汽车用65SiCrV6弹簧钢丝表面处理工艺改进

Improvement of surface treatment process of 65SiCrV6 spring steel wire for automobile

汽车用65SiCrV6弹簧钢丝拉拔时出现严重横向裂纹缺陷。利用体视显微镜、扫描电镜及能谱等手段对钢丝表面横向裂纹缺陷形成的原因进行分析,发现在横向裂纹缺陷附近的钢丝表面存在残留的氧化铁皮。对生产工艺流程和相关工艺参数进行改进,由原来的间歇式酸洗磷化改为在线酸洗磷化;充分利用正火余温并实施两道酸洗;使用酸性草酸表调剂并调整酸洗与磷化工艺参数。改进后的钢丝表面氧化层酸洗干净、磷化均匀,钢丝表面质量能满足拉拔工序使用要求。

Severe transverse cracking defects occurred during drawing of 65SiCrV6 spring steel wire for automobile.The causes of transverse cracking defects were analyzed by metallographic microscope,SEM and EDS.It was found that there were residual oxide scale on surface of steel wire near transverse crack defects.The process flow and process parameters are improved.The original intermittent acid pickling and phosphating has been changed to online acid pickling and phosphating.Fully utilize residual temperature of normalizing and implement two acid pickling procedures.Use acidic oxalic acid surface adjustment agent and adjust process parameters of acid pickling and phosphating.The oxide layer on surface of steel wire is pickled clean and phosphating film is uniform after improved,steel wire surface quality can meet requirements of drawing process.