Predictions of material properties in press-braked austenitic stainless steel sections

Abstract

Press-braking is one of the typical cold-forming techniques in manufacturing stainless steel members. In general, cold-forming process brings material strength enhancement, which can be utilized in advanced design methods to reduce the initial cost of stainless steel structures. This paper is targeted at the accurate predictions of material properties in the press-braked austenitic stainless steel sections. A series of material tensile tests were carried out on press-braked austenitic stainless steel corner sections with varied ratios of the inner corner radius over the thickness. Material properties of corner sections were obtained and compared with those of virgin sheets, which shows considerable increases in nominal yield stress and ultimate tensile stress, and reduction in elongation. Based on test data and “equivalent plastic strain” concept, material strength enhancement model was developed for each material parameter. Predictions using material strength enhancement models were compared with test data in this study and literature, which indicates that the proposed models could give not only accurate predictions for the normal yield stress in press-braked austenitic and ferritic stainless steel corner sections, but also provide reasonable predictions for full-range stress-strain curves.