Journal articles on the topic 'Steel, High strength Testing'
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1
Haiko, Oskari, Kati Valtonen, Antti Kaijalainen, Vahid Javaheri, and Jukka Kömi. "High-stress abrasive wear characteristics of ultra-high strength press-hardening steel." Tribologia - Finnish Journal of Tribology 39, no. 3−4 (December 31, 2022): 32–41. http://dx.doi.org/10.30678/fjt.122836.
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Ultra-high strength steels are widely utilized in many applications operating in harsh abrasive wear conditions. For instance, the machineries used in mining and mineral handling or in agricultural sector require robust, but cost-effective wear-resistant materials. Steels provide excellent combination of mechanical properties and usability. This study encompasses mechanical and wear testing of an experimental medium-carbon press-hardening steel. The as-received material was austenitized at two different temperatures and quenched in water. Additionally, low-temperature tempering was applied for one variant. In total, three variants of the press-hardening steel were produced. Microstructural characterization and mechanical testing were conducted for the steel samples. The wear testing was carried out with high-stress abrasive method, in which the samples were rotated inside a crushed granite bed. A commercial 400 HB grade wear-resistant steel was included in the wear testing as a reference. The experimental steel showed very high mechanical properties reaching tensile strength up to 2600 MPa with hardness of 750 HV10. Wear testing resulted in only minimal differences between the three variants indicating that the improved impact toughness by tempering did not significantly affect the wear resistance. The reference steel had nearly two times greater mass loss compared to the higher hardness press-hardening steels. Microhardness measurements on the worn surface showed drastic increase in hardness for the deformed structure for all samples. It was concluded that even the high-hardness martensitic steels exhibit notable wear surface work-hardening. Therefore, hardness was determined to be the most significant factor affecting the wear performance of studied steels.
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Hlebová, Stanislava, and Ladislav Pešek. "Toughness of Ultra High Strength Steel Sheets ." Materials Science Forum 782 (April 2014): 57–60. http://dx.doi.org/10.4028/www.scientific.net/msf.782.57.
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Currently only few methods exist for thin steel sheet testing, especially based on fracture mechanics concept. Charpy impact test is one of the most used method for testing notch toughness and fracture behaviors because of the simplicity and the other advantages [. This article deals with toughness testing of automotive ultra high strength steel sheets (UHSS). Several standard types of toughness test that generate data for specific loading conditions and/or component design approaches exist. Two definition of toughness will be discussed: i) Charpy V-notch toughness, method includes joining of thin steel sheets to one compact unit and ii) material (tensile) toughness [. Two steels were used, DP1000 and 1400M of 1,8 mm thickness and two joining techniques: bonding with adhesives and joining with holders. Effect of material, joining technology, structural adhesives, and number of joined plates on the toughness values was quantified at the room temperature. Toughness of steels by the tensile test was added for comparison. Fracture surface was observed using scanning electron microscope analysis.
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OCHIAI, Ikuo. "Manufacture and Testing of High Strength Steel Wires." Journal of the Japan Society for Technology of Plasticity 51, no. 593 (2010): 493–97. http://dx.doi.org/10.9773/sosei.51.493.
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Lee, Kang Min, Myung Jae Lee, Young Suk Oh, T. S. Kim, and Do Hwan Kim. "Compressive Testing of H-Shaped Steel Stub Columns Fabricated with Grade 800MPa High Performance Steel." Advanced Materials Research 671-674 (March 2013): 646–49. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.646.
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With the increased demand for high-rise and long-span structures, high strength with high performance steels have been utilized for these kind of structures. For the grade 800MPa high performance steel, although it was included in Korean Standard as high strength steel(HSA 800), however the HSA 800 steel was excluded in Korean Building Code-Structures due to the rack of research results for the structural behaviors of members fabricated with HSA 800 steel. Therefore, this paper describes basic study for the design specification of structural members using HSA 800 high performance steel. For this purpose, welded H-shaped stub column specimens with various width-to-thickness ratios were designed and tested in order to investigate the buckling behaviors and ultimate compressive strength.
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Shi, Jie, Wen Quan Cao, and Han Dong. "Ultrafine Grained High Strength Low Alloy Steel with High Strength and High Ductility." Materials Science Forum 654-656 (June 2010): 238–41. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.238.
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In this study a C-Mn High Strength Low Alloy steel (HSLAs) was processed by quenching and austenite reverted transformation during annealing (ART-annealing), which results in an ultrafine grained duplex microstructure characterized by scanning electron microscopy equipped with electron back scattered diffraction, transmission electron microscopy and x-rays diffraction (SEM/EBSD, TEM and XRD). Microstructural observation revealed that the full hard martensitic microstucture gradually transformed into ultrafine grained duplex structure with austenite volume fraction up to 30% at specific annealing conditions. Mechanical properties of this processed steel measured by uniaxial tensile testing demonstrated that an excellent combination of strength (Rm~1GPa) and total elongation (A5~40%) at 30% metastable austenite condition in studied C-Mn-HSLAs. This substantially improved strength and ductility were attributed to the strain induced phase transformation of retained austenite dispersed throughout the ultrafine grained microstructure. At last it is proposed that ART-annealing is a promising way to produce high strength and high ductility steel products.
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Nie, Lun, Min Zhu, Shirun Tu, Kefeng Yuan, and Kexin Lu. "Study on the Corrosion Resistance of 39SiCrVTiA High strength and high toughness spring steel." MATEC Web of Conferences 353 (2021): 01010. http://dx.doi.org/10.1051/matecconf/202135301010.
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39SiCrVTiA spring steel is heat-treated and compared with the existing high-strength spring steels 60Si2CrVA and SAE9254 for electrochemical impedance spectroscopy (EIS), polarization curve and slow strain rate testing (SSRT). The test results of electrochemical impedance spectroscopy (EIS), polarization curve show that the corrosion resistance of 60Si2CrVA was the best, followed by that of SAE9254 and 39SiCrVTIA.However, the test results of the SSRT test show that the three spring steels in 5% NaCl solution possess high SCC susceptibility. The SCC susceptibility of 39SiCrVTiA steel is slightly lower and the stress corrosion ability is better than the other two steels which may be related to its containing Ti, V elements and lower carbon content.
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Kalácska, Eszter, Kornél Májlinger, Enikő Réka Fábián, and Pasquale Russo Spena. "MIG-Welding of Dissimilar Advanced High Strength Steel Sheets." Materials Science Forum 885 (February 2017): 80–85. http://dx.doi.org/10.4028/www.scientific.net/msf.885.80.
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The need for steel materials with increasing strength is constantly growing. The main application of such advanced high strength steels (AHSS) is the automobile industry, therefore the welding process of different types of AHSSs in dissimilar welding joint was investigated. To simulate the mass production of thin steel sheet constructions (such as car bodies) automated metal inert gas (MIG) welding process was used to weld the TWIP (twinning induced plasticity) and TRIP (transformation induced plasticity) steel sheets together. The welding parameters were successfully optimized for butt welded joints. The joints were investigated by visual examination, tensile testing, quantitative metallography and hardness measurements. The TRIP steel side of the joints showed increased microhardness up to (450-500 HV0.1) through increased fraction of bainite and martensite. Macroscopically the tensile specimen showed ductile behaviour, they broke in the austenitic weld material.
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Tomášek, Radek, and Vratislav Mareš. "Dynamic Tensile Testing of High Strength Armor Steel Plates." Key Engineering Materials 741 (June 2017): 70–75. http://dx.doi.org/10.4028/www.scientific.net/kem.741.70.
