Calculate Carbon equivalent for estimating weldability with regard to the risk of cold cracking and as an auxiliary parameter for determining the preheating temperature during welding.
Carbon equivalents are used as a parameter for estimating weldability with regard to crack sensitivity, particularly in the heat affected zone. There are several formulae for describing the carbon equivalent, in which the individual alloy elements are weighted differently
The Carbon Equivalent CET is used for arc welding steels of material groups 1 to 4 ISO 15608, in particular high-strength steels. The carbon equivalent CET is preferably used to calculate the preheating temperature with this determined value. There is a linear relationship between the carbon equivalent CET and the preheating temperature. An increase in the carbon equivalent CET of around 0.01% leads to an increase in the preheating temperature of around 7.5 °C.
This carbon equivalent is included in various standards and codes for pressurised containers e.g. as method B of ISO/TR 17671-2 and method B of the PED harmonised standard EN 1011-2 Annex C par. 3.2.
Applicable steels: C-Mn steels, fine grain steels, low alloy steels ISO 15608 material groups 1 to 4.
Carbon equivalent calculation is performed according to the formula below:.
Limits of chemical composition for the main alloying elements [wt%]:
C = 0,05 to 0,32; Si = max. 0,8; Mn = 0,5 to 1,9; Cr = max. 1,5; Cu = max. 0,7; Ni = max. 2,5; Mo = max. 0,75; V = max. 0,18; Nb = max. 0,06; Ti = max. 0,12;
