The transformation induced plasticity (TRIP) steels effect occurs because of the martensitic transformation of retained austenite during plastic deformation,and it provides the steel with excellent strength and ductil...The transformation induced plasticity (TRIP) steels effect occurs because of the martensitic transformation of retained austenite during plastic deformation,and it provides the steel with excellent strength and ductility.While welding remains a vital part of auto body manufacturing,the weldability of TRIP steels is problematic,and this prevents its adoption for many applications in the automotive industry.This present work studies the effects of welding and post-weld heat treatment on the microstructure of TRIP steels.It is found that the microstructures of the fusion zone and the heat affected zone (HAZ) are changed after high-temperature heat treatment.Hardness tests revealed that fusion zone hardness decreased with increasing of temperatures in the post-weld heat treatment on the laser weld seam.The rolling performance of the welding seam and the seam of post-weld heat treatment were also studied.展开更多
The effect of intermetallic compounds on the heat resistance of transition joint was investigated. The experiment of post-weld heat treatment for the hot roll bonded titanium alloy-stainless steel joint using nickels ...The effect of intermetallic compounds on the heat resistance of transition joint was investigated. The experiment of post-weld heat treatment for the hot roll bonded titanium alloy-stainless steel joint using nickels interlayer was carried out, and the interface microstructure evolution due to heat treatment was presented. There was not found significant interdiffusion at stainless steel/nickel interface, when the specimens were heat treated in the temperature range of 600-800 °C for 10 and 30 min, while micro-cracks occurred at the stainless steel/nickel interface heat treated at 700 °C for 30 min. The thickness of intermetallic layers at nickel/titanium alloy interface increased at 600 °C, and micro-cracks occurred at 700 and 800 °C. The micro-cracks occurred between intermetallic layers or between intermetallic layer and nickel interlayer as well. The tensile strength of the transition joint decreased with the increase of heat treatment temperature or holding time.展开更多
High-boron steel is an important material used for thermal neutron shielding. The appropriate amount of added boron must be de- termined because excessive boron may deteriorate the steel＇s workability. A uniform micr...High-boron steel is an important material used for thermal neutron shielding. The appropriate amount of added boron must be de- termined because excessive boron may deteriorate the steel＇s workability. A uniform microstructure can be formed by adding titanium to boron steel. In this study, casting and hot rolling were used to fabricate laminated high-boron steel plates whose cores contained 2.25wt% boron and 0wt%-7.9wt% titanium. The effects of titanium content and hot-rolling and heat-treatment processes on the microstructure and properties of the laminated plates were studied. The results indicated that the optimum titanium content was 5.7wt% when the boron content was 2.25wt%, and that the best overall properties were obtained after heat treatment at 1100℃ for 4 h. The tensile strength, yield strength, and elongation at the specified temperature and holding time were as high as 526.88 MPa, 219.36 MPa, and 29%, respectively.展开更多
This paper reviews recent developments in the contin- uous processing of steels in Japan.The following items are discussed:continuous casting-direct rolling(CC-DR) process of hot-rolled strip:thermomechanical control ...This paper reviews recent developments in the contin- uous processing of steels in Japan.The following items are discussed:continuous casting-direct rolling(CC-DR) process of hot-rolled strip:thermomechanical control process(TMCP)of heavy plates:in—line heat treating pro- cess of rails:direct lead patenting(DLP)process of wire rods;and fully integrated processing line(FIPL)of cold-rolled strip.展开更多
为提高热轧态0Cr21A16合金板材的组织均匀性和塑性,以改善其高温性能及冷加工特性,分析研究了不同温度的热处理试验及组织性能。采用光学显微镜、X射线衍射仪、Gleeble高温热拉伸实验、扫描电镜和纳米压痕仪等研究了热处理前后0Cr21Al6...为提高热轧态0Cr21A16合金板材的组织均匀性和塑性,以改善其高温性能及冷加工特性,分析研究了不同温度的热处理试验及组织性能。采用光学显微镜、X射线衍射仪、Gleeble高温热拉伸实验、扫描电镜和纳米压痕仪等研究了热处理前后0Cr21Al6合金板材的显微组织和力学性能。结果表明,通过热处理的方式改善0Cr21Al6合金板材的组织均匀性,在960℃保温6 min 40 s后快速冷却,晶粒平均尺寸为42μm,整体的晶粒尺寸相对于940、980、1000、1020℃热处理后较为均匀、细小,硬度和塑性达到最佳匹配,断裂韧度KIC在960℃处理下达到最佳,拥有最佳的综合性能,可有效避免生产过程中材料的脆性断裂问题。另外Gleeble实验显示1000℃以上的热处理温度不再适合于热加工。展开更多
Heredity in the microstructure and mechanical properties of hot-rolled spring steel wire 60Si2MnA during heat treatment process was investigated comprehensively. The steel was isothermally transformed to obtain variou...Heredity in the microstructure and mechanical properties of hot-rolled spring steel wire 60Si2MnA during heat treatment process was investigated comprehensively. The steel was isothermally transformed to obtain various hot-rolled microstructure （pearlite fineness within the range of 140-510 nm） and mechanical properties, and followed by some quenching-tempering treatment. Afterwards, microstructure was characterized by optical microscopy, scanning electron microscopy and quantitative metallography, and mechanical properties were determined by tensile test. The results indicated that the hot-rolled microstructure with a coarsen pearlite structure had been changed after reheating, to a austenite microstructure with bigger and more uneven grain size, and finally to a coarsen tempered microstructure. And the average austenite grain size and standard deviation of its distribution in quenched microstructure were observed to depend linearly on the interlamellar spacing in hot-rolled microstructure. Besides, to obtain a good combination of the final strength and plasticity, an optimum value range （190-280 nm） of the interlamellar spacing had been determined for the interlamellar spacing in hot-rolled microstructure.展开更多
文摘The transformation induced plasticity (TRIP) steels effect occurs because of the martensitic transformation of retained austenite during plastic deformation,and it provides the steel with excellent strength and ductility.While welding remains a vital part of auto body manufacturing,the weldability of TRIP steels is problematic,and this prevents its adoption for many applications in the automotive industry.This present work studies the effects of welding and post-weld heat treatment on the microstructure of TRIP steels.It is found that the microstructures of the fusion zone and the heat affected zone (HAZ) are changed after high-temperature heat treatment.Hardness tests revealed that fusion zone hardness decreased with increasing of temperatures in the post-weld heat treatment on the laser weld seam.The rolling performance of the welding seam and the seam of post-weld heat treatment were also studied.
