焊丝用高合金铬钼钢线材拉拔缺陷分析

Drawing Defect Analysis of the High Alloy CrMo Steel Used for Welding Wire

利用光学显微镜观察了高合金铬钼钢线材经拉拔后出现的弧形裂纹和横截面显微组织形貌，分析了热轧盘条中马氏体的形成原因，探讨了弧形裂纹产生的机理并提出了工艺改进建议。结果表明，该材料临界淬火冷却速度约0．16℃／s（10℃／min），轧后冷却速度过快导致盘条组织为板条马氏体，拉拔过程中线材表面的马氏体在拉应力作用下开裂是弧形裂纹形成的主要原因，当线材组织为马氏体时应在拉拔前进行高温回火处理，为避免马氏体可从终轧奥氏体状态和轧后冷却工艺控制两方面开展研究。

The arc crack and cross section microstructtn＇e of the high alloy CrMo steel were observed by OM and SEM, the cause of martesite in the wire rod was analyzed by the CCT curves of the steel, both the formation mechanism and technology improvement were discussed. The results showed that the critical quenching cooling rate（v~＇） for the tested steel was about 0.16℃/s （10℃/min）, the formation of the martensite was caused by the too fast cooling rate after rolling, martensite cracked under tensile stress during drawing, this was the main cause for the arc cracks in the wire surface, the wire with martensite should be tempered by high temperature, austenite state and cooling process were two aspect can be studied to avoid martensite transformation.