Entry and Exit Stress Variation of Cold Rolling Strip

• Published in: Journal of iron and steel research, international Vol. 19; no. 6; pp. 19 - 24
• Main Author: WANG, Dong-cheng
• Format: Journal Article
• Language: English
• Published: Singapore Elsevier Ltd 01.06.2012; Springer Singapore
• Subjects: Applied and Technical Physics; Cold rolling; Computational efficiency; Engineering; Iron and steel industry; iteration method; Iterative methods; Machines; Manufacturing; Materials Engineering; Materials Science; Mathematical analysis; Metallic Materials; Physical Chemistry; Processes; relaxation factor method; Steels; stress variation; Stresses; Strip; velocity variation; 冷轧带钢; 出入境; 出口速度; 压力变化; 应力变化; 断裂伸长率; 计算结果; 速度变化; iteration method; stress variation; velocity variation; cold rolling; relaxation factor method
• ISSN: 1006-706X; 2210-3988
• DOI: 10.1016/S1006-706X(12)60121-6

The shortcomings of an exit stress variation formula which has been well accepted are analyzed~ it is found that the exit stress variation formula violates the premise of the law of volume constancy. The shortcomings of an en- try stress variation formula are analyzed too, and the basic assumption of the formula is uniform exit velocity. How- ever, for a rigid-plastic material uniform exit velocity implies that the lateral distributioi1 of elongation is uniform, so the exit stress must be uniform and any type of flatness defect is impossible, which is contrary to the practice. In fact, entry and exit velocity variation influence entry and exit stress variation, and entry and exit stress variation in- fluence entry and exit velocity variation too, so a precise explicit stress variation formula cannot be got easily. Con- sidering the relationship between stress variation and velocity variation, an iteration method is presented to calculate entry and exit stress variation of cold rolling strip. To avoid divergent phenomenon of the iteration course, a relaxa- tion factor method is adopted. The calculation results are compared with the entry and exit stress variation formula commonly used by many researchers. The difference is remarkable, while the result calculated agree more well with measured result if the exit elastic recovery zone is considered. Specially, the incoming flatnessI propagate efficiency calculated ~ives a more realistic result.