Welding Preheat Temperature Calculator
Calculate minimum preheat temperature for pipeline welding based on carbon equivalent and wall thickness. Supports IIW CE, Pcm (CEN), AWS D1.1 table method, API 1104 Appendix B, and EN 1011-2 (CET). Includes HAZ hardness prediction, PWHT assessment, and weldability classification. Select steel grade for auto-filled chemistry or enter manual composition from mill test reports.
Steel Grade & Chemistry
wt%
wt%
wt%
Alloying Elements
wt%
wt%
wt%
wt%
wt%
ppm
Weld Parameters
in
kJ/in
Typical: 25-35 SMAW, 30-45 GMAW, 40-60 SAW
Joint & Environment
°F
Understanding Welding Preheat
Why Preheat?
Preheat slows the cooling rate after welding, preventing the formation of hard, brittle martensite in the heat-affected zone (HAZ). It also allows hydrogen to diffuse out of the weld, preventing hydrogen-induced cold cracking.
Carbon Equivalent:
CE (IIW): Best for C > 0.12% steels
Pcm (CEN): Best for TMCP low-C steels
CET (EN 1011-2): European method
Higher CE = Higher preheat required
Typical Preheat Ranges:
CE < 0.35: No preheat needed (50°F min ambient) | CE 0.35-0.45: 50-150°F | CE 0.45-0.60: 150-300°F | CE > 0.60: 300-500°F + PWHT likely required
📚 Learn the Theory
Understand carbon equivalents, hydrogen cracking mechanisms, preheat methods, and PWHT requirements for pipeline welding