铜包钢和锌包钢双金属复合接地极材料的组织与缺陷分析

Analysis on Microstructure and Defect of Copper Clad Steel and Zinc Clad Steel Bimetallic Grounding Electrode Materials

采用金相显微分析、扫描电镜组织观察以及能谱分析等方式,对水平连铸生产的铜包钢和锌包钢两种双金属复合材料的界面组织和结构进行观察,探讨其结合机理。研究了其界面存在的缺陷,以提供工艺优化方案。结果表明,铜包钢中,Cu原子主要通过晶界深入扩散至钢基体,Cu/Fe界面已达到冶金结合;钢芯在熔炉中内部残余应力释放,发生微小形变,导致铜包钢包覆的铜层厚度不均。锌包钢中,Zn原子和Fe原子并未深入扩散至对方基体中;由于锌和钢热胀系数相差较大,Zn/Fe界面产生来了较大内应力,导致界面产生较大裂纹。

The interface microstructure and structure of copper clad steel（CCS） and zinc clad steel（ZCS） were analyzed with several methods, including optical microscopy, scanning electron microscopy, energy spectrum, etc. The bonding mechanism was discussed in details. Moreover, the defects in the interface were investigated in order to provide suggestions for process optimization. The results show that, for CCS, Cu atoms diffuse into Fe matrix through grain boundary. The metallurgical bonding of Cu/Fe can be completed by horizontal continuous casting. The thickness of Cu layer is not uniform,due to the internal residual stress released by steel core in the melting pot. For ZCS, the Zn atoms and Fe atoms never diffuse deeply into other matrix. The difference of thermal expansion coefficient between Zn and steel matrix induces remnant stress in the interface, which can result in the initiation and propagation of crack.