On the formability of 3.15 mm thick low-carbon steel sheets

Abstract

Low-pressure gas (LPG) cylinders are made from hot-rolled low-carbon steel sheets of 3.15 mm thickness as two halves (cups) which are then welded together. Investigations into the formability of this material are useful in ascertaining its likely press-shop performance. The formability of two heats of LPG grade sheet steel has been examined with a view to identifying the similarities as well as the heat-to-heat variations that are of practical consequence. The metallographic and the mechanical characteristics of the material and its fracture behaviour under different stress-states have been determined. The strain distribution along the longer meridian in blanks of different widths for both of the two heats was measured and the location of fracture was correlated to the average normal anisotropy r^- of the material. The role of the punch contact constraints (PCC) during deformation has been discussed in terms of a 'constraint factor', newly defined in this paper.