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1
Pietrowski, S. "Wearing Quality of Austenitic, Duplex Cast Steel, Gray and Spheroidal Graphite Iron." Archives of Foundry Engineering 12, no. 2 (April 1, 2012): 235–44. http://dx.doi.org/10.2478/v10266-012-0067-0.
Анотація:
Wearing Quality of Austenitic, Duplex Cast Steel, Gray and Spheroidal Graphite Iron The current work presents the research results of abrasion wear and adhesive wear at rubbing and liquid friction of new austenitic, austenitic-ferritic ("duplex") cast steel and gray cast iron EN-GJL-250, spheroidal graphite iron EN-GJS-600-3, pearlitic with ledeburitic carbides and spheroidal graphite iron with ledeburitic carbides with a microstructure of the metal matrix: pearlitic, upper bainite, mixture of upper and lower bainite, martensitic with austenite, pearlitic-martensitic-bainitic-ausferritic obtained in the raw state. The wearing quality test was carried out on a specially designed and made bench. Resistance to abrasion wear was tested using sand paper P40. Resistance to adhesive wear was tested in interaction with steel C55 normalized, hardened and sulfonitrided. The liquid friction was obtained using CASTROL oil. It was stated that austenitic cast steel and "duplex" are characterized by a similar value of abrasion wear and adhesive wear at rubbing friction. The smallest decrease in mass was shown by the cast steel in interaction with the sulfonitrided steel C55. Austenitic cast steel and "duplex" in different combinations of friction pairs have a higher wear quality than gray cast iron EN-GJL-250 and spheroidal graphite iron EN-GJS-600-3. Austenitic cast steel and "duplex" are characterized by a lower wearing quality than the spheroidal graphite iron with bainitic-martensitic microstructure. In the adhesive wear test using CASTROL oil the tested cast steels and cast irons showed a small mass decrease within the range of 1÷2 mg.
2
Çelik, G. Aktaş, Fulya Kahrıman, Ş. Hakan Atapek, and Şeyda Polat. "Characterization of the high temperature oxidation behavior of iron based alloys used as exhaust manifolds." MATEC Web of Conferences 188 (2018): 02001. http://dx.doi.org/10.1051/matecconf/201818802001.
Анотація:
Nowadays engine capacities of vehicles spread in a wide range due to different vehicle power demands. Power density of engines affects exhaust gas and therefore exhaust gas temperature varies from 650 °C to 1000 °C in exhaust manifolds. Depending on the exhaust gas temperature, different types of iron based alloys are used as manifold materials such as ferritic ductile cast irons (GGG40, SiMo), austenitic ductile cast irons (Ni-resist D5S), ferritic cast stainless steels (ACIHK30, AISI 409) and austenitic cast stainless steels (CF8C). In this study high temperature oxidation behavior of different cast alloys used as exhaust manifold materials like, (i) GGG40 ferritic ductile cast iron, (ii) SiMo ferritic ductile cast iron (iii) AISI 409 ferritic cast stainless steel and (iv) CF8C austenitic cast stainless steel, were investigated.
3
Kalandyk, B. "Microstructure and Abrasive Wear Resistance of 18Cr-4Ni-2.5Mo Cast Steel." Archives of Foundry Engineering 12, no. 4 (December 1, 2012): 81–84. http://dx.doi.org/10.2478/v10266-012-0111-0.
Анотація:
Abstract An influence of a decreased Cr content on the microstructure of the highly alloyed Cr-Ni cast steel, duplex type, melted under laboratory conditions, was characterized in the paper. The microstructure investigations were performed in the initial state and after the heat treatment (solution annealing) at 1060°C as well as the phase transformation kinetics at continuous cooling was measured. The wear resistance of the investigated cast steel was tested and compared with the 24%Cr-5%Ni-2.5%Mo cast steel. The Cr content decrease, in ferritic-austenitic cast steels (duplex), from 24-26%Cr to 18% leads to the changes of the castings microstructure and eliminating of a brittle σ phase. In dependence of the casting cooling rate, apart from ferrite and austenite, also fine martensite precipitates occur in the casting structure. It was shown that the investigated cast steel is characterised by a slightly lower wear resistance than the typical cast steel duplex grades.
4
Sakaki, Hayato, Masayuki Mizumoto, Takeshi Ohgai, and Akio Kagawa. "New Application of High Niobium Cast Iron as a Grain Refiner for Stainless Steels." Key Engineering Materials 457 (December 2010): 447–52. http://dx.doi.org/10.4028/www.scientific.net/kem.457.447.
Анотація:
In order to develop a new application of cast iron, high niobium cast iron has been developed as a grain refiner for stainless steel. High niobium cast iron was prepared by adding pure niobium to a commercial cast iron. Coarse primary niobium carbide crystals were observed in the microstructure of the cast iron. The effect of the high niobium cast iron as an inoculant on the grain size of austenitic and ferritic stainless steels was examined in various experimental conditions. When the amount of the cast iron inoculant more than 3 mass% was added into the steel melt, fine equiaxed grains were observed and grain size was significantly reduced to 210 μm. The results indicate that the high niobium cast iron is effective as a grain refiner for the austenitic and ferritic stainless steels. From the dissolution rate measurement, the grain refining mechanism was proposed.
5
Kalandyk, B., R. Zapała, Ł. Boroń, and M. Solecka. "Impact Strength of Austenitic and Ferritic-Austenitic Cr-Ni Stainless Cast Steel in -40 and +20°C Temperature." Archives of Metallurgy and Materials 59, no. 3 (October 28, 2014): 1103–6. http://dx.doi.org/10.2478/amm-2014-0190.
Анотація:
Abstract Studies described in this paper relate to common grades of cast corrosion resistant Cr-Ni steel with different matrix. The test materials were subjected to heat treatment, which consisted in the solution annealing at 1060°C followed by cooling in water. The conducted investigations, besides the microstructural characteristics of selected cast steel grades, included the evaluation of hardness, toughness (at a temperature of -40 and +20oC) and type of fracture obtained after breaking the specimens on a Charpy impact testing machine. Based on the results of the measured volume fraction of ferrite, it has been found that the content of this phase in cast austenitic steel is 1.9%, while in the two-phase ferritic-austenitic grades it ranges from 50 to 58%. It has been demonstrated that within the scope of conducted studies, the cast steel of an austenitic structure is characterised by higher impact strength than the two-phase ferritic-austenitic (F-A) grade. The changing appearance of the fractures of the specimens reflected the impact strength values obtained in the tested materials. Fractures of the cast austenitic Cr-Ni steel obtained in these studies were of a ductile character, while fractures of the cast ferritic-austenitic grade were mostly of a mixed character with the predominance of brittle phase and well visible cleavage planes.
6
Berezovsky, A. V., E. B. Votinova, and A. S. Smolentsev. "The technology of arc welding of dissimilar steels." Diagnostics, Resource and Mechanics of materials and structures, no. 5 (October 2023): 31–38. http://dx.doi.org/10.17804/2410-9908.2023.5.031-038.
Анотація:
Arc narrow gap welding of the 35L carbon cast steel (cast carbon steel J03502, grade 1) and the 110G13L high-manganese steel (austenitic manganese steel, ASTM A128) is performed using chromium-nickel-manganese wires in a shielding gas mixture (GOST R ISO 14175–2010 – M21). The welded samples are examined by different methods including optical metallography, hardness measurement, and mechanical tests. The weld metal structure along the weld height in the welded samples proves to be fairly uniform, namely austenite with ferrite inclusions. The experiment results show that the mechanical properties of the weld metal correspond to the intermediate values for the joined steels. The developed technology has made it possible to produce a welded joint with high mechanical properties and a ductile structure.
7
Aftandiliants, Y. G. "The effect of heat treatment on the mechanical properties of modified stainless steels." Metaloznavstvo ta obrobka metalìv 102, no. 2 (June 30, 2022): 45–51. http://dx.doi.org/10.15407/mom2022.02.045.
