The electrode configuration determines the thermophysical field during the electroslag remelting(ESR) process and affects the final microstructure of the ingot. In this work, ingot with a diameter of 400 mm was prepar...The electrode configuration determines the thermophysical field during the electroslag remelting(ESR) process and affects the final microstructure of the ingot. In this work, ingot with a diameter of 400 mm was prepared with two electrode configuration modes of single power ESR process, namely one electrode(OE) and two series-connected electrodes(TSCE). Finite element simulation was employed to calculate the electromagnetic field, flow field and temperature field of the ESR system. The results show that the temperature of the slag pool and the metal pool of the TSCE process is lower and more uniform than that of the OE process.The calculated temperature distribution of the ingot could be indirectly verified from the shape of the metal pool by the experiment. The experimental results show that the depth of the metal pool in the OE ingot is about 160 mm, while the depth of the TSCE ingot is nearly 40 mm shallower than that of the OE ingot. Microstructural comparisons indicate that coarse eutectic carbides are formed in the center of the OE ingot, whereas more even eutectic carbides appear in the center of the TSCE ingot. In general, compared with the OE process, the TSCE process is preferred to remelt high speed steel ingots.展开更多
Large-size primary MC carbides can significantly reduce the performance of M2 high-speed steel.To better control the morphology and size of primary MC carbides,the effect of melting rate on microsegregation and primar...Large-size primary MC carbides can significantly reduce the performance of M2 high-speed steel.To better control the morphology and size of primary MC carbides,the effect of melting rate on microsegregation and primary MC carbides of M2 steel during electroslag remelting was investigated.When the melting rate is decreased from 2 kg·min^(-1) to 0.8 kg·min^(-1),the columnar dendrites are gradually coarsened,and the extent of segregation of Mo and V is alleviated,while the segregation of Cr becomes severe.At 2 kg·min^(-1),the number of primary MC carbides per unit area with the sizes in the range of 2 μm to 6 μm accounts for about 75% of all MC carbides,while the carbides are mainly concentrated on the size larger than 8 μm at 0.8 kg·min^(-1).Thermodynamic calculations based on the Clyne-Kurz (simplified to C-K) model shows that MC carbide can be precipitated in the final solidification stage and a smaller secondary dendrite arm spacing caused by higher melting rate (2 kg·min^(-1) in this experiment) facilitates the refinement of primary MC carbides.展开更多
基金financially surpported by the Foundation of Hebei Provincial Department of Education,China(Grant No.QN2018034 and QN2017051)
文摘The electrode configuration determines the thermophysical field during the electroslag remelting(ESR) process and affects the final microstructure of the ingot. In this work, ingot with a diameter of 400 mm was prepared with two electrode configuration modes of single power ESR process, namely one electrode(OE) and two series-connected electrodes(TSCE). Finite element simulation was employed to calculate the electromagnetic field, flow field and temperature field of the ESR system. The results show that the temperature of the slag pool and the metal pool of the TSCE process is lower and more uniform than that of the OE process.The calculated temperature distribution of the ingot could be indirectly verified from the shape of the metal pool by the experiment. The experimental results show that the depth of the metal pool in the OE ingot is about 160 mm, while the depth of the TSCE ingot is nearly 40 mm shallower than that of the OE ingot. Microstructural comparisons indicate that coarse eutectic carbides are formed in the center of the OE ingot, whereas more even eutectic carbides appear in the center of the TSCE ingot. In general, compared with the OE process, the TSCE process is preferred to remelt high speed steel ingots.
基金financially supported by the National Natural Science Foundation of China(No.51904087)the Open Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2019-20)+2 种基金the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200)the Natural Science Foundation-Steel and Iron Foundation of Hebei Province(No.E2019202482)Tianjin Science and Technology Project(No.18YFZCGX00220)。
文摘Large-size primary MC carbides can significantly reduce the performance of M2 high-speed steel.To better control the morphology and size of primary MC carbides,the effect of melting rate on microsegregation and primary MC carbides of M2 steel during electroslag remelting was investigated.When the melting rate is decreased from 2 kg·min^(-1) to 0.8 kg·min^(-1),the columnar dendrites are gradually coarsened,and the extent of segregation of Mo and V is alleviated,while the segregation of Cr becomes severe.At 2 kg·min^(-1),the number of primary MC carbides per unit area with the sizes in the range of 2 μm to 6 μm accounts for about 75% of all MC carbides,while the carbides are mainly concentrated on the size larger than 8 μm at 0.8 kg·min^(-1).Thermodynamic calculations based on the Clyne-Kurz (simplified to C-K) model shows that MC carbide can be precipitated in the final solidification stage and a smaller secondary dendrite arm spacing caused by higher melting rate (2 kg·min^(-1) in this experiment) facilitates the refinement of primary MC carbides.