Alloy Optimization for Reducing Delayed Fracture Sensitivity of 2000 MPa Press Hardening Steel
Hardy Mohrbacher, Takehide Senuma
Abstract
Press hardening steel (PHS) is widely applied in current automotive body design. The trend of using PHS grades with strengths above 1500 MPa raises concerns about sensitivity to hydrogen embrittlement. This study investigates the hydrogen delayed fracture sensitivity of steel alloy 32MnB5 with a 2000 MPa tensile strength and that of several alloy variants involving molybdenum and niobium. It is shown that the delayed cracking resistance can be largely enhanced by using a combination of these alloying elements. The observed improvement appears to mainly originate from the obstruction of hydrogen-induced damage incubation mechanisms by the solutes as well as the precipitates of these alloying elements.
Topics & Concepts
Materials scienceAlloyMetallurgyHydrogen embrittlementEmbrittlementHardening (computing)CrackingMolybdenumUltimate tensile strengthNiobiumHydrogenComposite materialCorrosionChemistryOrganic chemistryLayer (electronics)Hydrogen embrittlement and corrosion behaviors in metalsNuclear Materials and PropertiesHigh Temperature Alloys and Creep