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微合金高强度钢连续冷却转变及显微组织研究 总被引:3,自引:0,他引:3
以国内某厂新型微合金高强度钢的开发研究为背景,在THERMECMASTOR-Z热模拟试验机上对试验钢种进行了不同变形程度、变形速率和冷却速度等工艺条件下的热模拟实验.分析比较了不同变形工艺参数对微合金高强度钢相变及组织的影响.实验结果表明,提高轧后冷却速度使 Ar3温度降低;高温加热抑制相变,变形促进相变;变形速率越大,相变开始温度越高,变形程度越大,相变开始温度越高.增大变形程度和轧后快速冷却有助于铁素体晶粒的细化和减少珠光体的含量.试验钢种的γ+α两相区的温度范围大于130℃. 相似文献
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利用热模拟试验方法系统研究了在线淬火型油罐用钢在不同轧制工艺和不同热处理工艺下的组织特征,并分析了微合金元素碳氮化物的粒子析出行为,研究结果表明,随终轧温度的降低,油罐用钢晶粒尺寸逐渐细化,铁素体数量逐渐增多;随冷却速度的增大,JGR610E组织类型由针状铁素体向粒状贝氏体到板条状下贝氏体转变,晶粒越来越细小。 相似文献
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利用热模拟试验方法系统研究了在线淬火型油罐用钢在不同轧制工艺和不同热处理工艺下的组织特征,并分析了微合金元素碳氮化物的粒子析出行为,研究结果表明, 随终轧温度的降低,油罐用钢晶粒尺寸逐渐细化,铁素体数量逐渐增多;随冷却速度的增大,JGR610E组织类型由针状铁素体向粒状贝氏体到板条状下贝氏体转变,晶粒越来越细小。 相似文献
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直接轧制工艺对中厚板组织与性能的影响 总被引:1,自引:0,他引:1
连铸坯直接轧制技术作为一种变革性的绿色钢铁生产流程,目前主要用于超薄带和线棒材生产,近年来国内外逐步开始了中厚板直接轧制工艺的探索性工作。直接轧制工艺与常规热轧工艺相比,具有不同的温度履历和物理冶金学过程。选取Nb-Ti微合金钢为研究对象,从产品组织与性能的角度,探讨中厚板直接轧制工艺的可行性。采用炼钢-连铸-轧制中试试验,对比研究了直接轧制工艺及常规热轧工艺下中厚板产品的组织和性能,并基于动态再结晶模型,探讨了直接轧制工艺下试验钢的组织细化机制。研究结果表明,直接轧制工艺下,虽然连铸坯轧前未经过γ-α-γ相变过程,仍保留铸态粗大的奥氏体晶粒,但轧制过程中较大的芯表温差有利于变形向芯部渗透,芯部再结晶进行得更加充分,可以用形变再结晶机制代替常规热轧工艺的相变机制细化成品芯部组织,获得与常规热轧工艺相近甚至更优的显微组织与力学性能。 相似文献
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V-N微合金化高强度铁塔用角钢的研究 总被引:1,自引:0,他引:1
利用V-N微合金化技术,在16Mn钢基础上进行铁塔用角钢的合金设计,并结合角钢的孔型轧制要求,考察了V/N合金设计以及板坯加热温度、轧制工艺参数对角钢组织性能的影响。结果表明,随着钢中V/N含量的增加,钢中弥散析出的第二相粒子数量显著增加,屈服强度显著提高,其中0.01%的钒含量对屈服强度贡献约为23 MPa。V-N微合金化角钢坯料再加热过程中V(C,N)粒子的溶解温度低于1 150℃,控制低的坯料加热温度有利于提高角钢的低温冲击韧性。终轧温度对低钒钢的屈服强度和韧性存在显著影响,但对高钒钢的组织性能影响不大。采用V-N微合金化设计后,角钢的综合性能得到显著提高,且力学性能对轧制工艺参数变化不敏感,因此,V-N微合金化技术适用于角钢的实际生产应用。 相似文献
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随着H型钢轧制工艺的发展,先后出现了5种常见的工艺布置形式。基于对热轧H型钢生产线的研究,创新性地提出了热轧生产H型钢的新工艺。在生产线中通过采用新型万能轧机的型式达到提高生产效率和产品精度的目的。提出的2种新型万能轧机的型式改变了自1848年在德国发明以来至今在世界各地一直沿用的万能轧机的设计,均已申报了专利。 相似文献
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通过金相、扫描、透射电镜研究不同轧制比工艺下V-Ti、Nb-V-Ti两种微合金化非调质钢的微观组织及机械性能。结果显示:Nb-V-Ti非调质钢轧制比大于10时,冲击韧性值可以达到50 J,而V-Ti非调质钢的轧制比却需要大于15以上,才能达到类似的冲击韧性值。从相同轧制比对比也可以发现,Nb-V-Ti非调质钢的冲击性能明显优于V-Ti非调质钢,这是因为Nb能够显著提高非调质钢的奥氏体粗化温度,有效阻止奥氏体晶粒的快速长大,细化非调质钢晶粒,降低珠光体片层间距,使渗碳体呈粒状或球状分布;另外,Nb能促进V-Ti非调质钢中细小含铌碳化物的弥散析出,细化基体组织,同时提高非调质钢的强度。因此,Nb-V-Ti复合非调质钢经过未再结晶区变形后可获得均匀细小的铁素体-珠光体组织,且在900℃未再结晶区进行大轧制比变形能够有效改善Nb-V-Ti非调质钢的强韧性。 相似文献
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超细晶粒钢及其力学性能特征 总被引:6,自引:0,他引:6
探索了在新一代钢中获得超细晶粒的方法。通过低温轧制和应变诱导铁素体相变,可以在碳素结构钢中获得晶粒尺寸小于5μm的超细晶粒,屈服强度大于400MPa。采用应变诱导铁素体相变可以在微合金钢中得到晶粒尺寸为1μm的超细晶粒。低碳微合金钢的屈服强度达到了600MPa,超低碳微合金钢的屈服强度超过了800MPa。采用微合金化和循环热处理可以在合金结构钢中获得2μm的奥氏体晶粒,1500MPa级抗拉强度下改善了耐延迟断裂性能。 相似文献
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《Baosteel Technical Research》2010,(Z1):87
