摘要
研究了超高碳钢进行二阶段等温淬火处理后的组织与冲击韧性。结果表明,二阶段等温淬火中较低温度的一阶段等温,与直接等温相比,贝氏体转变被推迟;随着提高一阶段的等温温度,二阶段的贝氏体转变大大加速;当一阶段等温未发生贝氏体转变或量很少时,最终贝氏体形态取决于二阶段等温温度。经250℃×10 min+300℃×10 min工艺处理后,获得以下贝氏体为主含有少量残余奥氏体或马氏体复合组织的超高碳钢,表现出高硬度(56 HRC)和高的冲击韧性(120 J)。
Microstructure and impact toughness of the ultrahigh carbon steel processed by two-stage austempering were investigated.Compared only one stage austempering with the two-stage austempering in which a low temperature was adopted during the first-stage,the bainite grown slowly.As the holding temperature rised of the first-stage holding,bainite transformation greatly accelerated in the second-stage holding.When bainite transformation occured in very small extent or not during first-stage,the final morphology of bainite depended on mainly the holding temperature of the second-stage.Tearted by 250 ℃×10 min ＋300 ℃×10 min of two stage austempering,ultrahigh carbon steel exhibited complex microstructucture containing bainite and a small amount of residual austenite or martensite with high hardness（56 HRC） and high impact toughness（120 J）.
出处
《热处理技术与装备》
2012年第6期20-24,31,共6页
Heat Treatment Technology and Equipment
关键词
超高碳钢
二阶段等温淬火
贝氏体
ultrahigh carbon steel
two-stage austempering
bainite
