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采用实验室25 kg高频真空感应炉熔炼M2钢,并用水冷铜模和砂模均浇铸为横截面100 mm×50 mm的M2钢铸锭,研究冷却速度对M2钢二次枝晶间距、渗透率、碳化物和晶粒尺寸及分布的影响.研究结果表明:M2钢凝固过程中,快的冷却速度能有效减小二次枝晶间距、渗透率、晶粒和网状碳化物的尺寸,同时可以改善晶粒和网状碳化物的分布和均匀性;砂模和水冷铜模M2钢铸锭的平均二次枝晶间距分别为42.5μm和21.6μm,平均冷却速度为1.06 K·s~(-1)和12.50 K·s~(-1),平均渗透率分别为0.13μm~2和0.035μm~2.快的冷却速度能有效减轻中心碳偏析程度,砂模和水冷铜模模铸的M2钢铸锭中心碳化物面积分数分别为0.46和0.30,且其较各自的平均值分别增大38.7%和2.2%;水冷铜模铸锭平均晶粒尺寸(43.1μm)较砂模铸锭的平均晶粒尺寸(72.6μm)减小约40.7%,铸锭中心晶粒尺寸减小43.2%,且水冷铜模铸锭的晶粒尺寸较砂模铸锭均匀.文中获得了M2钢凝固过程中晶粒尺寸与冷却速度的关系式.
The M2 steel was melted in a laboratory 25 kg high-frequency vacuum induction furnace and the M2 steel ingot with a cross-section of 100 mm × 50 mm was cast with a water-cooled copper mold and a sand mold. The effects of cooling rate on the secondary dendrite spacing, Rate, carbide and grain size and distribution.The results show that the fast cooling rate can effectively reduce the secondary dendrite spacing, permeability, grain size and network carbide size during the solidification of M2 steel, While the distribution and uniformity of grains and reticular carbide can be improved. The average secondary dendrite spacing of sand mold and water-cooled copper mold M2 steel ingot is 42.5μm and 21.6μm, respectively, the average cooling rate is 1.06 K · s ~ (-1) and 12.50 K · s -1, respectively. The average permeability was 0.13μm ~ 2 and 0.035μm ~ 2, respectively. The rapid cooling rate can effectively reduce the center carbon segregation degree. The sand mold and water- Of the M2 steel ingot central carbide area fraction were 0.46 and 0.30, respectively, and their respective average increase of 38.7% and 2.2%; water-cooled copper ingot ingot average grain size (43.1μm) than the sand mold ingot The average grain size (72.6μm) is reduced by about 40.7%, the grain size at the center of the ingot is reduced by 43.2%, and the grain size of the water-cooled copper mold ingot is smaller An ingot mold uniformly. Paper relationship obtained during solidification of M2 steel and the cooling rate of the grain size.