水淬调质态40Cr钢超塑性的研究

Investigation on Superplasticity of the Water-quenched and High-temperature Tempered 40Cr Steel

研究了 40Cr钢经水冷淬火和高温回火后的超塑性。结果表明 :40Cr钢的晶粒尺寸为 1 0～ 1 5 μm ,在温度为 75 0℃、初始应变速率为 1 0×1 0 - 3s- 1 的拉伸变形条件下 ,超塑伸长率为 30 4 % ,流变应力为 63 0MPa ,应变速率敏感性指数m值为 0 2 2 7,超塑性变形的机制可描述为原子扩散控制的晶界滑动。

The superplastic deformation characteristics of commercial 40Cr steel that was water-quenched and subsequent high-temperature tempered were investigated. The results show that the 40Cr steel has fine grain sizes of 10～15μm, and exhibits a tensile elongation of 304%, a flow stress of 63MPa and a strain rate sensitivity m value of 0 227 at the initial strain rate of 1 0×10 -3 s -1 and at the temperature of 750℃. The primary superplastic deformation mechanism was thought to be atom-diffussion-controlled grain boundary sliding.