A comparative study on the mechanical properties, and formability of heat treated dual-phase DP 600 steel against the conventional SPFH 590 steel

Abstract

The present work reports a comparative study on the mechanical properties, and the formability of dual-phase DP 600 steel against the conventional SPFH 590 steel which are widely used in automobile industry for its high specific strength properties. In the present study, grain refinement is proposed as an alternative solution to improve the mechanical properties of low alloyed DP steels. To achieve this, severe plastic deformation was applied to pre-processed DP steel by means of conventional cold rolling, followed by an appropriate final heat treatment with the aim to produce a homogeneous fine grained dual phase ferritic-martenistic micro structure. The method used in this work is to increase the tensile strength of dual phase steels by increasing the martensite fraction, by applying appropriate annealing techniques. The heat treated DP 600 steel has good formability compared to conventional steel. DP 600 grade steels under-goes bake hardening which increases yield strength by 55 MPa upon heating and ageing the same 175°C for 25 minutes. There is an improvement in the “In Field Performance”. Reduced sheet thickness results in reduction in the weight of body and also the cost of the product. The work finds its application in many areas which demand on better formability such as automobile wheel rim, automobile body covers, etc.