Using carbon equivalent value evaluation of steel weldability

Weldability refers to material welded construction under limited conditions into components according to the design requirements and meet the requirements of pre-service capabilities. By welding materials, welding methods, component type and requirements affecting the four factors.

Carbon steel is iron-based, iron-carbon alloy, alloy elements carbon, the mass fraction of carbon is not more than 1%, in addition, the manganese content does not exceed 1.2%, mass fraction of silicon does not exceed 0.5%, after neither as an alloying element. Other elements such as Ni, Cr, Cu etc. within the limits of the residual amount of control, but not as an alloying element. Impurity elements such as S, P, O, N, etc., depending on the kind and the grade of steel, are strictly limited. Therefore, the carbon steel welding depends on the carbon content, with increasing carbon content, and weldability gradually deteriorated, with low carbon steel welding best.

Using carbon equivalent value evaluation of steel weldability

1) If the two values are equal when carbon steel, but carbon content ranging from high carbon content of the steel in the welding process prone to hardening organization, its tendency to crack is clearly lower than the carbon content of steel far greater, poor weldability. Therefore, when the carbon steel when equal in magnitude, it can not be exactly the same as weldability.

2) calculate the carbon equivalent value expressed only affect the chemical composition of the weldability, without taking into account the different cooling rates, can get different organizations, cooling fast, easy to produce hardened tissue, weldability will deteriorate.

3) the impact of weld metal structure and thus affect the weldability of factors, in addition to the chemical composition and cooling rate, there are welding cycle maximum heating temperature and residence time at high temperature and other parameters in the formula for calculating the carbon equivalent values are not shown come out.