共查询到19条相似文献,搜索用时 468 毫秒
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通过对3种不同铌、钒含量的低碳钢进行多道次热压缩变形以模拟中厚板的超细晶轧制工艺,考察了显微组织演变过程、微合金元素和变形条件对组织演变的影响。结果表明:变形过程中有部分奥氏体通过形变诱导相变转变为铁素体;变形并快速冷却后得到平均晶粒尺寸为3~6μm的超细晶组织.铌促进、钒抑制形变诱导铁素体相变,铌、钒微合金化均有较好的细化作用,铌的作用优于钒.再结晶温度以上进行的粗轧有利于精轧时形变诱导铁素体的形成;在精轧温度范围内,增加变形道次、降低道次应变率有利于获得细化的显微组织;降低终轧变形温度对组织细化是最有效的. 相似文献
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为了研究Ti-Zr微合金钢轧制变形过程中变形温度和Zr含量对内部应力应变的分布及奥氏体组织演变的影响,通过热模拟实验和金相分析获得3种不同Zr含量的Ti微合金钢应力应变曲线及奥氏体的晶粒尺寸及分布情况。研究结果表明:变形温度的升高会降低3种实验钢的内部应力,促进应力均匀分布,其中0.12Ti-0.02Zr钢应力下降的最明显,Zr的加入会促进Ti微合金钢再结晶奥氏体的形核和形变诱导析出相的析出,形变储能消耗量增大,不容易在变形过程中积累应力和应变;但过多的Zr会因为大量析出相而使实验钢的变形抗力增大,导致应力和应变累积。综合考虑,使用Ti-Zr复合微合金化技术实现奥氏体组织的超细化均匀时,Zr元素的添加量应控制在0.02%左右。 相似文献
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在Gleeble热模拟试验机上,研究含铌微合金钢中铌的析出物在形变诱导相变过程中的作用机理,结果表明:当加热温度为1000℃时,部分铌的碳化物未溶解于奥氏体中,而加热温度为1100℃时,铌的碳化物能够全部溶解到奥氏体中,含铌微合金钢加热温度范围约在1000~1100℃之间。铌的未溶解碳化物和在冷却过程中析出的碳化物都能作为铁素体形核位置,从而促进γ→α相变的发生。 相似文献
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钒微合金化低碳钢多道次变形过程中的组织演变 总被引:4,自引:0,他引:4
采用热模拟实验研究了钒微合金化低碳锰钢(0.1%C-1.0%Mn)奥氏体化后在860~740℃范围内进行多道次变形过程中的组织演变,考察了变形和微合金元素V对铁素体相变的影响.结果表明,在多道次变形过程中,部分奥氏体通过形变诱导相变转变为铁素体;高温区的道次间隔期间部分形变诱导铁素体发生向奥氏体的逆相变;随变形温度降低,道次间隔期间有变形奥氏体向铁素体的亚动态相变发生。微合金元素V抑制形变诱导铁素体相变的进行,阻碍铁素体晶粒长大,起到细化晶粒的作用. 相似文献
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利用热模拟单道次压缩实验研究了45#钢在不同温度变形过程中微观组织的演变规律。通过对变形过程中组织形貌的观察和应力-应变曲线的分析,讨论了变形过程中的相变行为和软化过程。结果显示,实验钢在热变形过程发生铁素体(DIF)和珠光体(DIP)两种形变诱导相变,Ar3温度以上变形时,主要发生形变诱导铁素体相变,伴随少量珠光体生成,并且随着变形温度的降低铁素体增加,珠光体略微降低;Ar3温度以下变形时,形变诱导珠光体逐渐取代铁素体,且随温度的变化趋势相反。低温变形时,形变诱导相变是软化的主要原因,高温变形时主要发生动态再结晶,导致软化,并且动态再结晶的软化作用要比形变诱导相变的好。 相似文献
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为了研究S460ML钢中铌、钛的应变诱导析出行为,在变形温度为900~1 000℃、应变速率为0.1~5.0 s~(-1)、变形量为10%~50%和弛豫时间为0~15 min条件下利用热模拟试验机进行了应变诱导析出试验,通过物理化学相分析方法对不同试验条件下铌、钛的析出量进行了分析,并通过透射电镜对铌、钛析出相的形态及尺寸进行了表征。结果表明,随着弛豫时间的增加和变形温度的降低,铌、钛应变诱导析出率增加;增大变形量不仅可以使应变诱导析出发生的时间提前,还可以提高铌、钛应变诱导析出的总量;降低应变速率也可以使应变诱导析出提前发生,但对铌、钛应变诱导析出的总量影响不大;随着变形量增加、弛豫时间延长、温度降低,析出相的平均尺寸减小。 相似文献
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Modern steel developments often use additional deformation mechanisms like the deformation induced martensitic transformation (TRIP‐effect) and mechanical twinning (TWIP‐effect) to enhance elongation and strength. Three high‐alloyed cast CrMnNi‐steels with different austenite stabilities were examined. Dependent on the austenite stability, TRIP‐effect and TWIP‐effect were found. A low austenite stability causes a distinctive formation of deformation induced α'‐martensite and therefore a strong strain hardening. The increase of strain rate leads to an increase in yield strength and flow stress, but also to a counteractive adiabatic heating of the specimen. Dependent on the degree of deformation, low austenite stabilities and high strain rates lead to excellent values in specific energy absorption. 相似文献
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为了研究加载方向对一种TRIP型双相不锈钢板带力学性能的影响,利用拉伸试验机研究了加载方向与轧制方向分别成0°、45°和90°条件下试验钢板带的拉伸变形行为。利用EBSD、TEM、XRD等分析手段对比研究了不同加载方向下形变组织演化的特点及形变诱导马氏体相变动力学规律,探讨了作用机理。结果表明,试验钢表现出明显的各向异性,其中各方向塑性和抗拉强度(由高到低)的变化规律为0°>45°>90°,但屈服强度对加载方向不敏感。钢中奥氏体相发生了形变诱导马氏体相变,主要演化机制为γ→ε→α′,从而形成TRIP效应。0°加载有助于TRIP效应的发生与发展,而90°加载时,两相间的应变配分延迟了马氏体相变的进程,抑制了TRIP效应。通过回归分析分别建立了不同加载方向下形变诱导马氏体相变动力学模型,可实现各加载方向下不同变形阶段马氏体转变量的预测。 相似文献
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The change in the internal energy during uniaxial tensile deformation of austenitic stainless steels EN 1.4301 (AISI 304) and EN 1.4318 (AISI 301LN) was determined by measuring the extent of γ→α'‐martensite transformation and the temperature increase of the samples. From the results the fraction of the stored energy of cold work and the free energy change related to the strain‐induced γ→α'‐martensite transformation were determined. The fraction of stored energy varied around 0.4. With the metastable steel grades the free energy change related to the γ→α'‐martensite transformation was found to vary between ‐98 MJ/m3 and ‐206 MJ/m3 depending on the austenite stability of the steel. Furthermore, the magnitude of the mechanical driving force was estimated by comparing the results with the free energy change of thermally induced transformation. 相似文献