Анотація:
The paper presents the results of the study of the influence of structure on the mechanical properties of microalloyed and modified austenitic stainless steels. It is shown that the mechanical properties of cast austenitic stainless steels with a probability of 95 % and an error of 0.46 to 13.2 % are determined by such structural parameters as austenite grain size, carbide phase and ferrite content in austenite after quenching, quantity, size and distance between oxide, titanium sulfides and carbonitrides particles. Mathematical models of the structure influence on the yield strength, reduction of area and toughness of stainless steels are built. The structure parameter effectiveness is shown and it is shown that to increase the efficiency of strength, reduction of area and toughness of stainless steels at normal temperature structural factors affect in the following sequence: austenite grain size, volume fraction, size and distribution of titanium carbonitrides and sulfides, the total quantity of non-metallic inclusions, carbides and ferrite in austenite after hardening of stainless steel, as well as the volume fraction, size and distribution of oxide inclusions. Keywords: steel, structure, mechanical properties, strength, ductility, toughness.
8
Sydorchuk, O. M. "Steel with control austenitic transformation during operation." Metaloznavstvo ta obrobka metalìv 98, no. 2 (June 7, 2021): 47–53. http://dx.doi.org/10.15407/mom2021.02.047.
Анотація:
The intermediate class of steels, which at room temperature belong to the ferritic state, and at operating temperature pass into the austenitic region, are called steels with control of austenitic transformation during operation. The possibility of increasing the service life of such intermediate steels at high temperatures (above the critical point A3) is shown. For the first time, the cast structure and phase-structural state of steel (grade 4Kh3N5М3F) obtained by electroslag remelting were studied. An improved composition of steel (4Kh4N5М3F) for the production of stamping tools for hot pressing of copper, copper and aluminum alloys is proposed. When setting the critical points (A1 and A3) of the investigated steel, which was confirmed by the results of high-temperature X-ray phase analysis, it was possible to optimize the heat treatment (annealing) of steel 4Kh3N5M3F and 4Kh4N5M4F2 in cast and forged condition, which facilitated processing tool. The results of researches on optimization of modes of heat treatment (hardening, tempering) of steel are given. The mechanical properties (strength, toughness, heat resistance) of steel in cast and forged state depending on the tempering and tempering temperature are determined. The tempering brittleness of the experimental steel is determined. An experimental-industrial test of a stamping tool (die dies, extruder parts) made of the investigated steel was carried out. The possibility of using stamped steel with adjustable austenitic transformation for a wide range of operating temperatures of hot deformation of aluminum alloy AK7h (450-500 ºC), copper M1 (600-630 ºC) and copper-nickel alloy MNZh 5-1 (900-950 ºC) with increased service life in comparison with steels of ferrite class 4Kh5МF1S and 3Kh3М3F. Keywords: die steel, composition, thermal treatment, structure, mechanical properties.
9
Stradomski, G. "The Analysis of AISI A3 Type Ferritic-Austenitic Cast Steel Crystallization Mechanism." Archives of Foundry Engineering 17, no. 3 (September 1, 2017): 229–33. http://dx.doi.org/10.1515/afe-2017-0120.
Анотація:
AbstractHigh-alloy corrosion-resistant ferritic-austenitic steels and cast steels are a group of high potential construction materials. This is evidenced by the development of new alloys both low alloys grades such as the ASTM 2101 series or high alloy like super or hyper duplex series 2507 or 2707 [1-5]. The potential of these materials is also presented by the increasing frequency of sintered components made both from duplex steel powders as well as mixtures of austenitic and ferritic steels [6, 7]. This article is a continuation of the problems presented in earlier works [5, 8, 9] and its inspiration were technological observed problems related to the production of duplex cast steel.The analyzed AISI A3 type cast steel is widely used in both wet exhaust gas desulphurisation systems in coal fired power plants as well as in aggressive working environments. Technological problems such as hot cracking presented in works [5, 8], with are effects of the rich chemical composition and phenomena occurring during crystallization, must be known to the technologists.The presented in this work phenomena which occur during the crystallization and cooling of ferritic-austenitic cast steel were investigated using numerical methods with use of the ThermoCalc and FactSage® software, as well with use of experimental thermal-derivative analysis.
10
Garbiak, Małgorzata, and Bogdan Piekarski. "Phases in Austenitic Cast Steel." Defect and Diffusion Forum 326-328 (April 2012): 215–20. http://dx.doi.org/10.4028/www.scientific.net/ddf.326-328.215.
Анотація:
The paper presents the characteristics of intermetallic phases occurring in heat-resistant cast austenitic 0.3% C-30% Ni-18% Cr steel with additions of niobium and titanium. Five alloys were examined, in which the content of the examined elements was (wt.%) Nb 0.03, 0.55, 1.57 and 1.92, and Ti 0.03, 0.05, 0.30, 0.83 and 1.00. The phase composition of alloys in as-cast state and after annealing (temperature of 800°C and 900°C, time of up to 300 hrs) was examined by X-ray diffraction technique. Depending on the chemical composition of cast steel, carbides of MC type (NbC, TiC, (Nb,Ti)C), M23C6, titanium carbonitrides TiCN and G phase were identified in its microstructure. The phase morphology was examined on the polished sections and surfaces of metallographic specimens after deep etching by electrolytic extraction method. It was found that M23C6carbides assume the shape of rods, NbC carbides crystallise in the form of lamellae, and titanium carbonitrides TiCN in the form of cubes. An addition of both the stabilising elements favours the formation of double carbides (Nb,Ti)C of octahedral habit.
11
Stradomski, G. "The Cracking Mechanism of Ferritic-Austenitic Cast Steel." Archives of Foundry Engineering 16, no. 4 (December 1, 2016): 153–56. http://dx.doi.org/10.1515/afe-2016-0101.
Анотація:
Abstract In the high-alloy, ferritic - austenitic (duplex) stainless steels high tendency to cracking, mainly hot-is induced by micro segregation processes and change of crystallization mechanism in its final stage. The article is a continuation of the problems presented in earlier papers [1 - 4]. In the range of high temperature cracking appear one mechanism a decohesion - intergranular however, depending on the chemical composition of the steel, various structural factors decide of the occurrence of hot cracking. The low-carbon and low-alloy cast steel casting hot cracking cause are type II sulphide, in high carbon tool cast steel secondary cementite mesh and / or ledeburite segregated at the grain solidified grains boundaries, in the case of Hadfield steel phosphorus - carbide eutectic, which carrier is iron-manganese and low solubility of phosphorus in high manganese matrix. In duplex cast steel the additional factor increasing the risk of cracking it is very “rich” chemical composition and related with it processes of precipitation of many secondary phases.
12
Baek, Seung, Jae Mean Koo, and Chang Sung Seok. "Evaluation of the Degradation Characteristics of CF-8A Cast Stainless Steel Using Indentation Techniques and EDS." Key Engineering Materials 306-308 (March 2006): 869–74. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.869.
Анотація:
Cast austenitic stainless steel piping pump, valve casings and elbows are susceptible to reductions in toughness and ductility because of long term exposure at the operating temperatures in the LWR (light water reactor). In this study, the three classes of thermally aged CF-8A cast austenitic stainless steel specimens were prepared using an artificially accelerated aging method for 0, 2,679 and 3,572 hours at 400oC. An indentation technique was applied to evaluate of the thermal aging of CF-8A cast austenitic stainless steel. We have performed indentation tests (automated ball indentation and nano-indentation) and EDS (energy dispersive spectroscopy) in order to characterize the micro-structural changes of the phase with aging. The fracture toughness of aged CF-8A cast stainless steel was determined by standard fracture toughness tests and automated ball indentation techniques.
13
Ermakov, Boris, S. A. Vologzhanina, Sergej M. Bobrovskij, Aleksey A. Lukyanov, and Ranita Lee. "Cast Austenitic Steels for Cryogenic Technology." Key Engineering Materials 822 (September 2019): 60–65. http://dx.doi.org/10.4028/www.scientific.net/kem.822.60.
Анотація:
This article presents the results of a study of martensitic steels. Studied steels: OZH9K14N6MZD, 12X18N10TL, 07X13G28ANFL. The object of the study was the optimization of properties for use in cryogenic technology. The purpose of the study is to increase the strength and service life of products for various purposes. The destruction of steel 12X18N10TL and 07X13G28ANFL was investigated. It has been established that 07X13G28ANFL steel is more preferable for cryogenic use and is recommended by the authors.
14
Han, Bin, Yong Wang, Yi Shan Li, and Rui Liu. "Effect of Laser Scanning and Aging Treatment on Microstructure and Property of Austenitic Heat-Resistant Steel." Key Engineering Materials 373-374 (March 2008): 416–20. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.416.
