回炉料对K417G合金初熔温度及持久寿命的影响  

Effects of Reverts on Initial Melting Temperature and Stress-Rupture Life of K417G Superalloy

作　　者：满延林 王宇飞[1] 于兴福[2] 倪伟[1] 王兴雅 杨刚[1] 

机构地区：[1]沈阳黎明航空发动机(集团)有限责任公司,辽宁沈阳110043 [2]沈阳工业大学材料科学与工程学院,辽宁沈阳110870

出　　处：《铸造》2015年第3期251-255,共5页Foundry

摘　　要：采用回炉料熔炼K417G镍基铸造高温合金,共进行了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杂质含量。通过金相显微镜和扫描电镜对合金的疏松及夹杂进行观察,采用金相法和差热扫描量热法(DSC)测定出合金的初熔温度及固液相线温度,并测试了合金在950℃/235 MPa条件下的持久性能。结果表明:K417G采用返回料熔炼合金期间,合金中的O元素含量高于N元素含量;随返回次数增加,N元素含量呈下降趋势,而O含量呈上升趋势。采用返回料熔炼K417G合金,合金的初熔温度随返回次数增加而降低,固、液相线温度波动较小。随返回次数增加,合金的950℃/235 MPa条件下持久寿命呈下降趋势。合金中O、N、S杂质元素含量对合金的持久寿命具有显著的影响,随杂质元素含量的增加合金的持久寿命降低明显。返回料的铸造工艺性比新料略低。Nickel-based casting superalloy K417G was melted using 100% revert alloy, and the revert alloy was recycled 4 times. The chemical compositions and impurity contents of green alloy and revert alloy were measured, the microshrinkage and inclusions pattern was observed by optical microscope （OM） and scanning electron microscope （SEM）. The initial melting temperatures and solidus and liquidus temperature of alloy were determined by means of metallographic analysis and differential thermal analysis and scanning calorimetry （DSC）, the stress rupture life of alloy under 950 ℃/235 MPa conditions was examined. The results show that the content of element O is higher than element N in revert alloys and with the revert recycling times increasing the element N is decreased, but element O increased, and the stress creep rupture life was declined at 950 ℃/235 MPa. The initial melting temperature was reduced with revert times increasing, and the solidus and liquidus temperature show low fluctuation. The stress rupture life decreased with revert times increasing under the condition of 950℃ /235MPa. The content of elements O, N and S impact the stress rupture life that evidently declined with the impurity content increasing. The castablity of 100% revert alloy is slightly lower than the green alloy.

关 键 词：高温合金 返回料 初熔温度 持久寿命 

分 类 号：TG243[金属学及工艺—铸造]