关键词: GCr15轴承钢, 280 mm x 325 mm坯连铸, 凝固组织, 偏析, 数值模拟

Abstract: Based on the finite element method according to two dimensional solidification heat transfer model, the simulation of solidification structure of 280 mm x 325 mm bloom of GCr15 bearing steel casting with casting speed 0.6 m/min and 0.5 m/min, liquid superheated extent 30℃ and 10℃ , and secondary cooling water rate 0.25 L/kg and 0.20 L/kg has been carried out to study the effect of casting process parameters on structure of bloom. Results show that with increasing the liquid superheated extent from 10°C to 30℃ , the equiaxial crystal zone and mixed crystal zone decreases from 70% to 55% , so the effect of superheated extent on bloom solidification structure is very obvious ； with decreasing the casting speed from 0.6 m/min to 0.5 m/min the average length of columnar crystal grows by 6.5 mm, but the transition zone from columnar crystal to equiaxial crystal decreases, it is available to reduce the enrichment of solute elements in the zone ； with decreasing the sencondary cooling water rate from 0.25 L/kg to 0.20 L/kg, there is no obvious difference in columnar crystal and equiaxial crystal zone, therefore there is no obvious effect of decreasing secondary water rate on solidification of structure in casting bloom.

Key words: GCr15 Bearing Steel, 280 mm x325 mm Bloom Casting, Solidification Structure, Segregation, Numerical Simulation