Refinery heater and furnace coils

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.

9Cr-1Mo seamless pipe. Higher chromium for oxidation and sulphidic corrosion resistance in refinery heater coils and high temperature transfer lines.

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.

The high-temperature austenitic. 25Cr-20Ni gives scaling resistance to around 1035 C in continuous service, so 310S is the grade for furnace internals, radiant tubes and anything that lives in flue gas rather than in water.

The creep-optimised version of Alloy 800. Controlled carbon plus a combined aluminium and titanium window of 0.85 - 1.20% gives far better creep rupture strength above 600 C, so 800HT is the grade for the hottest reformer and pigtail service rather than plain 800.

Nickel-chromium-cobalt-molybdenum alloy for the extreme end of high temperature service. Solid solution strengthening keeps useful creep strength to 1100 C while the chromium and aluminium give oxidation resistance, so 617 is used where 800HT and stainless are long past their limit.