共查询到19条相似文献,搜索用时 265 毫秒
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利用Gleeble-3500热-力模拟试验机,在变形温度为750~1 200℃、应变速率为0.01~10 s~(-1)、应变量为0.7的条件下对Q345D钢进行单道次压缩试验,得到其真应力-真应变曲线,分析了变形温度、应变速率和变形程度对变形抗力的影响。结果表明,降低变形温度和提高变形速率,均可使Q345D钢的变形抗力增大;只有在较低的变形速率和较高的变形温度下,Q345D钢才发生动态再结晶。通过非线性拟合,建立了Q345D钢的变形抗力模型,并与试验变形抗力进行对比分析,结果表明该模型具有较高的拟合精度。 相似文献
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35CrMo钢热变形机制的模拟研究 总被引:1,自引:0,他引:1
以弯曲镦锻 3 5 Cr Mo钢火车曲轴为例 ,通过将该钢以 90 0℃~ 1 2 5 0℃变形温度 ;0 .0 5 s-1、0 .5s-1、1 .0 s-1的应变速率 ;在 Greeble-1 5 0 0试验机上进行压缩 1 5 %~ 80 %的热变形实验 ,和随后进行的微观组织分析得出了 :材料热变形屈服应力变化模型 ;材料热变形本构关系 ;动态与静态再结晶模型和热加工参数与微观组织变化的相关性资料。描绘了在 1 2 5 0℃ ,应变速率为 1 .0 s-1时 ,3 5 Cr Mo钢热变形应力应变曲线和相应的再结晶组织。通过对 3 5 Cr Mo钢在高温大变形条件下 ,试件内部各区域晶粒尺寸的回归计算 ,验证了该钢热变形晶粒计算模型。所得出的实验结果和计算模型为热成形工艺分析和质量控制提供了科学的依据 相似文献
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研究21CrMo10钢的塑性变形性能,对制造热作模具具有重要的意义。文章利用Gleeble 1500D热力模拟机,在不同的温度和变形速率条件下对21CrMo10钢进行试验,测得了P91不同变形条件下的真实应力-真实应变曲线。试验曲线表明,21CrMo10钢在变形的过程中存在着动态再结晶;而且,随着温度的升高或应变速率的降低,其流变应力下降。对比试验得出的变形曲线认为,FORGE 2005材料库的变形曲线由于未考虑到动态结晶过程,不符合实际。对各种变形条件下的峰值流变应力进行分析得出,流变应力基于Zener-Holloman参数存在函数关系。 相似文献
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The hot compression tests of 42CrMo steel were performed in the temperature range of 850–1150 °C at strain rates of 0.01–10 s?1 and deformation degrees of 10–60% on Gleeble-1500 thermo-simulation machine. The optical microstructures in the center region of the section plane were examined. Based on the results from thermo-simulation experiments and metallographic analysis, the dynamic recrystallization mathematical models of 42CrMo steel were derived. The effects of processing parameters, including the strain rate and deformation temperature, on the microstructure evolution of 42CrMo steel hot upsetting process were discussed by integrating the thermo-mechanical coupled finite element method with the derived microstructure evolution models. The fraction of dynamic recrystallization and dynamic recrystallization grain sizes during the hot upsetting process of 42CrMo steel were predicted. The results show that the effects of strain rates and deformation temperatures on the microstructure evolution of 42CrMo steel hot upsetting process are significant, and a good agreement between the predicted and experimental results was obtained, which confirmed that the derived dynamic recrystallization mathematical models can be successfully incorporated into the finite element model to predict the microstructure evolution of hot upsetting process for 42CrMo steel. 相似文献
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42CrMo钢亚动态再结晶行为研究 总被引:1,自引:0,他引:1
利用双道次热压缩的方法,研究了42CrMo钢在高温变形道次间隔时间内奥氏体的亚动态再结晶行为。基于试验结果,建立了42CrMo钢的亚动态再结晶动力学模型。讨论了工艺参数对亚动态再结晶晶粒大小的影响规律。结果表明,42CrMo钢很容易发生亚动态再结晶,道次间隔时间越长,材料软化程度增大,亚动态再结晶越明显。随着变形温度的升高、应变速率的增大,完全亚动态再结晶所需时间迅速减少;将亚动态再结晶动力学模型的预测结果与试验结果进行比较,二者吻合较好;变形温度越低、应变速率越大,亚动态再结晶晶粒越小。相同形变条件下,亚动态再结晶晶粒明显细于静态再结晶晶粒。 相似文献
