Search results
The Great Minds of Carbon Equivalent. Part lll: The Evolution of Carbon Equivalent Equations. Wesley Wang, Senior Engineer Materials Group, EWI. In welding, carbon equivalent (CE) calculations are used to predict heat affected zone (HAZ) hardenability in steels.
Carbon equivalent formulae were originally developed to give a numerical value for a steel composition which would give an indication of a carbon content which would contribute to an equivalent level of hardenability for that steel.
In 1958, eighteen years after Dearden and O’Neill’s initial proposal on carbon equivalent (CE), the concept was accepted by British Standard BS2642[1]. The standard was then amended to include the following modified version of their equation: C+Si/24+Mn/6+Cr/5+Ni/13+. CE = (1) V/5+Mo/4+Cu/15.
[1] [2] There are two commonly used formulas for calculating the equivalent carbon content. One is from the American Welding Society (AWS) and recommended for structural steels and the other is the formula based on the International Institute of Welding (IIW).
The carbon equivalent (CET) formula is convenient for analyzing Q + T steels and their cold cracking behavior. The CET equation gives information about the combined effects of different alloying elements, as compared to only carbon.
Pcm (Pcm =C+Si/30+(Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B) created by Ito and Bessyo in Japan and CEq (CEq=C+Si/25+(Mn+Cu)/16+Ni/40+Cr/10+Mo/15+V/10) devised by Düren became the public debut, where Pcm is commonly applied in modern steels containing no more than 0.11 wt% carbon typically in pipeline manufacture.
This document discusses factors that affect the weldability of metals, including carbon equivalent (CE) and composition parameter (Pcm). CE quantifies weldability and determines if preheat is needed for carbon steels. Pcm also indicates cold cracking susceptibility.