Анотація:
In order to improve surface properties, high chromium austenitic base heat-resistant cast steel was scanned with a 5kW continuous wave CO2 laser, the specimen was aged at the temperature of 600°C~900°C. The microstructure and phase composition of the specimen were analysed with optical microscopy, electronic microscope and X-ray diffractionse. The hardness was measured. The results show that as-cast structure of high chromium cast steel is coarse and non-homogeneous, and mainly consist of austenite, ledeburite and carbides. After laser surface melting, the section is divided into the melted zone consisted of fine austenite and carbides, the heat affected zone composed of austenite and eutectic carbides, and the base meta1. The melted zone is very fine structures with dendritic crystals, only at the bottom a cellular structure is observed. A continuous carbide network is located in the austenitic grain boundaries at the heat affected zone. Carbides particles distribute dispersed out, the hardness of melted zone increases 35% than the base metal after aging. The area and the hardness of various zones are related to the laser processing parameters. The hardening depth of melted zone and heat affected zone may be up to 200μm~300μm.
15
Liu, Hongbo, Jianhua Liu, Bowei Wu, Xiaofeng Su, Shiqi Li, and Hao Ding. "Influence of Ti on the Hot Ductility of High-manganese Austenitic Steels." High Temperature Materials and Processes 36, no. 7 (July 26, 2017): 725–32. http://dx.doi.org/10.1515/htmp-2016-0005.
Анотація:
AbstractThe influence of Ti addition (~0.10 wt%) on hot ductility of as-cast high-manganese austenitic steels has been examined over the temperature range 650–1,250 °C under a constant strain rate of 10−3 s−1 using Gleeble3500 thermal simulation testing machine. The fracture surfaces and particles precipitated at different tensile temperatures were characterized by means of scanning electron microscope and X-ray energy dispersive spectrometry (SEM–EDS). Hot ductility as a function of reduction curves shows that adding 0.10 wt% Ti made the ductility worse in the almost entire range of testing temperatures. The phases’ equilibrium diagrams of precipitates in Ti-bearing high-Mn austenitic steel were calculated by the Thermo-Calc software. The calculation result shows that 0.1 wt% Ti addition would cause Ti(C,N) precipitated at 1,499 °C, which is higher than the liquidus temperature of high-Mn austenitic steel. It indicated that Ti(C,N) particles start forming in the liquid high-Mn austenitic steel. The SEM–EDS results show that Ti(C,N) and TiC particles could be found along the austenite grain boundaries or at triple junction, and they would accelerate the extension of the cracks along the grain boundaries.
16
Muradyan, Sarkis, M. V. Kostina, V. S. Kostina, Ludmila Rigina, and Viktor M. Timokhin. "Cast High-Strength Wear- and Corrosion-Resistant Austenitic Nitrogen Steel for Fittings Used in Shipbuilding." Key Engineering Materials 909 (February 4, 2022): 41–47. http://dx.doi.org/10.4028/p-iqrjh9.
Анотація:
The paper presents the results of studies of a new cast high-strength austenitic corrosion-resistant steel, which can be successfully used in shipbuilding for the manufacture of fittings. The authors included data on the structural-phase state of steel, the results of evaluating the mechanical properties, wear and corrosion resistance of the metal of castings in the cast and heat-treated state. The mechanical properties of steel are considered in detail in a wide temperature range. The impact strength was considered at low temperatures and static strength at 20 to 350 ° C. It is shown that steel has higher mechanical and corrosive properties in a wide temperature range than those of traditional stainless steels. The corrosion resistance of steel is considered. This is intergranular and pitting corrosion; the main types of corrosion are peculiar for shipbuilding. It has been shown that cast steel is superior to traditional corrosion-resistant steels in pitting corrosion resistance estimated by the pitting coefficient PREN and the critical temperature of pitting. The new cast steel has the same wear resistance as Hadfield steel.
17
Tuleja, J., and Z. Zatorski. "Numerical Modelling of Micro-Stresses in Carbonised Austenitic Cast Steel under Rapid Cooling Conditions." Archives of Metallurgy and Materials 62, no. 2 (June 1, 2017): 635–41. http://dx.doi.org/10.1515/amm-2017-0093.
Анотація:
AbstractThe paper presents a method of the numerical modelling of micro-stresses in carbonised austenitic cast steel being developed during rapid cooling due to differences in the values of thermal expansion coefficients for this material phases – carbides and austenitic matrix. Micro-stresses are indicated as the main cause of crack initiation in the tooling elements of carburising furnaces being mainly made of austenitic cast steel. A calculation model of carbonised and thermally fatigued austenitic cast steel was developed based on the microstructure images obtained using light microscopy techniques and the phase composition evaluated with the X-ray diffraction method. The values of the stress tensor components and the reduced stress in the complex models of test material structure were determined numerically by the finite element method. The effort analysis was performed and the areas where development of cracks is to be expected were identified, which was experimentally confirmed.
18
Li, Jing Yuan, Fei Fang, Yi De Wang, Bo Li, and Xiang Jun Zhang. "Influences of Carbon and Nitrogen Content on the Precipitation of 18Cr18Mn Steel." Materials Science Forum 789 (April 2014): 297–302. http://dx.doi.org/10.4028/www.scientific.net/msf.789.297.
Анотація:
The effect of carbon and nitrogen contents on microstructure and the mechanism of precipitation of 18Cr18Mn steels at as-cast and aging treatment state were investigated by thermodynamics calculation, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results show that the increase in carbon and nitrogen contents promotes the precipitation of carbides and nitrides, respectively, inhibiting σ phase precipitation during solidification process. The rod-like σ phases present in 18Cr18Mn0.44N as-cast steel with 0.025%C. The coarse lamellar structure Cr23C6 phases with a space width of 0.34μm exist in 18Cr18Mn0.44N as-cast steel with 0.16%C. However, Cr23C6 and σ phase disappear in the interior of the grains and a small amount of nitrides exist only in grain boundaries of 18Cr18Mn0.72N0.020C as-cast steel. The precipitation of Cr23C6 and σ phases are greatly inhibited in high nitrogen austenitic stainless steels at 800°C aging treatment. Additionally, Cr2N, the main precipitation phase, nucleates at austenitic grain boundary and grows towards inner grains with a lamellar morphology. Moreover, the quantity of Cr2N increases and incubation time of it decreases as nitrogen or carbon content increasing.
19
Ritoni, Marcio, M. Martins, F. C. Nascimento, and Paulo Roberto Mei. "Phase Transformations on ASTM a 744 Gr. CN3MN Superaustenitic Stainless Steel after Heat Treatment." Defect and Diffusion Forum 312-315 (April 2011): 56–63. http://dx.doi.org/10.4028/www.scientific.net/ddf.312-315.56.
Анотація:
The superaustenitic stainless steel ASTM A 744 Gr. CN3MN (22Cr-25Ni-7Mo-0.2N) has as mainly characteristic high corrosion resistance in severe environment. As the corrosion resistance depends on the microstructure, it was investigated the phase transformations after a solution treatment at 1200°C. Thermocalc calculation for 53Fe-25Ni-22Cr alloy indicates austenitic phase between 1300 and 800°C and austenite + sigma phase below 800°C. The as-cast steel studied presented 2.7 % of precipitates volume fraction and the precipitates were located on the grain boundaries and inside the austenitic grains. X-ray diffraction confirmed the presence of sigma phase in as-cast sample. Scanning electron microscopy showed that the level of Cr and Mo was higher in the precipitates than in the austenitic matrix and the Ni content was higher in matrix compared to precipitates. After heating at 1200°C during 90 minutes, the precipitate volume fraction was reduced to 2.1 % and the grain boundaries precipitates were dissolved. The microstructural analyses made through transmission electron microscopy and X-ray diffraction showed the presence sigma phase and M6C carbide.
20
Morales-Cruz, E. U., M. Vargas-Ramírez, A. Lobo-Guerrero, A. Cruz-Ramírez, E. Colin-García, R. G. Sánchez-Alvarado, V. H. Gutiérrez-Pérez, and J. M. Martínez-Vázquez. "Effect of low aluminum additions in the microstructure and mechanical properties of hot forged high-manganese steels." Journal of Mining and Metallurgy, Section B: Metallurgy, no. 00 (2023): 7. http://dx.doi.org/10.2298/jmmb220919007m.
