论文部分内容阅读
本文研究了13Cr-4Ni型马氏体不锈钢中因回火脆化而导致的韧性下降的机理。韧性的变化、脆断的模式以及残留奥氏体的份额均被作为回火温度和550～450℃范围中的随后等温处理的函数而进行了考察。在较低的温度下回火和在较高的温度下进行随后等温处理之后,FATT的提高和晶间断裂在份额上的增加,被认为是回火脆化现象。业已发现,脆化及晶间断裂,与沿原始奥氏体晶界上的碳化物沉淀有关。脆化的程度,实质上与原始奥氏体晶界上的磷的偏析无关。晶间碳化物的沉淀,源自回火期间逆变奥氏体中碳的溶解度降低。随着回火温度的升高,该钢种的回火脆化敏感性受到了抑制。
In this paper, the mechanism of the ductility reduction caused by temper embrittlement in 13Cr-4Ni martensitic stainless steel was studied. Toughness changes, brittle modes, and residual austenite content were all examined as a function of tempering temperature and subsequent isothermal treatment in the 550-450 ° C range. After tempering at lower temperatures and subsequent isothermal treatment at higher temperatures, an increase in the FATT and an increase in intergranular fracture fraction are considered temper embrittlement phenomena. It has been found that embrittlement and intergranular fracture are associated with precipitation of carbides along the original austenite grain boundaries. The degree of embrittlement is virtually independent of the segregation of phosphorus on the original austenite grain boundaries. Precipitation of intergranular carbides results from reduced solubility of carbon in the transformed austenite during tempering. With the tempering temperature increases, the temper embrittlement sensitivity of the steel is suppressed.