Microalloyed steels

It's not easy to give a perfect definition of microalloyed steels, because while it's undeniable that these are steels in which certain elements have been deliberately introduced in very small quantities, the expression doesn't necessarily apply to all microalloyed grades, but rather to families of steels with high characteristics, especially in the field of structural steels (metallic and mechanical).

In this article, we will give an overview of the role of microalloying elements in any family of steels, wherever this is not too time-consuming, with priority given to high-performance structural steels.

The steel families concerned are as follows:

• Weldable high-strength steels (HSLA) in the form of plates, tube plates, thin plates, bars, sections and merchant bars (structural steels, pressure vessel steels, etc.);

• thin sheets for forming and stamping with high yield strength or without free interstitial elements, i.e. with C and N elements fixed in the form of carbides and nitrides;

• mechanical carbon steels for which microalloying makes it possible to avoid heat treatments or the development of combined treatments in the hot forging process (thermomechanical treatments);

• specific families, such as rail steels, reinforcing bars, bolting steels, etc. ;

• oxide dispersion steels, which are the most recent and are true dispersoid steels.