基金Project(AWPT-M07)supported by the State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology
文摘The effect of intermetallic compounds on the heat resistance of transition joint was investigated. The experiment of post-weld heat treatment for the hot roll bonded titanium alloy-stainless steel joint using nickels interlayer was carried out, and the interface microstructure evolution due to heat treatment was presented. There was not found significant interdiffusion at stainless steel/nickel interface, when the specimens were heat treated in the temperature range of 600-800 °C for 10 and 30 min, while micro-cracks occurred at the stainless steel/nickel interface heat treated at 700 °C for 30 min. The thickness of intermetallic layers at nickel/titanium alloy interface increased at 600 °C, and micro-cracks occurred at 700 and 800 °C. The micro-cracks occurred between intermetallic layers or between intermetallic layer and nickel interlayer as well. The tensile strength of the transition joint decreased with the increase of heat treatment temperature or holding time.
文摘High-boron steel is an important material used for thermal neutron shielding. The appropriate amount of added boron must be de- termined because excessive boron may deteriorate the steel＇s workability. A uniform microstructure can be formed by adding titanium to boron steel. In this study, casting and hot rolling were used to fabricate laminated high-boron steel plates whose cores contained 2.25wt% boron and 0wt%-7.9wt% titanium. The effects of titanium content and hot-rolling and heat-treatment processes on the microstructure and properties of the laminated plates were studied. The results indicated that the optimum titanium content was 5.7wt% when the boron content was 2.25wt%, and that the best overall properties were obtained after heat treatment at 1100℃ for 4 h. The tensile strength, yield strength, and elongation at the specified temperature and holding time were as high as 526.88 MPa, 219.36 MPa, and 29%, respectively.
文摘This paper reviews recent developments in the contin- uous processing of steels in Japan.The following items are discussed:continuous casting-direct rolling(CC-DR) process of hot-rolled strip:thermomechanical control process(TMCP)of heavy plates:in—line heat treating pro- cess of rails:direct lead patenting(DLP)process of wire rods;and fully integrated processing line(FIPL)of cold-rolled strip.
文摘为提高热轧态0Cr21A16合金板材的组织均匀性和塑性,以改善其高温性能及冷加工特性,分析研究了不同温度的热处理试验及组织性能。采用光学显微镜、X射线衍射仪、Gleeble高温热拉伸实验、扫描电镜和纳米压痕仪等研究了热处理前后0Cr21Al6合金板材的显微组织和力学性能。结果表明,通过热处理的方式改善0Cr21Al6合金板材的组织均匀性,在960℃保温6 min 40 s后快速冷却,晶粒平均尺寸为42μm,整体的晶粒尺寸相对于940、980、1000、1020℃热处理后较为均匀、细小,硬度和塑性达到最佳匹配,断裂韧度KIC在960℃处理下达到最佳,拥有最佳的综合性能,可有效避免生产过程中材料的脆性断裂问题。另外Gleeble实验显示1000℃以上的热处理温度不再适合于热加工。
文摘Heredity in the microstructure and mechanical properties of hot-rolled spring steel wire 60Si2MnA during heat treatment process was investigated comprehensively. The steel was isothermally transformed to obtain various hot-rolled microstructure （pearlite fineness within the range of 140-510 nm） and mechanical properties, and followed by some quenching-tempering treatment. Afterwards, microstructure was characterized by optical microscopy, scanning electron microscopy and quantitative metallography, and mechanical properties were determined by tensile test. The results indicated that the hot-rolled microstructure with a coarsen pearlite structure had been changed after reheating, to a austenite microstructure with bigger and more uneven grain size, and finally to a coarsen tempered microstructure. And the average austenite grain size and standard deviation of its distribution in quenched microstructure were observed to depend linearly on the interlamellar spacing in hot-rolled microstructure. Besides, to obtain a good combination of the final strength and plasticity, an optimum value range （190-280 nm） of the interlamellar spacing had been determined for the interlamellar spacing in hot-rolled microstructure.
