Material anisotropy and trimming method effects on total elongation in DP500 sheet steel

The objective of this study is to determine the influence of material anisotropy and trimming method on the total elongation of the trimmed edge of DP500 sheet steel. For various orientations, experimental analysis is carried out on rectangular shaped tensile test specimens featuring a polished edge on one side and a trimmed edge on the other side. It is shown that the total elongation in DP500 steel exhibits significant sensitivity to (1) specimen orientation with respect to rolling direction, and (2) trimming method employed. In particular, difference in total elongation between longitudinal and transverse orientations become more pronounced with increasing trim clearance for conventionally trimmed samples. Total elongation anisotropy, however, can be significant even at small trim clearances and when sheared surface of the blank has relatively good quality without the burr which is the case for samples trimmed by the technology with offal support and dulled upper trim edge. The observations provided herein may be instrumental in contributing to meaningful explanations for unexpected edge cracking problems observed in some DP500 stamping cases. Recommendations for manufacturing best practices are offered. (C) 2010 Published by Elsevier B.V.