CM690锚链钢发纹缺陷形成分析和工艺改善  

Analysis on Capillary Crack Defect in Anchor Steel CM690 and Process Improvement

作　　者：马建超 石可伟[2] 杨勰[2] 

机构地区：[1]江苏省(沙钢)钢铁研究院,张家港215625 [2]江苏沙钢集团淮钢特钢股份有限公司,淮安223002

出　　处：《特殊钢》2015年第3期17-20,共4页Special Steel

摘　　要：CM690锚链钢的生产流程为铁水预处理-80 t BOF-LF-RH-200 mm×200 mm方坯连铸-轧制成φ50mm圆钢工艺。钢材分析结果表明,酸蚀过程中,CM690钢(/%:0.29C,0.21Si,1.58Mn,0.017P,0.012S,0.017Ti)中条串状MnSTiN夹杂物及其周围带状富碳组织被腐蚀形成发纹状缺陷,另外,富碳贝氏体和珠光体亦逐渐腐蚀。通过控制RH终点[S]0.004%~0.007%,[N]从原55×10^(-6)~70×10^(-6)降至40×10^(-6)~50×10^(-6),钢水过热度从25~40℃降至25~35℃,控制连铸拉速在1.3 m/min,二冷比水量由0.35 L/kg增至0.40 L/kg,基本消除了钢中的发纹缺陷。The production flowsheet for anchor steel CM690 is hot metal pretreatment-80 t BOF-LF-RH-200 mm × 200 mm billet casting-rolling to Φ50 mm round bar process.The products analysis results show that during acid etching process the string cluster MnS and TiN inclusions with around banded rich carbon structure in steel CM690（/%：0.29 C,0.21 Si,1.58 Mn,0.017 P,0.012 S,0.017Ti） are corroded to form capillary crack defect,and the rich carbon bainite and pearlite also corroded gradually.With controlling RH end[S]0.004%0.007%,decreasing[N]from original 55 × 10-6 70 × 10-6 to 40 × 10 -6 50 × 10-6,decreasing liquid superheating extent from 25 40 ℃ to 25 35℃,controlling casting speed 1.3 m/min and increasing secondary cooling water ratio from 0.35 L/kg to 0.40 L/kg,the capillary crack defects in steel products are basically eliminated.

关 键 词：CM690锚链钢 发纹 MNS TIN 带状组织 

分 类 号：TF76[冶金工程—钢铁冶金]