40 t EBT EAF-LF-VD-铸锭工艺冶炼模具钢H13的洁净度分析

试验用热作模具钢H13(/%:0.36~0.38C、0.36~0.38Mn、0.89~0.91Si、0.007~0.010P、0.006~0.011s、5.10~5.15Cr、1.12~1.18Mo、0.84~0.89V)的冶炼工艺流程为40 t偏心炉底出钢电弧炉-钢包炉精炼-VD处理4.65 t铸锭工艺。通过对各冶炼工序钢水的总氧和氮含量-T[O]和[N]的分析以及钢中夹杂物的形貌和组成的分析,研究了该工艺流程生产的H13钢的洁净度。结果表明,经LF-VD精炼后H13钢中的平均总氧含量-T[O]为22×10^-6,平均氮含量-[N]为95×10^-6;Φ200 mm锻坯中夹杂主要以脱氧产物氧化铝为主,同时含有硫化锰等硫化物和偏析产生的氮化物;夹杂物尺寸集中在5μm左右,较大尺寸的夹杂物为10μm左右。采用该流程冶炼的H13钢可以满足对该钢种洁净度的要求。

An Analysis on Cleanliness of Die Steel H13 Steelmaking by 40 t EBT EAF-LF-VD-Ingot Casting Process

The steelmaking process for test hot working die steel H13 (/% : 0.36-0.38C, 0.36-0.38Mn, 0.89-0.91Si, 0.007-0.010P, 0.006-0.011S, 5.10-5.15Cr, 1.12-1.18Mo, 0.84-0.89V) is 40 t eccentric bottom tapping arc furnace-ladle furnace refining-VD treatment-4. 65 t ingot casting process. With analysis on total oxygen and nitrogen content in liquid- T [O] and [ N] , and analysis on morphology and ingredient of inclusions in steel, the cleanliness of steel H13 produced by this process flow sheet has been studied. Results show that after refining by LF-VD process the average total oxygen content in steel H13- T[O] is 22 x 10^-6 and the average nitrogen- [N] is 95 x 10^-6 ； the main inclusions in Φ200 mm forging are deoxidation products- aluminium oxide with sulHdes including manganese sulfide and nitride formed by segregation ； the sizes of inclusions are mainly about 5 μm, the sizes of some inclusions can come up to about 10 μm. The steel H13 steelmaking by this flow sheet could meet the requirement for cleanliness of that steel grade.