values of metal and alloy structures. The active development of software for quantitative analysis of the images in metallography will make it possible to legalize methods for measuring parameters of metal and alloy structures by computer techniques.
2
Arumugham Akilan, Arulselvan, Ravi K. Enneti, Vamsi Krishna Balla, and Sundar V. Atre. "Effects of Hot Isostatic Pressing on the Properties of Laser-Powder Bed Fusion Fabricated Water Atomized 25Cr7Ni Stainless Steel." Lubricants 10, no. 12 (December 1, 2022): 340. http://dx.doi.org/10.3390/lubricants10120340.
Повний текст джерелаАнотація:
25Cr7Ni stainless steel (super duplex stainless steels) exhibits a duplex microstructure of ferrite and austenite, resulting in an excellent combination of high strength and corrosion resistance. However, Laser-Powder Bed Fusion fabrication of a water-atomized 25Cr7Ni stainless steel of novel chemical composition resulted in a purely ferritic microstructure and over 5% porosity. The current study investigated the effects of two hot isostatic pressing parameters on the physical, mechanical, and corrosion properties as well as microstructures of water-atomized 25Cr7Ni stainless steel of novel composition fabricated by L-PBF for the first time in the literature. The corrosion behaviour was studied using linear sweep voltammetry in a 3.5% NaCl solution. The Hot Isostatic Pressing-treated sample achieved over 98% densification with a corresponding reduction in porosity to less than 0.1% and about 3~4% in annihilation of dislocation density. A duplex microstructure of ferrite 60% and austenite 40%was observed in the X-Ray Diffraction and etched metallography of the HIP-treated samples from a purely ferritic microstructure prior to the HIP treatment. With the evolution of austenite phase, the HIP-treated samples recorded a decrease in Ultimate Tensile Strength, yield strength, and hardness in comparison with as-printed samples. The variation in the morphology of the evolved austenite grains in the HIP-treated samples was observed to have a significant effect on the elongation. With a reduction in porosity and the evolution of the austenite phase, the HIP-treated samples showed a higher corrosion resistance in comparison with the as-printed samples.
3
Wen, Yu Ren, Yong Liu, Dong Hua Liu, and Bei Tang. "Preparation and Thermal Stability of a Mechanically Alloyed Oxide Dispersion Strengthened Ferritic Steels." Materials Science Forum 715-716 (April 2012): 605–10. http://dx.doi.org/10.4028/www.scientific.net/msf.715-716.605.
Повний текст джерелаАнотація:
Oxide dispersion strengthened ferritic steels (so-called nanostructured ferritic alloys, NFAs), which are candidate structural materials in next generation nuclear power plant, have attracted much attention during recent years. In this work, iron oxide as oxygen carrier and titanium, yttrium hydrides were together mechanically milled with Fe-14Cr-3W gas-atomized powder. The thermal stability and recrystallization behaviour of the as-milled ferritic powder were studied by means of metallography, SEM, TEM and microhardness test. After ball milling for 48h, complete solid solution of bcc-Fe was formed in the as-milled powder. The thermal analysis results show that dispersed oxides with an average diameter of 5nm precipitate from the supersaturated matrix at about 850 °C. During annealing at temperatures from 800 to 1000 °C, a large number of equiaxed grains as fine as few hundreds of microns were found embedding in the matrix; the recrystallized grains stay quite stable and show minor dependence on annealing temperature and time. After being heated to 1200 °C for extended time, abnormal grain growth took place and resulted in bimodal grained structure. The effect of secondary particles on the thermal stability and recrystallization behavior of the ferritic steel was also discussed.
4
Doomra, Akash, Sandeep Singh Sandhu, and Beant Singh. "Effect of post weld heat treatment on metallurgical and mechanical properties of electron beam welded AISI 409 ferritic steel." Metallurgical and Materials Engineering 26, no. 3 (September 30, 2020): 279–92. http://dx.doi.org/10.30544/545.
Повний текст джерелаАнотація:
The applicability of ferritic stainless steel is restricted due to its low weldability, and this can be attributed to the severe grain growth in the weld zone during the solidification of the weld pool and formation of fully ferritic structure. This study aims to investigate the weldability of 18 mm thick AISI 409 ferritic stainless steel plates using an electron beam welding process without the use of filler metal. The joints were investigated for metallography characterization (microstructure, macrostructure, and microhardness) and mechanical behavior (tensile strength and impact toughness) in as-welded condition and after post-weld heat treatment at 550 ºC for 75 minutes. The weld zone exhibited large columnar grains in the direction perpendicular to the weld centerline and got refined after post-weld heat treatment. The ultimate tensile strength, yield strength, and microhardness of the weld zone were found higher than the base metal. The impact toughness of weld zone was found to be reduced by 45%, but the post-weld heat treatment improved the toughness by 40%. Results revealed that the electron beam welding process could be successfully employed for welding of AISI 409 ferritic stainless steel, which will increase its application range that requires thicker section of welded plates. Post-weld heat treatment was found to be advantageous for improving the microstructure and mechanical properties.
5
Pei, Yu, Zhe Gao, Yi Liu, Shi Qian Zhao, Chang Yu Xu, Li Yong Ren, and Xing Liang Li. "Continuous Cooling Transformation Behavior and the Phase Transformation Model in Low Carbon High Strength Sheet Steel." Advanced Materials Research 1035 (October 2014): 27–35. http://dx.doi.org/10.4028/www.scientific.net/amr.1035.27.
Повний текст джерелаАнотація:
Phase transformation of austenite continuous cooling process in low carbon high strength sheet steel has been researched by DIL805 thermal mechanical simulate. The Austenite continuous cooling transformation (CCT) diagram of steel has been determined by dilatometry and metallography. With the increase of cooling rate, ferritic transformation, perlitic transformation, bainite transformation and martensitic transformation have produced in the organization. Mathematical equations of phase transformation point-cooling rate and phase variable-cooling rate have been established and phase transformation model of high fit degree has been gained by regression calculation. The results show that calculated value and experimental value are nearly similar, so the phase transformation model is feasible.
6
Guo, Jin, Shui Ping Hu, Zhen Li Mi, and Dong Bin Zhang. "Effect of Different Cooling Paths on the Microstructure and Properties of a Plain Carbon Steel." Materials Science Forum 762 (July 2013): 171–75. http://dx.doi.org/10.4028/www.scientific.net/msf.762.171.
Повний текст джерелаАнотація:
The effect of different cooling paths on the microstructure and properties of a plain carbon steel was carefully investigated by thermal simulation, hot rolling, tensile tests and quantitative metallography. Experimental results indicate that the more rapid the cooling rate is, the smaller the average ferritic grain size is and the higher the mechanical properties are. Both ultra fast cooling method and ultra fast cooling+accelerated controlled cooling method could refine grain size and improve mechanical properties. Without any alloy addition, using the ultra fast cooling immediately after hot rolling process, the yield strength of the plain carbon steel could reach 360 MPa and the elongation is 32%.
7
Subramanian, Chidambaram. "Experimental in-situ metallographic investigations of industrial hydrocarbon processed fired heater tubes." Metallurgical Research & Technology 116, no. 2 (2019): 203. http://dx.doi.org/10.1051/metal/2018062.
Повний текст джерелаАнотація:
In the present investigations, the coker unit heater tube has been evaluated using in-situ metallography, after an exposure at a temperature of 615 °C for around 52 000 h. The heater tubes in petroleum industries are mostly damaged by creep failures; hence metallography assessments are conducted for safe operation of industrial units. The primary material of construction for fired heater tubes is ASTM A213 GrT9 chromium molybdenum ferritic steel and maximum primary creep strains are estimated as 11.2761 × 10−2 and 11.2802 × 10−2 for temperature 888 and 923 K, respectively. In-situ metallography test was conducted at finish pass surface on one butt weld joint section of two different passes (pass I and pass II) of heater tubes. Hardness is within limit and chemical composition stands confirmed within material standards. A heater tube weld joint comprising weldment metal, heat affected zone and base metal were found in good condition, and no indications of creep were observed. Tempered martensite is observed only in weld metal and heat affected zone which aids in high temperature creep strength of metal at weld joint and heat affected zone. No martensitic structure was observed on the base metal; however base metal creep strength was ascertained by fine precipitated alloy carbides within the ferritic matrix base metal structure. Recommendations were further provided to monitor the performance of heater tubes and for an early prediction of secondary creep.
