共查询到19条相似文献,搜索用时 359 毫秒
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利用Gleeble-3500热模拟试验机在变形温度900~1 200℃和应变速率0.01~10 s-1范围内,对40Cr钢试样进行压缩实验。研究了40Cr钢真应力-应变曲线特征,建立了峰值应力、应变速率和变形温度间的本构方程,并确定了40Cr钢热变形激活能为310.625 kJ/mol。研究结果显示:40Cr钢热变形时的流变软化机制为动态回复和动态再结晶;随着变形温度增加和应变速率减小,流变应力减小;试样的变形温度越高,应变速率越低,显微组织中的动态再结晶越完全,并且动态再结晶晶粒越容易长大。 相似文献
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低碳钢热变形奥氏体的再结晶行为 总被引:2,自引:0,他引:2
对热变形奥氏体的再结晶动力学和微观组织演变进行了模拟计算,对晶粒尺寸的模拟值和实测值作了比较,分析了化学成分对动态再结晶率的影响以及残余应变与变形温度的关系.结果表明:在温度较高、应变速率较低的条件下容易发生动态再结晶,随着变形温度的降低,发生动态再结晶的几率减小,而静态再结晶在前几道次进行得比较充分,随后进行得不充分,增加碳和锰的含量可以促进动态再结晶的发生,残余应变随变形温度的降低而增大,晶粒尺寸的模拟值和实测值吻合较好,表明所选用的模型有一定的参考价值. 相似文献
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在Gleeble-3800热模拟实验机上利用双道次热压缩的实验方法,获得了GCr15轴承钢在不同实验条件下的应力-应变曲线,研究了该钢种在高温变形道次间隔时间内的静态软化行为以及再结晶规律,模拟材料热加工组织性能,为制定合理的轧制工艺提供实验基础和理论依据。分析了变形温度、应变速率和道次间隔时间对其静态再结晶行为的影响,建立了GCr15钢静态再结晶动力学模型,相应的静态再结晶激活能约为118.72kJ/mol。结果表明:静态再结晶体积分数随变形温度的升高、应变速率的提高或道次间隔时间的延长而增大。 相似文献
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通过Thermecmaster-Z热模拟机研究了(%)0.084C-1.05Mn-0.026Nb-0.003Ti-0.007Mo-0.003V微合金钢Q345E,在变形温度1000~1100℃,变形速率1~10s^-1时,单道次变形时变形温度和变形速度对临界应变和动态再结晶的影响,以及在变形温度950—1050℃,变形速率10s^-1双道次变形时变形温度和停留时间对静态再结晶的影响。试验结果表明,单道次变形时高的变形温度促进钢的再结晶,但高的变形速度加速钢的硬化;双道次变形时,停留时间延长和变形温度升高均增加静态再结晶百分率。 相似文献
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采用Gleeble 3500热模拟机,研究了D36船板奥氏体的再结晶温度以及奥氏体的变形温度、变形量和变形速率对热变形奥氏体再结晶的影响。结果表明:当变形速率为0.1~1 s-1、温度达到950℃时,开始发生动态再结晶;当变形速率为5 s~(-1)、温度在1 000~1 050℃时,发生动态再结晶;当变形速率为10 s~(-1)时,不发生动态再结晶。当变形温度为1 050℃、单道次变形率在10%~20%时,D36钢在10s左右的道次间隔内发生了完全的静态再结晶。当单道次变形率在20%以上,D36钢在5 s左右的道次间隔内发生了完全的静态再结晶。 相似文献
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利用Gleeble-3500热力模拟试验机,在温度为1123~1423K,应变速率为0.5~10s-1的条件下,对航空用高强韧性的二次硬化超高强度钢(AF1410钢)进行了高温轴向压缩试验,测得了AF1410钢的高温流变曲线,并观察了变形后的显微组织。试验结果表明,AF1410钢的流变应力和峰值应变随着变形温度的升高和应变速率的降低而减小;AF1410钢在真应变为0.8,应变速率为0.5~10s-1的条件下,随着变形速率的提高,其发生完全动态再结晶的温度也逐渐升高。当变形速率为10s-1时,其变形温度高于1373K,才会发生完全动态再结晶;AF1410钢的热变形激活能Q值为430.39kJ/mol,并确立了其热变形方程。 相似文献
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利用Gleeble-3500热力模拟试验机,在温度为1123~1423 K,应变速率为0.1~10 s-1,真应变为0.8的条件下,对一种传动部件用高强度渗碳钢(SAE9310钢)进行了高温轴向压缩试验,测得了SAE9310钢的高温流变曲线,并观察其变形后的显微组织。试验结果表明,SAE9310钢的流变应力和峰值应变随着变形温度的升高和应变速率的降低而减小;SAE9310钢在真应变为0.8的条件下,随着变形速率的提高,其发生完全动态再结晶的温度也逐渐升高,当热变形温度高于1323 K时,应变速率在0.1~10 s-1范围内,试验钢均会发生动态完全再结晶;测得9310钢的热变形激活能Q值为416.78 kJ/mol,并确立了其热变形方程。 相似文献
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采用Gleeble-1500热模拟试验机对FGH96合金进行双道次真应变量为0.6+0.6和0.3+0.9的等温间断热压缩试验,研究了变形温度为1050~1125℃、变形速率为0.001~0.1 s-1时合金的热变形行为和组织演变.热变形过程中合金发生了再结晶,第一道次较小的真应变量减轻了合金的开裂.当第一道次真应变量小时,随着温度和变形速率的上升,合金道次间再结晶软化率增加.不同应变量以及不同道次真应变量均对合金热加工图产生明显影响.在相同变形条件下,当能量耗散率随应变量的增加而下降时,合金中组织由细晶向粗晶转变,反之则由粗晶向细晶转变;当能量耗散率不随应变量的变化而变化时,能量耗散率低于20%的合金中出现大量的不完全再结晶组织,能量耗散率高于35%的合金中出现细小完全再结晶组织. 相似文献
