Research on the failure reasons of the cooling tube were carried out by means of macroexamination, thickness measurement, X ray diffraction, optical microscopy and chemical analysis.

采用宏、微观、化学成等手段,对冷却水管的蚀穿孔进行了失效。

Analysis of the Stem-fillet blend fracture of exhaust valve was conducted by means of macroexamination, microstructure examination, chemical composition analysis and hardness test.

采用宏、微观检验、化学成和硬度测试等方法对断头的排气门进行了。