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In this paper was studied dynamic behavior of the armor steels Armox 500T and Secure 500 by testing specimens in quasi-static tensile test with strain rate 1∙10-3 s-1 and high-speed tensile test within range of intermediate strain rates from 100 s-1 to 400s-1 at the room temperature. Hardness test and quasi-static tensile test confirmed material properties specified by the manufacturer. Stress-strain diagrams showed very low strain-rate hardening effect at investigated strain rates. Total elongation at fracture was larger in case of Armox 500T for the whole strain rate range. Deformation energy density was calculated from the stress-strain curve and temperature rise due to adiabatic heating was estimated. Because of higher total elongation, Armox 500T was able to withstand higher deformation energy.
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Stern, I. L., M. Wheatcroft, and D. Y. Ku. "Higher-Strength Steels Specially Processed for High Heat Input Welding." Journal of Ship Production 1, no. 04 (November 1, 1985): 222–37. http://dx.doi.org/10.5957/jsp.1985.1.4.222.
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ABS Grade EH36 steel plates, specially formulated and produced with advanced metallurgical techniques, are shown to have a significantly greater resistance to weld heat-affected zone (HAZ) degradation that conventional EH36 steel. Welds made in these steels with the electroslag welding process at high heat input rates retained adequate toughness in the heat-affected zone at --4°F (-20°C); similar welds in conventional EH36 steel plate exhibit excessive HAZ toughness loss. This effect was confirmed on the basis of small-scale Charpy V-notch and large-scale explosion bulge testing. In view of their superior resistance to HAZ degradation, the steels should also be useful for applications where HAZ degradation is of particular concern, such as for American Bureau of Shipping (ABS), U.S. Coast Guard, and International Maritime Organization (IMO) weld requirements for liquefied gas carriers.
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Bulatović, Srđan, Vujadin Aleksić, Ljubica Milović, and Bojana Zečevićc. "High strength low-alloy steels impact toughness assessment at different test temperatures." Advanced Technologies & Materials 46, no. 2 (December 15, 2021): 43–46. http://dx.doi.org/10.24867/atm-2021-2-007.
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In many production processes, as well as in the exploitation of machine components and structures, materials are exposed to impact loads. In structures made of welded joints of high strength low-alloy steels with their constituents (parent metal, weld metal and heat-affected-zone), the toughness test determines the tendency of steel to brittle fracture, respectively the tendency to increase brittleness during exploitation. The strain rate is high and the material manifests much more brittle behavior than is shown by tensile testing. Toughness as a mechanical property is an important factor that is defined as the energy that needs to be spent in order to achieve fracture. Parameters obtained by testing the properties of plasticity are the basis for the design of structures in order to achieve strengths under applied load. The test results of high strength low-alloy steel toughness assessment at different test temperatures show that temperature significantly affects the impact toughness of steels and their alloys. At higher temperatures the impact energy on fracture is high (the material shows the properties of plasticity) while at lower temperatures the impact energy is small (the material is brittle).
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Mohtasham Moein, Mohammad, Ashkan Saradar, Komeil Rahmati, Arman Hatami Shirkouh, Iman Sadrinejad, Vartenie Aramali, and Moses Karakouzian. "Investigation of Impact Resistance of High-Strength Portland Cement Concrete Containing Steel Fibers." Materials 15, no. 20 (October 14, 2022): 7157. http://dx.doi.org/10.3390/ma15207157.
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Impact resistance of Portland cement concrete (PCC) is an essential property in various applications of PCC, such as industrial floors, hydraulic structures, and explosion-proof structures. Steel-fiber-fortified high-strength concrete testing was completed using a drop-weight impact assessment for impact strength. One mix was used to manufacture 320 concrete disc specimens cured in both humid and dry conditions. In addition, 30 cubic and 30 cylindrical specimens were used to evaluate the compressive and indirect tensile strengths. Steel fibers with hooked ends of lengths of 20, 30, and 50 mm were used in the concrete mixtures. Data on material strength were collected from impact testing, including the number of post-first-crack blows (INPBs), first-crack strength, and failure strength. Findings from the results concluded that all the steel fibers improved the mechanical properties of concrete. However, hooked steel fibers were more effective than crimped steel fibers in increasing impact strength, even with a smaller length-to-diameter ratio. Concrete samples containing hybrid fibers (hooked + crimped) also had lower compressive strength than the other fibers. Comparisons and analogies drawn between the test results and the static analyses (Kolmogorov–Smirnov and Kruskal–Wallis) show that the p-value of the analyses indicates a more normal distribution for curing in a humid environment. A significant difference was also observed between the energy absorptions of the reinforced mixtures into steel fibers.
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McDonald, Brodie, Huon Bornstein, Ali Ameri, Juan P. Escobedo-Diaz, and Adrian C. Orifici. "High strain rate and high temperature response of two armour steels: Experimental testing and constitutive modelling." EPJ Web of Conferences 183 (2018): 01022. http://dx.doi.org/10.1051/epjconf/201818301022.
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Under ballistic impact or blast loading, the high strain rate and high temperature behaviour of armour steels is key to their response to a given threat. This experimental and numerical investigation examines the tensile response of a class 4a improved rolled homogenous armour steel (IRHA) and a high hardness armour steel (HHA). Cylindrical tensile specimens were tested at a range of strain rates from 0.001 s-1 to 2700 s-1. Quasi-static, elevated temperature tests were performed from room temperature up to 300° C. While the HHA is strain rate insensitive, the IRHA displays a significant increase in strength across the range of loading rates reducing the ultimate strength difference between the materials from 19% at 0.001s-1 to 4.6% at 2700s-1. An inverse numerical modelling approach for constitutive model calibration is presented, which accurately captured the dynamic material behaviour. The modified Johnson-Cook strength and Cockcroft-Latham (C-L) fracture models were capable of predicting the ballistic limit of each material to within 5% of the experimental result and to within 10% for deformation under blast loading. The blast rupture threshold of both materials was significantly over-estimated by the C-L model suggesting stress state or strain rate effects may be reducing the ductility of armour steel under localised blast loading.
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Hietala, Mikko, Markku Keskitalo, and Antti Järvenpää. "The Comparison between Mechanical Properties of Laser-Welded Ultra-High-Strength Austenitic and Martensitic Steels." Key Engineering Materials 841 (May 2020): 132–37. http://dx.doi.org/10.4028/www.scientific.net/kem.841.132.
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The paper investigates experimentally the usability of ultra-high-strength stainless steel and abrasion resistant steel in laser-welded sandwich structures. The fatigue and shear strength of laser joints were investigated using lap joints that were welded using two very different energy inputs. Also the effect of multiple weld tracks was investigated. The properties of separate laser welds were characterized by hardness testing and optical microscopy. Results of the hardness measurements showed that there was softened area at heat-affected-zone and weld metal of the ultra-high-strength stainless steel welds. AR steels weld metal was harder than base metal and there was softened zone in heat-affected-zone of the weld. The shear strength of tested single weld joints of the ultra-high-strength stainless steel was higher compared abrasion resistant steel single weld joints, but stronger joint can be made with multiple weld seams for abrasion resistant steel. Fatigue strength of investigated ultra-high-strength stainless steel lap joint was lower than fatigue strength of abrasion resistant steel lap joint in the low-cycle regime, but there was no practical difference in fatigue limit (10e7 cycles).
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Giskaas, Shane, Preston Wolfram, Kip O. Findley, Bernard S. Levy, and Chester J. Van Tyne. "Yield Strength of Hot Forging Die Steels at Working Temperatures." Materials Science Forum 773-774 (November 2013): 56–62. http://dx.doi.org/10.4028/www.scientific.net/msf.773-774.56.