8
Lhabitant, Solène, Alain Toufine, and Anis Hor. "Heat Treatments of P295GH Steel Made by Directed Energy Deposition: Metallography and Hardness." Materials Science Forum 1046 (September 22, 2021): 65–70. http://dx.doi.org/10.4028/www.scientific.net/msf.1046.65.
Повний текст джерелаАнотація:
Directed energy deposition (DED) is an Additive Manufacturing process deposing fused metal powder on a preexisting substrate. This document shows the influence of heat treatment on P295GH deposit made by DED, for hybridization process. The heat treatment must reduce the macroscopic differences between the rolled substrate and the deposited DED material. The experimental plan has been defined around AC3 temperature, according to P295GH existing literature. XRD analysis, hardness measurements and metallographic inspections have been performed on samples before and after heat treatment. XRD analysis and hardness measurements have shown an isotropic material. The as-built microstructure is ferritic and acicular, but coarsens after the heat treatment. The study promotes a heat treatment at 800°C during 3 hours to obtain the best compromise between properties, impact on the substrate and differences with the rolled substrate.
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Costa Viana, Carlos Sergio da, F. S. Candido, and Andre Luiz Pinto. "An EBSD Analysis of the Origins of Ridging in AISI 430 Steel Sheets." Materials Science Forum 495-497 (September 2005): 173–78. http://dx.doi.org/10.4028/www.scientific.net/msf.495-497.173.
Повний текст джерелаАнотація:
In the present work the characterisation of both the microstructure and the microtexture of two ferritic stainless steel sheets - AISI 430 (Fe17% Cr) and AISI 434 (17% Cr, 1% Mo) - known to display different ridging behaviours, was carried out by optical metallography, EBSD and OIM techniques. It was concluded that severe ridging is a consequence of: (a) presence of {111}<uvw> and {001}<uvw> colonies of grains alternating throughout the sheet plane; (b) through thickness texture inhomogeneity with layers of {001}<110> oriented large grains of low Rvalues sandwiched between layers of higher R-value textured material.
10
Liang, Xiao Jun, Ming Jian Hua, C. Isaac Garcia, and Anthony J. DeArdo. "The Thermomechanical Controlled Processing of High-Strength Steel Plate: A New View of Toughness Based on Modern Metallography." Materials Science Forum 762 (July 2013): 38–46. http://dx.doi.org/10.4028/www.scientific.net/msf.762.38.
Повний текст джерелаАнотація:
Modern thermomechanical controlled processing (TMCP) of advanced steels is now an important processing route in the production of engineering structures and products that are of value to society. The principles of TMCP are now practiced in the hot mill, cold mill and press forming shops around the world. Successful TMCP means that the proper metallurgical microstructure has been obtained in the required areas of the steel. The ideal microstructure is often defined by the correct phase balance and dimensions either of the parent austenite or final ferritic phase. Technological and economic demands have led to ever increasing levels of strength, especially for applications such as large diameter linepipe. The operative yield strengths in 18mm hot rolled plate have increased from X52(ferrite pearlite) in 1970 to X80(ferrite-bainite) today. The next frontier is the X100-X120 strength range, where bainitic or martensitic microstructures are required. It is clear that achieving a high-strength bainitic microstructure in heavy plate requires a high Carbon Equivalent value (C. E. II or Pcm), a rapid cooling rate, and a low water-end temperature. The requirement of high toughness and good weldability also means a low carbon content. This paper will describe the results of a research program where a steel of C. E. 0.56 and Pcm 0.23 was reheated, rough rolled for grain refinement, finish rolled for austenite pancaking, and direct quenched to below the Bs temperature. It was found that the strength and especially the toughness of the fully processed plates could not be explained using conventional metallographic techniques in conjunction with known structure-property relationships. However, the application of modern metallographic techniques based on FEG-SEM incorporating OIM led to microstructural characterization that more fully explained the observed mechanical properties. Of particular importance were the amount of MA micro-constituent, the crystallographic packet size of the bainite, and the high angle boundary character, especially the CSL boundaries, found in the microstructure. In the future, improved modeling of microstructural evolution and attendant mechanical properties will incorporate these important features.
11
Li, Li Zhang, He Wei, Lin Lin Liao, Yin Li Chen, Hai Feng Yan, Guang Hua Liu, and Zhi Wei Sun. "Continuous Cooling Phase Transformation Rule of 20CrMnTi Low-Carbon Alloy Steel." Materials Science Forum 944 (January 2019): 303–12. http://dx.doi.org/10.4028/www.scientific.net/msf.944.303.
Повний текст джерелаАнотація:
Gear steel is a ferritic steel. In the rolling process, the ideal structure is ferrite + pearlite, and bainite or martensite is not expected. However, due to the high alloy content, the hardenability is good, and the bainite or martensite structure is very likely to be generated upon cooling after rolling. In this paper, phase transformation rules during continuous cooling of 20CrMnTi with and without deformation were studied to guide the avoidance of the appearance of bainite or martensite in steel. A combined method of dilatometry and metallography was adopted in the experiments, and the dilatometer DIL805A and thermo-simulation Gleeble3500 were used. Both dynamic and static continuous cooling transformation (CCT) diagrams were drawn by using the software Origin. The causes of those changes in starting temperature, finishing temperature, starting time and transformation duration in ferrite-pearlite phase transformation were analyzed, and the change in Vickers hardness of samples with different cooling rate was discussed. The results indicate that with different cooling rate, there are three phase transformation zones: ferrite-pearlite, bainite and martensite. Deformation of austenite accelerates the occurrence of transformation obviously and moves CCT curve to left and up direction. When the cooling rate is lower than 1 °C/s, the phases in samples are mainly ferrite and pearlite, which is the ideal microstructure of experimental steel. As the cooling rate increases, starting temperature of ferrite transformation in steel decreases, starting time reduces, transformation duration gradually decreases, and the Vickers hardness of samples increases. Under the cooling rate of 0.5 °C/s, ferrite transformation in deformed sample starts at 751.67 °C, ferrite-pearlite phase transformation lasts 167.9 s, and Vickers hardness of sample is 183.4 HV.
12
Wiednig, Christopher, Ernst Plesiutschnig, Stefan Mitsche, Coline Beal, Norbert Enzinger, and Claus Lochbichler. "Dissimilar Electron Beam Welds of Nickel Base Alloy A625 with a 9% Cr-Steel for High Temperature Applications." Materials Science Forum 879 (November 2016): 2100–2106. http://dx.doi.org/10.4028/www.scientific.net/msf.879.2100.
Повний текст джерелаАнотація:
Welding of thick walled components with an electron beam has great potential due to the minimal heat input, high reproducibility and cost-efficiency. In the present work electron beam welding was used to weld 50mm thick plates of cast Ni-base alloy A625 to ferritic/martensitic 9% Cr steel plates. The welds were creep exposed at 625°C with stress levels ranging between 156 - 100MPa. Microstructure analysis of the weld-seam and the heat affected zone was carried out using metallography and scanning electron microscopy employing the EBSD technique to determine the location of the creep rupture. Creep fracture is located in the heat affected zone of the 9% Cr steel. Electron beam welded samples were compared to shield metal arc welded samples regarding welding and creep resistance. The performance and related microstructure properties of the electron beam welded specimen are more than competitive to conventional metal-arc-welding procedures.
13
DERHACH, T. O., H. D. SUKHOMLYN, L. M. DEINEKO, A. Ye BALEV, and A. V. KRASIUK. "LABORATORY AND OPERATING TESTING OF HIGH-ALLOY STEEL PIPES MADE BY THE LATEST TECHNOLOGIES." Ukrainian Journal of Civil Engineering and Architecture, no. 4 (October 22, 2022): 46–57. http://dx.doi.org/10.30838/j.bpsacea.2312.250822.46.877.
