Investigation on the Effect of Chemical Composition on the Texture and Bake Hardening IF Steels

Interstial free steels have good formability and also excellent deep drawability. These features make them one of the applicable materials in automotive industry. Chemical composition and thermomechanical treatment used to process these steels have important role in final properties of them. In this study, the effect of chemical compositon on texture, anisotropical properties and bake hardenability of these steels were investigated. The results showed that contribution of vanadium as a weak carbonitride former element with titanium as strong carbonitride former could change the texture of steels. Replacing titanium with vanadium caused harmful effect on mechanical properties. In this research deep drawing properties of five steels were compared based on parameters. The results of bake hardenability test showed that there were critical limits for vanadium volume fractions above which bake harden properties was improved. It was shown that the bake harden properties of Nb-steels were better than that of Ti-steels. This was due to the better solution of Nb(C,N) compared to Ti(C,N). Addition of vanadium to Ti-steels may improve bake harden properties of IF-steels.