Abstract: The steel B7(40CrMnMo) for high strength heat-resisting bolts is produced by 70 t Consteel UHP arc furnace - 70 t ladle refining furnace - 4 strand 150 mm×150 mm concasting- continuous rolling process at Egang. The charge of arc furnace is 30% pig iron + 70% quality scrap of which the preheating temperature is no less than 600 ℃. The ex- amination shows that the chemical compositions of products are controlled in range of 0.39~0.42C,0.86～0.91Mn,0.22 ~0.31Si,0.013～0.018P,0.005～0.013S,0.85～0.94Cr,0.16～0. 18Mo,0.019～0.028 Als, the ratings of segregation and porosity are 0.5~1.0, the ratings of inclusion are 0.5~2.0 and the grain size of φ18~史50 mm products are 8.5 ~9 which satisfy the using requirement of heat-resisting standardized piece bolts.

摘要： 鄂钢股份有限公司采用70tConsteel超高功率电弧炉70t钢包精炼炉4流150mm×150mm方坯连铸连轧工艺生产耐热螺杆高强度标准件用钢B7(40CrMnMo)。电弧炉炉料为30%生铁+70%优质废钢,废钢预热温度≥600℃。生产结果表明,该钢成品化学成分可稳定控制(%):0.39～0.42C,0.86～0.91Mn,0.22～0.31Si,0.013～0.018P,0.005～0.013S,0.85～0.94Cr,0.16～0.18Mo,0.019～0.028Als,偏析与疏松级别为0.5～1.0,夹杂物0.5～2.0级,Φ18～Φ50mm钢材晶粒度8.5～9级,满足耐热螺杆标准件的使用要求。