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One mode that limits the usefulness of hot forging die steels is localized plastic deformation in regions of high pressure. To understand this behavior the yield strength of the steel needs to be measured at working temperatures in order to determine the likelihood of localized plasticity. One of the issues in using die steels for hot forging applications is that they are initially tempered to a hardness value when put into service. As the die is used to produce forged components, the contact with the hot forging causes the die to continue to temper and hence soften with continued used. To explore these issues three different die steels were obtained and tested experimentally. Experimental compressive yield strengths were determined for the three die steels (FX, 2714 and WF). The die steels were tempered to various hardness values prior to compression testing. The five room-temperature hardness values after tempering ranged from 20 to 38 HRC. The five temperatures for compression testing ranged from 593 to 704 °C (1100 to 1300 oF). From these tests a good characterization of the high temperature plastic behavior of each steel was obtained. It was found that the WF steel which had the highest alloy content was the strongest of the three steels under all test conditions. The FX and 2714, which had similar alloy contents (with FX having slightly less carbon, nickel and vanadium), had yield strengths that were close to each other at the intermediate temperatures, but at the high and low end of the testing range for temperature the FX was stronger than the 2714. Hence, to obtain the greatest resistance to localized plastic deformation during operations the choice of die steel should be WF, followed by FX and then 2714.
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Bulatović, Srđan, Vujadin Aleksić, Ljubica Milović, and Bojana Zečević. "AN ANALYSIS OF IMPACT TESTING OF HIGH STRENGTH LOW-ALLOY STEELS USED IN SHIP CONSTRUCTION." Brodogradnja 72, no. 3 (July 1, 2021): 1–12. http://dx.doi.org/10.21278/brod72301.
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Brittle damages have been examined widely since welding became common practice when it comes to carrying out robust structures. Welded structure of the ship hull has to be continuous. Brittle damages that occur on hull structures have always been examined thoroughly. Cracks are most commonly initiated at locations where stress concentrators exist. These concentrators can originate due to flaws that occur during the design phase or due to mistakes that occur during the assembly of the structure. When it comes to failures and damages that occur at ship structures, it has been noticed that damages due to brittleness practically always happen at low temperatures. Impact test analysis is significant due to the fact that it replicates the ductile to brittle transition of steel in practically identical range of temperatures for all ship structures. Impact of ductile-brittle transition temperature is an important factor especially because there have been many ship failures and damages in history. In ship structures made of welded joints of high strength low-alloy (HSLA) steels with their segments (parent metal, weld metal and heat-affected-zone), the toughness test determines the tendency of steel to brittle fracture, respectively the tendency to increase brittleness during exploitation. Parameters obtained by testing the properties of plasticity are the fundamental for the composition of ship structures with the aim of realize strengths under tested load. The test results of high strength low-alloy steel toughness assessment at different test temperatures show that temperature significantly affects the impact toughness of steels and their alloys.
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Zhao, Zheng Zhi, Zhi Gang Wang, Ai Min Zhao, and Jie Yun Ye. "Microstructure, Properties and Work Hardening Behavior of High Strength Cold Rolled Dual-Phase Steel." Advanced Materials Research 399-401 (November 2011): 1682–86. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.1682.
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Two kinds of high strength cold rolled dual-phase steel with different Si content were trial-produced in the laboratory. Tensile strength and elongation of the two steels exceed 1000MPa and 15%, respectively. The phase transformation behaviors of both steels were compared and investigated in continuous cooling process by thermal dilatometer. The effects of Si on the mechanical properties and microstructures of dual-phase steel were studied by tensile testing, OM and SEM observation. The results show that the two phase region (α+γ) is enlarged, the precipitation and growth of pro-eutectoid ferrite is promoted, and the morphology and distribution patterns of martensite are improved for high Si steel. Both steels show two-stage strain hardening characteristics. StageⅠ (ε<0.05), the solution of Si hinder the movement of dislocations, make the work hardening exponent of high Si steel is higher than that low Si steel. At stage Ⅱ (ε>0.05), the compatibility and delivery between hard phase and soft phase eliminate the differences between the two steels.
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Qamar, Sayyad Zahid. "Heat Treatment and Mechanical Testing of AISI H11 Steel." Key Engineering Materials 656-657 (July 2015): 434–39. http://dx.doi.org/10.4028/www.scientific.net/kem.656-657.434.
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Belonging to the class of chromium tool steels, AISI H11 possesses very good toughness and hardness, and is therefore suitable for hot metalforming jobs performed at very high loads. Mostly used in fabrication of helicopter rotor blades, H11 also has great potential as a die steel in hot-work forging and extrusion. This alloy steel can be heat treated to increase the service life and dimensional accuracy of the die and tooling. Main aim of the current investigation was to formulate an optimum heat treatment strategy for H11 steel, especially for hot work applications. High-speed milling and electric discharge machining were used to fabricate samples for tensile and impact testing. After various types of heat treatment (annealing, austenitizing, air cooling or oil quenching, single and double tempering), these samples were tested for hardness, toughness (impact), yield strength, tensile strength, and ductility. Microstructural analysis was also performed to analyze the effect of heat treatment on mechanical properties. As tempering temperature increases, hardness initially increases and then starts to gradually decrease; impact strength first decreases and then increases; and yield strength exhibits a fluctuating pattern of initial decline followed by an increase and another decrease. Even though H11 steel is highly suitable for both hot and cold-work, it is surprisingly not a common choice for metalworking dies and tools. Results presented here can encourage die designers and hot-work practitioners to explore the versatility of this tool steel, and to adopt appropriate heat treatment strategies for different applications.
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Wu, Yong Hua. "Strengthen Experimental Study of High Strength Steel 40CrNi2Si2MoVA Based on Laser Shock Processing." Advanced Materials Research 774-776 (September 2013): 1122–26. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.1122.
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40CrNi2Si2MoVA high-strength steel is widely used in aircraft industry because of its unique combination of ultrahigh strength with high fracture toughness. However, 40CrNi2Si2MoVA is vulnerable to both corrosion fatigue and stress corrosion cracking failures with catastrophic consequences for aircraft. The high strength steel 40CrNi2Si2MoVA is enhanced and strengthen by usage of laser shock processing (LSP) with a optimal shock processing parameters, and after a series of comparion experiment in different overlap rate,the surface compressive residual stress in the testing specimen is measured and compared, and the experiment results show that the specimen surface has-962MPa compressive residual stress. Finally, the enhanced effect of compressive residual stress in surface of specimen by laser shock is discussed. The results of laser shock processing has a guiding significance to the engineering applications of high strength steel.
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Poh-Yap, S., U. Johnson-Alengaram, K. Hung-Mo, and M. Zamin-Jumaat. "High strength oil palm shell concrete beams reinforced with steel fibres." Materiales de Construcción 67, no. 328 (October 23, 2017): 142. http://dx.doi.org/10.3989/mc.2017.11616.
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The utilization of lightweight oil palm shell to produce high strength lightweight sustainable material has led many researchers towards its commercialization as structural concrete. However, the low tensile strength of Oil Palm Shell Concrete (OPSC) has hindered its development. This study aims to enhance the mechanical properties and flexural behaviours of OPSC by the addition of steel fibres of up to 3% by volume, to produce oil palm shell fibre-reinforced concrete (OPSFRC). The experimental results showed that the steel fibres significantly enhanced the mechanical properties of OPSFRC. The highest compressive strength, splitting tensile and flexural strengths of 55, 11.0 and 18.5 MPa, respectively, were achieved in the OPSFRC mix reinforced with 3% steel fibres. In addition, the flexural beam testing on OPSFRC beams with 3% steel fibres showed that the steel fibre reinforcement up to 3% produced notable increments in the moment capacity and crack resistance of OPSFRC beams, but accompanied by reduction in the ductility.
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Dobosy, Ádám, Marcell Gáspár, and János Lukács. "The Influence of Mismatch Effect on the High Cycle Fatigue Resistance of High Strength Steel Welded Joints." Advanced Materials Research 1146 (April 2018): 73–83. http://dx.doi.org/10.4028/www.scientific.net/amr.1146.73.
