Metallurgical design of boron microalloyed steels for forged components

To fulfill the industrial demand of forged steels with high mechanical and microstructural requirements coupled with reduced cost, the possibility to decrease the content of Mo and other alloying elements has been evaluated. The effect of boron addition (up to 30 ppm) on the steel hardenability has been investigated on two steels with different chemical com-position at laboratory scale. In particular, the steel chemical composition has been designed in order to make effective the B addition in terms of hardenability. Two 80 kg ingots cast by a vacuum induction melting plant have been hot rolled by a pilot mill. The effect of B addition on hardenability has been evaluated and compared to that of steel for same application but without B. Results show an improvement of hardenability if 30 ppm B are added even if a Mo reduction is performed.Keywords: steel, hardenability, boron