Steel- An Important Material for Energy Critical Era

摘要

High strength and ductility steels are the new developing tendency in steel and automobile industries worldwide. The use of high strength steels can reduce the thickness of steel use under the same safety condition that makes vehicle lightening, energy and pollution saving possible. TWIP steel possesses both high strength ( > 800 MPa) and high ductility ( > 70% of elongation) what is interesting for the steel industry.The development of the new generation steel is from DP steel to TWIP steel, including BH steel, IF steel, TRIP steel, PM steel, and CP steel. As the newly developed steel type TWIP steel has huge potential among the high strength steels. In our research, Fe-Mn-C steel was doped with 2 wt% and 4 wt% Al element through a vacuum melting process. The result showed that the grain size increased from 75 to 100 im with Al content increasing to 4 wt%. The austenite phase was the main phase of TWIP steels at room temperature. Tensile test results showed excellent mechanical properties with the value of T.S. x EL reaching 70000 MPa% and the hardness Hv 234.