Analysis of 00Cr17Ni14Mo2 Bellows Leakage

Abstract

A multi-layer welded bellows made of 00Cr17Ni14Mo2 was found to have leakage points in the heat-affected zone of the weld during airtight inspection and leak detection by helium mass spectrometry. In view of the leakage of multilayer welded bellows, the reasons for the leakage of multilayer welded bellows areanalyzed by means of macroscopic observation, electron microscope observation, energy spectrum analysis, metallographic examination, microhardness test and chemical composition analysis. The results show that there are liquefaction cracks in the heat-affected zone of the outer bellows, which results in air leakage in the airtight test. The generation of liquefaction crack is related to the low Ni content in the material and the pollution of S and Cu elements. The cleaning treatment of the material surface in the welding area should be strengthened before welding to reduce the generation of cracks. At the same time, should be paid attention to the control of welding raw material composition.