Formability Characterization of 3rd Generation Advanced High-Strength Steel and Application to Forming a B-Pillar

Gutierrez, Jon Edward; Noder, Jacqueline; Paker, Neil; Bowman, J.W.; Zhumagulov, Amir; Dykeman, James; Malcolm, Skye; Ezzat, H. A.; Butcher, Cliff

doi:10.4271/2021-01-0267

Cited by 1 publication

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“…The process parameters of the friction test were carefully selected to represent an industrial forming process for AHSS using the CommDraw TM 220 (Commonwealth Oil Corporation, Harrow, ON, Canada) lubricant provided by the automotive toolmaker, Bowman Precision Tooling. An interface pressure of 25 MPa, and a sliding distance of 75 mm were obtained from a forming simulation of a structural B-Pillar of the studied 3rd Gen 980 documented in Gutierrez et al [ 41 ]. The sliding speed of 5 mm/s is on the lower bound of the forming speed in the B-pillar stamping process but was selected to produce a smooth and stable friction response.…”

Section: Friction Characterizationmentioning

confidence: 99%

A Comparative Evaluation of Third-Generation Advanced High-Strength Steels for Automotive Forming and Crash Applications

et al. 2021

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While the third generation of advanced high-strength steels (3rd Gen AHSS) have increasingly gained attention for automotive lightweighting, it remains unclear to what extent the developed methodologies for the conventional dual-phase (DP) steels are applicable to this new class of steels. The present paper provides a comprehensive study on the constitutive, formability, tribology, and fracture behavior of three commercial 3rd Gen AHSS with an ultimate strength level ranging from 980 to 1180 MPa which are contrasted with two DP steels of the same strength levels and the 590R AHSS. The hardening response to large strain levels was determined experimentally using tensile and shear tests and then evaluated in 3D simulations of tensile tests. In general, the strain rate sensitivity of the two 3rd Gen 1180 AHSS was significantly different as one grade exhibited larger transformation-induced behavior. The in-plane formability of the three 1180 MPa steels was similar but with a stark contrast in the local formability whereas the opposite trend was observed for the 3rd Gen 980 and the DP980 steel. The forming limit curves could be accurately predicted using the experimentally measured hardening behavior and the deterministic modified Bressan–Williams through-thickness shear model or the linearized Modified Maximum Force Criterion. The resistance to sliding of the three 3rd Gen AHSS in the Twist Compression Test revealed a comparable coefficient of friction to the 590R except for the electro-galvanized 3rd Gen 1180 V1. An efficient experimental approach to fracture characterization for AHSS was developed that exploits tool contact and bending to obtain fracture strains on the surface of the specimen by suppressing necking. Miniature conical hole expansion, biaxial punch tests, and the VDA 238-100 bend test were performed to construct stress-state dependent fracture loci for use in forming and crash simulations. It is demonstrated that, the 3rd Gen 1180 V2 can potentially replace the DP980 steel in terms of both the global and local formability.

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Section: Friction Characterizationmentioning

confidence: 99%