Повний текст джерелаАнотація:
The purpose of the research: evaluation of the quality and durability for pipes made of high-alloyed austenitic and ferritic-austenitic steels, which are manufactured at PJSC "CENTRAVIS PRODUCTION UKRAINE" using the latest technologies, by conducting complex laboratory studies and long-term operational tests at chemical industry enterprises. Materials and methods: the research materials were experimental pipes made of high-alloyed austenitic and ferritic-austenitic chromium-nickel-molybdenum steels of the new generation, manufactured using the latest technologies. The microstructure of the pipes was investigated by metallography and electron microscopy using developed and improved methods. Corrosive researches in laboratory terms included a test on firmness against the local types of corrosion inherent in high-alloy steels: intergranular corrosion (IGC), pitting corrosion (PC), corrosion cracking (CC) and sulfide stress corrosion cracking (SSCC). The mechanical properties of the pipes were determined by tensile and impact bending tests. Long-term operational tests of pipes were carried out in conditions of industrial production at chemical industry enterprises in apparatus for the urea and caustic soda production. Research results: A high content of special low-energy grain boundaries in the theory of coincident nodes’ lattices (SG CSL) was established in the structure of pipes manufactured according to the latest technologies (≥ 75 %); high resistance of pipes against various types of the most dangerous local corrosion compared to existing analogues, a high level of mechanical properties, as well as high corrosion resistance during long-term operational tests in environments at chemical industry enterprises. The implementation of the obtained results will contribute to increasing the efficiency of production and operation for highly alloyed steel pipes in demand on the world market and increasing the competitiveness of domestically produced pipes on the European and world markets.
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Xie, Bin, Jiaxiang Xue, and Xianghui Ren. "Wire Arc Deposition Additive Manufacturing and Experimental Study of 316L Stainless Steel by CMT + P Process." Metals 10, no. 11 (October 25, 2020): 1419. http://dx.doi.org/10.3390/met10111419.
Повний текст джерелаАнотація:
The cold metal transfer plus pulse (CMT + P) process was performed to produce a 316L vertical wall through the single-channel multi-layer deposition method. The microstructure of different regions on deposited samples was observed by an optical microscope and a scanning electron microscope (SEM). The phase composition of the as-deposited wall was checked by X-ray diffraction, and the element distribution in the structure was analyzed by an energy-dispersive spectrometer. The tensile strength and microhardness of samples were tested, and the fracture morphology was observed by an SEM. Finally, the electrochemical corrosion characteristics of the as-deposited wall in different regions along the building direction were tested. Results from the experiments indicated that the microstructure of metallography showed a layer band. The metallurgical bounding between layers was carried out by dendrite remelting and epitaxial growth. Along the building direction, the alloy of different regions solidified in an ferritic-austenitic (FA) manner, and due to having undergone different heat histories, their SEM microstructures were significantly distinct. The ultimate tensile strength (UTS) and yield strength (YS) of the vertical specimens were higher than those of the horizontal specimens, displaying obvious anisotropy. Due to a large amount of precipitation of precipitated phases in terms of intermetallic compounds in the middle and upper regions, the tensile strength and microhardness along the building direction showed a trend of first decreasing and then increasing. In the bottom region, a small amount of ferrite precipitated in the austenite matrix, while in the middle of the as-deposited wall, the amount of ferrite gradually increased and was distributed in the austenite matrix as a network. However, due to the heat accumulation effect, the ferrite dissolved into austenite in large quantities and the austenite showed an obvious increase in size in the top region. A stable passivation film was caused by a relatively low dislocation density and grain boundary number, and the middle region of the arc as-deposited wall had the best corrosion resistance. The large consumption of chromium (Cr) atoms and material stripping in the top region resulted in the integrity of the passivation film in this region being the weakest, resulting in the lowest corrosion resistance.
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Ниркова, Л. І., Л. В. Гончаренко, Ю. В. Борисенко та Ю. О. Харченко. "ОСОБЛИВОСТІ ЛОКАЛЬНОЇ КОРОЗІЇ ЗВАРНОГО З’ЄДНАННЯ ТРУБНОЇ СТАЛІ Х70, ОБУМОВЛЕНОЇ ЙОГО ЕЛЕКТРОХІМІЧНОЮ ГЕТЕРОГЕННІСТЮ". Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 148, № 4 (10 березня 2021): 117–29. http://dx.doi.org/10.30857/1813-6796.2020.4.11.
Повний текст джерелаАнотація:
Establishing the influence of chemical composition and structure on local corrosion of the welded joint of X70 pipe steel in the conditions simulating operating conditions, and determining the main corrosion factors. Methodology. Standard methods were used: potentiometry, polarization curves method, research of corrosion resistance at constant deformation, profilometry, optical metallography. Results. The electrochemical heterogeneity of the welded joint (on the example of X70 steel) with the factory weld was studied. It was found that in the weld of this joint has a slightly lower content compared to the base metal of the following elements: Al (0.025% and 0.02%, respectively) and Nb (0.033% and 0.058%, respectively), but a higher content of Mo and Cr. The structure of base metal is ferritic-bainite, has small pearlite formations, the structure of the seam is heterogeneous, contains dispersed needle, grain boundary polygonal, pre-eutectoid ferrite and separate areas of lamellar ferrite. It is concluded that in the welded joint under studied, the greater electrochemical activity of any zone can be attributed to the lower content of alloying elements or features of the microstructure. According to the results of electrochemical and accelerated corrosion-mechanical tests in the simulated operating conditions, it was found that the determinative factor for initiating of local corrosion of welded joints is the corrosive environment and conditions of the corrosion process flying, in particular – thin-film corrosion in a two-phase medium (hydrocarbon water). Scientific originality. According to the results of complex research, new data on the influence of the chemical composition and structure of the welded joints of steel X70 with factory extensional weld on the susceptibility to local corrosion were obtained. It was found that in a welded joint, the greater electrochemical activity of any zone is due to the lower content of alloying additives (this applies to the weld metal) and/or the peculiarities of the microstructure (for weld metal and high affected zone). Practical value. The methodological approach to investigation of local corrosion of welded joints in the conditions which are simulating the condition of operation, on an example of welded joints of X70 steel is developed and substantiate. A laboratory stand for research has been developed. It is established that the determinative factor for initiating of local corrosion of welded joints is the corrosive-active medium and the conditions of the corrosion process flying, particularly – thin-film corrosion in a two-phase medium (hydrocarbon-water).
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Werner, E., T. Siegmund, H. Weinhandl, and F. D. Fischer. "Properties of Random Polycrystalline Two-Phase Materials." Applied Mechanics Reviews 47, no. 1S (January 1, 1994): S231—S240. http://dx.doi.org/10.1115/1.3122817.
Повний текст джерелаАнотація:
The physical properties of polycrystalline two-phase alloys depend on the properties and the amounts of the constituent phases and on the geometrical arrangement of the grains in the two-phase microstucture. Establishing microstructure-property relationships for two-phase materials requires the correct quantitative characterization of all topological features of the microstructure. Stereology and quantitative metallography provide the means to analyse both real and idealized model microstructures with this respect. The two most important quantitative parameters involved in the formulation of microstructure-property relationships are the contiguity C and the fraction of clusters r which quantify the continuity of the phases and to which extent the phases are present as matrix or as inclusion, respectively. Idealized random model microstructures closely approximating real microstructures are generated and joined with continuum and micromechanical models. The essence of the micromechanical model is the unit cell approach combined with finite element calculations. Properties computed for the unit cell are then representative for the overall microstructure. With this method four important physical properties of a ferritic-austenitic stainless duplex steel are modeled successfully: the magnetic permeability, the diffusion of hydrogen, the thermal expansion behavior and the mechanical properties at elevated temperatures. From these examples the relevance of the parameters C and r is evident. Furthermore, the linear rule of mixture is not appropriate to describe both experimentally obtained properties and the results from the numerical analyses for the respective entity.
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Speicher, M., and R. Scheck. "“Metallography to go”: Mobile metallographic examinations directly on components." Practical Metallography 59, no. 8-9 (August 1, 2022): 532–44. http://dx.doi.org/10.1515/pm-2022-0054.
