Abstract: The production flowsheet of test cold-working die flat steel Crl2MolVI (D2) (/% ： 1. 50C, 0. 35Si, 0. 40Mn, 12. 00Cr, 0. 95Mo, 0. 80V) is 30 t EAF-LF-VD-3 t ingot casting-rolling-annealing at 890 °C process. The effect of cross-section size (/mm: 30 x 400, 70 x 360 and 90 X 605) of cold-working die flat steel D2 on the size, distribution and uniformity of eutectic carbide, the structure and the impact toughness of steel has been studied. The results show that with decreasing the cross-section size, the size of particles, morphology and distribution uniformity of eutectic carbide in flat are improved, the rating of carbide in flat decreases from 4 ~6 rating of 90 mm x605 mm flat to 1 ^4 rating of 30 mm x 400 mm flat, and the impact toughness of steel increases ； the distribution of eutectic carbide at core of flat is worst ( rating 4 ~ 6) and that at edge is best (rating 1 ~ 4) , and the impact toughness of steel at core is obviously lower than that at edge.

摘要： 试验用Crl2MolV1(D2)冷作模具扁钢(/%:1.50C,0.35Si,0.40Mn,12.00Cr,0.95Mo,0.80V)的生产流程为30 t EAF-LF-VD-3 t铸锭轧制-890℃退火工艺。研究了D2冷作模具钢的断面尺寸(/mm:30×400,70×360,90×605)对该钢组织、共晶碳化物的尺寸、分布以及不均匀度、冲击韧性的影响。结果表明,随着扁钢截面尺寸的减小,共晶碳化物的颗粒尺寸、形态以及分布均匀性得到改善,扁钢的碳化物级别由90 mm×605 mm扁钢的4~6级降至30 mm×400 mm扁钢的1~4级,冲击韧性提高;钢的心部共晶碳化物分布最差(4~6级),边部最好(1~4级),心部的冲击韧性明显低于边部。