Analysis of formability of AISI 304 steel sheets with different thicknesses by the tensile properties

Abstract

Although AISI 304 steel is widely used and its manufacturers provide resistance data in the quality certificate, these are not sufficient to characterize and predict the behavior of the sheets in the drawing and drawing processes. This is why the objective of this work was to analyze the formability of AISI 304 steel sheets with 16- (thickness 1.5 mm), 18- (1.2 mm), and 20- (0.9 mm) gauges used by the metalworking industry in Colombia by determining intrinsic properties related to the ability of the sheet to withstand stretching and drawing operations such as the strain hardening exponent n, the normal anisotropy r_m, and the planar anisotropy Δr. The methodology consisted of analyzing the chemical composition, a metallographic study, and a series of tensile tests. The results show that the steel has a microstructure of twinned austenite grains of size between 15-30 mm. Regarding the mechanical resistance, it was observed that all the mean values of ultimate resistance, elastic limit, and elongation are above the minimum established in the standard. Furthermore, all of the tensile test results changed according to the variation of angles concerning the rolling direction (0°, 45°, and 90°), which indicates the anisotropic character of the sheet. The most relevant result allows us to infer that the 20-gauge sheet has better formability and therefore, better behavior against the stretching and drawing processes.