82B盘条网状渗碳体形成原因及控制措施探析  

Analysis on Formation Mechanism and Control Measures of Reticulated Carburizing Body for 82B Rod

作　　者：刘颖 Liu Ying(Technology Center,HBIS Group Xuanhua Steel Company,Xuanhua Hebei 075100,China)

机构地区：[1]河钢宣钢技术中心,河北宣化075100

出　　处：《山西冶金》2023年第7期50-52,56,共4页Shanxi Metallurgy

摘　　要：为探明Φ12.5 mm 82B硬线盘条网状渗碳体形成机理,采用碳元素分析与金相组织检测相结合的方法,研究盘条径向上碳元素分布规律及不同级别网状渗碳体的显微金相组织。研究结果表明:在铸坯冷却过程中渗碳体沿奥氏体晶界析出,而w(C)高是形成网状渗碳体的主要原因,在盘条径向上w(C)呈抛物线规律分布,w(C)随距中心点距离的增大先升高后降低,在距中心点4~4.5 mm的点位上w(C)达到峰值,最高为0.827%,C偏析指数为1.02;网状渗碳体等级随着w(C)增大而升高,当网状渗碳体达到2级时,晶界处存在较强的应力集中,裂纹快速发展,盘条的质量大幅降低,引发拉拔脆断;通过优化控冷参数,1级以下级别网碳出现概率提高了4.73%,达到96.33%,钢材质量均匀性大幅提升。In order to investigate the formation mechanism of Φ12.5 mm 82B hard wire rod mesh cementite,the carbon element analysis and microstructure detection were combined to study the distribution law of carbon element in the radial direction of the wire rod and the microstructure of different levels of mesh cementite.The results show that the cementite precipitates along the austenite grain boundary during the cooling process,and the high mass fraction of carbon element w(C)is the main reason for the formation of network cementite.The distribution of w(C)is parabolic in the radial direction of the wire rod.The w(C)increases first and then decreases with the increase of the distance from the center point.The w(C)reaches the peak at the point of 4~4.5 mm from the center point,the maximum is 0.827%,and the C segregation index is 1.02.The network cementite grade increases with the increase of w(C).When the network cementite reaches grade 2,there is a strong stress concentration at the grain boundary,the crack develops rapidly,and the quality of the wire rod is greatly reduced,which leads to brittle fracture.By optimizing the cooling control parameters,the carbon mesh below grade 1 has increased by 4.73 percentage points to 96.33%,and the uniformity of steel quality has been greatly improved.

关 键 词：82B 硬线盘条 金相检测 碳偏析 网状渗碳体 

分 类 号：TG356[金属学及工艺—金属压力加工]