Custom 450钢热加工图及显微组织分析

 为了探究Custom 450高强度不锈钢最佳的热变形区间以指导实际生产过程的工艺参数设计,利用Gleeble-3800热模拟试验机在变形温度为900~1 200 ℃、应变速率为0.01～10 s-1的条件下开展了热压缩试验,探讨了Prasad和Murty两种失稳判据在Custom 450钢中的适应性,确定了最佳的热变形区间和塑性失稳机制。研究结果表明,该钢在应变速率为0.2~10 s-1、变形温度为900~1 080 ℃的条件下变形时产生了大量的局部变形带和“项链状”组织,是导致塑性失稳发生的主要原因,显微组织观察结果与Murty准则预测的塑性失稳区更为接近。基于Murty准则建立了Custom 450钢的热加工图,并确定了其最佳的热加工工艺区间分别为1 050~1 200 ℃、0.1~1 s-1和1 100~1 200 ℃、1~10 s-1。

Hot processing map and corresponding microstructural analysis of Custom 450 stainless steel

In order to explore the best thermal deformation range of Custom 450 high-strength stainless steel to guide industrial production,the hot deformation test of Custom 450 steel was performed by a Gleeble-3800 thermal-mechanical simulator under the conditions of a temperature range of 900-1 200 ℃ and a strain rate range of 0.01-10 s-1.The applicability of Prasad and Murty instability criteria in Custom 450 steel was studied,and the best thermal deformation parameter interval and plastic instability mechanism were determined. A large number of local deformation bands and "necklace" structures formed when deformed at a strain rate range from 0.2 s-1 to 10 s-1 and a deformation temperature range from 900 ℃ to 1 080 ℃,which was the main reason in leading to the plastic instability. The Murty instability criteria was used in constructing the processing map of Custom 450 steel because the plastic instability zone predicted by the Murty criterion are more consistent with microstructure observation. Then,the optimal hot deformation conditions were also determined as 1 050-1 200 ℃,0.1-1 s-1,1 100-1 200 ℃,and 1-10 s-1.