1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083，China 2. Technical Center, Xining Special Steel Co., Ltd., Xining 810005, Qinghai, China 3. No.2 Steelmaking Plant, Xining Special Steel Co., Ltd., Xining 810005, Qinghai, China
Abstract：The characteristics of large precipitates in H13 tool steel were studied and the results were compared with the predicted solidification process calculated by Thermol- calc software to study the generating mechanism. The results showed that three kinds of large phases were existing in the as- cast ingot, which were V- rich (V,Mo,Cr，Fe)C phase, Mo- Cr- rich (V,Mo,Cr，Fe)C phase and manganese sulfide. For the V- rich (V,Mo,Cr，Fe)C phase, the shape of the majority big precipitates was strip and the size could be tens of microns, while a part of ones precipitating on manganese sulfide had an oval shape. For Mo- Cr- rich (V,Mo,Cr，Fe)C phase, the precipitates were irregular phase, the content of Mo was similar to that of Cr and the content of V was slightly lower. The precipitation order could be speculated according to the combining form of complex large phase. Sulfide, V- rich (V,Mo,Cr，Fe)C phase and Mo- Cr- rich (V,Mo,Cr，Fe)C phase were precipitated successively. The calculation results of Thermo- calc were basically consistent with the experimental results combined with the component characteristics of large precipitates.
2016, Vol. 26 
