K465低涡转子叶片表面缺陷分析

Defect analysis of K465 vortex rotor blade

某型发动机所使用的低涡转子叶片材料牌号为K465,叶片在装入发动机进行检测时,发现有异常显示,要求低涡部分的叶片零件逐一排查。当叶片用荧光渗透检测时,发现该批中的一件叶片有缺陷显示,并存在叶片榫头底部冷却孔附近呈线性缺陷。通过对该叶片缺陷进行宏观检查、扫描电镜检查、缺陷断口扫描检查以及铸造过程复查,结果表明:K465合金低涡叶片的材质正常,判断该缺陷由材料疏松导致;此缺陷产生的主要原因是该叶片在装机试验后,经过一系列的高温气流、反复振动、热循环应力与暴露在表面细小的疏松等综合因素作用下导致开裂,这些疏松是导致裂纹萌生的根源,形成了线性开口缺陷。针对此缺陷提出了处理办法,并对合金的浇铸工艺提出改进措施。

The material grade of the vortex rotor blades used in a certain type of engine is K465.When the blades were installed in the engine and inspected,abnormal indications were found,and the blade parts were investigated one by one.When using fluorescent penetrant testing on the blades,it was found that one of the blades had linear defects near the cooling hole at the bottom of the blade tenon.By macroscopic inspection,scanning electron microscopy inspection,defect fracture scanning inspection,and casting process review of the blade,it was found that the texture of the blade was normal,and it was judged that the defect was caused by material porosity.The main reason for the defect was that after the installation and inspection,the blade underwent a series of high-temperature airflow,repeated vibration,and thermal cycling stress,and the small surface porosity evolved into cracks,resulting in the linear defects.Aiming at the defects,solutions and improvement measures for alloy casting were proposed.