Cause Analysis on Fracturing of Crane Rail

By means of metallographic analysis, chemical compositions analysis, mechanical properties test and fracture analysis, the fracture reason of crane rail was analyzed. The results indicate that fracture of the rail was one-time brittle fracture and the fracture started from the scratch pits at the rail bottom. And there had serious decarburization phenomenon at the scratch pits area, which greatly reduced mechanical properties of the material. At the same time, Si content was higher than the required value, which also increased the brittleness of the material. So during the operation process of the crane rail, stress concentration formed at the scratch pits and cracks initiated and expanded quickly, and finally resulted in the fracture of the rail. The existence of decarburization phenomenon showed that the scratch pits area had been heated seriously, so it was thought that the scratch pits were caused by the electric arc abrasion.