DEEP DRAWING BEHAVIOUR OF CRCA SHEET AND WRINKLING CONGESATION OF ROUND FLANGE CUP

Abstract

In this publication, an investigative study of deep drawing behavior and wrinkling congestion during metal forming operation for manufacturing of round flange cup of 1.6 mm thick material of CRCA (cold rolled cold alloy) sheet have been carried out. A drawbility characteristic of deforming of sheet metal has been found out. It has been trace out that the strain hardened material has a great impact on controlling of wrinkling behavior. It gives the resistance to wrinkling through its mechanical properties and chemical composition of material and stop tearing. The exponential strain distributions also influence the drawing during sheet metal operation. Higher circumferential compressive stress has produced in the cup walls from the high strain hardened exponent   material thus resists the wall to wrinkling and also reduces the effect of high radial tension in the sheet of a high radial stress bearable material. The possibilities of wrinkling can also be reduced by increasing the blank holder load, decreasing the die profile radius or using a high grade lubricant on both sides of blank in the press tool. A high strain hardened material to wall wrinkling always begins first in the lowest r-value direction. Therefore both high r (anisotropic plasticity) and n (strain hardening exponent) are required for high strength low alloy steel due to its high flow stress. The required parameter have been tried to establish to reduce the wrinkle as minimum as possible to eliminate the fracture during deep drawing operation.