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目的 确定42CrMo钢感应淬火过程的奥氏体相变动力学参数,并验证其可靠性。方法 根据不同加热速率下42CrMo钢奥氏体膨胀曲线,基于经典JMAK(Johnson-Mehl-Avrami-Kolmogorov)模型和Kissinger方法,确定了42CrMo钢奥氏体化相变动力学的参数。建立ABAQUS局部移动式感应淬火模型,选取淬火区域加热过程中点的温度变化曲线作为验证奥氏体化模型的对象。基于Scheil法则和JMAK相变动力学模型,采用文中求解得到的奥氏体化参数,采用Matlab对42CrMo连续转变过程离散为每个时间间隔的等温相变并求解,并对照相关学者采用的扩展解析动力学模型和JAMK模型,加以验证。结果 根据上述方法,得到的42CrMo奥氏体相变动力学参数为:激活能Q为2.04×106 J/mol,指前因子lnk0的值取230.78,Avrami指数n取0.427。将淬火加热过程离散为数量很大的均匀时间间隔,并以求解的动力学模型在每个间隔内进行对应温度条件下奥氏体体积分数的求解并顺次叠加,以模拟得到的奥氏体转变时间和转变温度等作为依据,该模型有良好的表现性。结论 对42CrMo非等温且加热速度不恒定的连续奥氏体转变过程,JAMK模型拟合表现良好,采用文中求解的参数组对表面感应淬火的奥氏体转变历程进行仿真预测是可行的。 相似文献
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Y.C. Lin Ge Liu Ming-Song Chen Jue Zhong 《Journal of Materials Processing Technology》2009,209(9):4611-4616
The static recrystallization behaviors in 42CrMo steel were investigated by isothermal interrupted hot compression tests. Based on the experimental results, an efficient artificial neural network (ANN) model was developed to predict the flow stress and static recrystallized fractions. The effects of the deformation temperature, strain rate and deformation degree, as well as initial grain sizes, on the static recrystallization behaviors in two-pass hot compressed 42CrMo steel were investigated by the experiments and ANN model. A very good correlation between the experimental and predicted results from the developed ANN model has been obtained, which indicates that the excellent capability of the developed ANN model to predict the flow stress level and static recrystallization behaviors in two-pass hot deformed 42CrMo steel. The effects of strain rate, deformation temperature and degree of deformation on the static recrystallization behaviors are significant, while those of the initial austenite grain size are slight. 相似文献
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The metadynamic recrystallization behaviors in deformed 42CrMo steel were investigated by isothermal interrupted hot compression tests on Gleeble-1500 thermo-mechanical simulator. Compression tests were performed using double hit schedules at temperatures of (850–1150) °C, strain rates of (0.01–1) s?1 and inter-stage delay time of (1–50) s. The kinetic equations have been proposed to predict the metadynamic recrystallization behaviors in hot compressed 42CrMo steel. Comparisons between the experimental and predicted results were carried out. Results show that the effects of deformation parameters, including strain rate and deformation temperature, on the softening behaviors in the two-pass hot deformed 42CrMo steel are significant. However, the deformation degree (beyond the peak strain) has little influence on the metadynamic recrystallization behaviors in 42CrMo steel. The predicted results well agree with the experimental ones, which indicate that the proposed kinetic equations can give a precise estimate of the softening behaviors and microstructural evolution for the hot deformed 42CrMo steel. 相似文献