# Determining the carbon equivalent value (CEV)

In order to calculate the CEV, please provide the quantity of each element with up to three decimal places. (calculation is subject to correction – the formula from the International Institute of Welding (I.I.W.) used here is recommended for a carbon value of at least 0.18%).

# Carbon equivalent value definition – term and formula

The carbon equivalent is a comparative figure that provides information about the weldability of steel. It is possible to weld non-alloy steels with a carbon content of up to 0.2%. In most cases, however, steel contains any number of other alloy elements which can have various degrees of influence on their weldability.

That is why attempts have been made to create a formula where the influence of these elements is included. Because of the great number of steels, it is easy to see that it is virtually impossible for a single equation to provide a sufficient description of the problem. That is why the literature is full of several equations. Here are two examples of equations. The first is recommended by the International Institute of Welding (I.I.W.) and is for steel with more than 0.18% carbon

CEV (%) = %C + %Mn/6 + (%Cu + %Ni)/15 + (%Cr + %Mo + %V)/5

and the second is

CEV (%) = %C + %Si/30 + (%Mn + %Cu + %Cr)/20 + %Ni/60 + %Mo/15 + %V/10 + 5(%B) the Ito-Bessyo formula for steel with less than 0.18% carbon.

The carbon equivalent value allows statements to be made about the susceptibility to cold-cracking.