FRACTURE ANALYSIS OF THE EXTRUDED AT RAIL

The AT rail fractured in the extrusion process and straightening process. The chemical composition was analyzed, the marcostructure and microstructure of the fracture-rail was examined. The fracture appearance was analyzed by the X-650 scanning electronic microscope and EDAX electronic probe. The results show that the chemical composition, macrostructure and microstructure are normal, the fracture appearance is brittle crowbarand, and the fracture was oxygenated severely. The conclusion is that the improper heating process is the direct reason of the AT rail′s fracture in the extrusion and strengthening process.