管坯表面缺陷对应在成品管上的形貌试验研究

Experimental Research on Defect Morphology of Finished Tube as Corresponding to Surface Detects of Shell

介绍了不同类型的管坯表面缺陷经过PQF连轧管工艺轧制变形后,对应在成品管上所产生外折的形貌特征。管坯表面的圆孔伤产生了沿钢管轴线的直线发纹,直线的裂纹深度与管坯的圆孔伤深度有关;管坯的纵向伤也产生了沿钢管轴线的直线发纹,随着轴向伤深度的加深,裂纹的深度和长度加深加长;管坯的周向伤在成品管上产生了环向的翘皮,翘皮均呈锯齿状,且极易脱落。通过对管坯表面缺陷在成品管上的形貌特征的研究分析,探索PQF连轧管机组的变形规律,进而为制订管坯检验验收标准、确定成品管探伤检验方法提供参考依据。

Described here in the article are the morphological characteristics of the outer surface fold defects of the finished pipes as corresponding to different types of billets that is rolled and deformed by the PQF process.The circular hole damage on the surface of the shell produces straight hairlines along the axis of the steel pipe,and the depth of the straight crack is related to the depth of the circular hole damage on the shell.The longitudinal damage of the shell also produces straight hairlines along the axis of the steel pipe,and as the axial damage deepens,the depth and the length of the cracks increase.The circumferential damage of the shell produces circumferential fins on the finished pipe which are serrated-shaped and thus easily peel off.Owing to studying and analyzing the morphological characteristics of then finished pipes as originated from the shell surface defects,the deformation regularity of the PQF mill is investigated,which furthermore provides a reference basis for formulating inspection and acceptance criteria for the billet and determining the NDT methods for the finished pipe.