Abstract: The production flowsheet for anchor steel CM690 is hot metal pretreatment-80 t BOF-LF-RH-200 mm x 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. 29C, 0. 21 Si, 1. 58Mn, 0. 017P, 0. 012S, 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 x 10^-6 ~ 70 x 10^-6 to 40 x 10^-6 ~50 x 10^-6 , decreasing liquid superheating extent from 25 ~ 40 ℃ to 25 ~ 35 °C , 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.

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。

关键词: CM690锚链钢, 发纹, MnS, TiN, 带状组织