GCr15轴承钢250mm×280mm铸坯至138mm×150mm坯粗轧数值模拟及工艺优化

Numerical Simulation and Process Improvement on Rough Rolling of 250 mm × 280 mm Cast Bloom to 138 mm ×150 mm Billet of GCr15 Bearing Steel

生产Φ50~75 mm的GCr15轴承钢时,轧后棒材存在中心疏松缺陷。通过数值模拟研究,观察棒材心部等效应变的渗透情况,并对粗轧孔型工艺进行优化,将优化前一二道次的压下量从21 mm、58 mm分别增加到51 mm、85 mm,第三道次的压下量从60 mm减小到34 mm。等效应变值随着道次的增加,呈逐渐增大趋势,棒材中的拉应力在经工艺优化后变为压应力,变形均匀度也得到提升,促进了铸坯心部的变形,有利于中心孔洞的压合。工艺优化后轴承钢的探伤合格率由原93.25%提高到96.06%。

When producing GCr15 bearing steel Φ50~75 mm bar,there is center porosity in rolled bar.A numerical simulation is carried out to study the penetration of effective strain in the core of bar and optimize the rough rolling pass technology,increase the reduction of the first two passes from original 21 mm and 58 mm to 51 mm and 85 mm respectively,and reduce the third pass from 60 mm to 34 mm.Through the effective strain value gradually increases with the increase of the pass,the tensile stress in the bar becomes compressive stress after the optimized process,and the uniformity of deformation is also obtained to promote the deformation of core of casting slab be availabe to the closure of the center porosity.After the process optimization,the qualified rate by ultrasonic detection of bearing steel increases from original 93.25% to 96.06%.