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The objective of this article is to present the newest results of our research work related to the high cycle fatigue resistance of advanced high strength steels. In order to determine and compare the fatigue resistance, high cycle fatigue (HCF) tests were performed on two strength categories (S690 and S960) of high strength steels including quenched and tempered (Q+T) and thermomechanical (TM) types. During the HCF tests base materials and their welded joints were investigated at different mismatch conditions (matching, undermatching, overmatching). Measured and analysed data about base materials and welded joints were compared and discussed. Statistical approach was applied during the preparation and the evaluation of the investigations, which increased their reliability. The parameters of the HCF design curves were calculated based on the Japanese testing method (JSME S 002-1981) which uses 14 specimens. During the evaluation the results were compared with each other and with literary data. According to the presented examinations the HCF resistance of the base materials is more advantageous than the welded joints. The TM steel indicated better fatigue resistance than the quenched and tempered one of the same category. The matching problem had influence on the HCF resistance of high strength steels, depending on the strength category and the steel type.
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Durães, M., and Nuno Peixinho. "Dynamic Material Properties of Stainless Steel and Multiphase High Strength Steels." Materials Science Forum 587-588 (June 2008): 941–45. http://dx.doi.org/10.4028/www.scientific.net/msf.587-588.941.
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This work presents results of tensile testing of H400 stainless steel, DP600 and TRIP600 at different strain rates. Mechanical properties were determined from tensile test using flat sheet specimens and recurring to different test techniques: servo-hydraulic machine and a tensile-loading Hopkinson bar. The test results were used to compare different mechanical properties of the tested steels and to validate constitutive equations intended to provide a mathematical description of strain rate dependence, namely the Cowper-Symonds equation. Following previous research work in dynamic material proprieties of multiphase and stainless steel grades, the energy absorption in quasi-static crushing of thin walled section made of the tested materials was subsequently investigated. Crush tests were performed in top-hat and hexagonal section tubes manufactured using laser welding. The experimental results were compared in order to assess the efficiency of the different steel grades for energy absorption.
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da Silva, Érika Aparecida, and Marcelo dos Santos Pereira. "Comparison of the Microstructural Effects between the BH Steel Obtained from Heat Treatment and the IF Steel of High Strength Concerning the Springback Effect." Materials Science Forum 805 (September 2014): 215–20. http://dx.doi.org/10.4028/www.scientific.net/msf.805.215.
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This work aimed to obtain microstructural changes due to the springback effect in order to compare two conventional high strength steels: the interstitial free steel (IF) and the bake hardening steel (BH). The mechanical characterization of the springback effect was performed by a mechanical forming testing called as the three-point air bending. The geometric changes resulting from the forming process were measured by calculating the aspect ratio. The results show that the BH steel suffers a greater springback effect rate than the IF steel due to the greater mechanical strength of the BH steel, and to the variation of this steel’s aspect ratio, depending on the combination of elongation and mechanical strength. It was concluded that the heat treatment performed on the BH steel increased the mechanical strength of the material without losing its formability.
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Drobne, Matej, Peter Göncz, and Srečko Glodež. "High Cycle Fatigue Parameters of High Chromium Steel." Key Engineering Materials 488-489 (September 2011): 299–302. http://dx.doi.org/10.4028/www.scientific.net/kem.488-489.299.
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The determination of monotonic mechanical properties and high cycle fatigue parameters of high chromium steel (HCS) is presented. The monotonic mechanical properties (ultimate compressive and ultimate tensile strength) are determined using standardized testing procedures according to DIN 50125 standard. The high cycle fatigue parameters are determined using uniaxial fatigue test where the tests specimens are loaded with pure pulsating compression load (load ratio R=0 in compression) at different load levels. Therefore, a typical S-N curve and appropriate fatigue parameters (fatigue strength coefficient sf’ and fatigue strength exponent b) are determined. The experimental results determined in this study can serve as a basis for the determination of service life of rolls using stress-life approach. However, a few guidelines for the further research work considering increased temperatures and multiaxial fatigue are given in the conclusions of this study.
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Ebo-Quansah, Ignatius, Ahmed H. Hassanin, Tadaharu Adachi, and Mohsen A. Hassan. "Ballistic Testing Simulation of Ultra-High Strength Steel Water Layer Sandwich Structure." Materials Science Forum 1069 (August 31, 2022): 23–29. http://dx.doi.org/10.4028/p-79ur58.
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In designing materials to resist impact and penetrations, numerical simulation offers effective means to ascertain impact mechanism close to practical experimental procedures. This work presents penetration characteristics of water as an inter-layer between ultra-high strength steel sandwich structure. Residual velocities for both monolithic and sandwiched structures have been investigated. In the case of the monolithic structure, good agreement was found between experimental and simulation results in reducing projectile initial velocity of 854 m/s to obtained residual velocities of 487 m/s and 460 m/s respectively. Energy dissipation capability of water as an interlayer has also been investigated. Water, proving very effective in decreasing projectile velocity of 390 m/s to zero in a 2 mm steel-2 mm water – 2 mm steel sandwich system. Numerical simulation has been carried out using Ansys Explicit / Autodyn – a commercial software based on finite element method which is very effective in solving non-linear problems. Lagrange elements were used in the discretization of both the water and steel media.
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Krbata, Michal, Maros Eckert, Jozef Majerik, and Igor Barenyi. "Wear Behaviour of High Strength Tool Steel 90MnCrV8 in Contact with Si3N4." Metals 10, no. 6 (June 6, 2020): 756. http://dx.doi.org/10.3390/met10060756.
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Tool steels are used in technological processes of forming and cutting and as cutting tools due to their good mechanical properties. During their working cycle, steels are exposed to several aggressive conditions, such as thermal stress, fatigue and various forms of wear. In this article, the selected 90MnCrV8 tool steel slid against the Si3N4 testing ceramic bearing ball. All measurements were performed on a universal tribometric device UMT TriboLab (TA Instruments, New Castle, Delaware, USA) under dry conditions. The main objective of the performed experiments was to analyse the frictional properties and compare the wear of the 90MnCrV8 tested tool steel in contact with the 6.35 mm diameter ceramic ball at different friction speeds. In this measurement evaluation, the authors of the article mainly focused on the influence of the magnitude of the peripheral speed on the wear change and coefficient of friction. Further analysis was focused on the change of surface roughness of the counterpart ceramic balls as well as of the tested tool steel samples. Experimental results show the fact that tested tool steels, which can also be considered as high strength steels, can also successfully represent wear-resistant steels. It has been shown experimentally that increasing the friction speed also leads to significant degradation of the material on the sample surface. Finally, the effect of hardness on wear has also been experimentally demonstrated. The Si3N4 ceramic ball with its high strength also behaves like an abrasive, thus increasing the wear rate on the experimental tool steel samples.
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Klein, M., H. Spindler, A. Luger, R. Rauch, P. Stiaszny, and M. Eigelsberger. "Thermomechanically Hot Rolled High and Ultra High Strength Steel Grades - Processing, Properties and Application." Materials Science Forum 500-501 (November 2005): 543–50. http://dx.doi.org/10.4028/www.scientific.net/msf.500-501.543.
