论文部分内容阅读
30CrNi5MoV是近年来国内发展的一种应用于高压容器等大型锻件的高强度合金结构钢。生产中发现,它的奥氏体晶粒度一般为4～5级。大锻件晶粒粗大,是由整个生产工艺过程的特点所决定的,其中重要原因是加热速度缓慢,保温时间长。钢中加入微量强碳化物形成元素,如Nb,细化奥氏体晶粒,对于小型工件很是有效,但是对大型锻件的效果却有不同的看法。Nb、V等微量元素.引起奥氏体晶粒细化,一般认为是由于未溶解的碳化物在加热过程中阻止晶粒长大的结果。Zener和Gelandman的理论指出,在
30CrNi5MoV is a kind of high-strength alloy structural steel used in large-scale forgings such as high-pressure vessels developed in China in recent years. Found in production, its austenite grain size is generally 4 to 5. Large forgings coarse grain, is the characteristics of the entire production process is determined, of which the important reason is the slow heating, holding a long time. Adding trace amounts of strong carbides to steel to form elements such as Nb and refine austenite grains is effective for small workpieces but has a different view on the effectiveness of large forgings. Nb, V and other trace elements cause austenite grain refinement, generally considered to be due to undissolved carbides in the heating process to prevent the grain growth results. The theory of Zener and Gelandman points out