返回熔炼对K414合金组织及性能的影响

Effect of Returns Smelting on Structure and Mechanical Properties of K414 Alloy

采用100%的返回料熔炼镍基K414合金并进行了4次返回熔炼试验,测试了新料和返回料合金的化学成分及力学性能,并对合金的微观组织进行了观察。结果表明:随返回次数增加,合金中的主要成分无明显波动、气体含量未出现明显增加,返回料熔炼过程中可不添加B、Ce元素;返回料合金与新料合金的组织形貌无明显差别;返回料合金的室温强度有所降低,断后伸长率有所增加,冲击韧度略高于新料;合金在600℃条件下的抗拉强度有所增加,断面收缩率略有所下降,合金的持久寿命较新料合金略有降低,但均明显超出标准规定的要求。熔炼的返回料合金与新料质量水平相当。

The Ni-based superalloy K414 was melted by using of 100% returns, and the returns was recycled 4 times. The chemical composition, mechanical properties and the microstructure of green and reverted alloy were investigated. The results show that with the returns smelting times increasing, the main chemical compositions of the reverted alloy was stable basically, the gas element contents did not distinctly increase, and it was not necessary to add B and Ce elements to the melt during the melting process; there was no substantial difference between reverted alloy and green alloy in morphology; with the return times increasing the tensile properties of reverted alloy at room temperature show a slight downtrend, while their elongation and impact toughness were increased compared to the green alloy; the tensile strength properties increased slightly, reduction of necking area decreased slightly at 600 ~C, while their creep rupture life were reduced compared to the green alloy, and the mechanical properties and creep rupture life time for these reverted alloys are clearly better than the current standard requirements for K414 alloy. The quality of reverted alloy is similar to the green alloy.