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In all application fields for hot rolled strip products for direct processing, e.g. construction and engineering but also crane and truck industry, there is a strong customers demand for grades with increased strength levels and well balanced formability. At voestalpine Stahl GmbH these requirements were met with the development of the high strength microalloyed steel grade ALFORM700M and the ultra high strength steel grade ALFORM900M with a minimum yield strength (YS) of 700 MPa and 900 MPa, respectively. In the present paper investigations on the steel grades ALFORM700M and ALFORM900M are introduced. To explain the evolution of the obtained complex microstructures consisting of bainitic ferrite, bainite and martensite alloy design and industrial production process is discussed on the base of dilatometric experiments and TEM investigations. The formation of precipitates is studied by using a numerical model, chemical methods and mechanical testing after heat treatment. Mechanical and mechanic-technological properties of the two steel grades are compared. Furthermore, some processing aspects as weldability an bending behaviour are highlighted. Finally, some typical applications for this high and ultra high strength steel grades are presented.
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Sadek, Mohamed, Jens Bergström, Nils Hallbäck, and Christer Burman. "20 kHz 3-point bending fatigue of automotive steels." MATEC Web of Conferences 165 (2018): 22020. http://dx.doi.org/10.1051/matecconf/201816522020.
Full textAbstract:
The 20 kHz load frequency enables fatigue tests for very high cycle fatigue life, 109-1013 cycles, within conveniently short time. In automotive applications, many components are subjected to flexural loading and hence bending fatigue is an important test mode. Ultrasound fatigue test instruments have been used successfully in several assessments of fatigue strength and more commonly in uniaxial loading. Here, a 3-point bending fatigue test rig operating in resonance at 20 kHz load frequency has been designed to test plane specimens at R=0.1 loading. The test rig design and stress calculations are presented. Testing for fatigue strength was conducted using the staircase method with 15 specimens of each steel grade, specimens reaching 108 cycles were considered run-outs giving fatigue strength at 108 cycles. Additional 15 specimens of each grade were tested for S-N curves with the upper limit above 109 cycles. Two different common automotive steels, 38MnSiV5, a micro-alloyed ferritic-pearlitic steel, and 16MnCr5, a carburizing martensitic steel, were tested. The fatigue strengths achieved from the staircase testing are 340 and 419 MPa stress amplitudes for the 38MnSiV5 and 16MnCr5 steels, respectively. The S-N curves of the steels appear to be quite flat in the tested life range 107 – 109.
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Lipiński, Tomasz. "Effect of Non-Metallic Inclusions on the Fatigue Strength Coefficient of High-Purity Constructional Steel Heated in Industrial Conditions." Applied Sciences 12, no. 18 (September 16, 2022): 9292. http://dx.doi.org/10.3390/app12189292.
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Steel fatigue strength testing is a process that requires large amounts of time, resources and appropriate equipment. The industry seeks to replace cumbersome destructive testing with non-destructive testing. Coefficients were developed that allow the comparison of the parameters of material properties. One such factor is the fatigue strength coefficient, which allows the estimate of fatigue strength using the known hardness of a given material. The fatigue strength factor should be developed for conditions that are as close to the industrial conditions as possible. It should take into account not only the expected properties of the material and the technological process but also its imperfections, e.g., the share of non-metallic inclusions and the steel microstructure. This paper presents the results of research on the influence of non-metallic inclusions on the fatigue strength coefficient of structural steel subjected to rotary bending. The tests were carried out in seven heats obtained in a 140-ton electric furnace under industrial conditions. The steel was desulfurized and refined with argon. The paper presents the bending fatigue strength of hardened and tempered steel at temperatures from 200 °C to 600 °C as a function of the relative volume of inclusions. The non-metallic inclusions occurring in steel were determined qualitatively and quantitatively. The derived fatigue strength coefficient, k, for different tempering temperatures makes it possible to estimate the fatigue strength of the analyzed steel as a function of its hardness for various microstructures represented by the respective tempering temperatures.
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Hofmann, Harald, Thomas Heller, and Sascha Sikora. "Design of Modern Steels for Automotive Application." Materials Science Forum 638-642 (January 2010): 3111–16. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.3111.
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Advanced high-strength steels offer a great potential for the further development of automobile bodies-in-white due to their combined mechanical properties of high formability and strength. New types of grades – multi-phase steels, superductile steels and density reduced steels – are under development at ThyssenKrupp Steel with tensile strength levels of up to 1000 MPa in combination with excellent formability for the high demands of cold formed structural automobile components. New forming technologies at increased temperatures – hot forming, semi-hot forming and superplastic forming - enable the processing of complex parts with extreme high strength. ThyssenKrupp Steel identifies potential future steels and technology concepts by technology monitoring and evaluates their potential for future applications in pre-development projects. University research institutions are significantly involved in this essential future oriented challenge. Seminal concepts are being implemented together with automotive manufactures by simultaneous engineering processes with coordinated phases of production and testing.
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Kvackaj, Tibor, Jana Bidulská, and Róbert Bidulský. "Overview of HSS Steel Grades Development and Study of Reheating Condition Effects on Austenite Grain Size Changes." Materials 14, no. 8 (April 15, 2021): 1988. http://dx.doi.org/10.3390/ma14081988.
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This review paper concerns the development of the chemical compositions and controlled processes of rolling and cooling steels to increase their mechanical properties and reduce weight and production costs. The paper analyzes the basic differences among high-strength steel (HSS), advanced high-strength steel (AHSS) and ultra-high-strength steel (UHSS) depending on differences in their final microstructural components, chemical composition, alloying elements and strengthening contributions to determine strength and mechanical properties. HSS is characterized by a final single-phase structure with reduced perlite content, while AHSS has a final structure of two-phase to multiphase. UHSS is characterized by a single-phase or multiphase structure. The yield strength of the steels have the following value intervals: HSS, 180–550 MPa; AHSS, 260–900 MPa; UHSS, 600–960 MPa. In addition to strength properties, the ductility of these steel grades is also an important parameter. AHSS steel has the best ductility, followed by HSS and UHSS. Within the HSS steel group, high-strength low-alloy (HSLA) steel represents a special subgroup characterized by the use of microalloying elements for special strength and plastic properties. An important parameter determining the strength properties of these steels is the grain-size diameter of the final structure, which depends on the processing conditions of the previous austenitic structure. The influence of reheating temperatures (TReh) and the holding time at the reheating temperature (tReh) of C–Mn–Nb–V HSLA steel was investigated in detail. Mathematical equations describing changes in the diameter of austenite grain size (dγ), depending on reheating temperature and holding time, were derived by the authors. The coordinates of the point where normal grain growth turned abnormal was determined. These coordinates for testing steel are the reheating conditions TReh = 1060 °C, tReh = 1800 s at the diameter of austenite grain size dγ = 100 μm.
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Li, Yadong, Rongchun Wan, Xing Wang, Hui Zhao, and Xun Gong. "Effects of Nb on Elevated-Temperature Properties of Fire-Resistant Steel." Crystals 12, no. 12 (December 16, 2022): 1842. http://dx.doi.org/10.3390/cryst12121842.
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Objective: Two kinds of fire-resistant steel with different Nb content (Nb-free and 0.03 wt.%) were prepared for studying the effects of Nb addition on the elevated-temperature strength of fire-resistant steel. Methods: Two stages of heat treatment were carried out on the steels to obtain different microstructures. Typical microstructures, dislocation, and precipitates morphology of steels were observed by SEM and TEM. The dislocation density was calculated by the X-ray data from the microstructures. High temperature and room temperature mechanical properties of steels were determined by tensile testing. Results: The results showed that the YS of N2-HR steel (addition of 0.03 wt.% Nb) at RT and 600 °C was higher than N1-HR steel (Nb-free) by about 81 and 30 MPa, respectively. This indicates that Nb is an alloying element as effective as Mo in increasing the elevated-temperature strength of fire-resistant steel. The dominant strengthening mechanisms of Nb addition on elevated-temperature yield strength are precipitation strengthening and bainite strengthening. Conclusions: Theoretical analysis shows that there are two precipitation strengthening stages in fire-resistant steel: (1) increasing dislocation density during hot rolling, and (2) blocking dislocation movement and recovery in tensile testing. The results also show that the effect of fine grain strengthening is not obvious at high temperature, but is obvious at room temperature.