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The static recrystallization of 316LN austenitic stainless steel was studied by double-pass hot compression tests on a Gleeble-3500 thermomechanical simulator. The specimens were compressed at the deformation temperatures of 950, 1050, 1150 °C, strain rates of 0.01, 0.1, 1s?1, strains of 0.1, 0.15, 0.2, and intervals of 1 — 100 s. The results show that the volume fraction of static recrystallization of 316LN increases with the increase of deformation temperature, strain rate, strain and interval, which indicates that static recrystallization occurs easily under the conditions of higher deformation temperature, higher strain rate and larger strain. Deformation temperature has significant influence on static recrystallization of 316LN. The volume fraction of static recrystallization could easily reach 100% at higher deformation temperatures. By microstructure analysis, it can be concluded that the larger the volume fraction of static recrystallization, the more obvious the grain refinement. The static recrystallization activation energy of 317 882 J/mol and the exponent n of 0.46 were obtained. The static recrystallization kinetics was established. The predicted volume fraction of static recrystallization is in good agreement with the experimental results. 相似文献
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为研究高强钢300 M静态再结晶行为,采用Gleeble-3800型热模拟试验机对300M钢进行单/双道次热压缩试验.通过双道次热压缩试验分析了变形温度、应变速率、变形量和初始晶粒尺寸对静态再结晶体积分数的影响.变形温度越高,应变速率越大,变形量越大,初始晶粒尺寸越小,则静态再结晶体积分数越大.其中变形温度、变形量和应变速率对静态再结晶体积分数影响较大,初始晶粒尺寸的影响相比较小.基于双道次热压缩试验结果建立了300 M钢的静态再结晶体积分数模型,基于单道次热压缩试验结果建立了300 M钢完全静态再结晶晶粒尺寸模型,并验证了静态再结晶体积分数模型的正确性. 相似文献
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利用 Gleeble-3500型热模拟机,研究700MPa 管线钢(/%:0.07C,0.90Si,0.60Mn,0.008P,0.002S, 0.30Ni,0.10Cr,0.12Mo,0.06V,0.03Nb,0.28Cu,0.04Alt,0.0060N) 20mm热轧板在850~1250℃ 和应变速率0.01~1s-1下单道次热压缩变形及组织演变,得出单道次压缩变形真应力-真应变曲线,热压缩再结晶动态图和动态再结晶开始时间与变形温度关系(RTT)曲线。研究结果表明,发生再结晶由变形温度和应变速率共同决定,该700MPa管线钢在温度1100~1250℃和应变速率0.01~1s-1下压缩变形时容易发生再结晶。再结晶发生机制是热压缩应变,使得原始晶粒破碎、新晶界产生迁移促使新晶核生成。 相似文献
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To explore the hot compression recrystallization behaviours of low carbon CrNiMo carburized bearing steel, isothermal compression simulation experiment was carried out by the Gleeble 1500D thermal-mechanical simulator at temperatures between 900 and 1050??, strain rates between 0??1, 1 and 10s-1 and deformations among 10%, 30%, 50%. Thermal deformation dynamic recrystallization process was analyzed by grain sizes and true strain-true stress curves in different conditions. Material??s deformation activation energy and hot deformation equation was regressed, the hot working map of material was calculated, and the critical time of static recrystallization was experimented. The results show that, high deformation temperature, low strain rate and large deformation are conducive to the occurrence of dynamic recrystallization. The fine recrystallized grains were abtained at 1050??, 50% deformation and strain rate 1s-1 in this experiment, and the average grain size is 14??97??m; The activation energy of low carbon CrNiMo carburized bearing steel decreases slowly when deformation larger than 30%. It is deduced to 436??016kJ/mol in 50% deformation, and the experimental results are also matched to the hot working map. The material has reached to the dynamic recrystallization thermodynamic condition in 900??, 1s-1, 50% deformation ,and the critical static recrystallization time is 5min after continue heated. 相似文献