Abstract: The production process flowsheet of steel C38N2 (/% : 0. 36 〜0.40C, 0. 50 ~0. 65Si, 1.40 ~ 1. 55Mn, ≤ 0.025P, 0.010 ~0.040S, 0. 10 ~0,25Cr, ≤ 0.01A1, 0.015 ~0.020N) is 120 t-BOF-LF-RH-410 mm x 530 mm bloom casting-continuous rolling to Φ170 mm products. The statistics of effect of refining slag basicity (2. 0 ~ 2. 5 ) , Ca content in finished steel (0 ~ 0.075%), tundish shielding agent basicity (5. 94 and 1.70), secondary cooling water (0. 14 ~0. 24 L/kg) and mould electromagnetic stirring current (250 A and 100 A) on sulfide in steel has been analyzed. With process measures including using 2 ~3 low basicity slag .in refining, controlling [ Ca]/[ S]>0. 03 , using tundish shielding agent basicity 1. 70, secondary cooling water rate 0. 24 L/kg and mould electromagnetic stirring current 100 A, the ratio of rating ≤2. 5 of A-thin series sulfide in steel increases from 80% before process improvement to 95% , and the fine, dispersed distributed spheroidal and spindle-shaped sulfide in steel increases markedly.

摘要： C38N2钢(/%:0. 36～0.40C,0. 50～0.65Si,1. 40～1. 55Mn,≤0. 025P,0. 010～0.040S,0.10～0.25Cr,≤0.01Al,0. 015～0.020N)的生产工艺流程为120 t BOF-LF-RH-410 mm×530 mm连铸坯-连轧成Φ170 mm材。统计分析了精炼渣碱度(2. 0～5. 5)、成品钢中Ca含量(0～0. 075%)、中间包覆盖剂碱度(5. 94和1.70)、二冷水(0. 14～0. 24 L/kg)和结晶器搅拌电流(250 A和100 A)对钢中硫化物的影响,通过采用2～3低碱度精炼渣,控制[Ca]/[S]>0.03,使用1.70碱度中间包覆盖剂,二冷水0.24 L/kg,结晶器搅拌电流100 A等工艺措施,使钢中A类细系硫化物≤2.5级的比率从工艺改进前80%提高至95%,钢中小尺寸、弥散分布的球形或纺锤形硫化物明显增多。

关键词: 含硫易切削钢C38N2, MnS, 钙处理, 形态控制, 二冷水, 结晶器电磁搅拌