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Bhat, Sunil, and Vijay G. Ukadgaonker. "Fatigue Life Enhancement of Welded Steel-Steel Composite during Crack Growth from Weak to Strong Steel: An Experimental Validation." Key Engineering Materials 417-418 (October 2009): 825–28. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.825.
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Strength mismatch effect across weld interfaces, generated by welding weak and strong steels, influences fatigue and fracture properties of a welded bimetallic composite. Advancing fatigue crack tip in weak parent steel is shielded from the remote load when it reaches near the interface of ultra strong weld steel. Entry of crack tip plasticity into weld steel induces load transfer towards weld which dips crack growth rates thereby enhancing the fatigue life of the composite. A computational model for fatigue life prediction of strength mismatched welded composite under K dominant conditions is validated by experimental work in this paper. Notched bimetallic compact tension specimens, prepared by electron beam welding of weak alloy and strong maraging steels, are subjected to fatigue testing in high cycle regime.
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Deev, A. A., G. Yu Kalinin, and K. E. Sadkin. "Promising use of high-strength nitrogen steel for the ice belt of marine machinery operating in the extreme arctic conditions." Voprosy Materialovedeniya, no. 3(107) (December 4, 2021): 229–37. http://dx.doi.org/10.22349/1994-6716-2021-107-3-229-237.
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This article shows the possibility of using high-strength nitrogen-containing corrosion-resistant steel grade 04Kh20N6G11M2AFB for the construction of critical elements and units of marine equipment operating at low temperatures, including the Arctic. The advantages of nitrogen-containing steel over clad steel AB2 + 08Kh18N10T always used in shipbuilding and welded steel of F500W category are considered. According to the assessment of testing of homogeneous nitrogen steel sheets, the level of its physical and mechanical properties exceeds the analogous parameters of traditional AB2 + 08Kh18N10T steels in a wide temperature range, up to –90°C.
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Kong, Zhengyi, Ya Jin, Shaozheng Hong, Quanwei Liu, Quang-Viet Vu, and Seung-Eock Kim. "Degradation Behavior of the Preload Force of High-Strength Bolts after Corrosion." Buildings 12, no. 12 (December 2, 2022): 2122. http://dx.doi.org/10.3390/buildings12122122.
Full textAbstract:
Corrosion significantly affects the structural behavior of members in a connection (i.e., the thickness of steel plates, the preload force of bolts, and the friction factor of steel plates). Safety assessment of corroded steel frames (i.e., beam-to-column connection, beams, or columns) has been a major concern in engineering. In this work, an experiment of accelerated corrosion testing is carried out to obtain corroded specimens connected with high-strength bolts, and the preload force of high-strength bolts (PF-HSB) is monitored throughout the whole stage of the corrosion testing. Before the corrosion testing, the PF-HSB caused by the stress relaxation is also recorded. The PF-HSB decreases rapidly in the first five hours after the final screwing of bolts and it keeps stable after 100 h. The PF-HSB is seriously affected by corrosion, which decreases by 30.0% of the original preload force when the corrosion rate of steel plate reaches 3.5%. A finite element method for predicting the PF-HSB after corrosion is proposed. An estimation model for the PF-HSB considering the stress relaxation is established. A degradation model for predicting the PF-HSB after corrosion is also suggested, and is in good agreement with experimental data. The results of this research are of great significance for the safety assessment of in-service steel structures.
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Luo, Xiao Yu, Yu Zhang, Zi Jian Wang, and Yi Sheng Zhang. "Non-Destructive Testing Device for Hot Forming High Strength Steel Parts Based on Barkhausen Noise." Applied Mechanics and Materials 423-426 (September 2013): 2555–58. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.2555.
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In order to realize the nondestructive testing for hot forming high strength steel parts, a hardness testing device based on Magnetic Barkhausen Noise (MBN) was developed. By measuring MBN of standardized blocks of Rockwell hardness and extracting feature values of the noise, a fitted curve between hardness and MBN peak was calibrated. Good linearity was found between hardness and MBN peak within high hardness range 35~60HRC. The testing device was proved to be high-precision and stable by measuring the practical high strength steel parts.
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Wang, Jiantao, and Qing Sun. "Cyclic testing of Q690 circular high-strength concrete-filled thin-walled steel tubular columns." Advances in Structural Engineering 22, no. 2 (August 14, 2018): 444–58. http://dx.doi.org/10.1177/1369433218790769.
Full textAbstract:
Under seismic action, the severe damage in critical regions of structures could be ascribed to the cumulative damage caused by cyclic loading. This article describes an investigation of the hysteresis behaviour of Q690 circular high-strength concrete-filled thin-walled steel tubular columns with out-of-code diameter-to-thickness ratios. A total of eight specimens were tested under constant axial compression and cyclic lateral loading. The study results of phase I testing consisting of a benchmark test were summarized to examine the seismic behaviour under standard loading, and those of the phase II testing that considered different fatigue loading modes and different concrete strengths were summarized to investigate the low-cycle fatigue behaviour. The load–displacement hysteretic curves, energy dissipation, strength and stiffness degradation were discussed in detail. A simplified method was proposed to predict the low-cycle fatigue life, which can be applied in the damage-based seismic design of circular concrete-filled steel tubular structures.
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Xiong, Jun, Yue Mao, and Huihui Zhao. "Additive manufacturing of high-strength weathering steel parts fabricated by gas tungsten arc: Microstructure and mechanical properties." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 233, no. 11 (February 6, 2019): 2127–37. http://dx.doi.org/10.1177/0954405419828590.
Full textAbstract:
This study focuses on microstructure and mechanical properties as a function of location in additively manufactured high-strength weathering steel components using gas tungsten arc as the heat source. Variations of microstructure and mechanical properties in various locations are presented and analysed. The as-deposited high-strength weathering steel is composed of columnar grain morphology with proeutectoid ferrite, acicular ferrite, side plate ferrite and a small amount of pearlite microstructure in the top region, equiaxed grains with ferrite and pearlite in the middle region, and columnar grains in the near-substrate region with the microstructure similar to that in the top region. There exist obvious layer bands in the middle region, and the forming mechanism of the bands is addressed. Microhardness measurement and tensile strength testing indicate obvious changes in different regions, depending on location and direction of testing specimens. The microhardness in the middle region is inferior to that in both near-substrate and top regions. The ultimate tensile strengths in the travel and deposition height directions are approximately 553 and 506 MPa, respectively. Different locations exhibit heterogeneous tensile strength and elongation due to various microstructures and boundaries. The results indicate the feasibility to fabricate high-strength weathering steel components with good tensile properties using gas tungsten arc–based additive manufacturing.
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Troiano, Edward, Anthony P. Parker, John Underwood, and Charles Mossey. "Experimental Data, Numerical Fit and Fatigue Life Calculations Relating to the Bauschinger Effect in High Strength Armament Steels." Journal of Pressure Vessel Technology 125, no. 3 (August 1, 2003): 330–34. http://dx.doi.org/10.1115/1.1593072.
