40Cr钢流变应力的分析及模拟

研究了不同变形条件下流变应力的变化,发现流变应力与变形温度呈递减关系而与变形速率呈递增关系.在LudWik-Hollomon模型的基础上,提出了一个描述热/温变形的改进模型,该模型在对40Cr钢的模拟中表现出了较好的效果.硬化指数对变形温度不敏感,在低的应变速率下有一个不变值,而在高的应变速率下突然跃变.对峰值应力进行了预测,结果较为理想,预测值与实验值之间的平均相对误差和均方根分别为7.7%和17.59MPa.

Analysis and Modeling of Flow Stress of 40Cr Steel

The flow stresses at various deformation conditions were studied. The results show that flow stress decreases with deformation temperature increasing, and increases with strain rate increasing. Based on Ludwik-Hollomon model, an improved model suiting for hot and warm working was discussed. A good result was got when modeling flow stress of 40Cr steel in the improved model. Hardening exponent n is insensitive to deformation temperature. At low strain rate, n value is hardly changed; when up to a high strain rate, n jumps to a high value. By simplifying some parameters, peak stress can be predicted. The average relative error and the mean square root between predicted and experimental flow stresses are 7.7% and 17.59MPa, respectively.