Effect of pre-strain on edge formability of high strength steels for chassis applications

Abstract There is a high level of uncertainty in the prediction edge cracking during design and manufacturing strength sheet metal products. Edge ductility complex parameter to measure since it not an intrinsic property material, but also depends on trimming strategy/parameters that have been applied (edge preparation method, cutting/punching clearance, etc.). Furthermore, most forming processes involve more than one operation where material can be deformed first stage, then trimmed or punched further final step obtain desired shape. Therefore, order robust safe process able predict risk cracking, crucial understand influence pre-strain residual formability edges. This paper analyses effect different levels paths (uniaxial tension, plane strain equi-biaxial stretching) sheared Complex Phase (CP) steel low alloy (HSLA) used for automobile chassis applications. To this purpose, rectangular specimens are cut out from pre-strained samples punched. Hole Tension Tests (HTTs) combination with Digital Image Correlation (DIC) carried determine fracture undeformed samples. The results discussed terms major strains obtained DIC. proposed methodology allows describing sensitivity high-strength sheets as function pre-deformation state useful accurately simulations.