Effect of chemical composition on properties of plain carbon steel plate

The main chemical composition is iron (Fe, accounting for about 99% in carbon structural steel), and a small amount of elements - carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), oxygen (0), nitrogen (N), titanium (Ti), vanadium (V).

(1) Carbon and carbon are the most important elements that determine the properties of steel. Carbon structural steel is commonly used in construction steel, which belongs to low carbon steel with carbon content less than 0.25%; low alloy steel used in engineering has carbon content less than 0.52%.

(2) Silicon exists in steel as deoxidizer and is a beneficial element in steel. When the silicon content is lower (less than 1.0%), the strength of the steel can be improved, but the plasticity and toughness have no obvious influence.

(3) Manganese is a useful element in steel, which is used to deoxidize and remove sulfur in steel. Manganese has a strong ability of deoxidization and desulfurization, which can eliminate or reduce the thermal brittleness caused by oxygen and sulfur, and improve the strength and hardness of steel.

(4) Phosphorus is a very harmful element in steel. With the increase of phosphorus content, the strength, yield ratio and hardness of the steel increased, while the plasticity and toughness decreased significantly. Especially, the lower the temperature, the greater the impact on plasticity and toughness, and increase the cold brittleness of steel.