09CrCuSb钢方坯表面裂纹形成机理及控制实践  

Formation mechanism and practical control of surface crack for 09CrCuSb steel billet

作　　者：史伟宁 叶明在 徐吉尤 王军[1] 王柳 袁渊 SHI Weining;YE Mingzai;XU Jiyou;WANG Jun;WANG Liu;YUAN Yuan(Steelmaking Plant,Xiangtan Iron&Steel Group Co.,Ltd.,Xiangtan 411101,Hunan,China;Technology and Quality Department,Xiangtan Iron&Steel Group Co.,Ltd.,Xiangtan 411101,Hunan,China)

机构地区：[1]湘潭钢铁集团有限公司炼钢厂,湖南湘潭411101 [2]湘潭钢铁集团有限公司技术质量部,湖南湘潭411101

出　　处：《连铸》2023年第4期41-47,共7页Continuous Casting

摘　　要：09CrCuSb钢以其优异的耐硫酸露点腐蚀性能在省煤器、热交换器等设备的制造中广泛应用,但09CrCuSb钢在连铸过程中极易出现表面裂纹,从而严重影响成材率,成为亟待解决的问题。通过金相显微镜及扫描电子显微镜分析明确了原工艺参数条件下裂纹缺陷产生的原因为铸坯表层晶界上Cu及先共析铁素体的析出。通过将结晶器水量从2 166.67 L/min提高至2 666.67 L/min,结晶器电磁搅拌电流从400 A提高至450 A,二冷比水量从1.10 L/kg提高至1.20 L/kg,拉速从2.5 m/min提高至3.2 m/min,并在进出拉矫机范围内施加保温装置,有效抑制了铸坯表层晶界Cu及先共析铁素体的析出,铸坯表面质量优异,轧制圆钢磁粉探伤合格率从19.19%提高至99.07%。09CrCuSb钢方坯裂纹控制的开发实践为同系列低碳含Cu钢的铸坯裂纹控制提供了新思路。09CrCuSb steel is widely used in the manufacturing industry of economizer,heat exchanger and other equipment due to its excellent sulfuric acid dew point corrosion resistance.However,09CrCuSb steel is prone to surface cracks during continuous casting,which seriously affects the yield,so it becomes an urgent problem to be solved.Through the analysis of metallographic microscope and scanning electron microscope,it was clear that the cause of crack defects under the original process parameters was the precipitation of Cu and proeutectoid ferrite on the grain boundary of the billet surface.By increasing the mold water flow rate from 2166.67 L/min to 2666.67 L/min,the mold electromagnetic stirring current from 400 A to 450 A,the specific water volume of the secondary cooling system from 1.10 L/kg to 1.20 L/kg,the casting speed from 2.5 m/min to 3.2 m/min,and applying the thermal insulation device within the range of in and out tension leveler,the precipitation of Cu and proeutectoid ferrite on the grain boundary of the billet surface layer is effectively inhibited.As a result,the excellent surface quality of the billet is obtained,and the qualified rate of magnetic particle flaw detection of rolled round steel is increased from 19.19%to 99.07%.The idea and development practice of 09CrCuSb steel billet crack control provide a new idea for the billet crack control of the same series of low carbon steel containing Cu.

关 键 词：09CrCuSb钢 铸坯表面裂纹 Cu析出 先共析铁素体 磁粉探伤合格率 

分 类 号：TF777[冶金工程—钢铁冶金]