提高铸造高速钢模具韧性和耐磨性的研究

The study on improving the toughness and wear resistance of cast high speed steel die

用RE Mg Ti对低碳铸造高速钢 (6W6Mo5Cr4V)模具进行变质处理 ,消除了钢中网状共晶碳化物 ,并细化了基体组织 ,还可减轻W、Mo元素偏析。变质处理后 ,高速钢硬度、红硬性和强度变化不大 ,断裂韧性 (K1c)和疲劳裂纹扩展门槛值 (△Kth)有所提高 ,冲击韧性 (αk)提高了 1倍以上 ,耐磨性也明显提高。各项性能指标达到了锻造高速钢水平 ,用RE Mg Ti变质处理低碳铸造高速钢 ,可以实现“以铸代锻”。

Low carbon cast high speed steel(6W6Mo5Cr4V)die had been modified using rare earths(RE)-Mg-Ti, network eutectic carbides were eliminated, matrix structures were refined and the segregation of W and Mo elements were relieved.After RE-Mg-Ti complex modification, a little effects can be found on the strength, hardness and red hardness, but the fracture toughness(K 1c) and threshold of fatigue crack growth(△K th) are improved meantime, impact toughness (α k) is increased by over one time, and wear resistance is also improved mostly too. The properties of modification cast high speed steel are near to forging high speed steel, “the cast's replacing forge” of high speed steel will realize after modification by RE-Mg-Ti.