Dual Phase Steel -780（DP780）

It has a tensile strength of 

780–900 MPa and a yield strength of 440–550 

MPa. The main production processes include 

hot rolling, pickling, cold rolling, annealing, and 

heat treatment. It takes the concept of 

composite materials as its design philosophy, 

introducing strong and tough martensite into 

high ductility ferrite for strengthening. Its 

structural characteristics are the coexistence of 

ferrite and martensite, composed of soft phase 

ferrite and more than 20% hard phase 

martensite. Soft phase ferrite endows dual 

phase steel with good ductility, while hard 

phase martensite endows dual phase steel 

with good strength. This special organization 

determines that duplex steel has the 

characteristics of low yield to strength ratio, 

high work hardening ability, good plasticity, 

and high collision energy absorption, which is 

in line with the development concept of "high

performance, safety, environmental protection, 

and energy saving" for automotive 

lightweighting.