Carbon Equivalent according to Dearden and O'Neill
The Dearden-O'Neill carbon equivalent indicates how much a steel hardens and its susceptibility to cold cracking. It helps in choosing the right welding process.
Physical-Chemical Mechanism
The carbon equivalent (CE) is calculated as the sum of carbon and other elements like nickel, chromium, molybdenum, and niobium. These additions affect the hardenability and microstructure of the steel.
Metallurgical Relevance & Welding Risks
A high CE leads to greater hardening and increases the susceptibility to hot cracking. With a low CE, the steel remains softer, which is helpful for fine microstructures, but may offer insufficient strength.
Workshop Practice & Instructions
For steels with a CE above 0.4%, a slow cooling method (e.g., placing in a furnace after welding) is required to avoid hot cracking. For low CE, faster cooling is possible, but ensure adequate strength.