Анотація:
The present paper analyzes the effect of low aluminum additions and the hot forging process on the microstructure and non-metallic inclusions of high manganese steels. Four high-manganese steels (HMnS) were obtained by adding low aluminum contents of 1.1 and 1.5 wt. % in four medium carbon austenitic steels (0.3 - 0.4 wt% C) with manganese contents of 17 and 22 wt. Samples of the as-cast steels were hot forged to 1100 ?C to obtain a whole reduction of 70 %. The microstructural evolution was studied by microscopy techniques (OM, and SEM-EDS) and X-Ray diffraction measurements for the as-cast and hot forged steels. A typical grain columnar zone obtained during solidification of an ingot casting was obtained in the as-cast condition where the microstructure was constituted by non-metallic inclusions in a fully austenitic matrix. The non-metallic inclusions were identified as Al2O3 and MnS particles. The thermomechanical treatment allows the formation of an austenitic microstructure characterized by twins in high manganese steels while a duplex austenitic-martensitic microstructure was obtained for HMnS which contained the lowest manganese contents. The highest tensile properties were obtained for the steel 17Mn-1Al which showed the lowest grain size and higher non-metallic inclusions content. The hardness values were similar to those obtained in the as-cast condition.
21
Tęcza, Grzegorz. "Changes in Abrasive Wear Resistance during Miller Test of High-Manganese Cast Steel with Niobium Carbides Formed in the Alloy Matrix." Applied Sciences 11, no. 11 (May 24, 2021): 4794. http://dx.doi.org/10.3390/app11114794.
Анотація:
High-manganese Hadfield cast steel is commonly used for machine components operating under dynamic load conditions. The high fracture toughness and abrasive wear resistance of this steel are the result of an austenitic structure, which—while being ductile—at the same time tends to surface harden under the effect of cold work. Absence of dynamic loads (e.g., in the case of sand abrasion) causes rapid and premature wear of parts. To improve the abrasive wear resistance of high-manganese cast steel for operation under the conditions free from dynamic loads, primary niobium carbides are produced in this cast steel during the melting process to obtain in castings, after melt solidification, the microstructure consisting of an austenitic matrix and primary niobium carbides uniformly distributed in this matrix. The measured hardness of the tested samples as cast and after solution heat treatment is 260–290 HV and is about 30–60 HV higher than the hardness of common Hadfield cast steel, which is 230 HV. Compared to common Hadfield cast steel, the abrasive wear resistance of the tested high-manganese cast steel measured in the Miller test is at least three times higher at the niobium content of 3.5 wt%. Increasing the niobium content to 4.5 wt%. in the tested samples increases this wear resistance even more.
22
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.
Анотація:
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.
23
Kalandyk, B., R. Zapała, J. Kasińska, M. Wróbel, and M. Balicki. "Microstructure and Mechanical Properties of High-Alloyed 23Cr-5Mn-2Ni-3Mo Cast Steel / Mikrostruktura I Właściwości Mechaniczne Wysokostopowego Staliwa 23Cr-5Mn-2Ni-3Mo." Archives of Metallurgy and Materials 60, no. 4 (December 1, 2015): 2529–34. http://dx.doi.org/10.1515/amm-2015-0410.
Анотація:
The article presents the microstructure and mechanical properties of cast duplex stainless steel type 23Cr-5Mn-2Ni-3Mo. It has been shown that the structure of the tested cast steel is composed of ferrite enriched in Cr, Mo and Si, and austenite enriched in Mn and Ni. In the initial state, at the interface, precipitates rich in Cr and Mo were present. A high carbon content (0.08%C) in this cast steel indicates that probably those were complex carbides of the M23C6type and/or σ phase. Studies have proved that the solution annealing conducted at 1060°C was not sufficient for their full dissolution, while at the solutioning temperature of 1150°C, the structure of the tested material was composed of ferrite and austenite.Partial replacement of Ni by two other austenite-forming elements, which are Mn and N, has ensured obtaining mechanical properties comparable to cast duplex 24Cr-5Ni-3Mo steel of the second generation. Basing on the results of static tensile test, a twice higher yield strength was proved to be obtained, compared to the cast austenitic 18Cr-9Ni and 19Cr-11Ni-2Mo steel commonly used in the foundry industry. In addition to the high yield strength (YS = 547 ÷ 572 MPa), the tested cast steel was characterized by the following mechanical properties: UTS = 731 ÷ 750 MPa, EL = 21 ÷ 29.5%, R.A. = 43 ÷ 52%, hardness 256 ÷ 266 HB. Fractures formed in mechanical tests showed ductile-brittle character.
24
Tęcza, Grzegorz. "Changes in Abrasion Resistance of Cast Cr-Ni Steel as a Result of the Formation of Niobium Carbides in Alloy Matrix." Materials 16, no. 4 (February 19, 2023): 1726. http://dx.doi.org/10.3390/ma16041726.
Анотація:
Cast austenitic chromium-nickel steel is commonly used for the manufacture of machine parts and components, which are exposed to the attack of corrosive media and abrasive wear during operation. The most commonly used grades include GX2CrNi18-9 and X10CrNi18-8 as well as GX2CrNiMo17-12-2 and X6CrNiMoNb17-12-2. To improve the abrasion resistance of cast chromium-nickel steel, primary niobium carbides were produced in the metallurgical process by increasing the carbon content and adding Fe-Nb. The microstructure of the obtained test castings consisted of an austenitic matrix and primary niobium carbides evenly distributed in this matrix. The measured hardness of the samples after heat treatment ranged from 215 to 240 HV and was higher by about 60 units than the hardness of the reference cast GX10CrNi18-9 steel, which had a hardness of about 180 HV. Compared to the reference cast steel, the abrasive wear resistance of the tested cast chromium-nickel steel (measured in Miller test) with contents of 4.4 and 5.4 wt% Nb increased only slightly, i.e., by 5% for the lower niobium content and 11% for the higher niobium content. Compared to ordinary cast GX10CrNi18-9 steel, the addition of 9.2 wt% Nb reduced the abrasive wear by almost 2.5 times.
25
Villanueva-Perez, O. E., I. Mejía, V. García-García, and A. Bedolla-Jacuinde. "Metallographic, Structural and Mechanical Characterization of a Low Density Fe-Mn-Al-C Steel Microalloyed with Ti/B in As-Cast and Homogenized Conditions." MRS Advances 3, no. 64 (2018): 3971–78. http://dx.doi.org/10.1557/adv.2019.64.
Анотація:
ABSTRACTLow density (LD) steels have shown particular characteristics in terms of mechanical properties and microstructure, since they have high strength, high ductility and density reduction up to 18%. On the other hand, the addition of microalloying elements such as Ti and B generate hardening by solid solution and precipitation, as well as grain refinement effect. LD steels generate nano-sized kappa phase precipitated from the austenite matrix, and these advanced steels can reach strength and elongation up to 780 MPa and 60%, respectively. The main objective of this research work is the metallographic, structural and mechanical characterization of a LD steel microalloyed with Ti/B in as-cast and -homogenized conditions. For this purpose a Fe-27Mn-7Al-1.2C (%wt) LD steel microalloyed with Ti/B was melted in a vacuum-induction furnace and cast in metallic mold. LD-Ti/B steel samples were homogenized at 1100 °C during 20, 50, 100, 150 and 200 minutes followed by water quenching. Metallographic, structural and mechanical characterization was carried out by optical (LOM) and scanning electron (SEM) microscopy, X-ray diffraction (XRD) and microhardness Vickers testing (HV10), respectively. In general, results showed a typical dendritic microstructure with average grain size of 1256 μm in the as-cast condition. On the other hand, the as-homogenized condition showed an austenitic equiaxial microstructure with average grain size from 164 to 940 μm. Austenite, ferrite and kappa phases were detected by X-ray diffraction (XRD). Also, second-phase particles such as AlN, TiC and MnS were detected by LOM and SEM-EDS analysis. LD steel microalloyed with Ti/B exhibited the highest microhardness Vickers value (235 HV10) in the as-cast condition, whilst in the as-homogenized condition microhardness gradually decreases from 223 to 198 HV10 as holding time increases.
26
Kolpishon, Eduard Yl'evich, Ludmila Vladimirovna Razumova, and Sergey Vladimirovich Ryaboshuk. "Modification of Nitrogen-Containing High-Chromium Steels by Nanosized Lanthanum Hexaboride." Key Engineering Materials 822 (September 2019): 37–43. http://dx.doi.org/10.4028/www.scientific.net/kem.822.37.
