高强韧低合金冷作模具钢6CrNiMnSiMoV的强韧化特性  

ON THE CHARACTERISTICS OF STRENGTHENINGTOUGHENING IN A HIGH-STRENGTH HIGHTOUGHNESS LOW ALLOY COLD-WORKING DIE STEEL 6CrNiMnSiMoV

作　　者：黄光晖[1] 曹念荪[1] 孙培祯 乔学亮[1] 

机构地区：[1]华中理工大学

出　　处：《材料研究学报》1994年第1期29-34,共6页Chinese Journal of Materials Research

基　　金：国家自然科学基金

摘　　要：研究了钢的微观结构、残余奥氏体的稳定性及力学性能随回火温度的变化，结果表明：钢的基体为细晶马氏体，且大部分具有位错亚结构；马氏体板条界上存在着较稳定的残余奥氏体薄膜；马氏体内均匀分布着大量固溶时未溶、５－５０ｎｍ大小的Ｖ４Ｃ３；２００－３００℃回火析出大量细小的ε－碳化物．这种微观结构对于获得高强韧性是理想的、Ｓｉ使ε－碳化物的溶解和渗碳体的形成温度提高到３００℃以上。A new high-strength high-toughness low alloy cold-working die steel 6CrNiMnSiMoV (GD Steel) has been developed. The amount of alloy elements in the steel is less than 5%, but the strength and toughness of the steel are superior to that of CrWMn and Cr12MoV steels. In addition, the new steel is of high wear resistance and good process properties. The composition (wt-%) of experimental steel is following: 0.71 C, 1 .1 1 Mn, 1 .11I Si, 1 .22 Cr, 0.92 Ni, 0.22 V, 0. 18p and an amount of Mo.The strength and hardness of GD steel decrease with increase of tempering temperature. However, thehigh levels, σ0.2comp more than 2.4GPa and HRC hgiher than 58, are still retained as the tempering temperatures are lower than 300t. The changes of toughnesses of the steel with tempering temperature are notmonotonically. It can obtain good toughness, 20-23J/cm2 in ah and 20-24MPaml/2 in K1c' after tempering at temperature of 200-300℃.The microstructure of GD steel quenched and tempered consists mainly of martensite. In morphology,martensite is of parallel and inter-cross in various angles lath types. The arrangement of laths is disordered. Most laths have the width of 0. 1-0.4μm. The thin martensite laths contribute to increasing both strength and toughness very much. TEM observation found that the volume fraction of lath martensite with dense and tangled dislocations was about 80%, even more.. The retained austenite in GD steel predominantly exists at martensite lath boundaries in the form of continuous thin film, which has the thickness of 5-25nm. It is identified that the interlath retained austenite hasK-S and N-W orientation relationships to the neighbouring laths on two sides, respectively. The investigations indicate that the retained austenite of GD steel is of thermal and mechanical unstability to some extent,but not serious. It is worthy to notice that whether deformed specimens or undeformed, the quantity of retained austenite in them are all 8% after tempering at 400℃. It indicates that some of retained auste

关 键 词：强韧性 冷作模具钢 结构 

分 类 号：TG142.33[一般工业技术—材料科学与工程]