焊接结构用钢SM490B冷弯开裂原因分析及改进措施  

Causes Analysis and Corrective Measures of Cold Bending Crack of SM490B Steel Plate for Welded Structure

作　　者：周桂成 洪君 李明 Zhou Guicheng;Hong Jun;Li Ming(Nanjing Iron and Steel Co.,Ltd.)

机构地区：[1]南京钢铁股份有限公司

出　　处：《宽厚板》2024年第6期18-21,共4页Wide and Heavy Plate

摘　　要：通过低倍酸浸腐蚀、金相和电子探针扫描等检测手段,对焊接结构用SM490B钢板在冷弯过程中出现的裂纹进行分析。结果表明:钢中存在磷元素偏析带和长条状硫化物聚集两种不利因素交织影响,是SM490B钢板出现冷弯开裂的主要原因。在炼钢工序采取铁水预脱硫、转炉加入脱磷剂、钙处理等措施,降低钢水中硫、磷含量,提高钢水的纯净度,可有效解决SM490B钢板冷弯开裂问题。The cracking occured in cold bending of SM490B steel plate for welding structure is analyzed by means of low magnification acid eching,metallographic and electronic microprobe examination.The results show that the interweaving influence of the two negative factors such as the phosphorus segregation band and aggregated long strip sulfide in the steel is the major cause of the SM490B steel plate cracking in cold bending.Measures such as hot metal pre-desulurization,adding dephosphorizing agent into converter,calcium treatment in the process of steelmaking are taken,so that the sulfur and phosphorus contents in the molten steel are reduced and the cleanliness of the molten steel is improved,which can effectively resolve the SM490B steel plate cracking problem in cold bending.

关 键 词：冷弯开裂 磷偏析 硫化物夹杂 微裂纹 铁水预脱硫 钙处理 

分 类 号：TF7[冶金工程—钢铁冶金]