Повний текст джерелаАнотація:
Abstract In this work, the fields of application of mobile metallography in technical practice are presented on the basis of numerous examples. This nearly non-destructive testing method (NDT) is used primarily for quality assurance of components in operational applications. It includes the fabrication of microstructure replicas, mobile hardness testing and analysis methods for the determining of the chemical composition of materials. The microstructure replicas are taken for different purposes. On the one hand, it can be used to document the initial state of the microstructure, to evaluate the microstructure condition for the control of the manufacturing quality, and conclude on the required properties. On the other hand, this method can be used to evaluate defects (formation of cracks, performance of welds, correct heat treatment, creep damage, etc.). On the basis of different test cases, the results for low-alloyed and highalloyed ferritic and austenitic steels, for nickel alloys and for the possibility of subsequent determination of precipitation populations in the transmission electron microscope (TEM) are presented.
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Strobl, Susanne, Roland Haubner, and Wolfgang Scheiblechner. "New Steel Combinations Produced by the Damascus Technique." Advanced Engineering Forum 27 (April 2018): 14–21. http://dx.doi.org/10.4028/www.scientific.net/aef.27.14.
Повний текст джерелаАнотація:
Multilayered forged steel plates, which combine the properties of diverse steel qualities, are referred to as Damascus steels. Since the 3rd century AD blades and weapons have been produced by the Damascus technique in Europe. In this work four different steel combinations were investigated. Combining Fe with carbon steel C60 resulted in a ferritic-pearlitic microstructure. By forging two heat-treatable steels C40 and C60 martensite with an inhomogeneous carbon distribution was formed. Combining Fe with an austenitic stainless steel showed ferrite and austenite with grain boundary carbides and segregation bands. The last combination of two cold working steels K110 and K600 led to a complex microstructure with martensite, retained austenite and two special types of carbides. After metallographic preparation and using of different etchants the various microstructures were characterized by light optical microscopy and confirmed by Vicker ́s microhardness measurements. Of high interest are the interfaces and the quality of the weld between the individual steel layers. In some regions oxidation and carbon diffusion were observed.
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Torkar, Matjaz, Aleksandra Kocijan, Roman Celin, Jaka Burja, and Bojan Podgornik. "Metalografska preiskava in korozijska odpornost zvarov feritnega nerjavnega jekla." Materiali in tehnologije 50, no. 5 (October 18, 2016): 829–34. http://dx.doi.org/10.17222/mit.2016.059.
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Ledoux, Xavier, Francois Buy, Aurélien Perron, Eric Suzon, José Farré, Bernard Marini, Thomas Guilbert, et al. "Kinetics of Sigma Phase Precipitation in Niobium-Stabilized Austenitic Stainless Steel and Effect on the Mechanical Properties." Materials Science Forum 783-786 (May 2014): 848–53. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.848.
Повний текст джерелаАнотація:
Stabilized austenitic stainless steels are widely used in nuclear and oil industries. The 316 Nb steel grade presented in this study holds a small amount of delta ferrite in the austenitic matrix which tends to transform into sigma phase during prolonged exposures in the temperature range of 600-1000°C. Sigma phase is promoted by ferritic elements such as chromium, molybdenum, niobium and silicon. Time-Temperature-Transformation (TTT) diagram of the δ-ferrite evolution is established thanks to DSC experiments and quantitative metallographic analysis. It is observed that the highest sigma phase formation rate occurs between 800 and 900°C, and that the transformation of ferrite begins after a few minutes of exposure in this temperature range. The microstructure of transformed δ-ferrite is mostly dominated by the eutectoid mixture σ + γ2. Tensile tests were performed for three different cooling conditions: a significant embrittlement attributed to the δ-ferrite transformation is measured by a ductility loss for the lowest cooling rate.
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Vurobi, Selauco, Thiago Ferreira de Andrade, and Osvaldo Mitsuyuki Cintho. "Utilization of Color Metallography in Characterization of a Modified SAE 4118H Steel Submitted to Isothermal Treatments." Materials Science Forum 805 (September 2014): 242–47. http://dx.doi.org/10.4028/www.scientific.net/msf.805.242.
Повний текст джерелаАнотація:
A modified SAE 4118H steel was subjected to isothermal treatments between 700 °C and 400 oC every 50 °C range, with the intention of evaluating the decomposition of austenite at constant temperature. It was varied time of stay in the isothermal treatment between 15 and 28800 seconds depending on the treatment temperature. After each isothermal treatment and standard metallographic preparation, the samples were etched with color metallography reagents for revealing the microstructure obtained. At temperatures of 700oC to 550°C the steel showed microstructure composed of ferrite and pearlite. Between 500oC and 400°C bainitic microstructure was quickly formed. The reduction of treatment temperature provided finer microstructures, which increased the hardness of steel. With the use of color metallography reagents, excellent contrast for determining the volume fraction of microstructural constituents formed isothermally was obtained, helping the study of isothermal decomposition of austenite.
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Mejía, Ignacio, Gladys Y. Díaz-Martínez, and Arnoldo Bedolla-Jacuinde. "Metallographic Characterization of a Ti-Containing Low-Density Fe-Mn-Al-C Steel in As-Cast Condition." MRS Proceedings 1812 (2016): 47–52. http://dx.doi.org/10.1557/opl.2016.17.
Повний текст джерелаАнотація:
ABSTRACTLow-density steels, with an excellent combination of outstanding mechanical properties, ultimate tensile strength and specific weight reduction, have been attracting great attention as a new group of materials in many industrial applications, particularly in the automotive industry. The aim of this work was to characterize the microstructure of a Ti-containing low-density Fe-Mn-Al-C steel in the as-cast condition. For this purpose, Ti-containing low-density steel was melted in an induction furnace using high purity raw materials and cast into a metal ingot mold. Chemical composition of the studied steel was Fe-32Mn-7.0Al-2.2C-0.5Ti (wt%). Samples were prepared by standard metallographic technique (grinding and polishing) and chemically etched with 2% nital solution, in order to reveal the dendritic microstructure. Microstructure observations were performed by scanning electron microscopy and the chemical nature of the present phases was determined by energy-dispersive X-ray. X-ray diffraction was performed at room temperature using a diffractometer with Cu Kα radiation. Phase equilibria by thermodynamic calculations for the studied steel were performed using JMatPro® software package. In general, results revealed a finer dendritic microstructure composed of ferritic matrix and austenite islands. The presence of ferrite and austenite in the steel was also confirmed by X-ray diffraction.
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Park, Jin Sung, Si On Kim, Young Jae Jeong, Soon Gi Lee, Jong Kyo Choi, and Sung Jin Kim. "Long-Term Corrosion Behavior of Strong and Ductile High Mn-Low Cr Steel in Acidic Aqueous Environments." Materials 15, no. 5 (February 25, 2022): 1746. http://dx.doi.org/10.3390/ma15051746.
Повний текст джерелаАнотація:
To expand the industrial applicability of strong and ductile high Mn-Low Cr steel, a deeper understanding and mechanistic interpretation of long-term corrosion behavior under harsher environmental conditions are needed. From this perspective, the long-term corrosion behaviors of 24Mn3Cr steel under acidic aqueous conditions were examined through a comparison with conventional ferritic steels using the electrochemical measurements (linear polarization resistance and impedance), and immersion test followed by the metallographic observation of corrosion morphologies. In contrast to conventional ferritic steels, 24Mn3Cr steel, which had the lowest corrosion resistance at the early immersion stages (i.e., the highest corrosion current density (icorr) and lowest polarization resistance (Rp)), showed a gradual increase in corrosion resistance with prolonged immersion. Owing to the slow formation kinetics of (Fe,Cr)-enriched oxide scale, a longer incubation time for ensuring a comparatively higher corrosion resistance is required. On the other hand, conventional ferritic steels had an oxide scale with less densification and a lower elemental enrichment level that did not provide an effective anti-corrosion function. From the results, this study can provide significant insight into the industrial applicability of the high Mn-low Cr steel by providing the mechanistic interpretation of corrosion behaviors in acidic aqueous environments.