Анотація:
The paper presents the results of a study of the lanthanum hexaboride nanosized powder modification effect on the cast structure of martensitic and austenitic steels deoxidized with aluminum and silicon. The study was conducted on high-chromium steels of austenitic and martensitic classes, and nanosized lanthanum hexaboride powder was used as a modifier. Studies of the chemical composition of the obtained samples, qualitative and quantitative analysis of non-metallic inclusions, the structure of the steel and thermodynamic modeling were carried out.
27
Głownia, J., G. Tęcza, M. Asłanowicz, and A. Osciłowski. "Tools Cast from The Steel of Composite Structure." Archives of Metallurgy and Materials 58, no. 3 (September 1, 2013): 803–8. http://dx.doi.org/10.2478/amm-2013-0075.
Анотація:
Abstract Hardness, microstructure and abrasive wear resistance of cast high-manganese steel (cast Hadfield steel) were compared with the cast steel of the same austenitic matrix but having vanadium carbides uniformly distributed within its entire volume. The chemical composition of the cast steel was chosen in such a way as to produce a composite structure after the alloy solidification. A similar hardness of the matrix was obtained with carbides evenly distributed in it, while abrasive wear resistance doubled its value. Using the investment casting process, working elements of teeth for the excavators and mechanical coal miners were cast.
28
Gajewski, M., and J. Kasińska. "Effects of Cr - Ni 18/9 Austenitic Cast Steel Modification by Mischmetal." Archives of Foundry Engineering 12, no. 4 (December 1, 2012): 47–52. http://dx.doi.org/10.2478/v10266-012-0105-y.
Анотація:
Abstract This paper presents the results of Cr - Ni 18/9 austenitic cast steel modifications by mischmetal. The study was conducted on industrial melts. Cast steel was melted in an electric induction furnace with a capacity of 2000 kg and a basic lining crucible. .The mischmetal was introduced into the ladle during tapping of the cast steel from the furnace. The effectiveness of modification was examined with the carbon content of 0.1% and the presence of δ ferrite in the structure of cast steel stabilized with titanium. The changes in the structure of cast steel and their effect on mechanical properties and intergranular corrosion were studied. It was found that rare earth metals decrease the sulfur content in cast steel and above all, they cause a distinct change in morphology of the δ ferrite and non-metallic inclusions. These changes have improved mechanical properties. R02, Rm, and A5 and toughness increased significantly. There was a great increase of the resistance to intergranular corrosion in the Huey test. The study confirmed the high efficiency of cast steel modification by mischmetal in industrial environments. The final effect of modification depends on the form and manner of placing mischmetal into the liquid metal and the melting technology, ie the degree of deoxidation and desulfurization of the metal in the furnace.
29
Podany, Pavel, Tomas Gregor, Tomas Studecky, and Crtomir Donik. "High Manganese TWIP Steel with Increased Corrosion Resistance." Metals 12, no. 10 (October 20, 2022): 1765. http://dx.doi.org/10.3390/met12101765.
Анотація:
The paper describes the development of austenitic steel with the TWIP effect, which is alloyed with chromium to increase corrosion resistance. The experimental heat of this steel was cast in an experimental melting furnace and subsequently subjected to hot and cold rolling. After cold rolling, the appropriate recrystallization annealing temperature was applied to obtain the optimal austenitic grain size. X-ray diffraction proved that the steel contains a fully austenitic structure. After recrystallization annealing, the sheets achieved a TS of more than 950 MPa with an elongation of 40%. The corrosion resistance of this steel is increased with the addition of chromium.
30
Kalandyk, B. "Wear Resistance of 18%Cr-9%Ni Steel Used for Cast Parts of Pumps Operating in Corrosive – Erosive Environments." Archives of Metallurgy and Materials 58, no. 3 (September 1, 2013): 841–44. http://dx.doi.org/10.2478/amm-2013-0083.
Анотація:
Abstract This paper presents the results of experimental studies, the main aim of which has been to demonstrate that changes in the microstructure of austenitic 18%Cr-9%Ni cast steel provoked by the addition of 1.4% boron, and boron with titanium, give increased wear resistance. After melting the high-alloyed 18%Cr-9%Ni cast steel with an addition of boron, and boron with titanium, metallographic examinations were conducted using light microscopy and SEM. These examinations revealed in the austenitic structure of the 18%Cr-9%Ni cast steel, the presence of a eutectic rich in boron and chromium, and characterised by a microhardness of 1838-1890 μ HV20. Additionally, in the cast steel inoculated with boron and titanium, the presence of titanium nitride precipitates was observed. Changes that have occurred in the microstructure as a result of introducing the additions of boron, and boron with titanium, also caused an increase of the cast steel hardness from 212 HV30 to 290-320 HV30 and 320-350 HV30, respectively. To determine the abrasive wear resistance, 16-hour Miller test was performed (ASTM G 75-07), wherein the abrasive medium was a mixture of SiC and water. Obtaining the hard, rich in boron and chromium, eutectic and titanium nitride precipitates in the structure of 18%Cr-9%Ni cast steel increased the abrasive wear resistance by approximately 21%, according to the data recorded in the sixteenth hour of the test cycle. As an additional benchmark point for the results obtained served the wear resistant, structural, L35GSM steel used for castings working in difficult conditions. Comparing the values of abrasive wear resistance obtained for the 18%Cr-9%Ni cast steel and cast L35GSM steel, an increase in the wear resistance of the 18%Cr-9%Ni cast steel by about 35% has been proved.
31
Kalandyk, B., R. Zapała, and M. Starowicz. "The Effect of Si and Mn on Microstructure and Selected Properties of Cr-Ni Stainless Steels." Archives of Foundry Engineering 17, no. 1 (March 1, 2017): 192–96. http://dx.doi.org/10.1515/afe-2017-0034.
Анотація:
Abstract Cast stainless steel of the Cr-Ni duplex type is used, among others, for the cast parts of pumps and valves handling various chemically aggressive media. Therefore, the main problem discussed in this article is the problem of abrasion wear resistance in a mixture of SiC and water and resistance to electrochemical corrosion in a 3% NaCl-H2O solution of selected cast steel grades, i.e. typical duplex cast steel, high silicon and manganese duplex cast steel, and Cr-Ni austenitic cast steel (type AISI 316L). The study shows that the best abrasion wear resistance comparable to Ni-Hart cast iron was obtained in the cast duplex steel, where Ni was partially replaced with Mn and N. This cast steel was also characterized by the highest hardness and matrix microhardness among all the tested cast steel grades. The best resistance to electrochemical corrosion in 3% NaCl-H2O solution showed the cast duplex steel with high content of Cr, Mo and N. The addition of Ni plays rather insignificant role in the improvement of corrosion resistance of the materials tested.
32
Shimizu, Kazumichi, Takeshi Naruse, Yaer Xinba, Hideki Teramachi, Shinji Araya, and Masahide Ishida. "High Temperature Erosion Behaviors of High V-Cr-Ni Spheroidal Carbides Cast Iron." Key Engineering Materials 457 (December 2010): 255–60. http://dx.doi.org/10.4028/www.scientific.net/kem.457.255.
Анотація:
High temperature erosion occurs in production of the inorganic fibrous insulator in plant. Austenitic and martensitic stainless steels are often used for these severe high temperature erosion conditions. The paper presents erosion properties of some stainless steels, several cast iron and cast steel using a blast type high temperature erosion furnace. The solid particle erosion behavior at high temperatures (900°C) of carbon steel of S50C, carbon tool steel of SK3, SUS403, SUS630, and High V-Cr-Ni spheroidal carbides cast iron (SCI-VCrNi) are investigated. Alumina balls entrained in a stream of hot air impact on the target materials at an air velocity of 100 m/s. the impingement angle is 90°. The influence of the test temperature and the material removal are discussed. The high temperature erosion behaviors of specimens are discussed by the eroded surface morphology and vertical section observation using SEM and optical microscopy observations.
33
Wahyudi, Haris, Swandya Eka Pratiwi, Adolf Asih Supriyanto, and Daisman Purnomo Bayyu Aji. "The influence of heat rate and austenitization temperature on microstructure and hardness of Hadfield steel." SINERGI 27, no. 2 (April 27, 2023): 241. http://dx.doi.org/10.22441/sinergi.2023.2.012.
