Formability of Al-killed AISI 1040 Medium Carbon Steel for Cylindrical Cup Formation

摘要

The basic formability of Aluminum-killed AISI 1040 graded medium carbon steel (cold rolled followed by hardening and spheroidization tempering) has been characterized by uniaxial tension, compression, bending, and Erichsen cup tests. The results shows a good strength (～634 MPa) - ductility combination, high strain hardening exponent, normal plastic anisotropy value ＞ 1 and a considerably low planar anisotropy. The compressibility, bend-ability and biaxial strechability characteristics of the steel also signify its formability behavior in different loading states. The strain analysis on tensile and Erichsen cup specimens has provided deeper information on its strain dispersibility as well as necking tendency in both uniaxial and biaxial states. The actual press formability also has been investigated by applying a process consisting of multistage deep drawing accompanied with wall ironing, without using blank holder and with intermediate stress relieving treatment. Thus ～56 mm long cylindrical cups, ～36.85 mm diameter and ～3.8 mm wall thickness, have been manufactured from 12 mm thick and 60 mm diameter circular blanks in a preformed shape. This experiment has yielded significant values of few press formability parameters in terms of draw ratio, draw reduction, ironing ratio, ironing reduction and etc. Further, by drawing comparisons with few sheet metals, the competitiveness of the steel has been shown with an objective to enlighten on its line of applications as per customer demands.