铸锭加热和锻后热处理工艺对18CrNiMo7-6钢Ф540mm棒材带状的影响

试验18CrNiMo7-6重型齿轮钢(/%:0.165C,0.59Mn,0.24Si,0.006S,0.008P,1.56Ni,1.71Cr,0.28Mo,0.034M,0.0129N)的生产流程为60 t UHP EAF-LF-VD-12.5 t铸锭工艺。试验研究了钢锭加热工艺(1 200~1 220℃,7-8 h~13-15 h),锻材完全退火(900℃12 h,≤80℃/h至650℃50 h,空冷)、等温退火(900℃12 h,空冷至650℃50 h,空冷)和正火(900℃12 h,空冷)工艺对Φ540 mm锻材带状组织的影响。结果表明,钢锭1 200~1 220℃7-8 h加热,锻材经完全退火、等温退火或正火处理后其带状级别分别为4.0,3.5和3.0,钢锭经1 200~1 220℃13-15 h加热,锻材经正火处理后其带状级别为2.5,为最佳工艺。