FRACTURE FAILURE ANALYSIS OF STRAIGHT JOINT WITH EXTERNAL SCREW-THREAD

In a new building,water supply pipe was broke. The broken part was analyzed by macroscopic and microscopic examination,chemical analysis,comparison of mechanical properties and so on. The result showed that fracture failure was caused by using wrong material and grain-boundary corrosion and micro structure change in the affect of mediator,that made the properties of metal worsen and result in fracture failure.