Charpy Impact Fracture Energy and Ductile-Brittle Transition Temperature of Dual-Phase 590 Steel

Advanced High strength steels (AHSS) have been introduced and gradually adopted in vehicle structures as lightweight materials in the past years. Engineering performance of AHSS in many areas have shown that they are superior to the conventional steels such as mild steel, IF (interstitial-free) steel or even HSLA (high strength, low alloy) steel. In this paper, we present the results from Charpy V-Notch impact tests on Dual Phase 590 (DP590) steel, which belongs to the family of AHSS. Tests were conducted at temperatures ranging from -120 °C (-184 °F) to 90 °C (194 °F). Specimens oriented in both L-T and T-L directions were tested. Due to its reduced thickness relative to the ASTM testing standards, specimens from a medium low carbon steel AISI-1018, having both standard and reduced thicknesses, were tested as well to justify the correction method for the DP590 data. It is shown that the ductile-brittle transition temperature (DBTT) based on 20.4 J (15 ft-lb) absorbed energy is about -95 °C (-139 °F) for DP590 which is far below the 5 °C (41 °F) of the AISI-1018 steel.