Because special steels are the basic materials for industrialization,a national R&D program on special steel technology for high quality products have been granted to promote the special steel production and applications since 2008.Since then,great progresses have been achieved on ferritic stainless steel sheets,heat resistance steel pipes and tubes,microalloyed forging steel bars,and mould steel forgings for hot working. The ratio of ferritic stainless steel sheets produced by TISCO and Baosteel has been promoted through technology innovations and increased 42%and 48 in 2009 respectively.439M steel sheets have been used to exhaust system,and 444 steel sheets have been applied to kitchen and architecture.The production technologies for heat resistance steel pipes and tubes(T/P92,S3043,S31042 steels) have been developed in Baosteel and Pansteel to meet the market requirements.Meanwhile,the round bloom technology has been initiated in Xingcheng Steel.The new technologies for microalloyed forging steels,low cost steel bar,and tailored steel and components,were proposed by CISRI based on the understanding of precise chemical composition and segregation control.And the applications of microalloyed forging steel bars have been promoted remarkably.The researchers have developed high quality mould steel technologies,heavy section forgings of 718 steel,high premium H13 steel blocks and large diameter mandrels used for seamless pipe rolling.The technology innovations of the program could lead to the progress of production technology in special steel sheets,pipes,bars and forgings,and meet the demands from market.For the moment,it is actually believed that there still strong requirements for the technology innovations on special steels. 相似文献
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Effect of Heat Treatment Process on Properties of 1000 MPa Ultra-High Strength Steel 总被引:1,自引:0,他引:1
Two types of steel, C-Mn-Cr-Mo-B microalloyed steel and C-Mn-Mo-Nb-Cu-B microalloyed steel, are designed to develop 1000 MPa ultra-high strength steel. Two kinds of processes, thermomechanical controlled process (TMCP) combined with traditional off-line quenching and tempering (QT) process versus controlled rolling process (CR) combined with direct quenching and tempering (DQ+T) process, are applied. The effect of heat treatment processing mode on the microstructure and mechanical properties is studied. The relationship between microstructure and mechanical properties is investigated by SEM and TEM. After tempering at 450 to 550 ℃ for 1 h, the steel produced by TMCP+QT process shows combination of excellent strength and low temperature toughness. The yield strength is above 1000 MPa, elongation above 15% and impact energy at -40 ℃ more than 30 J. After tempering at 450 ℃, a large number of ε-Cu particles precipitated in C-Mn-Mo-Nb-Cu-B steel produced by CR+DQ+T process lead to a significant increase in yield strength. And after tempering at 500 to 600 ℃, the yield strength of the steel is further improved to 1030 MPa because of precipitates, such as nitride or carbide of niobium, carbide of molybedenum and vanadium. When the tempering temperature is increased above 620 ℃, the yield strength is still higher than 1000 MPa and elongation is above 20% and impact energy at -40 ℃ is more than 35 J. After tempering at above 500 ℃, the toughness of the steel treated by TMCP+QT process is superior to that of steel by CR+DQ+T process. 相似文献