Bellows compensators are commonly used in heating systems for steam and high temperature water. Dead zones, condensation and deposition give chloride ions the opportunity to concentrate and easily cause corrosion fatigue damage to austenitic stainless steel.
When corrosive media are present, the expansion of the bellows is reduced. Cross-sectional fatigue life. Therefore, the influence of environmental factors should be considered when designing the fatigue life of corrugated compensators. It is not enough to focus only on mechanical loads. Measures should be taken in material selection and structure. When selecting materials, suitable materials should be selected according to the actual working medium. Experimental research should be conducted on the corrosion fatigue performance of expansion joints in important parts.
As the dangerous section of the expansion joint is in the local high strain cycle conditions, it is not appropriate to use the post-forming heat treatment process to reduce the forming stress, or by changing the wall thickness to eliminate the corrosion fatigue crack. The location of the corrosion fatigue crack is the same as the fatigue crack in the air, both in the location of higher stress. Single-layer expansion joints appear near the trough of the medium wave, and corrosion fatigue cracks appear on the side in contact with the medium. The measurement method of corrosion potential value is simple and reliable, which helps the experimenter to understand the whole process of bellows crack sprouting, expansion and penetration in the fatigue test.
