循环淬火-回火处理对90CrMnTi钢冲击韧性的影响  

Effect of cyclic quenching-tempering process on impact toughness of 90CrMnTi steel

作　　者：鲁军[1] 王春燕[1] 蔡叶青[1] 韦习成[1] 王武荣[1] 

机构地区：[1]上海大学材料科学与工程学院,上海200072

出　　处：《材料热处理学报》2014年第1期71-76,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金项目(50975166);2012年上海高校青年教师培养资助计划(B.37-0110-12-017)

摘　　要：采用OM、SEM、TEM和XRD等分析方法，研究了90CrMnTi钢经780℃淬火（1～3）次和180℃回火处理后的组织和性能，分析了循环淬火-回火处理对冲击韧性的影响。研究表明，循环淬火显著改善了90CrMnTi钢的冲击韧性，但对其硬度的影响较小。经3次淬火后其晶粒尺寸从1次淬火的约18μm减小到3μm，马氏体片的宽度明显变窄，未溶碳化物减少和残留奥氏体量增加。宽度20—70nm的薄膜状残留奥氏体分布于马氏体片间或马氏体片与碳化物的交界处，且与相邻马氏体满足K—S或N—W位向关系。90CrMnTi钢冲击韧性显著提高的根本原因是循环淬火一回火处理所致的晶粒超细化、马氏体片细化和碳化物减少及残留奥氏体量增加的综合作用的结果。Microstructure and properties of 90CrMnTi steel after cyclic quenching at 780 ℃ and tempering at 180 ℃ were investigated by means of OM, SEM, TEM, and XRD methods, and the effect of cyclic quenching-tempering on impact toughness was analyzed. The results show that the impact toughness of the steel after the cyclic quenching is effectively enhanced and its hardness is hardly changed. After quenching at 780 ℃ for 15 min by three times, the austenite grain size significantly decreases from about 18 μm to 3 μm, quenched by one time the width of martensite plates obviously decreases, undissolved carbide content decreases and retained austenite content increases. The film-shaped retained austenite with width of 20 - 70 nm locates on the boundaries of martensite plates or carbides, and has K-S and N-W orientation relationships with neighboring martensites. The obvious enhancement of impact toughness is attributed to the comprehensive function of the refined austenite grain and martensite plate, the decreasing carbide content and the increasing of retained austenite content.

关 键 词：循环淬火 冲击韧性 奥氏体晶粒 残留奥氏体 

分 类 号：TG142.4[一般工业技术—材料科学与工程]