718Plus高压涡轮机匣超声波探伤缺陷分析

Analysis of defects in ultrasonic flaw detection of 718Plus high pressure turbine case

Leap发动机高压涡轮机匣用718Plus合金棒料,经锻造碾环、热处理、机加等工序加工为环形锻件,在超声波探伤检验后,发现内部存在几处异常显示不合格。通过对锻件临近缺陷处的金相组织检验、力学性能测试,并以0.1 mm逐层打磨抛光直至显示缺陷,对缺陷处进行了光学显微观察及EDS成分分析。结果表明,锻件的锻造、热处理过程正常,缺陷形貌及化学成分表明缺陷为镍基718Plus合金冶炼过程中夹渣型缺陷,属冶炼缺陷。

718 Plus alloy bars for high pressure turbine case of Leap engine was processed into ring forgings by forging,ring rolling,heat treating and machining. During the ultrasonic flaw detection,it was found that there were several abnormal indications inside the forgings. The tests of metallographic inspection and mechanical property of the forging near the defects were conducted. Moreover,the sample was polished stepwise (0. 1 mm) to display the defects. Then the defects were analyzed by optical microscopic observation and EDS. The results showed that the processes of forging and heat treatment were normal. The morphology and chemical composition analysis indicated that the defects were slag inclusion defects in smelting of nickel-based 718 Plus alloy. It belonged to metallurgical defects.