AISI 410SS钢Ф200mm锻材轴心晶间裂原因分析与工艺改进

Cause Analysis and Process Improvement of Centre Intergranular Crack of Ф200 mm Forging of Steel AISI 410SS

规格Φ200 mm的AISI 410SS钢生产流程为20t电弧炉冶炼→LF→VD→3t铸锭→锻造。通过对轴心晶间裂的微观形貌、形成机理进行综合分析,钢液凝固过程中心部位置冷却慢导致成分偏析而形成的铁素体增加和夹杂物聚集,最终导致锻材轴心晶间裂。通过对成分进行调整,奥氏体形成元素分别由原0.11C-0.16Ni-0.55Mn增加至0.14C-0.45Ni-0.78Mn和铁素体形成元素由原12.84Cr-0.46Si-0.20Mo-0.0022 Nb减少至11.81Cr-0.31Si-0.10Mo-0.005Nb,铁素体由4%降至0.5%,轴心晶间裂由0.5级降至0级。

The production process of Φ200 mm steel AISI 410 SS is 20 t EAF-LF-VD-3 t ingot-forging.Through comprehensive analysis on the micro-morphology and formation mechanism of centre intergranular cracks,it is found that slow cooling of the central part of the liquid steel during solidification results in composition segregation,increasing ferrite formation and inclusion clustering finally led to forgings axis intergranular cracks.By adjusting the composition,increasing austenite-forming elements from original 0.11 C-0.16 Ni-0.55 Mn to 0.14 C-0.45 Ni-0.78 Mn and reducing ferrite-forming elements from original 12.84 Cr-0.46 S1-0.20 Mo-0.022 Nb to 11.81 Cr-0.31 Si-0.10 Mo-0.005 Nb,the ferrite in steel decreases from original 4% to 0.5% and the axis intergranular crack rating decreases for 0.5 rating to 0.