MITTAL HI FORM HF 70Y80T is a dual-phase steel with 550 MPa tensile strength used for automotive body structures. The dual-phase steel microstructure typically consists of a soft ferrite phase with dispersed islands of a hard martensite phase. The martensite phase is substantially stronger than the ferrite phase. The dual-phase 550 MPa grades are high yield strength to tensile strength ratio alloys for improved structural behavior. This datasheet provides information on tensile properties as well as deformation. It also includes information on forming. Filing Code: SA-557. Producer or source: Mittal Steel USA Flat Products.