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Emun, Y., H. S. Zurob, and J. R. Kish. "Corrosion Evaluation of Ferritic Stainless Steels for Automotive Exhaust Applications." CORROSION 75, no. 11 (August 20, 2019): 1276–80. http://dx.doi.org/10.5006/3319.
Повний текст джерелаАнотація:
This study compares the localized (exterior) corrosion susceptibility of chromized steel to bench-mark ferritic stainless steels for automotive exhaust applications. Continuous near-neutral salt fog exposure (ASTM B117) was used for this purpose. Corrosion susceptibility was determined using mass loss measurements coupled with a post exposure metallographic examination. Complementary potentiodynamic polarization measurements were made in the bulk salt solution to help interpret the relative performance. The elevated Cr content provided by the chromizing surface treatment provides comparable corrosion resistance to the more highly alloyed ferritic stainless steels studied. The major factor affecting localized corrosion susceptibility is the formation of rust deposits, which act as effective pit-like corrosion initiation sites.
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Satbayeva, Zarina A., Laila Gylymmeddenovna Zhurerova, and Erkezhan Erkinbekkyzy Tabieva. "Plasma Electrolytic Cementation of 0.3C-1Cr-1Mn-1Si-Fe Steel." Key Engineering Materials 839 (April 2020): 196–202. http://dx.doi.org/10.4028/www.scientific.net/kem.839.196.
Повний текст джерелаАнотація:
This work is devoted to research of the structural-phase condition and changes in the mechano-tribological properties of 0.3C-1Cr-1Mn-1Si-Fe structural steel after plasma electrolytic cementation. Using metallographic and X-ray analysis, mechano-tribological tests, it was found that 0.3C-1Cr-1Mn-1Si-Fe steel in the initial state belongs to the ferritic-pearlitic class, which contains ~ 65% of pearlite grain and 35% of ferrite grain. When samples of 30HGSA steel are saturated with carbon, a modified surface layer with a thickness of 25μm is formed on the surface of the studied samples, including α-Fe ferrite, cementite Fe3C, iron Fe3C2 carbide and an alloying element. It was established that the intensity of wear of the samples after modifying decreased by 2 times, and the surface microhardness after cementation increased 3 times, depending on the original sample.
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Hotała, Eugeniusz, Rajmund Ignatowicz, and Maciej B. Lachowicz. "Metallographic Testing of 19th Century Steel in an Operating Water Tower." Materials 14, no. 9 (April 25, 2021): 2204. http://dx.doi.org/10.3390/ma14092204.
Повний текст джерелаАнотація:
The world’s first steel structures were built towards the end of the 19th century. Some of them are still in use today, whereas others are maintained as precious technical heritage. In both cases, there may be a need to assess their technical condition and carry out repairs and reinforcements, which requires an understanding of the properties of the steel used. The few studies that have been undertaken of such steel structures indicate that the properties depend on the history of use. This paper presents the results of metallographic tests of a steel tank in a water tower built in 1884 in Lower Silesia. The chemical composition was consistent with that of the puddled steel used in the 19th century. The carbon content showed significant segregation and ranged from 0.011% to 0.072% mass. As a consequence, a typical microstructure for low-carbon steels (ferritic) was observed, changing locally to ferritic-pearlitic. The tested steel contained a very high content of phosphorus and silicon. The microstructure with numerous slags favoured the formation of surface delamination caused by the corrosion processes. The degree of corrosion of the steel of the tank was also assessed, as well as the type of corrosion inside the tank. Corrosion was favoured by the oxygen concentration cell. The results of the research will be used to assess the potential for continuing tank use and the reinforcements that have been planned. The results presented will add to the somewhat limited research results available for steel dating back to the 19th century, which is still present in many building structures. Such a database is especially needed by those designing technical measures aimed at maintaining these historical structures in good technical condition.
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Dias, Erica, Laís Horimoto, and Marcelo dos Santos Pereira. "Microstructural Characterization of CP Steel Used in Automotive Industry." Materials Science Forum 775-776 (January 2014): 141–45. http://dx.doi.org/10.4028/www.scientific.net/msf.775-776.141.
Повний текст джерелаАнотація:
This study aims to characterize the microstructure of the complex phase steel (CP). Using the conventional and colored metallographic analysis with 3% Nital etchant, sodium metabisulfite 10% and LePera. Techniques were applied in this work of optical microscopy, using, besides the lighting in bright field, dark field illumination of the reverse contrast in bright field illumination, the method of polarized light, which generates colorful contrast, providing a complementary identification phases present in the microstructure, and the system by differential interference contrast (DIC). The results obtained by metallography CP indicates that the steel has a microstructure composed of ferrite, retained austenite, bainite and martensite and precipitates arranged in a refined and complex morphology. Besides bright field illumination others optical microscopys techniques such as dark field illumination were applied.
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Thillairajan, K., V. Balusamy, and V. Ramaswamy. "An Investigation on the Development of Hard and Strong Bainitic Steels by very Short Heat Treatments." Applied Mechanics and Materials 592-594 (July 2014): 1240–44. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.1240.
Повний текст джерелаАнотація:
An attempt has been made in this research work to develop strong and tough bainitic steels in shorter transformation durations of less than three hours leading to ease of production for steel industries making these steels. High carbon medium alloy steel with high amounts of silicon, cobalt and aluminum was taken up for this study. The steel samples were austempered at 473, 523, 573, and 623K for 30, 45, 60, 90, 120, 150, and 180 minutes and then characterized by optical metallography, scanning electron microscopy, transmission electron microscopy and X-ray diffraction investigations. Microstructure containing plates of bainitic ferrite and substantial amounts of retained austenite placed in between the bainitic ferrite laths was produced. The steel after austempering had hardness in the range 450 – 720 HV at 30 kg load, tensile strength of about 560-620 MPa and room temperature notch impact toughness of about 10J with very less ductility. The details of alloy design and making, metallurgical and mechanical characterizations are discussed.
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Camurri, Carlos, C. Carrasco, I. Bello, and M. Trucco. "Development of Low Carbon Boron Steel for Wire Drawing." Materials Science Forum 539-543 (March 2007): 4238–42. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.4238.
Повний текст джерелаАнотація:
From the mechanical point of view, the successful cold drawing of wire-rods of low carbon steel requires a high ductility and a ratio between the yield stress and tensile strength as lowest as possible, both for diminish the fractures during the process. Small boron additions in the cast of this kind of steel produce an increase in the size of austenitic grain, and consequently the ferritic one, and a diminution of the deformation hardening due to the reduction in the nitrogen content in the solid solution. In this way, the goal of this work is to study the effect of small boron additions (67 to 117 ppm) in the mechanical properties of 5.5 mm diameter wire-rods of low carbon steel. The wire-rods were characterized by means of traction tests, metallographic analysis with optic and electronic microscopy, and the results were compared with the corresponding one for wire-rod of standard steel, i.e., without boron contents. The metallographic analysis confirms the increase in size of ferritic grain. The measured ductility present only slight increases in boron steel, no significant from the quality point of view, however, the ratio between yield stress and tensile strength in boron steels shown a clear improvement respect to the standard. Traction tests in samples obtained at the exit of each one of the matrixes used during the cold drawing process shows an improve in the behavior of low carbon steel with boron contents.
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Varbai, Balázs, Timothy Pickle, and Kornél Májlinger. "Development and Comparison of Quantitative Phase Analysis for Duplex Stainless Steel Weld." Periodica Polytechnica Mechanical Engineering 62, no. 3 (May 17, 2018): 247–53. http://dx.doi.org/10.3311/ppme.12234.
Повний текст джерелаАнотація:
In duplex stainless steels the ideally 1:1 ratio of austenite-to-ferrite phases ensures the outstanding mechanical and corrosion properties compared to other, conventional stainless steel grades. However, this phase balance can be easily shifted to a mostly austenitic or mostly ferritic microstructures, depending on the welding process and heat input. In order to determine the phase ratio, several methods are available to use, such as Feritscope measurements, ASTM E562 manual point count method (on metallographic images) or quantitative image analysis. From these methods, Feritscope measurements cannot be applied to determine phase quantification in the narrow heat affected zone of duplex stainless steel welds – because of the very limited heat input. The manual point count method is very dependent of the assessor and cannot be automated. In this paper a histogram-based image analyzing process was developed, using Beraha's etchant solution. The results were compared to Feritscope measurements and a very good correlation (R2 = 0.9995) was found. This method will give the ability to easily and automatically measure phase ratio in weld metal, heat affected zone or in subsurface regions of multi-pass welds.
