淬火对含ZrC的20Mn2钢的组织及力学性能的影响  

Effect of quenching process on the microstructure and mechanical property of 20Mn2 steel containing ZrC particles

作　　者：刘志义[1] 许晓嫦[1] 邓小铁[1] 李海[1] 

机构地区：[1]中南大学

出　　处：《材料研究学报》2004年第1期39-45,共7页Chinese Journal of Materials Research

基　　金：国家自然科学基金59971031资助项目.

摘　　要：研究了淬火冷却对含0.2％(体积分数)ZrC颗粒(粒径0.2-1.2μm)的20Mn2钢在大形变量轧制后的组织与力学性能的影响.结果表明, ZrC粒子作为大形变量热轧变形中的奥氏体形变核心及再结晶核心,对奥氏体晶粒的超细化有显著的作用,而显著细化的晶粒提高了完全获得马氏体组织的临界冷却速度,使水冷淬火态马氏体的数量、长度和宽度减小,使油淬态珠光体的数量减少、渗碳体片变短、变薄.在冷却过程中,细小的奥氏体晶粒转变为更细小(1-2μm)的铁素体晶粒,保留了热轧变形时的形变位错组织,使水淬态20Mn2钢的延伸率不下降的同时强度成倍提高,油淬态20Mn2钢在强度大幅度提高的同时延伸率成倍提高.Effect of quenching process on the microstructure and mechanical property of 20Mn2 steel containing ZrC of 0.2% in volume fraction and 0.2-1.2 μm in diameter after rolling with large total reduction has been investigated. The experimental results show that when quenched in water, the mechanical property of 20Mn2 reaches σ0.2=1722 MPa, δ5=12.6%, after tempered at 200°C for 200 min, σb=1685 MPa, σ0.2=1582 MPa, δ5=14.1%; while quenched in oil, σb=1073 MPa, σ0.2=839, δ=19%, after tempered at 200°C for 200 min, σb=1039 MPa, σ0.2=810 MPa, δ5=21.1%. It is indicated that ZrC particle plays an obvious active role in grain super-refining of austenite by acting as a deformation nucleus and recrystallization nucleus, and obvious refined grain increases critical cooling rate for obtaining martensite that decreases the number, length and width of martensite in water-quenching state, and the number of pearlite in oil-quenching sate, while the ferric carbide becomes shorter and thinner. Meanwhile, in subsequent cooling refined austenite grain transforms to a finer ferrite grain (1-2 μm), and keeps deformed microstructure in hot rolling, which leads to a double increase in the strength of 20Mn2 in water-quenching state without decrease in elongation, and a double increase in elongation of oil-quenching state with a concurrent great increase in the strength.

关 键 词：金属材料 ZRC粒子 超塑预处理 20MN2钢 晶粒细化 强韧化 

分 类 号：TG113[金属学及工艺—物理冶金]