Kohlenstoffäquivalent- und Sauerservice
Hochfeste, windbeständige Kraftübertragungstürme – Forschung und Entwicklung
Januar 31, 2026Kohlenstoffäquivalent- und Sauerservice
3. Chemical Integrity: Kohlenstoffäquivalent- und Sauerservice
For subsea pipelines, weldability is paramount. To ensure the heat-affected zone (Gefahr) does not become brittle, das Kohlenstoffäquivalent (EG) is strictly limited.
We typically use the IIW Formula:
$$CE_{IIW} = C + \frac{Mn}{6} + \frac{Cr + Mo + V}{5} + \frac{Ni + Cu}{15}$$
For X65QO, $CE_{IIW}$ is usually kept below 0.39, ensuring that offshore welding can be performed with minimal preheating, speeding up the pipe-lay process.
Zusätzlich, because many offshore reservoirs contain $H_2S$, these pipes are often tested for HIC (Hydrogen Induced Cracking) und SSCC (Sulfide Stress Corrosion Cracking). This requires extremely low sulfur levels ($\leq 0.002\%$) and calcium treatment for inclusion shape control (converting elongated sulfides into spherical shapes).
