回火冷却速率对30CrMnSiA组织与性能的影响

Effect of Cooling Rates During Tempering on Structure and Properties of 30CrMnSiA Steel

对退火态30CrMnSiA钢进行了回火冷却速率实验,探究回火后冷却速率对30CrMnSiA钢性能的影响及其组织演变规律。结果表明,回火冷却速率对30CrMnSiA钢硬度影响较小、对冲击韧性有一定影响,30CrMnSiA钢经510℃回火后表面主要受到压应力、心部受到拉应力,且回火冷速越快,试样表面残余应力越大。回火过程中C元素主要与Fe元素结合形成铁碳化合物,少量C元素与Cr、Si元素形成铬碳化合物、硅碳化合物。快冷范围内冷却速率对碳化物含量及尺寸影响较小。

Experiments on tempering at different cooling rates were conducted for annealed 30CrMnSiA steel to investigate the effect of cooling rate during tempering on the properties of tempered 30CrMnSiA steel and its microstructure evolution.The results show that the cooling rate during tempering has brought slight effect to the hardness,and a certain influence to impact properties of 30CrMnSiA steel.After tempering at 510℃,the 30CrMnSiA steel has its surface mainly subjected to compressive stress and the center subjected to tensile stress.A faster cooling rate during tempering will result in a higher residual stress on the surface of the sample.During the tempering process,C element mainly combines with Fe element to form Fe⁃C compounds,while a trace of C element,together with Cr and Si elements,forms Cr⁃C compounds and Si⁃C compounds.It is found that the rapid cooling rate has slight effect on the content and size of carbides.