铝包钢线拉拔断裂原因分析

Analysis of the Causes of Aluminum-clad Steel Wire F racturing During Drawing

铝包钢线是采用连续挤压包覆技术生产的双金属丝材,在拉拔过程中有时会断裂。为揭示铝包钢线断裂的原因,对一在同步拉拔工序断裂的直径4.3mm的高碳钢铝包钢线采用体视显微镜、扫描电子显微镜、能谱仪等进行了化学成分分析、断口分析和金相检验。结果表明:该铝包钢线为脆性断裂,显微组织为索氏体和上贝氏体,后者是由于高碳钢盘条存在严重的Mn元素偏析所致,增大了材料的脆性,同时,两种组织的变形性能不同,在拉拔过程中不能同步变形,从而导致断裂。

Aluminum-clad steel wire is a bimetal wire produced by a continuous extrusion cladding technology,breaks sometimes during drawing.To discover the cause of the aluminum-clad wire breaking,a high-carbon aluminum-clad wire 4.3 mm in diameter that broke in synchronous drawing was subjected to chemical composition analysis,fracture test and microstructure survey by means of stereomicroscope,scanning electron microscole,and spectrometer.The results demonstrated that the aluminum-clad wire was a brittle fracture,exhibited microstructure consisting of sorbite and upper bainite which stemmed from manganese segregation present in the high-carbon steel coil,render the material relatively brittle.At the same time,these two structures differ in deformability,thereby can not be synchronously deformed during drawing,resulting in the aluminum-clad wire fracturing.