T型结晶器抽锭电渣重熔高速钢90mm方锭新工艺

New manufacture of high speed steel 90 mm billets by electroslag remelting withdrawing process

晶界处碳化物严重影响高速工模具钢的红硬性和耐磨性能,电渣重熔工艺能够有效地改善钢锭中碳化物尺寸及分布。传统电渣重熔生产较小钢锭的截面尺寸约为?200 mm,减小钢锭截面尺寸和增大冷却速率将会进一步减轻碳化物的偏析程度,但将降低生产效率、提高生产成本。采用双极串联、T型结晶器、抽锭电渣重熔新工艺生产90 mm方锭,并与相同熔化速度传统电渣重熔生产?200 mm钢锭进行对比试验。对钢锭成分、低倍、夹杂物、显微组织进行检验分析结果表明,90 mm方钢锭中碳化物尺寸和分布明显优于?200 mm钢锭,碳化物在后序锻造或轧制过程中更容易被破碎。新工艺电耗也低于传统电渣重熔工艺。

Carbide segregation at grain boundary is a main reason to reduce high temperature hardness and wear resis- tance of high speed steel. Electroslag remelting（ESR） technology can effectively improve the distribution and size of car- bides in ingot solidification process. The ingot diameter is usually ~ 200 mm by traditional ESR, but there are still a large amount of reticulated carbides. The carbide segregation degree can be reduced by further decreasing the size of ingot and increasing the cooling rate. However, it will reduce the production efficiency and increase, the cost of production. There- fore, new technology on 90 mm billets by electroslag remelting withdrawing （RESW） with bifilar mode and T-mold was developed. The results indicate that macroscopic organization and the size of grain and carbides of 90 mm billets are better than the φ 200 mm ingot produced by traditional ESR technology. Reticulated carbides in 90 mm billets are easier to be broken into small particles in the sequence forging or rolling process. With same production efficiency, the cost is reduced.