40Cr钢低温超塑性的研究

INVESTIGATION ON LOWTEMPERATURE SUPERPLASTICITYOF40Cr STEEL

研究了40Cr钢的低温超塑性。结果表明:经3次840℃×40 min水淬+650℃×2h回火的超塑性预处理后,40Cr钢的组织为回火索氏体,晶粒尺寸为5-10μm,在温度为650℃、初始应变速率为3.16×10-4 s-1的拉伸变形条件下,流变应力为:108.1 MPa,断后伸长率为254％,应变速率敏感性指数m值为0.221,超塑变形的主要机制可描述为原子扩散控制的晶界滑动。

The low temperature superplastic characteristics, of commercial 40Cr steel that is 3 cycles water-quenched and subsequent high-temperature tempered, are investigated. The results show that the 40Cr steel has a fine grain of 5-10 μm, and exhibited a elongation of 254%, a flow stress of 108.1 MPa and a strain rate sensitivity m-value of 0.221 at the temperature of 650 ℃ and at the initial strain rate of 3.16×10-4 s-1. The primary superplastic deformation mechanism is thought to be atom-diffusion-controlled grain boundary sliding.