Steam headers and main steam piping

Modified 9Cr-1Mo-V (P91) seamless pipe for supercritical steam. The creep strength allows a much thinner wall than P22 at 580 - 600 C, cutting weight and thermal fatigue on main steam and hot reheat lines. Hardness after PWHT is reported on every length.

2.25Cr-1Mo seamless pipe — the main steam and hot reheat standard. P22 carries creep strength and hydrogen resistance across refinery hot wall piping, superheater headers and heater coils, and is the pipe most often paired with SA387 Grade 22 vessels.

1.25Cr-0.5Mo seamless pipe. The matching pipe grade to SA387 Grade 11, used for moderate temperature steam and process lines where plain carbon steel loses strength and oxidation resistance.

Modified 9Cr-1Mo-V (Grade 91) plate. Vanadium and niobium micro-alloying gives roughly twice the creep rupture strength of Grade 22 at 550 - 600 C, enabling thinner, lighter pressure parts in supercritical steam and high temperature process plant. Heat treatment and PWHT control are critical and are recorded on the certificate.

2.25Cr-1Mo pressure vessel plate — the refinery standard for hydroprocessing. The higher chromium and molybdenum push the Nelson curve limit well above Grade 11, which is why reactors, separators and hot wall equipment in hydrogen service specify it.

Precipitation-hardened nickel alloy developed for advanced ultra-supercritical boilers. Gamma-prime strengthening plus about 25% chromium holds creep rupture strength and coal-ash corrosion resistance at 750 C and above, which is beyond what 617 can carry in thick section steam headers.