Investigations on the influence of blank thickness (t) and length/wide punch ratio (LD) in rectangular deep drawing of dual-phase steels

The paper starts with a brief summary describing the need of using the Advance High Strength Steels (AHSS) and particularity dual-phase steels in the automotive industry, pointing the added manufacturing issues that appear with this kind of steels. The study is centered in the rectangular deep drawn, a very usual forming operation, that affects to several automotive parts like oil pans, cases, etc., and mainly in three of the main parameters: blank thickness (t), length/wide punch ratio (LD) and dual-phase steel used; through a finite element model, a large range of dual-phase steels combined with different values of t and LD (values that cover the usual industrial manufacture using) have been studied and based in the researched results some conclusions have been exposed, above all the influence of these parameters in the percentage of thickness reduction pt(%), a very important result in a deep drawn manufacturing that affects to the integrity and the service behavior of the part. At the same time, a relation between the thickness reduction percentage and the three studied parameters (t, LD and dual-phase steel) has been stabilised through a collection of equations that will be useful in order to predict approximate results without big efforts.