Effect of Groove Shape on Closure of Center Defects in Symmetric Rolling of Round Billets

• Published in: ISIJ International Vol. 55; no. 11; pp. 2397 - 2405
• Main Authors: Katsumura, Tatsuro, Kato, Yasushi, Yanagimoto, Jun
• Format: Journal Article
• Language: English
• Published: The Iron and Steel Institute of Japan 01-01-2015
• Subjects: bar rolling; closure; defect; deformation behavior; equivalent strain; grooved roll; hydrostatic stress; rolling
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.ISIJINT-2015-192

Although the closure of defects at the center of round billets on rolling such billets is an important subject, a method of quantity evaluation for such closure has not yet been clarified. Therefore, to explain the effect of rolling conditions including grooved shape, we carried out the experiments with round billet which has an artificial defect and finite element analysis, especially with respect to the integration of the hydrostatic stress Gm. The results showed that grooved shape affected the closure of center defect, and Gm could express the relationship between closure and rolling conditions without the consideration of the difference in the ratio of defect size and roll size. However we found that original Gm could not express the influence of the grooved shape, at the same time.