冷芯复合钢锭组织及力学性能的实验研究

冷芯铸造技术是一种以固-液复合方式生产钢锭的铸造技术。本研究采用热物态模拟法制备冷芯钢锭,并利用光学显微镜、扫描电镜(SEM)等表征手段,分别观察了冷芯钢锭复合界面、芯材和外材的宏观及微观结构组织,并利用真空电火花仪、夏比冲击试验机和洛氏硬度仪检测了冷芯钢锭的碳元素含量分布及其力学性能。实验结果表明:冷芯钢锭结构自内而外分别为芯材组织层、扩散层、激冷凝固层、方向性生长层、正常凝固层及等轴细晶粒层;芯材与外材结合效果良好,结合界面平整、无孔洞或夹杂物等缺陷;冷芯钢锭各位置的冲击韧性大小关系为:芯材结合处外材;各位置碳含量分布与洛氏硬度值分布曲线相吻合。

Study of macro and micro structure and mechanical property of cold core ingot

To solve the defects that occur in the center of large steel ingot with metal mold,cold core casting process is rasied based on the liquid-solid composite casting technology. In this paper,the cold core ingot is fabricated in the laboratory. The surface appearance,fracture morphology,impact toughness and the hardness of the cold core ingot are characterized by optical microscopy,SEM,charpy impact test machine and rock-well hardness tester,respectively. The results show that cold core ingot was composite with core material lay-er,diffusion layer,chilling layer,directional solidification layer,normal solidification layer and equiaxed fine grain layer from the central line to the edge of cold core ingot; Moreover,a sound diffusion bond was achieved by atom transfer across the interface between the constituent steels. The impact toughness of core ma-terial(CM)is highest but outer material(OM)is lowest,and the impact toughness of interface material only a continuum between CM and OM. And it can be observed that the results of hardness is well matched with the results of carbon content.