Improve the strength of steel is one of the main purpose of adding alloying elements. To improve the strength, we should try to increase the resistance to dislocation motion. Metal reinforcement mechanism of solid solution strengthening, dislocation strengthening, fine grain strengthening, second phase (precipitation and dispersion) strengthening. Strengthen the role of alloying elements, it is the use of these strengthening mechanisms.
1. Impact on the mechanical properties of the steel in the annealed condition
Structural steel basic phase in the annealed condition is ferrite and carbides. Alloying elements dissolved in ferrite, forming alloy ferritic, relying on solid solution strengthening effect, increase strength and hardness, but lower ductility and toughness.