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通过实验室模拟试验,研究了高氮钒钢的金相组织和形变诱导铁素体体积分数,分析了钒对高氮钒钢变形诱导相变的影响.试验结果表明,钒的加入促进了形变诱导铁素体相变,细化了铁素体晶粒,提高了形变诱导铁素体体积分数. 相似文献
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The microstructure evolution of a eutectoid steel during the deformation induced pearlite transformation of undercooled austenite was investigated by uniaxial hot compression simulation experiment. The effects of different deformation degree, deformation rates and deformation temperature on the deformation induced pearlite transformation were explored. The results indicate that the induced pearlite transformation can occur rapidly during the deformation, for the stress accelerates phase transition. With the increase of the deformation degree, the dislocation density and phase transition driving force in the microstructure are improved, accelerating the occurrence of phase transition and the process of cementite spheroidization. For the diffusion- controlled phase transition, the deformation rates decrease to prolong the deformation time, so the carbon atoms can diffuse sufficiently to obtain spheroidized cementite. At lower deformation temperature from A1 to Ar1, significant refinement of the fragmentation of cementite occurs due to the increase of supercooling and spheroidized time. The ultrafine microstructure of cementite particles can be obtained through the high deformation degree, low deformation rates and low deformation temperature. It is also observed that the pro- eutectoid ferrite nucleates along the austenite boundary in the process of deformation. 相似文献
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采用热力模拟试验机、光学显微镜、显微硬度计研究了耐蚀钢12CuCrNiV在不同冷却速率下的连续冷却组织转变规律,并绘制其CCT曲线,同时研究了形变温度和冷却速度对耐蚀钢热变形后的组织和硬度的影响规律。结果表明:连续冷却转变情况下,耐腐蚀钢在冷速小于15℃/s时,有铁素体转变;冷速小于1℃/s时,有珠光体转变;冷速在0.5~20℃/s之间时,有贝氏体转变。控制冷速在5~15℃/s可得到铁素体和贝氏体复相组织。随变形温度的降低,试验钢形变过程中形变诱导铁素体相变现象显著,且伴随有M/A岛生成;随冷却速度的增高,形变诱导相变现象减弱,M/A岛数量减少。与连续冷却试验相比较,形变诱导析出现象明显,其硬度增量为40~50HV,形变可使试验钢的析出向更高冷速移动。 相似文献
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WANG Xiao WANG Zuo-cheng WANG Xie-bin WANG Yi-ran GAO Jun-qing ZHAO Xiu-ling 《钢铁研究学报(英文版)》2012,19(2):62-66
Microstructures and critical phase-transformation temperature of boron-nickel added Nb-treated high strength low alloy (HSLA) H-beams cooled at different cooling rate, with different deformation were investigated. Continuous cooling transformation (CCT) diagram of this new type of steel was obtained by using Gleeble 1500 thermomechanical simulator. Microstructures and hardness, especially micro-hardness of the experimental steel were investigated by optical microscopy (OM), scanning electron microscope (SEM), Rockwell and Vickers hardness tests. Phase analysis was also studied by X-ray diffraction (XRD). The results indicated that with increase of cooling rate, microstructures of continuous cooled specimens gradually transformed from polygonal ferrite and pearlite, grain boundary ferrite and bainite, bainite and martensite to single martensite. The CCT diagram revealed that slow cooling was needed to avoid austenite-bainite transformation to ensure toughness of this steel. By plastic deformation of 40%, austenite-ferrite transformation temperature increased by 46 ℃, due to deformation induced ferrite transformation during continuous cooling, but Rockwell hardness has little change. 相似文献
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XUYun-bo YUYong-mei LIUXianghua WANGGuo-dong 《钢铁研究学报(英文版)》2005,12(2):49-51
Thedeformation inducedferritetransformation (DIFT)inthelowtemperatureregioncanbeusedto effectivelyproduceultra finegrainedsteels[1-7]. Thedeformationleadstotheincreaseofstoredener gyandshortenstheincubationperiod.Abovethe pointAr3,ferritetransformationwi… 相似文献