摘要
针对大型渗碳件在深层渗碳时的组织粗化和性能较差的问题,研究了添加稀土元素对渗碳钢在长时间加热渗碳热处理过程中,加稀土元素的钢对阻止奥氏体晶粒长大和提高力学性能的作用。结果表明:稀土元素对细化渗碳钢的奥氏体晶粒及提高其力学性能具有很好的效果,稀土钢20CrNi2MoRE 在930℃经140h 加热后奥氏体晶粒仍旧细(>7级),渗碳层的弯曲强度、断裂韧性很高,而原钢种20CrNi2Mo 钢的奥氏体晶粒很粗(3～4级),其渗碳层即使经二次淬火,其强度和韧性仍不能较好恢复,具有遗传性。
Aimed at coarse structures and bad properties of large-size parts in deep carburizing influence of rare-earth elements on fining austenite grain and deep case carburizing has been studied. The results show that rare-earth elements have a good effect on structures and properties of case-hardened steel.Carburized at 930℃×140 h,20CrNi2MoRE had finer austenitic grain(No.7),much high bending strength and fracture toughness property;while original 20CrNi2Mo has coarse grain (grain size No.3～4),and its strength and toughness can not be recovered obviously,even though secondary quenching is carried out.
关键词
深层渗碳
奥氏体
晶粒度
钢
稀土族
deep-case carburizing
austenite grains size
rare-earth element
