| Abstract Scope |
Due to the ultra-high strength and excellent formability, press-hardened steels (PHS) with an ultimate tensile strength of 1500 MPa have been increasingly used for vehicle body structure components with the aim of lightening. New PHS grades with higher strength are developed for further weight reduction. However, the increase in strength usually leads to reduced fracture resistance and increased risk of hydrogen embrittlement. It has been reported that retained austenite (RA) in PHS plays an important role in the fracture and hydrogen embrittlement resistance. However, it could also be harmful if the volume fraction, morphology and stability of the RA are not properly controlled. To guide the microstructural design of PHS, a certain amount of RA has been introduced and its effects on the fracture and hydrogen embrittlement resistance of ultra-high strength PHS steel sheets were studied in the present work. |