Анотація:
The As-Cast condition of Hadfield alloy usually contains (Fe, Mn)3C carbides around the austenitic grains, which promote brittleness, making the steel impractical in industry. Heat treatment is normally applied to reduce carbide content, lower carbides, and improve toughness. However, a complete austenitic structure is not attainable during solution treatment. The dissolution temperature and dissolution time are critical to obtaining complete carbide content. Furthermore, heating must be done slowly, and the quenching speed must be fast enough. This study examines the effect of heat rate and austenitization temperatures in the solution treatment on the microstructure and hardness of Hadfield steel. The heat rate of 3, 6 and 10 oC/min is selected to determine whether there is a change in the microstructure of Hadfield steel. The four austenitization temperatures of 1000, 1100, 1150 and 1200 oC are used to ascertain carbide dissolution into the austenite matrix. Grain boundary, hardness, and phase transformation will confirm the microstructural change and hardness properties. The optical microscope shows carbide content is reduced as the austenitization temperature increases. The consequence of carbide dissolution affects the hardness. Its hardness decreases as temperature increase due to the loss of carbide. The as-Cast specimen has the highest hardness of 227.8 HV30, and the lowest hardness is 176.7 HV30 belongs to a specimen that is heated up to 1200 °C and quenched into water. Grain size is measured by the line intercept method, which shows its increase as temperatures increase. The result of grain measurement is as follows: As-Cast 224.6 mm, T 1000 °C 323.3 mm, T1100 °C 409.2 mm, T1150 °C 1014.4 mm, T1200 °C 881.6 mm. SEM-EDS confirms that the main phase is austenite, and a small amount of carbide is detected in the austenite matrix.
34
Tian, Jihong, Fei Chen, Fengming Qin, Jiansheng Liu, and Huiqin Chen. "MODIFIED PHYSICALLY-BASED CONSTITUTIVE MODEL FOR As-CAST Mn18Cr18N AUSTENITIC STAINLESS STEEL AT ELEVATED TEMPERATURES." Materiali in tehnologije 55, no. 2 (April 15, 2021): 243–51. http://dx.doi.org/10.17222/mit.2020.168.
Анотація:
The hot-deformation behavior of the as-cast Mn18Cr18N high-nitrogen austenitic stainless steel, produced with the electroslag-remelting metallurgical technology, was studied using isothermal-compression tests in a temperature range of 1223–1473 K) and a strain-rate range of 0.001–1 s–1). The flow-stress curves of the Mn18Cr18N steel were obtained under different hot-deformation conditions. By establishing the hyperbolic sine-law Zener-Hollomon equation, the hot-deformation activation energy of the Mn18Cr18N steel was obtained. Based on the mechanism of dislocation evolution, a physically-based constitutive model was established. In addition, the expression of the dynamic-recovery coefficient of the model was modified. Compared with the model before the modification, the modified constitutive model could effectively improve the prediction accuracy of the flow stress for the as-cast Mn18Cr18N austenitic stainless steel.
35
Weidner, Anja, and Horst Biermann. "Microstructure Evolution and Phase Transformation in a Novel High-Alloyed TRIP Steel Observed during in-Situ Tensile and Cyclic Deformation." Key Engineering Materials 465 (January 2011): 350–53. http://dx.doi.org/10.4028/www.scientific.net/kem.465.350.
Анотація:
The tensile and cyclic deformation behaviour of a new metastable austenitic stainless cast steel were studied in-situ in a scanning electron microscope (SEM). The metastable steel was investigated in cast condition. The in-situ tests in the SEM show the evolution of the microstructure in dependence on the deformation degree for uniaxial deformation and the number of cycles during fatigue, respectively. The development of the microstructure (i.e. deformation bands) are correlated with the places, where the phase transformation of the metastable austenite into the hcp structure or the bcc ’- martensite (TRIP – effect; TRansformation Induced Plasticity) takes place by applying different SEM-techniques as electron backscatter diffraction (EBSD). In addition, calculations of local deformation fields developing during tensile and cyclic deformation using digital image correlation (DIC) are presented.
36
Stradomski, Grzegorz, Arkadiusz Szarek, and Dariusz Rydz. "Influence of Copper Addition on Sigma Phase Precipitation during Hot Deformation of Duplex Steel." Materials 13, no. 7 (April 3, 2020): 1665. http://dx.doi.org/10.3390/ma13071665.
Анотація:
The paper presents an experimental study on microstructure changes in duplex steel after hot deformation. Duplex steels and cast steels are characterized by a multiphase microstructure. They are relatively new materials with great contributions to the many fields of industries. Due to the fact of deforming two different phase austenite and ferrite those materials have a complex plasticity. This work is a continuation and complementation of previous works and is a significant supplement to information presented in them. The article concerns precipitation phenomena and changes in the microstructure of two grades of ferritic-austenitic steels: X2CrNiMoN25-7-4 and X2CrNiMoCuN25-6-3. Those steels have a very similar chemical composition, differing by only 2.5% copper content. An important aspect presented in the work is we observed that adding 2.5% copper prevented precipitation of the destructive sigma phase during the hot deformation.
37
Martin, Guilhem, Muriel Véron, B. Chéhab, R. Fourmentin, Jean Denis Mithieux, S. K. Yerra, Laurent Delannay, Thomas Pardoen, and Yves J. M. Bréchet. "Duplex Stainless Steel Microstructural Developments as Model Microstructures for Hot Ductility Investigations." Solid State Phenomena 172-174 (June 2011): 350–55. http://dx.doi.org/10.4028/www.scientific.net/ssp.172-174.350.
Анотація:
Duplex stainless steels (DSS) are alloys made of ferrite and austenite, with a proportion of each phase around 50%. Their main advantage in comparison with other austenitic and ferritic stainless steels is the attractive combination of high strength and corrosion resistance together with good formability and weldability. Unfortunately, DSS often present a poor hot workability. This phenomenon can stem from different factors associated to the balance of the phases, the nature of the interface, the distribution, size and shape of the second phase, and possibly also from difference in rheology between ferrite and austenite. In order to determine the specific influence of phase morphology on the hot-workability of DSS, two austenite morphologies (E: Equiaxed and W: Widmanstätten) with very similar phase ratio have been generated using appropriate heat treatments. It was checked that the latter treatments generate stable microstructures so that subsequent hot mechanical tests are performed on the microstructures of interest. One microstructure consists of a ferritic matrix with austenitic equiaxed islands while the other microstructure is composed of a ferritic matrix with Widmanstätten austenite. The latter morphology corresponds to the morphology observed in as-cast slabs.
38
Aftandiliants, Y. G. "The influence of modification on the fracture of austenitic stainless steels under dynamic loads." Metaloznavstvo ta obrobka metalìv 103, no. 3 (September 30, 2022): 34–40. http://dx.doi.org/10.15407/mom2022.03.034.
Анотація:
The paper presents the results of studying the cold resistance of cast stainless steels of austenitic grade and developed mathematical models showing the effect of cerium, boron, vanadium and copper on cold resistance, which is associated with austenite grain size, carbide phase and ferrite content in austenite after quenching, particle volumes, size and distance between particles of oxides, sulfides, titanium carbonitrides and the total content of non-metallic inclusions in cast stainless steel. It was established that with complex microalloying and modification of Ce, B, V and Cu, the impact toughness of stainless steels increases by 2.7-3.1 times, as a result of the increase of nucleation and crack propagation work. It showed that the crack nucleation and their development is associated with non-metallic inclusions, while in the original steels around non-metallic inclusions significant zones of brittle failure are observed, and in the fracture of complex microalloyed and modified steels there are practically no areas of brittle failure around non-metallic inclusions. It was established that the impact toughness and crack initiation and propagation of the investigated stainless steels are determined by the patterns of changes in such structural factors as the size of the austenite grain, the content of the carbide phase and ferrite in the austenite after quenching, the volume fraction, the size and distance between oxide particles, titanium sulfides and carbonitrides, as well as the total content of non-metallic inclusions. Mathematical models of the influence of structural factors have been developed, which show the predominant influence of non-metallic inclusions on the process of destruction of stainless steels under dynamic loads, in comparison with other structure characteristics, in conditions of negative temperatures is shown. It is established that the mechanism of influence of Ce, B, V and Cu on this process is connected, mainly, with dispersion of oxides and their more homogeneous distribution. Keywords: steel, toughness, fracture work, crack formation, crack propagation, modification.
