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The die wear up to 80,800 hits on a prog-die setup for bare DP1180 steel was investigated in real production condition. In total, 31 die inserts with the combination of 11 die materials and 9 coatings were evaluated. The analytical results of die service life for each insert were provided by examining the evolution of surface wear on inserts and formed parts. The moments of appearance of die defects, propagation of die defects, and catastrophic failure were determined. Moreover, the surface roughness of the formed parts for each die insert was characterized using Wyko NT110 machine. The objectives of the current study are to evaluate the die durability of various tooling materials and coatings for flange operations on bare DP 1180 steel and update OEM tooling standards based on the experimental results. The current study provides the guidance for the die material and coating selections in large volume production for next generation AHSSs.

With the implementation of Advanced High Strength Steel (AHSS) becoming more common for automotive manufacturers to reduce mass and/or improve performance, special stamping considerations must be made. Certain production parts may split at trimmed edges where strain levels are well below the forming limit curve of the respective grade, which is more applicable to necking fractures/splits. Similar to the presence of hard inclusion stringers (i.e. MnS) that can cause edge fractures in high strength low alloy steels, AHSS steels most susceptible to this phenomenon typically consist of dual phase or multiphase microstructures containing both a hard phase (martensite) and a soft phase (ferrite). Specific examples of these parts will be discussed, including studies to determine the root cause of the edge fracture and to communicate the solutions for consideration in appropriate standards and specifications.