C.E. IIW = Pcm = CET =
CE is Carbon Equivalent as given in AWS D1.1.
Pcm formula is by Japanese Welding Engineering Society’s critical metal parameter:
C.E.
Weldability
0.15 Max.
Excellent Weldability with all process, No preheat, Interpass or Postheat necessary
0.15 to 0.30
Readily weldable with all process, No preheat, Interpass or Postheat necessary except thick sections
0.30 to 0.50
Readily weldable with all process if Preheat, Interpass temp. contols & PWHT are followed
0.50 to 1.0
Usually require preheat interpass temperature control and postheat. Special heating and cooling procedures in a furnace such as normalizing may be required to restore the properties of the metal after welding. High carbon Electrodes designed for welding tool steels or the specific alloy are readily available from welding supply companies.
CE% < 0.14 Excellent weldability, no special precautions necessary
0.14 < CE% < 0.45 Martensite is more likely to form, and modest preheats with low hydrogen electrodes become necessary.
CE% > 0.45 Extreme complications, weld cracking is very likely, hence preheat in the range 100-400°C and low hydrogen electrodes are required.
