Composition design of a new type low-alloy high-strength steel

摘要

Taking the Fe-Mn-W-Nb-Si polybasic alloy as the main alloying additive and adding micro amounts of Boron (B), a type of hot-rolled low-carbon low-alloy bainite steel with a 750 MPa yield strength and a 5 ～ 10-mm diameter after air cooling is designed by means of our own calculated formulas which give the chemical composition and the cooling rate of supercooled austenite on the microstructure and strength in steels. The results show that the experimental steel after smelting and rolling is in accordance with the design idea that in alloying element contents, they should be kept to a minimum level, 0.2/100 in the case of carbon content, assuring the steel strength requirement and obtaining bainite or bainite and martensite.