Silicon contributes greatly to the production of sound steel because of its deoxidizing and degasifying
properties. When added in amounts up to 2.5%, the ultimate strength of the steel is increased without
loss in ductility. Silicon in excess of 2.5% causes brittleness, and amounts higher than 5% make the steel
non-malleable.
Resistance to oxidation and surface stability of steel are increased by the addition of silicon. These
desirable effects partially compensate for the tendency of silicon to lower the creep properties of steel.
Silicon increases the electrical resistivity of steel and decreases hysteresis losses.