39
Stradomski, G. "The Role of Carbon in the Mechanism of Ferritic-Austenitic Cast Steel Solidification." Archives of Foundry Engineering 14, no. 3 (August 8, 2014): 83–86. http://dx.doi.org/10.2478/afe-2014-0067.
Анотація:
Abstract The paper presents the results of research on the microstructure of GX2CrNiMoCuN25-6-3-3 and GX2CrNiMoCuN25-6-3 cast steels with a varying carbon content. The cause for undertaking the research were technological problems with hot cracking in bulk castings of duplex cast steel with a carbon content of approx. 0.06% and with 23% Cr, 8.5% Ni, 3% Mo and 2.4% Cu. The research has shown a significant effect of increased carbon content on the ferrite and austenite microstructure morphology, while exceeding the carbon content of 0.06% results in a change of the shape of primary grains from equiaxial to columnar.
40
Tęcza, Grzegorz. "Changes in Microstructure and Abrasion Resistance during Miller Test of Hadfield High-Manganese Cast Steel after the Formation of Vanadium Carbides in Alloy Matrix." Materials 15, no. 3 (January 28, 2022): 1021. http://dx.doi.org/10.3390/ma15031021.
Анотація:
Hadfield cast steel is characterized by high wear resistance, but this is only when it is subjected to the effect of dynamic loads. During unloaded abrasion, e.g., sand abrasion, its wear resistance is very low and comparable to the wear of carbon cast steel. To increase the wear resistance of this alloy for operation under the conditions of low pressure or low stress, primary vanadium carbides were produced by the metallurgical process to obtain a two-phase structure after alloy solidification. Compared to samples made of Hadfield cast steel, the primary, very hard carbides, evenly distributed in an austenitic or austenitic-martensitic matrix, increase (at least three times) the wear resistance of samples tested in an abrasive mixture of silicon carbide and water. The changes in microstructure and hardness obtained in alloys after heat treatment (quenching at 1000–1150 °C in water and tempering at 600 °C) are presented. The bulk hardness of the matrix ranged from 370 HV to 660 HV. After heat treatment, the secondary, dispersed vanadium carbides, precipitated in the alloy matrix.
41
Kalandyk, B., G. Tęcza, R. Zapała, and S. Sobula. "Cast High-Manganese Steel – the Effect of Microstructure on Abrasive Wear Behaviour in Miller Test." Archives of Foundry Engineering 15, no. 2 (June 1, 2015): 35–38. http://dx.doi.org/10.1515/afe-2015-0033.
Анотація:
Abstract The results of the modification of austenitic matrix in cast high-manganese steel containing 11÷19% Mn with additions of Cr, Ni and Ti were discussed. The introduction of carbide-forming alloying elements to this cast steel leads to the formation in matrix of stable complex carbide phases, which effectively increase the abrasive wear resistance in a mixture of SiC and water. The starting material used in tests was a cast Hadfield steel containing 11% Mn and 1.34% C. The results presented in the article show significant improvement in abrasive wear resistance and hardness owing to the structure modification with additions of Cr and Ti.
42
Pokusová, M., A. Brúsilová, Ľ. Šooš, and I. Berta. "Abrasion Wear Behavior of High-chromium Cast Iron." Archives of Foundry Engineering 16, no. 2 (June 1, 2016): 69–74. http://dx.doi.org/10.1515/afe-2016-0028.
Анотація:
Abstract High-chromium cast irons are used as abrasion resistant materials. Their wear resistance depends on quantity of carbides and the matrix supporting these carbides. The paper presents the results of cast irons of chemical composition (in wt. %) 19–22 Cr and 2–4.5 C alloyed by 1.7 Mo + 5 Ni + 2 Mn to improve their toughness, which were tested in working conditions of ferroalloys crushing. Tests showed that these as-cast chromium cast irons with mostly austenitic matrix achieved the hardness of 38-45 HRC, but their relative abrasion resistance Ψ ranged from 1.3 to 4.6, was higher comparing to the tool made from the X210Cr12 steel heat treated on hardness 61 HRC. The transformation of austenite into martensite occurs not only at the worn strained areas (on a surface of scratch) but also in their neighbourhood. Due to the work hardening of relatively large volumes of transformed austenite the cast iron possesses high abrasion resistance also on the surfaces where low pressures are acting. The tough abrasion-resistant cast iron well proved for production of dynamic and wear stressed castings e.g., crusher hammers, cutting tools for ceramic etc.
43
Cheng, Xiuming, Wumu Liu, Fei Huang, Zhenan Ren, and Xinge Zhang. "Study on bonding properties between arc surfacing layers and 1045 steel substrate using pull-lift test method." E3S Web of Conferences 268 (2021): 01072. http://dx.doi.org/10.1051/e3sconf/202126801072.
Анотація:
Three kinds of surfacing layers of the austenitic steel, niobium alloyed steel and hypereutectic high chromium alloyed cast iron were prepared on 1045 steel substrate by arc surfacing process with self-shielding flux-cored wires. The bonding strength between surfacing layers and the substrate was tested by pull-lift test method. The experimental results show that the bonding strength between austenitic steel surfacing layer and the substrate is the highest up to 549.1 MPa, and the fracture location is near the fusion line with quasi-cleavage fracture characteristic. The bonding strength between the surfacing layer of niobium alloyed steel and the substrate is 314.4 MPa and the fracture mainly occurred at the bottom of the surfacing layer, which also presents quasi-cleavage characteristic. While the bonding strength between hypereutectic high chromium alloyed cast iron surfacing layer and the substrate is as low as 170.7 MPa and the specimen ruptures along the fusion line with brittle fracture characteristic. The bonding properties between surfacing layers and the substrate are directly related to the compositions and microstructures near the fusion line.
44
Lee, Hyunju, Cheolmin Ahn, Walid Khalfaoui, Brajendra Mishra, Ilguk Jo, and Eunkyung Lee. "Effects of Iron Oxidation State and Chromium Distribution on the Corrosion Resistance of High Interstitial Stainless Steel for Down-Hole Application." Metals 10, no. 10 (September 29, 2020): 1302. http://dx.doi.org/10.3390/met10101302.
Анотація:
The corrosion properties of Fe-Cr-Mn-C-N high interstitial austenitic stainless cast steels were investigated for down-hole application in sour environments. The two cast alloys contained 0.66% and 0.71% of total nitrogen and carbon. The corrosion properties of the alloys that were solution-treated and fast-cooled were directly responsible for high corrosion resistance in NaCl solution, including resistance to pitting corrosion resulting from a better distribution of chromium chemical compound in the high interstitial stainless cast steel. However, the sour corrosion resistance of the alloys decreased with the fast cooling rate, which can be attributed to the increased amount of ferrite containing Fe2+, which causes iron sulfide precipitate formation in H2S.
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Sydorchuk, O. M., A. A. Mamonova, Y. V. Lukianchuk, K. O. Gogaiev, O. K. Radchenko, L. A. Myroniuk, V. P. Konoval, G. L. Shvedova, and D. V. Myroniuk. "Cast steel with adjustable austenitic transformation during operation, obtained by electroslag remelting." Uspihi materialoznavstva 2020, no. 01 (December 1, 2020): 77–85. http://dx.doi.org/10.15407/materials2020.01.077.
Анотація:
The ligature for finishing of base steel 3H3M3Ftype for obtaining steel 4H3N5M3Ftype with adjustable austenitic transformation is developed in the article. The phase-structural state of steel in the cast state is investigated. The uniform distribution of alloying components on the body of grains is shown. It was found that the investigated hardened steel is softening above the tempering temperature of 620 °C, because the heat resistance of steel decreases (below 40 HRC). It was developed a 3H3M3F base steel ligature for steel production with adjustable austenitic transformation of 4H3N5M3F brand. Ingots (ligature of the Fe―Ni―Mo―V―Mn system) weighing 25 kg were obtained. The ligature was obtained by means of an induction furnace in a casting mold. The temperature of the metal in the furnace before release was 1550 °C. The duration of refining did not exceed 20 minutes. The phase-structural state of cast steel is studied. The uniform distribution of alloying components on the body of grains is shown, as well as the absence of coarse carbide eutectic in metal. This allows to reduce energy-intensive technological operations (diffusion annealing, forging) for the die toolsmanufacture. The presence of martensitic structure in the steel in the cast state of the investigated ingot requires the main thermal operation — annealing. It is established that incomplete annealing at a temperature of 750 ± 20 °C under the condition of partial recrystallization of the investigated steel allows to improve the mechanical processing (cutting) for the production of the die tool. It was determined that the investigated hardened steel hardens above the tempering temperature of 620 °C, because the heat resistance of steel decreases (below 40 HRC). Thus, a die tool of the investigated steel for hot deformation, capable of operating up to the temperature of 620 °C. Keywords: steel, ligature, temperature, structure, hardness.
