Investigation on microstructures and mechanical properties of Al-TRIP steel

A kind of cold-rolled TRIP steel containing 1.2 % aluminum for galvanizing was investigated in this paper.Optical microscopy,scanning electron microscopy,X-ray diffraction techniques and tensile test were used to characterize the microstructures and to determine the mechanical properties.It was showed that Ac1 was 747 ℃ and Ac3 was 930 ℃ for the TRIP steel and the maximum product of strength and elongation was obtained at 30 s during isothermal holding temperatures.By varying the annealing temperature within the austenite-ferrite region and the isothermal holding time,the amount of retained austenite and the amount of carbon within the retained austenite in the final microstructures can be controlled.