What is API 5L X52 carbon equivalent

API 5L X52 steel is carbon steel, with 0.16% Carbon, 0.45% Silicon, 1.65% Manganese, 0.02% Phosphorus, 0.01% Sulphur, 0.07% Vanadium, 0.05% Niobium, 0.04% Titanium. That makes API 5L X52 carbon steel has superior mechanical properties. What is API 5L X52 carbon equivalent?

API 5L X52 carbon equivalent indicates what carbon content would contribute to an equivalent level of hardenability for API 5L X52 steel. Taking this further, API 5L X52 carbon equivalent represents the material composition’s contribution to the cold-cracking (hydrogen cracking) susceptibility of the X52 steel.

API 5L X52 carbon equivalent CEIIW is 0.43% max and CEPcm is 0.25% max. Carbon equivalent calculations are used in welding to predict the heat-affected zone (HAZ) hardenability.