Full textAbstract:
The uniaxial Bauschinger effect has been evaluated in several high strength steels being considered for armament application. The steels investigated include ASTM A723 (1130 and 1330 MPa), PH 13-8 Mo stainless steel (1380 MPa), PH 13-8 Mo super tough stainless steel (1355 MPa), and HY 180 (1180MPa). Tests were conducted at plastic strains up to 3.5%. Results of testing show a progressive decrease in Bauschinger effect up to plastic strains of approximately 1% (for all materials investigated), after which there is little further decrease in the Bauschinger effect. Several key features were discovered during testing. First, all of the materials tested exhibited a changing modulus, where the elastic modulus on unloading after tensile plastic straining is consistently lower than that observed in the original loading of the specimens. The amount of modulus reduction is dependent upon the material tested, and larger reductions are observed with increasing amounts of tensile plastic strain. Prior work by Milligan reported Bauschinger effect factor β for a modified 4340 steel (old vintage A723 steel), which compares well with the present work. However, his results failed to mention any observations about a modulus reduction. The second observation was the expected strength reduction where a reduced compressive strength is observed as a result of prior tensile plastic straining. Numerical curve fits used to calculate residual stresses, which take into account both the modulus reduction and strength reduction are presented for all materials. Fatigue life calculations, utilizing the numerical curve fits, show good agreement with full size A723 laboratory fatigue test results.
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Singh, Nilamber Kumar, Ezio Cadoni, Maloy K. Singha, and Narinder K. Gupta. "Mechanical Behavior of Advanced High Strength Steel at High Strain Rates." Applied Mechanics and Materials 82 (July 2011): 178–83. http://dx.doi.org/10.4028/www.scientific.net/amm.82.178.
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This paper presents the mechanical behavior of advanced high strength steel, Dual Phase 1200 steel (DP1200) at high strain rates (250s-1- 750s-1) under tensile loading. The mechanical behavior of materials depends on the loading rates. The accurate knowledge of the mechanical behavior of materials at high strain rates is essential in order to improve the safety against crash, impacts and blast loads. High strain rate experiments are performed on modified Hopkinson bar (MHB) apparatus; however, some quasi-static (0.001s-1) tests are also conducted on electromechanical universal testing machine at tensile loads. Based on the experimental results, the material parameters of the existing Cowper-Symonds and Johnson-Cook models are determined. These models fit the experimental data well and hence can be recommended for the numerical simulation of the problems involving this material at high strain rates.
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Yi, San Zhou, Yong Su, Bin Wan, and Ran Wei. "Study on Preparation of a High-Strength and High-Toughness Low-Alloy Steel for Cross Member of Forklift Mask." Advanced Materials Research 1002 (August 2014): 61–64. http://dx.doi.org/10.4028/www.scientific.net/amr.1002.61.
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According to the performance requirements of the cross member for forklift mask, a new type of high-strength and high-toughness low-alloy steel is designed by multi-element alloying. Through orthogonal testing, the optimized heat treatment technique is obtained. After being normalized at 870°C, quenched at 910°C and tempered at 600°C, the steel produces tempered sorbite which makes the steel the optimum combination of tensile strength Rm and percentage elongation δ (Rm≥750MPa, δ≥20%). Then, the investment casting process is determined. The casting with excellent comprehensive properties is determined.
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Kadam, Shriganesh Shantikumar, V. V. Karjinni, and C. S. Jarali. "Prediction of Fiber Reinforced Concrete Strength Properties by Micromechanics Method." Civil Engineering Journal 5, no. 1 (January 27, 2019): 200. http://dx.doi.org/10.28991/cej-2019-03091238.
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High strength steel fiber reinforced concrete (HSSFRC) was prepared with the help of steel fiber. 0.5%, 1.0%, and 1.5% steel fiber by volume of concrete specimen was used in concrete for present investigation. Compressive strength test and flexural strength test were conducted on cubical and prismatic specimens respectively.The main objective of the research work is to validate the experimental out comes by a numerical technique such as micromechanics approach. A high strength steel fiber reinforced concrete whose compressive strength is greater than 60 N/mm2 was prepared and tested on concrete testing machine. Flexural strength test was conducted on universal testing machine to evaluate the bending properties of concrete. It was observed that with increase in the percentage of steel fiber volume the compressive strength and flexural strength also increases. However the workability of concrete declines and concrete is no longer in working condition. Micromechanics technique helps to predict the strength properties which save time required for casting and such technique was found to be beneficial.
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Bao, Jun, Hong Sheng Liu, Zhong Wen Xing, Bao Yu Song, and Yu Ying Yang. "Flow Behavior of Ultra-High Strength Boron Steel at Elevated Temperature." Materials Science Forum 704-705 (December 2011): 191–95. http://dx.doi.org/10.4028/www.scientific.net/msf.704-705.191.
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Ultra-high strength boron steel is widely used in a new hot stamping technology which is hot formed and die quenched simultaneously in order to obtain stamping parts with 1500MPa tensile strength or higher. Tensile experiments were carried out with ultra-high strength boron steel in a range of temperature 500°C~860°Cand strain rate 0.01/s~1/s with the thermal simulation testing machine Gleeble 3800, and the stress-strain curves were obtained. The influences of the deformation temperature and strain rate on the stress-strain curves were analyzed. The results show that hot behavior at elevated temperature of ultra-high strength boron steel consists of strain hardening and dynamic recovery mechanism, which can be accurately described by the mathematic model. Keywords: Ultra-high strength boron steel, hot stamping, hot flow behavior
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Ma, Fei, Yong Li, and Zhi Ming Song. "Jet Performance Testing of High-Pressure Waterjet Descaling Nozzles." Advanced Materials Research 314-316 (August 2011): 2408–13. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.2408.
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Descaling nozzles, generator of high-speed waterjets, are key components in high-pressure waterjet descaling system. Jet performance of the nozzle has great effect on hot-rolling steel billet descaling. Most domestic manufactures provide nozzle structural data and impact force scale with rated pressure, such as orifice diameter, injecting angle and scattering angle. However, jet distribution shape and jet impact force distribution and strength, which are major parameters affecting steel billet descaling quality, are not available from manufactures. A jet performance test device for nozzles was developed in this paper. Two and three dimensional graphs of jet impact force distribution with different standoff distance were obtained. Shape of jet distribution area was indicated in two dimensional graphs while jet impact strength and distribution were given in three dimensional graphs, providing evidence for jet performance judgement. Injecting angle, scattering angle and flow volume coefficient could also be measured with the device. A fan-type nozzle used for scale removal was tested. Results obtained were presented and discussed.
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Mentl, Vaclav, and Josef Bystricky. "Compression Tests of High Strength Steels." Advanced Materials Research 59 (December 2008): 293–98. http://dx.doi.org/10.4028/www.scientific.net/amr.59.293.
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Mathematical modelling and virtual testing of components and structures represent a useful and economic tool for design and safety assessment. The basic mechanical properties which can be found in material standards are not relevant in cases where the real service conditions differ from those applied during standardised testing. Thus e.g. mechanical behaviour at higher strain rates can be interesting for the car components when the simulation of crash situations is used during structure development. The dynamic compression tests are usually performed by means of drop towers, by means of high speed hydraulic testing machines or Hopkinson bar method. At the Mechanical Testing Laboratory of the SKODA Research Inst. in Pilsen, Czech Republic, an instrumentation of Charpy pendulum testing machine was realised in order that it was possible to perfom dynamic compression tests, [1], and the compatibility of obtained results in comparison with traditional impact compression tests was verified within the round–robin carried out by TC5 ESIS Sub-Committee on “Mechanical Testing at Intermediate Strain Rates“, [2]. A new striking tup and load measurement system were designed and callibrated. At the same time, a new software was developed which makes it possible to evaluate the test force-deformation record. The goal of this study was 1. to check the possibility of compression testing of high strength materilas by mens of Charpy pendulum, and 2. to study the strain rate influence on basic mechanical properties.
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Wang, Na, Li Yang Xie, Wan Li Song, and Chong Du Cho. "Residual Strength Degradation Model for Low-Alloy Steel in High Cycle Fatigue Load." Advanced Materials Research 118-120 (June 2010): 474–78. http://dx.doi.org/10.4028/www.scientific.net/amr.118-120.474.
