Analysis of Outer Surface Fold of N80 Q Oil Casing

The cause for the outer surface fold of the N80 Q oil casing is identified by analysis of the morphology,microstructure and chemical composition of the defective area. The defect is in embryo as pre-rolling cracks on the outer surface of the bloom,and then gradually extended and oxidized during the reheating and deforming processes that follow,and finally developed into the said outer surface spiral fold. With strict quality inspection and control of the bloom,it is possible to effectively prevent occurrence of such defect so as to ensure the quality of the oil casing.