In recent decades

advanced high strength steel (AHSS) for car is focal point of research and development work for materials. Strength -elongation product of 1st generation AHSS steel with ferrite matrix is 15 GPa • %

and the strength -elongation product of 2nd generation AHSS steel with austenite matrix is 50 GPa

%

its higher alloy content and harder control of process lead to high production cost

therefore the 3rd generation AHSS steel with multi-phase is developed by multi-phase

metastable and multi-size structure fine control to get strength-elongation product 30 GPa . % . The research and development of 3rd generation AHSS steel is carried out by both field of increasing 1 st generation AHSS steel strength and elongation and decreasing 2nd generation AHSS steel alloy content and production cost. The progress of research and development of 3rd generation AHSS steel is presented in this article including extra-fine DP (dual phase) steel

modified TRIP (Transformation Induced Plasticity) steel

Quenching & Partitioning (Q&P) steel

ultra-fine grain bainite steel

rapid heating and cooling bainite-ferrite-martensite steel

high manganese ferrite-austenite steel and medium manganese metastable austenite-ultra-fine grain matrix steel.