3种模具钢组织与性能的对比研究
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摘要
采用金相显微镜、洛氏硬度计、冲击试验机与扫描电镜(SEM)对淬火+回火热处理后的SKD11钢、GD钢和LD钢的组织、硬度、冲击韧性及断口形貌进行了测试和分析。研究结果表明:3种钢经淬火+回火后的组织均由针状马氏体+碳化物+少量残余奥氏体构成,但马氏体和碳化物的形态有明显不同;淬火+回火后SKD11钢的硬度值为55.6 HRC,冲击能量约为63 J,GD钢的硬度值为58.6 HRC,冲击能量约为31 J,LD钢的硬度值为58.8 HRC,冲击能量约为75 J。3种模具钢断口宏观形貌均呈现出微量塑性变形的微晶瓷状特征,微观断口形貌为撕裂棱相连的小块解理面,3种钢的断裂机理均为准解理脆性破断。
The microstructure, hardness, impact toughness and fracture morphology of SKD11 steel, GD steel and LD steel after quenching and tempering treatment were tested and analyzed by metallographic microscope, Rockwell hardness tester, impact tester and scanning electron microscopy(SEM). The results showed that the structures of three steels after quenching and tempering were composed of needle martensite, carbide and a small amount of retained austenite, but the morphology of martensite and carbide was obviously different. The hardness of SKD11 steel after quenching and tempering was 55.6 HRC and the impact energy was about 63 J. The hardness of GD steel was 58.6 HRC and the impact energy was about 31 J. The hardness of LD steel was 58.8 HRC and the impact energy was about 75 J. The fracture morphology of the three kinds of die steels presented microcrystalline ceramic-like characteristics of microplastic deformation. The microfracture morphology was a small cleavage surface connected by tearing edges. The fracture mechanism of the three kinds of steels were quasi-cleavage brittle fracture.
The microstructure, hardness, impact toughness and fracture morphology of SKD11 steel, GD steel and LD steel after quenching and tempering treatment were tested and analyzed by metallographic microscope, Rockwell hardness tester, impact tester and scanning electron microscopy(SEM). The results showed that the structures of three steels after quenching and tempering were composed of needle martensite, carbide and a small amount of retained austenite, but the morphology of martensite and carbide was obviously different. The hardness of SKD11 steel after quenching and tempering was 55.6 HRC and the impact energy was about 63 J. The hardness of GD steel was 58.6 HRC and the impact energy was about 31 J. The hardness of LD steel was 58.8 HRC and the impact energy was about 75 J. The fracture morphology of the three kinds of die steels presented microcrystalline ceramic-like characteristics of microplastic deformation. The microfracture morphology was a small cleavage surface connected by tearing edges. The fracture mechanism of the three kinds of steels were quasi-cleavage brittle fracture.
引文
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