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Shakirov, Ivan V., Pavel A. Kuznetsov, Anton Z. Zhukov, Vitaliy V. Bobyr, Sergey P. Bogdanov, and Nikolay A. Khristiuk. "Effect of Heat Treatment on Structure of Austenitic Steels Fabricated by Laser Synthesis." Key Engineering Materials 910 (February 15, 2022): 1127–35. http://dx.doi.org/10.4028/p-a75340.
Повний текст джерелаАнотація:
In this work, the evolution of the microstructure, phase composition and crystal structure of 3D products before and after heat treatment, obtained from the original steel 12Cr18Ni10Ti by various metallurgical methods of melting, was studied. The obtained 3D steel samples were subjected to heat treatment, then structural changes were investigated by metallography, X-ray phase (XRD) and X-ray structure (XRD) analyzes. The analysis showed that heat treatment did not increase the grain size of austenite in additive steels, but could lead to an increase in the proportion of ferrite.
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Radović, Nenad, Ankica Koprivica, Dragomir Glišić, Abdunnaser Fadel, and Djordje Drobnjak. "Influence of V and N on Transformation Behavior and Mechanical Properties of Medium Carbon Forging Steels." Materials Science Forum 638-642 (January 2010): 3459–64. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.3459.
Повний текст джерелаАнотація:
The influence of vanadium and nitrogen on microstructure and mechanical properties of medium-carbon steels has been studied by means of metallography and mechanical testing. Vanadium addition to the low nitrogen steel suppresses the formation of ferrite-pearlite following the low reheating temperatures and microstructure consists of bainitic sheaves. Increasing nitrogen at the same vanadium level promotes the acicular ferrite formation. For high reheating temperatures, dominantly acicular ferrite structure in both the low nitrogen and the high nitrogen vanadium steels is obtained. The results suggest that vanadium in solid solution promotes the formation of bainite, whereas the effect of nitrogen is related to the precipitation of VN particles in austenite with high potency for intragranular nucleation of acicular ferrite and to the precipitation of V(C,N) particles in ferrite with high potency for precipitation strengthening. Addition of both vanadium and nitrogen considerably increases the strength level, while CVN20 impact energy increases on changing the microstructure from bainitic ferrite to the fine ferrite-pearlite and acicular ferrite.
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Sopko, Martin, František Kováč, Ivan Petryshynets, Mária Molnárová, and Petra Gavendová. "Differential Scanning Calorimetry and Metallographic Analysis of Fe-Si Electrical Steel." Materials Science Forum 782 (April 2014): 129–32. http://dx.doi.org/10.4028/www.scientific.net/msf.782.129.
Повний текст джерелаАнотація:
The microstructure development in cold rolled electrical steel under dynamic heat treatments was subjected to investigation. Significantly distinguish types of microstructures were obtained in the investigated steels confirming the different character of grain boundary motion. Application of annealing temperature within two phase region (austenite+ferrite) leads to abnormal grain growth in silicon steels. Moreover, in the optimum temperature range, there was a particular temperature leading to the most optimal microstructure and texture[1]. The effect of Si content on the phase transition temperature of the electrical steel (0.6, 1, 2.5, 2.9 % Si) was studied by using differential scanning calorimetry (DSC) analysis. The result indicated that DSC analysis could be used to detect the shift temperature of phase transformation in the electrical steel with different Si addition. DSC have been used in thermochemical studies and as complementary to the study of phase transformation. It can be used as a compliment to optical and electron microscopy.
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Liu, Xiao, and Jian She Li. "Effect of Rare Earth on the Inclusions and Pitting Resistance of Ferrite Stainless Steel." Advanced Materials Research 531 (June 2012): 47–50. http://dx.doi.org/10.4028/www.scientific.net/amr.531.47.
Повний текст джерелаАнотація:
The anodic polarization curves of 430 ferrite stainless steels with various RE contents in 3.5% NaCl neutral solutions have been measured by electrochemical methods. The effect of RE on pitting corrosion resistance of 430 ferrite stainless steels has been studied by the metallographic examination. The results show that sulfide and other irregular inclusions are modified to round or oval-shaped RE2O2S and RES after adding RE to 430 ferrite stainless steesl. RE makes sulfide, and other irregular inclusions change to dispersed round or oval-shaped RE inclusions, effectively inhibits the occurrence of pitting corrosion, thereby enhancing the corrosion resistance of 430 ferrite stainless steels.
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Feng, Yun Li, Ming Cai, and Li Bin Chen. "Comparative Study on Microstructure and Texture of Ti-IF Steel Sheets Produced by Different Hot Rolling Processing." Advanced Materials Research 418-420 (December 2011): 726–30. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.726.
Повний текст джерелаАнотація:
It was analyzed by metallographic observation and X-ray diffraction method that the microstructure and texture in two kinds of Ti-IF steels, which produced by different hot rolling process,and it also was discussed that the formability and the texture in Ti-IF steels. The results showed that the microstructures of these two kinds of steels are Equiaxed ferrite grains, but the grain sizes are greatly different. Respectively the average grain size of steel A and B are 24.85μm and 11.85μm, and the average grain size number are 7.4 and 9.5. The {111} texture of steel B is stronger than A, besides, the deep drawing properties of steel B is better than A in the reason that disadvantaged texture{001} and {112} are not founded in steel B.
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Reyes-Calderón, F., R. Vences-Hernández, J. A. Salazar-Torres, H. J. Vergara-Hernández, I. Aguilera-Navarrete, and V. Pérez-González. "Parameter Optimization: Force (F), Time (T) and Current Intensity (I), in the RSW Welding Process of DP-290 Steel Plates Using the Taguchi Method." Soldagem & Inspeção 23, no. 2 (June 2018): 157–67. http://dx.doi.org/10.1590/0104-9224/si2302.04.
Повний текст джерелаАнотація:
Abstract Automotive industries are trying to use new light materials for structural parts of vehicles. However, the steels are being the best manufacturing material option in the automotive industry. One of the advanced steels commonly used due to the high mechanical properties is the Dual Phase Steel (Ferritic-Martensitic). Therefore, the welding process is still very important and a matter of improvement. The present work shows the design of an experimental matrix using the Taguchi method with the optimal parameters to apply in the spot welding process (RSW) of a DP-290 steel; the metallographic characterization, the microhardness and the Peel tests were also carried out in each specimen. The results determined that the lower intensity of current and a medium pressure for a longer time the better resistance to tearing, due to the microstructural changes in the specimens.
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Badji, R., B. Belkessa, H. Maza, M. Bouabdallah, Brigitte Bacroix, and C. Kahloun. "Effect of Post Weld Heat Treatment on Microstructure and Mechanical Properties of Welded 2205 Duplex Stainless Steel." Materials Science Forum 467-470 (October 2004): 217–22. http://dx.doi.org/10.4028/www.scientific.net/msf.467-470.217.
Повний текст джерелаАнотація:
Duplex stainless steels 2205 are widely used in constructional and petrochemical applications because of their good mechanical and corrosion properties. The objective of this work was to study the influence of aging at high temperature on the austenite and d ferrite equilibrium. After welding by TIG process, duplex stainless steel was aged in the range of 800 – 1150 °C temperatures for 60 min. The microstructure was characterized by metallography and X-ray methods. The toughness of welded structure was also measured.
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Dudek, A., B. Lisiecka, and R. Ulewicz. "The effect of alloying method on the structure and properties of sintered stainless steel." Archives of Metallurgy and Materials 62, no. 1 (March 1, 2017): 281–87. http://dx.doi.org/10.1515/amm-2017-0042.
