摘要
研究了挤压不锈钢管时产生“桔皮”状缺陷的形成机理，其要点为：润滑剂使用不当或其它原因造成挤压时变形金属流动的严重不均所形成的附加拉应力与变形之基本应力相叠加，当接触表面处拉应力超过该处金属之强度极限时，则由缩颈而发展到微裂纹产生一裂纹扩展→裂纹钝化（应力松驰）→产生二次微裂纹……，发展而形成“桔皮状”缺陷；其内因是钢材基体组织性能不均匀或微量元素及有害元素富集，在高温条件下局部区域塑性下降，抗剪强度降低，在附加拉应力作用下产生微裂纹，扩大而最后形成“桔皮”状缺陷。
Improper application of lubricants or other factors bring about serious n on-uni-form metal flow in extrusion deformation along with additional stress tensile,As te nsile stress is su-perimposed with the essential deforming stress,the resultant tensile stress over the interface will ex-ceedthe yield stress,thus leading to the occurrence of notch crachs.The cracks develop in the stages of:occurrence →development→cracks softening(stress relieving)→second micro→cracks.and so forth and its ultimate shape looks llke an'orange peel', The internal cause is structural,imhomo-geneity or loeal pile-up of rare or harmful elements,As result,local plastic index and shear strength will decrease at elevated temperature.And the additionl tensile stress activates the formtion of micro-cracks and its developmen,consequently the”orange peel' shaped crack displays in the end.
出处
《重庆大学学报（自然科学版）》
CAS
CSCD
1994年第4期110-114,共5页
Journal of Chongqing University
关键词
微裂纹
缺陷
挤压
不锈钢管
micro-cracks
non-uniform deformations/'orange peel'shaped defect