46
Hotta, S., Taichi Murakami, Takayuki Narushima, Yasutaka Iguchi, and Chiaki Ouchi. "Effects of Cooling Rate and Direct Hot Deformation Conditions after Solidification on the Austenitic Microstructure Evolved by Simulated Strip Casting and Thin Slab Casting Processes in HSLA Steels." Advanced Materials Research 15-17 (February 2006): 726–31. http://dx.doi.org/10.4028/www.scientific.net/amr.15-17.726.
Анотація:
Currently new continuous casting processes such as thin slab caster or strip casting are industrialized or under developing in the world steel makers. In these casting processes, cooling rate after solidification becomes much faster compared with thick slab caster, and hot rolling mill connected directly with casting machine tends to be installed. The present study was conducted to investigate variations of austenitic grain size and micro segregation with cooling rate after solidification and also direct hot deformation conditions in austenite immediately after solidification in HSLA steels. HSLA steels were 0.15%C-0.25%Si-1.50%Mn, 0.028%Nb and 0.028%Nb-0.015%Ti with the same basic compositions. A hot working simulator of THERMECMASTER-Z was used, and the center part of tensile specimen set up in this machine was partially or fully levitation-melted by induction heating under argon gas atmosphere. After melting, specimens were cooled at cooling rate from 0.4K/s to 40K/s, and this range covered cooling rates after solidification in heavy thick slab caster and strip casting. Direct hot tensile straining in austenite after solidification was conducted at strain rates from 1.4×10-3s-1 to 2.6s-1, corresponding to an extracting speed in a respective caster. The increase of cooling rate refined continuously as cast austenitic grain size, and it was enhanced in micro alloyed steels. Micro segregation such as Mn was improved by faster cooling. Direct straining after solidification markedly refined austenitic grain size through dynamic or static recrystallization occurring depending on strain rate.
47
Dyja, D., Z. Stradomski, Cezary Kolan та Grzegorz Stradomski. "Eutectoid Decomposition of δ-Ferrite in Ferritic-Austenitic Duplex Cast Steel - Structural and Morphological Study". Materials Science Forum 706-709 (січень 2012): 2314–19. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.2314.
Анотація:
The influence of time and temperature of ageing on the σ-phase morphology in ferritic-austenitic cast steel have been investigated in this study. The morphology and quantity of the σ-phase were analyzed by using optical microscope, X-ray diffractometry, scanning electron microscope and image analysis, respectively. The annealing temperature has a significant influence on the morphology, volume fraction and the dynamics of σ-phase precipitation. Surface development of the σ-phase decreases from R=4.3, for the cast steel annealed at 700°C to R=2.4 for the cast steel annealed at 900°C, and the volume fraction Vvσ from 50.8% to 26.5%, respectively. The most rapid progress of δ → σ + γ’ transformation was observed at 800°C.
48
Moskvina, V. A., E. V. Melnikov, and E. A. Zagibalova. "CHARACTERISTICS OF A GRADIENT MATERIAL BASED ON NI-CR STAINLESS STEEL AND H20N80 ALLOY PRODUCED BY ELECTRON-BEAM 3D-PRINTING." Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta, no. 3 (2021): 57–66. http://dx.doi.org/10.18323/2073-5073-2021-3-57-66.
Анотація:
The main problem of additively manufactured chromium-nickel austenitic stainless steels is the formation of a two-phase γ-austenite/δ-ferrite dendritic microstructure, which complicates their use and distinguishes them from cast single-phase analogs. The reasons for the formation of a two-phase structure are nonequilibrium solidification conditions, complex thermal history, and melt depletion by austenite-forming elements (nickel and manganese). Therefore, additional nickel alloying under the additive manufacturing of steels can stabilize the austenitic structure in them. In this work, the authors used electron-beam additive production with simultaneous feeding of two wires from austenitic stainless steel Fe-18.2Cr-9.5Ni-1.1Mn-0.7Ti-0.5Si-0.08C wt.% (SS, Cr18Ni10Ti) and alloy 77.7Ni-19.6Cr-1.8Si-0.5Fe-0.4Zr wt.% (Ni-Cr alloy, Cr20Ni80) to obtain two gradient billets. The authors used two wire-feeding strategies (the first one is four layers of SS/one layer of Cr20Ni80; the second one is one layer of SS/one layer of a mixture 80 % SS + 20 % Cr20Ni80). The study identified that the Ni-Cr alloying in the process of electron-beam additive production of SS billets suppressed δ-ferrite formation and contributes to the stabilization of the austenite phase. The deposition of Ni-Cr alloy next to the four layers of SS leads to inhomogeneity of the structure and chemical composition in the billet, low plasticity, and premature failure of these specimens during tensile tests. The sequential alternation of pure SS layers with those of a mixture of wires (80 % SS + 20 % Cr20Ni80) promotes the uniform mixing of two wires components and the formation of a more homogeneous structure in the gradient billet, which leads to an increase in the ductility of the specimens during mechanical tests.
49
LISIECKA, Barbara, Agata DUDEK, and Katarzyna STRZELCZAK. "ANALYSIS OF THE STRUCTURE AND TRIBOLOGICAL PROPERTIES OF SINTERED STAINLESS STEELS." Tribologia 272, no. 2 (April 30, 2018): 99–105. http://dx.doi.org/10.5604/01.3001.0010.6312.
Анотація:
Increasing development of civilization encourages the search for modern engineering materials. At present, very interesting and promising materials are sintered stainless steels that are considered to be the most rapidly developing group of materials, which is related to the demand for materials with good mechanical properties and high resistance to corrosive agents. Taking into account sintered austenitic–ferritic steels, it is possible to obtain a structure with different proportions of the two basic structural components. The main problem limiting the applicability of sintered stainless steels is porosity, which deteriorates not only the strength properties but also the usability as compared to their cast and materials after plastic working. Extremely valuable factors influencing tribological properties are the chemical composition, proportion of individual powders and sintering conditions. In this study, the microstructure and tribological properties of sintered stainless steels obtained by sintering in different proportions of 316L austenitic steel and 409L ferritic steel were compared. The abrasion wear resistance test for individual sintered steels was performed by pin-on-disc method.
50
Kongpuang, M., R. Culwick, N. Cheputeh, A. Marsh, V. L. Jantara Junior, P. Vallely, S. Kaewunruen, and M. Papaelias. "Quantitative analysis of the structural health of railway turnouts using the acoustic emission technique." Insight - Non-Destructive Testing and Condition Monitoring 64, no. 7 (July 1, 2022): 398–403. http://dx.doi.org/10.1784/insi.2022.64.7.398.
Анотація:
Rail defects such as fatigue cracks have been one of the leading root causes of a number of derailments in the past. Cracks that initiate and propagate below the surface are difficult to detect using traditional non-destructive testing (NDT) methods. Acoustic emission (AE) is a more effective method for detecting and monitoring crack growth in rails online. This study investigates the applicability of AE for quantifying damage propagation in austenitic cast manganese steel used in manufacturing railway turnouts. The relationship between AE and crack growth rate in austenitic cast manganese steel samples that were fatigue tested in a three-point bending configuration was investigated by evaluating the AE activity with respect to direct current potential drop (DCPD) measurements and scanning electron microscopy (SEM) fractographic analysis of the tested samples. From the results obtained, it was not possible to observe a clear relationship between AE activity and the actual crack growth rate. Based on the SEM fractographic analysis, this is likely due to the plasticity occurring at the tip of the fatigue crack in the tested samples. This is plausible since the cast manganese steel samples had been cut off from a plate that had not been previously work hardened. The effect of carbides present in the microstructure is an additional contributing factor. Further tests should be carried out on cast manganese steel samples that have been work hardened prior to fatigue testing.