Effects of Aluminum on Microstructures and Mechanical Properties of Hot-Rolled TRIP Steels

The newly developed hot-rolled TRIP steel had been developed with well balanced comprehensive mechanical properties of 570MPa tensile strength and 33% elongation as well as ductile-brittle transition temperature lower than −80 °C based on microstructures of 7.2% retained austenite volume fraction and around 5 μ u fine ferrite grain size. The experimental results showed that the retained austenite volume fraction dramatically increased from zero to 7.2% when aluminum increased from 1.33%, consequently, the elongation increased from 28% to 33% and tensile strength simultaneously increasing from 520MPa to 570MPa.