Dearden-Ando Carbon Equivalent
The Dearden-Ando carbon equivalent is a value used to estimate the cold cracking tendency of unalloyed and low-alloy steels during welding. It takes into account the carbon content as well as alloying elements and indicates how high the maximum hardness in the heat-affected zone will be.
Physical-Chemical Mechanism
The Dearden-Ando carbon equivalent is calculated based on the carbon content and alloying elements such as nickel, chromium, and molybdenum. It indicates how high the maximum hardness in the heat-affected zone can become during welding.
Metallurgical Relevance & Welding Risks
A high carbon equivalent increases the risk of cold cracking and hot cracking. If the carbon content is too high (over 0.7%), the microstructure can become glass-hard martensite, making the weld prone to cracking. A low carbon equivalent reduces this risk.
Workshop Practice & Instructions
Before welding, calculate the Dearden-Ando carbon equivalent. For steels with a carbon equivalent above 0.7%, use a slow cooling method (e.g., heat exchanger) and ensure continuous cooling of the weld. For lower values, a fast cooling method is acceptable.