Equivalent carbon content

The equivalent carbon content of a steel alloy refers to method of measuring the maximum hardness and the weldability of the alloy based on the chemical composition of the alloy. Higher concentrations of carbon and other alloying elements such as magnesium, chromium, silicon, molybdenum, vanadium, copper, and nickel tend to increase the hardness and decrease the weldability of the material. Each of these materials tends to influence the hardness and weldability of the steel to different magnitudes, however, making a method of comparison necessary to judge the difference in hardness between two alloys made of different alloying elements. The equivalent carbon content is the most common such standard, but others exist, such as the equivalent nickel content and equivalent chromium content. A commonly used formula for calculating the equivalent carbon content is:

<math>E_c = %C + \left(\frac{%Mn+%Si}{6} \right) + \left(\frac{%Cr+%Mo+%V}{5} \right) + \left(\frac{%Cu+%Ni}{15} \right)<math>

The resulting equivalent carbon coefficient allows the alloy to be categorized alongside plain carbon steels, and have their weldability and hardness properties compared with them.

References

• Lincoln Electric (1994). The Procedure Handbook of Arc Welding. Cleveland: Lincoln Electric. ISBN 9994925822.
• Weman, Klas (2003). Welding processes handbook. New York: CRC Press LLC. ISBN 0–8493–1773–8.