Effect of Modifying the Chemical Composition on the Properties of Spring Steel

The aim of the present work was to experimentally examine the effect of modifying the chemical composition on the properties of Si-Cr-V spring steel. The investigation was based on a commercial 51CrV4 spring steel, with its composition modified in terms of Si, Cr, and V contents, targeting a yield strength of over 2000 MPa in the tempered condition. The experimental evaluation included decarburization and scale resistance, tensile properties, fracture toughness, and fatigue resistance. The results show that the simulation software gave greatly exaggerated values when it comes to the yield-strength prediction and the influence of the steel’s composition. In terms of experimental results, the most influential element in terms of improving the decarburization resistance, the yield and tensile strengths, the fracture toughness, and most importantly the fatigue limit and the fatigue life is Si, followed by Cr, while increasing the amount of V has a mainly negative effect. However, when the Si content exceeds 1.6 pct, this leads to an increased decarburization depth and a drop in the tensile properties.