Weldability refers to the ability of the material to be welded under defined construction conditions to meet the required service requirements. Weldability by the material, welding methods, component types and the use of four factors.

Carbon steel is based on iron elements, iron-carbon alloy, carbon as alloying elements, the carbon content of not more than 1%, in addition, the mass fraction of manganese does not exceed 1.2%, silicon mass fraction of not more than 0.5% Neither of them is an alloying element. Other elements such as Ni, Cr, Cu, etc. are controlled within the limits of the residual amount, but not as an alloying element. Impurity elements such as S, P, O, N, etc., according to the different varieties and grades of steel, are strictly limited. Therefore, the carbon steel welding depends mainly on the carbon content, with the increase in carbon content, welding gradually deteriorated, of which the best low-carbon steel welding.