冷作模具钢奥氏体化过程的碳化物溶解情况

Carbides Dissolution of Cold Work Die Steels During Austenitizing

采用OM、SEM并结合Thermo-calc计算和Image-proplus 6.0分析,研究了不同奥氏体化温度对冷作模具D2(Cr12Mo1V1)和DC53(Cr8Mo2SiV)钢碳化物溶解情况的影响。结果表明:在950℃以后,两种钢中的碳化物的体积分数相差10%左右,D2钢的碳化物类型主要为M7C3型,DC53钢的碳化物在低于1 000℃时主要为M23C6型,高于1 000℃时为M7C3型。高于1 200℃时,DC53钢碳化物基本溶解,而D2钢在1 300℃高温时还有少量的碳化物。平均粒径为0.2～0.4μm的碳化物数量最多,在0.6～1.2μm粒径区间的碳化物数量随温度的增高而递减。随着奥氏体化温度的升高,未溶碳化物的面积分数逐渐减少,并得到了未溶碳化物体积分数、面积分数随加热温度变化的拟合方程。

Carbides dissolution of austenitizing procedure of D2 and DC53 cold work die steel at different tempera- ture were studied by OM, SEM and combined with Thermo-calc calculation and Image-proplus 6.0 analysis. The results indicate that： the differ of volume fraction is about 10% of these two steels after 950℃, the main type of carbide in D2 steel is M7C3, but the type of carbide in DC53 steel is M23C6 before the temperature of 1 000 ℃, fol- low it is M7C3. The carbides of DC53 steel have been nearly dissolved after 1 200℃ , while there are a few numbers of carbides appear at the temperature of 1 300 ℃ in D2 steel. The number of carbides in average size of 0.2 -- 0.4 μm is the most than the other, and decreases as the temperature increasing in the average particle size of 0.6-- 1.2μm. With the rise of the austenitizing temperature, the content of the area percentage of undissolved carbides gradually reduces, and get the fitting equation of volume and area of undissloved carbides with the heating temperature.