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Residual strength degradation of 35CrMo alloy steel is investigated experimentally and theoretically in this paper. The experimental results were obtained by high-frequency fatigue testing machine and electro-hydraulic servo testing machine at room temperature. The experimental results showed the true tensile strength under static load and the residual strength under different cycle ratio, respectively. An exponential degradation model was proposed relating the initial strength, residual strength to the applied fatigue cycles and the constant amplitude stress. The residual strength distribution was described using three-parameter Weibull probability density function. The mathematical software MatLab was used for parameter estimation. Finally, the distribution function and failure probability density function of the residual strength was received, which was significant in fatigue reliability.
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Rydval, Milan, Jiří Kolísko, Petr Huňka, and Tomáš Mandlík. "Experimental Testing of Layered UHPFRC Beams." Advanced Materials Research 1000 (August 2014): 346–51. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.346.
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Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) is fine-grained cement-based material characterized by high compressive strength (exceeding 150 MPa) and high modulus of rupture (over 15 MPa). The results of strengths depend on the size of the tested element, the loading rate and the boundary conditions during a testing. This type of material is used in a lot of countries (e.g. Germany, France, the USA, Japan, Austria, and the Netherlands) but it is not commonly used in the Czech Republic. The bridge over R10 road from Prague to Mlada Boleslav near Benatky nad Jizerou was the first structure where UHPFRC materials were used for lost shuttering slabs. Due to inhomogeneity of the steel fiber distribution the maximum attained force ranged between 9.6 kN and 25.7 kN for different lost shuttering slabs. The amount of steel fibers was very low at a tension zone at slabs with the lower load-bearing capacity. Steel fibers in these slabs were at the bottom of the formwork. The inhomogeneity of the steel fiber distribution was the foundation for producing of functionally layered beams with controlled inhomogeneity due to the mixtures with different fibers volumes. The results and behaviors of the layered beams and the homogeneous beams are presented in this paper.
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Minote, Toru, Yoshimasa Funakawa, Naoko Saito, Mitsugi Fukahori, Hiroshi Hamasaki, and Fusahito Yoshida. "Mechanical Behavior of 980MPa NANOHITENTM at Elevated Temperatures and its Effect on Springback in Warm Forming." Key Engineering Materials 611-612 (May 2014): 11–18. http://dx.doi.org/10.4028/www.scientific.net/kem.611-612.11.
Full textAbstract:
High tensile strength steel sheets have large springback after being formend at room temperature. Warm forming can be a solution to reduce springback of high tensile strength steel parts. NANOHITENTM is a high strength ferritic steel precipitation-strengthened by nanometer-sized carbides developed by JFE Steel Corporation. Tensile strength of the steel at room temperature does not change before and after deformation at elevated temperatures up to 873K since the carbides in the steel are stable at high temperatures less than 973K. Therefore, the steel is suitable for warm forming. Springback of 980MPa NANOHITENTM parts warm formed at 873K is the same level of that of cold formed conventional 590MPa steel parts. In this study, two kinds of material testing at room temperature and at elevated temperatures between 573K and 937K were performed to understand the mechanical behavior of 980MPa NANOHITENTM: uniaxial tensile tests and bending tests. The steels flow stress depends on not only material temperature but also strain rate in uniaxial tensile tests. After a bending test, the specimen shows springback measured by the change of an angle between the two sides. Stress relaxation happens while a test specimen is held at the bottom dead point after bending. And the stress relaxation could be used to reduce springback of warm formed parts.
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Du, Wen Wen, Qian Wang, Lin Wang, and Ding Wang. "Effect of Isothermal Heat Treatment on Dynamic Properties of a High Strength Steel." Applied Mechanics and Materials 782 (August 2015): 124–29. http://dx.doi.org/10.4028/www.scientific.net/amm.782.124.
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The high strength steel which was subjected with isothermal heat treatment at three different temperatures, namely 330°C, 350°Cand 380°C after different quenching temperature namely 880°C and 900°C,was investigated in this paper. The quasi-static and dynamic mechanical properties of new high strength steel was tested by universal material testing machine and Split Hopkinson Pressure Bar (SHPB). Experimental results have showed that the yield strength and tensile strength of the steel reach 1100MPa and 1400MPa respectively. Hardness, yield strength and toughness are found to decrease with the consequently increasing of isothermal temperature under the same quenching temperature. The compression properties of the steel under quenching temperature of 880°C are higher than that of 900°C with the same isothermal temperature. It can be found that the steel which is subjected with isothermal heat treatment show strain rate sensitivity under high velocity impact. When isothermal temperature is set 380°C, the steel exhibits the most obvious strain rate hardening effect.
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Kharchenko, Valeriy, Оleg Каtоk, Roman Kravchuk, Andriy Kravchuk, and Alyona Sereda. "An experimental technique for studying the behavior of high-strength steel under static punching." Scientific journal of the Ternopil national technical university 103, no. 3 (2021): 117–22. http://dx.doi.org/10.33108/visnyk_tntu2021.03.117.
Full textAbstract:
High-strength steels are widely used in the defense and civil industries. During operation, high-strength and armored steels are subjected to extreme static and dynamic loads. Material specimens or full-scale structures testing at such loads is a very complex and expensive process. Therefore, numerical calculation methods are commonly used to assess their strength. To determine the parameters of these models as an express method, it is reasonable to use tests that are similar in nature of the loading, deformation, and failure to full-scale or standard ones, but which are cheaper and easier to perform in the laboratory conditions. One of the key properties of high-strength steels is their resistance to penetration by various types of armor-piercing strikers. To simplify the testing procedure and minimize materials consumption, static and dynamic punching methods have been developed. A set of experimental and numerical investigations on the deformation of various specimens from high-strength steels has been made under static and dynamic load conditions, in particular, plate specimens punching (punches of different shapes) by the G. S. Pisarenko Institute for Problems of Strength of the NAS of Ukraine. This paper presents the experimental procedure and equipment for the investigation of the materials’ behavior under static punching. High-strength steel plate specimens have been tested on an upgraded servohydraulic machine Instron 8802 using three types of punches: flat, spherical, and conical. It is established that the diagram describing the spherical punching is the most informative, while the diagram showing the conical punching is less informative. The nature of the specimen fracture is consistent with the results of field tests in the barrier penetration by armor-piercing strikers. The obtained results are in good agreement with the known literature data and can be used to validate the results obtained by numerical simulations.
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MARTINEZ KRAHMER, DANIEL OSVALDO, GERMAN ABATE, ALEJANDRO SIMONCELLI, NAZARENO ANTUNEZ, VITALIY MARTYNENKO, DANIELA PEREZ, and LUIS NORBERTO LOPEZ DE LA CALLE MARCAIDE. "GRID LASER MARKING INFLUENCE ON HIGH-STRENGTH STEELS TENSILE TEST BEHAVIOR." DYNA 96, no. 1 (March 1, 2021): 173–78. http://dx.doi.org/10.6036/9869.
Full textAbstract:
Automotive car companies are using AHSS (advanced high strength steels) over the last 20 years, to reduce vehicle weight and improve safety. The new steels can achieve higher strength and good fatigue resistance, but some issues related to springback and low formability are also a big concern. Thus, companies need to extend their know-how regarding material behaviour, design rules and manufacturing processes. Therefore, materials characterization laboratories are working to obtain the new formability charts of the steels. The grid laser marking of test pieces is a recent approach. However, the marking process must accomplish three main aspects: indelibility during the tensile testing procedure, precision, and of course, it must not affect the mechanical properties of studied steels. This work is focused on the laser marking of test pieces, using Ytterbium fiber laser. A dual phase steel (JFE CA 1180) is studied. Process parameter are defined. Keywords: grid marking, laser, advanced high-strength steels, AHSS, formability diagrams, mechanical properties