Повний текст джерелаАнотація:
AbstractSintered duplex stainless steels (SDSSs) appear to be very interesting and promising materials that can be used in many industrial sectors. Ferrite improves material strength while austenite increases hardness and corrosion resistance. This study proposes a method to improve functional properties (e.g. hardness and wear resistance) by means of alloying the surface of the sintered duplex steel with Cr3C2+ 10% NiAl powder. The results of optical microscope metallography, SEM/EDX, XRD analysis and microhardness and wear resistance measurements are also presented. The surface alloying with Cr3C2is a manufacturing method of surface layer hardening in sintered stainless steels and modification of surface layer properties such as hardness and coefficient of friction.
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Węgrzyn, Tomasz, Tadeusz Szymczak, Bożena Szczucka-Lasota, and Bogusław Łazarz. "MAG Welding Process with Micro-Jet Cooling as the Effective Method for Manufacturing Joints for S700MC Steel." Metals 11, no. 2 (February 5, 2021): 276. http://dx.doi.org/10.3390/met11020276.
Повний текст джерелаАнотація:
Advanced high-strength steel (AHSS) steels are relatively not very well weldable because of the dominant martensitic structure with coarse ferrite and bainite. The utmost difficulty in welding these steels is their tendency to crack both in the heat affected zone (HAZ) and in weld. The significant disadvantage is that the strength of the welded joint is much lower in comparison to base material. Adopting the new technology regarding micro-jet cooling (MJC) after welding with micro-jet cooling could be the way to steer the microstructure of weld metal deposit. Welding with micro-jet cooling might be treated as a very promising welding S700MC steel process. Tensile and fatigue tests were mainly carried out as the main destructive experiments for examining the weld. Also bending probes, metallographic structure analysis, and some non-destructive measurements were performed. The welds were created using innovative technology by MAG welding with micro-jet cooling. The paper aims to verify the fatigue and tensile properties of the thin-walled S700MC steel structure after welding with various parameters of micro-cooling. For the first time, micro-jet cooling was used to weld S700MC steel in order to check the proper mechanical properties of the joint. The main results are processed in the form of the Wöhler’s S–N curves (alternating stress versus number cycles to failure).
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Astashchenko, V. I., G. F. Mukhametzyanova, and A. G. Shagiev. "Criteria for Evaluating the Manufacturability of Steels when Cutting with an Edge Tool." Materials Science Forum 1052 (February 3, 2022): 62–67. http://dx.doi.org/10.4028/p-rim7y5.
Повний текст джерелаАнотація:
Comprehensive metallographic studies of steel forgings with different machinability by cutting with an edge tool were also completed. Structural features and properties of steel were revealed, having adversely influence on tool life and the process of chip formation during cutting. Metal Science criteria have been given for assessing the manufacturability of steel at machining operations. Microstructures of steel with satisfactory and unsatisfactory machinability are presented. The technological parameters of heat treatment of steel 18HGR have been established, causing a show of banding of ferrite-pearlite structure. The thermokinetic diagram shows an area of development of the segregation banding structure. An important role in assessing the manufacturability of steels is shown of the microhardness of individual structural components and the difference in values between them. The best results in machinability by cutting are observed when the microhardness of pearlite is not more than 350 HV, ferrite is not more than 210 HV and the difference in microhardness between these components is not more than 80 HV.
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Bigg, Timothy D., and David Edmonds. "Microstructural Evolution during the Novel Quenching and Partitioning (Q&P) Heat Treatment of Steel." Materials Science Forum 654-656 (June 2010): 33–36. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.33.
Повний текст джерелаАнотація:
The novel non-equilibrium heat treatment procedure known as Quenching and Partitioning (Q&P) may offer the prospect of higher strength steel products with enhanced formability based upon martensitic microstructures containing controlled quantities of carbon-enriched retained austenite. The Q&P process requires an interrupted quench and isothermal annealing (partitioning) step at intermediate temperatures, whereby untransformed austenite can be thermodynamically stabilised by carbon migration from supersaturated martensite regions. The concept is comparable to that producing carbide-free bainite, for example, in TRIP-assisted steel, although Q&P allows separation of the ferrite formation and austenite enrichment stages of the process. However, although the Q&P concept is readily understood, evolution of the microstructure during interrupted quenching and partitioning has been inferred indirectly from dilatometer studies and metallographic examination after final quenching to room temperature. Consequently, a model alloy was developed in which the sequential steps of heat treatment could be separated for direct inspection by conventional metallography, X-ray diffraction and neutron diffraction techniques.
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Davidson, Karl P., and Sarat B. Singamneni. "Metallographic evaluation of duplex stainless steel powders processed by selective laser melting." Rapid Prototyping Journal 23, no. 6 (October 17, 2017): 1146–63. http://dx.doi.org/10.1108/rpj-04-2016-0053.
Повний текст джерелаАнотація:
Purpose This paper aims to establish the microstructures and the process-structure relationships in duplex stainless steel powders consolidated by selective laser melting (SLM). Design/methodology/approach A priori data on energy density levels most appropriate to consolidation of duplex stainless steel powders through SLM served as the basis to converge on the laser settings. Experimental designs with varying laser power and scan speeds and test pieces generated allowed metallographic evaluations based on optical and scanning electron microscopy and electro backscatter diffraction analyses. Findings Duplex stainless steel powders are established for processing by SLM. However, the dynamic point heat source and associated transient thermal fields affect the microstructures to be predominantly ferritic, with grains elongated in the build direction. Austenite precipitated either at the grain boundaries or as Widmanstätten laths, whereas the crystallographic orientations and the grain growth are affected around the cavities. Considerable CrN precipitation is also evidenced. Originality/value Duplex stainless steels are relatively new candidates to be brought into the additive manufacturing realm. Considering the poor machinability and other difficulties, the overarching result indicating suitability of duplex powders by SLM is of considerable value to the industry. More significantly, the metallographic evaluation and results of the current research allowed further understanding of the material consolidation aspects and pave ways for fine tuning and establishment of the process-structure-property relationships for this important process-material combination.
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Zhao, Yi Sheng, Zhi Guo Gao, and Yun Lai Deng. "Effects of Cooling Rate on Metallographic Structure of Boron-Bearing Steel." Applied Mechanics and Materials 778 (July 2015): 92–95. http://dx.doi.org/10.4028/www.scientific.net/amm.778.92.
Повний текст джерелаАнотація:
Effects of cooling rate on metallographic structure of boron-bearing steel were investigated in present research. The results showed it consists of ferrite and pearlite formed in the initial stage of the transformation in the studied boron-bearing steels cooled at the rate from 1 to 10°C/s. For the higher cooling rate than 15 to 33°C/s, it consisted of bainite formed in the second stage of the transformation. For increasing presently cooling rate than 66°C/s, it consisted of martensite formed in the third stage of the transformation. All the transformation of metallographic structure was proved by CCT diagram.
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Yin, Sheng, Yi Xue, Haotian Cui, Xinhua Pei, Chundong Hu, Yangxin Wang, and Qingchao Tian. "Effect of Material Anisotropy on the Mechanical Response of Automotive Steel under High Strain Rates." Materials 15, no. 2 (January 17, 2022): 669. http://dx.doi.org/10.3390/ma15020669.
Повний текст джерелаАнотація:
A constitutive model for automobile steel with high elongation needs to be established to predict the dynamic deformation behavior under hydroforming applications. In order to clarify the confusing discrepancy in the essential parameters of the classical Cowper-Symonds (C-S) model, a series of automobile structural steels have been employed to investigate the strain rate response by conducting tensile dynamic deformation. Metallographic microscopy and orientation distribution functions were used to characterize the microstructure and texture components of the steels. The microstructure observation discloses that the matrix of all steels is mainly of ferrite and the texture constituent provides a framework for steel to withstand external deformation. The C-S model can be applied to simulate the dynamic deformation with satisfied expectations. It is concluded that the essential parameters D and p in the model show a specific relationship with the steel grade, and the parameter D is proportional to the steel grade and related to material anisotropy, while the parameter p is inversely proportional to the steel grade and has close links with the grain boundary characteristics.
