Effects of electrode configuration on electroslag remelting process of M2 high-speed steel ingot

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.

Effect of titanium and rare earth microalloying on microsegregation,eutectic carbides of M2 high speed steel during ESR process

The effects of RE and Ti microalloying during electroslag remelting(ESR)process on the microsegregation and morphology of eutectic M2C carbides in M2 high speed steel were investigated.The results show that the addition of 0.2 wt%RE can alleviate the segregation of C,W,Mo,V and Cr,while the morphology of eutectic M2C carbides hardly changes.The microalloying with the addition of 0.5 wt%Ti has the lowest degree of microsegregation due to the improvement of primary dendrites by the effective heterogeneous nucleating agent of(Ti,V)(C,N)particles.The addition of Ti makes the mo rphology of M2C carbides change from rod-like or maze-like shape into a coarse feathery shape,exhibiting anisotropic facet growth characteristics.For the microalloying of 0.2 wt%RE and 0.5 wt%Ti,the segregation of the main metal alloying elements is slightly more severe than that of the addition of only RE or Ti.Under the combined action of RE and Ti,the feathery eutectic M2C becomes thinner and shorter and tends to be isolated or distributed in a discontinuous network.