Failure Analysis on Cracking of DN50 Stainless Steel Bellows

The cracking reasons of 304 austenite stainless steel DN50 bellows were analyzed by means of macroscopic examination,scanning electron microscope inspection and X-ray energy dispersive spectrum analysis.The results indicate that the cracking of the bellows was induced by corrosion fatigue.Under the comprehensive effect of corrosive mediums and external stress,intergranular corrosion micro cracks and honeycomb shaped corrosive patterns occurred on outer and inner surfaces of the bellows.Under the action of alternating stress,multi-source fatigue fracture failure took place on both sides of the bellows.