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Zmienko, Dmitry, Aleksey Korneev, and Vladimir Bogachev. "Study of Modified Layer on Exterior Surface of Superheater Tubes." Materials Science Forum 706-709 (January 2012): 890–95. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.890.
Повний текст джерелаАнотація:
Renewal of overhaul period of power plants equipment, especially superheater tubes, is important problem in energy sector of every country. Investigation of processes on tube’s surfaces is necessary to obtain information of equivalent temperature during maintenance. In this work the austenitic chrome-manganese steel 10Cr13Mn12Si2Ni2Cu2Nb (DI59) and chrome-nickel steel 12Cr18Ni12Ti were studied. Application of these steels provides the desired heating resource of the steam superheater (100000 h) and reliable exploitation of the boilers at high temperature (~650°C). Between the oxide layer and the base metal layers with different crystal structure compared with matrix are observed. Qualitative and quantitative electron microscopic techniques, optical metallography and X-ray phase analysis are employed to investigate the morphological evolution, elemental redistribution in the alloy system and formation and growth of discovered layers. In steel DI59 the discovered layer had a ferrite structure. In steel 12Cr18Ni12Ti it was first shown that this layer is consist of different sulfides which disposed in FeNi3matrix. This intermetallic phase and ferrite layer are ferromagnetic. Changes in the structure of steel on its surfaces are caused by high exploitation temperature and type of fuel which is used in power plants (combination of natural gas and mazut). This opens the possibility to use connection between thermal irregularity in metal and thickness of discovered layers in order to search most damaged part of tubes with ferrite meter.
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Man, Zeng Qiang, Wei Yu, Huan Yang, Wen Gao Chang, and Yun Fei Cao. "Effects of Final Cooling Temperature on Microstructure Transformation and Properties of Q550 Low Carbon Bainite Steel." Materials Science Forum 993 (May 2020): 550–58. http://dx.doi.org/10.4028/www.scientific.net/msf.993.550.
Повний текст джерелаАнотація:
The mechanical properties of low carbon bainite steel are closely related to the microstructure and proportion after phase transformation. The microstructure of the deformed austenite of low carbon bainite steel after isothermal transformation and continuous cooling transformation was studied by thermal simulation test. The metallographic structure was observed by optical microscopy (OM) and scanning electron microscopy (SEM). The metallographic and microhardness were used to judge the microstructure type, and the CCT (continuous cooling transformation) curve and TTT (time-temperature-transformation) curve of the test steel were drawn. It was found that at 700-430 °C isothermal, undergo a variety of medium-temperature microstructure transformations appeared for the test steels, such as ferrite, pearlite, granular bainite and lath bainite. The cooling rate and final cooling temperature have great influence on the type and performance of the final microstructure. The final cooling temperature was controlled at about 515°C. The mixed microstructures of granular bainite (GB) and fine martensite-austenite (M-A) island, a small amount of acicular ferrite and lath bainite were obtained. The yield and tensile strengths of this type of microstructure reached 639 MPa and 750 MPa respectively, the shrinkage rate reached 17%, and the better low-temperature impact performance was realized.
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Liu, Xiao, and Hong Wang Dong. "Effect of Rare Earth on Microstructure and Mechanical Property of Ferrite Stainless Steel." Advanced Materials Research 690-693 (May 2013): 110–13. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.110.
Повний текст джерелаАнотація:
The effect of rare earth element on structure and mechanical properties of the 430 ferrite stainless steel was studied by metallographic examination, scanning electron microscope (SEM), tensile test and impact test. The results show that the proper amount of RE can refine microstructure of 430 ferrite stainless steel. The fracture mode of 430 ferrite stainless steel is typical dimple fracture. 430 ferrite stainless steel containing 0.056% RE can improve its impact toughness and the high temperature strength, and the transverse impact toughness increases 37.2% at 253K respectively comparing with that of 430 ferrite stainless steel without RE. And at 1273K, the high temperature strength increases by 38.3% than that of 430 ferrite stainless steel without RE.
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Lad’yanov, V. I., G. A. Dorofeev, E. V. Kuz’minykh, V. A. Karev, and A. N. Lubnin. "ALUMINOBAROTHERMIC SYNTHESIS OF HIGH-NITROGEN STEEL." Izvestiya. Ferrous Metallurgy 62, no. 2 (March 30, 2019): 154–62. http://dx.doi.org/10.17073/0368-0797-2019-2-154-162.
Повний текст джерелаАнотація:
High-nitrogen austenitic steels are promising materials, combining high strength, plasticity and corrosion resistance properties. However, to produce high-nitrogen steel by conventional metallurgical methods under high nitrogen pressure, powerful and complex metallurgical equipment is required. From energy-saving viewpoint, an alternative and simpler method for producing high-nitrogen steels can be aluminothermy (reduction of metal oxides by metallic aluminum) under nitrogen pressure. Thermodynamic modeling of aluminothermic reactions in a nitrogen atmosphere was carried out by the authors. Aluminothermy under nitrogen pressure was used to produce high-nitrogen nickel-free Cr – N and Cr – Mn – N stainless steels with a nitrogen content of about 1 %. Microstructure (X-ray diffraction, metallography and transmission electron microscopy techniques) and mechanical properties were examined. Thermodynamic analysis has shown that the aluminothermic reduction reactions do not go to the end. The most important parameter of the synthesis is the ratio of Al and oxygen in the charge, the correct choice of which provides a compromise between completeness of oxides reduction, content of aluminum and oxygen in steel (the degree of deoxidation), and its contamination with aluminum nitride. Cr – N steel ingots in the cast state had the structure of nitrogen perlite (ferrite-nitride mixture), and Cr – Mn – N steel – ferrite-austenite structure with attributes of austenite discontinuous decomposition with Cr2 N precipitations. Quenching resulted in complete austenization of both steels. The compliance of the austenite lattice parameter obtained from the diffractograms for quenched Cr – Mn – N steel with the parameter predicted from the known concentration dependence for Cr – Mn – N austenitic steels indicated that all alloying elements (including nitrogen) were dissolved in austenite during aging at quenching temperature and fixed in the solid solution by quenching. Study of the mechanical properties of quenched Cr – Mn – N steel has shown a combination of high strength and ductility. It is concluded that by the aluminothermic method a high-nitrogen steel can be obtained, which, by mechanical properties, is not inferior to industrial steel – analog manufacted by electroslag remelting under nitrogen pressure.
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Liu, Xiao, and Zhi Jie Fan. "Effect of Rare Earth on Inclusions and Impact Property of Ferrite Stainless Steel." Advanced Materials Research 535-537 (June 2012): 662–65. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.662.
Повний текст джерелаАнотація:
The effects of RE metals on the inclusions and the impact property of 430 ferrite stainless steel were studied by metallographic examination, scanning electron microscope (SEM) and energy spectrum analysis. The results show that the morphologies and sizes of inclusions in 430 ferrite stainless steel are changed, and RE played a very good role of modifying inclusions. The fracture mode of 430 ferrite stainless steel is typical cleavage fracture, but quasi-cleavage and dimple fracture after adding RE into the steel. The transverse impact property of 430 ferrite stainless steel is improved obviously by RE. In comparison with 430 ferrite stainless steel without RE, the transverse impact property of 430 ferrite stainless steel with RE is increased 38.53% at -20°C, respectively.
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Lalik, Stanisław, and Joanna Gucwa. "Welding Duplex Steel Type X2CrNiMoN25-7-4 with Analysis of Ferrite Content Measurements in Welded Joints." Solid State Phenomena 226 (January 2015): 107–10. http://dx.doi.org/10.4028/www.scientific.net/ssp.226.107.
Повний текст джерелаАнотація:
The paper presents tests results of mechanical properties, hardness measurements, microstructure and the content of ferrite with the use of ferrite meter (feritscope) FMP30 and quantitative metallography technique with the use of Met-Ilo program in welded joints of steel X2CrNiMoCuWN25-7-4 with the use of TIG method. On the basis of achieved results of tests it was concluded that the applied technology of welding was correct and the usefulness as well as limitations of both methods were proved in the assessment of ferrite and austenite content in welded joints from duplex steel.