Grade Finder

1.25Cr-0.5Mo-Si pressure vessel plate. The silicon addition improves oxidation resistance, making Grade 11 the common choice for hot wall vessels and hydrogen service up to around 550 C where full 2.25Cr strength is not required.

1Cr-0.5Mo pressure vessel plate. The economical Cr-Mo grade for moderate temperature pressure parts, widely used for separator and drum shells where creep and hydrogen resistance are needed but the duty is below the 2.25Cr range.

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.

5Cr-0.5Mo plate. The chromium level lifts resistance to sulphidic corrosion and high temperature oxidation, so Grade 5 is specified for crude and vacuum unit hot sections where naphthenic and sulphur attack dominate.

9Cr-1Mo plate for high temperature service. Used where sulphidic corrosion resistance and creep strength have to be carried above the 5Cr range, typically in refinery heaters and transfer line equipment.

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.

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.

1Cr-0.5Mo seamless pipe. The economical Cr-Mo pipe grade for boiler feed, steam and hot process service up to around 540 C, and the usual partner to SA387 Grade 12 plate.

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.

5Cr-0.5Mo seamless pipe for sulphidic and naphthenic service. Specified on crude and vacuum transfer lines and heater passes where sulphur attack, not pressure, sets the material.

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.

Weathering structural plate. Copper, chromium and nickel additions let a dense, adherent oxide patina form that seals the surface, so the structure can be left unpainted and the maintenance coating cycle disappears.

Carbon pressure vessel plate for moderate and lower temperature service. The lower carbon of Grade 60 gives better formability and weldability than Grade 70, which suits cold-formed heads, thin shells and plant where notch toughness matters more than tensile strength.

The default carbon pressure vessel plate. Grade 70 carries the highest tensile of the SA516 family, and for sour service it is supplied with controlled sulphur, calcium treatment and HIC / SSC testing so wet H2S equipment can be built from a qualified plate rather than an upgrade alloy.

The default seawater alloy. 90% copper with 10% nickel and a controlled iron addition builds a protective cuprous oxide film in seawater, and the inherent copper toxicity stops macrofouling — barnacles and mussels do not settle, so cooling lines stay clean without chlorination. Specified for ship and platform seawater systems, firewater ring mains and condenser tubing where the velocity stays below about 3.5 m/s.

The higher-duty cupro nickel. Tripling the nickel to 30% raises strength, erosion-corrosion resistance and the allowable seawater velocity to around 4.5 m/s, and lifts the service temperature well above 90/10. It is the grade for pump and valve-adjacent piping, hot brine and MSF desalination heat recovery, and any line where turbulence or sand loading would strip the film off 90/10.

The desalination variant of 70/30. Raising iron and manganese to about 2% each stabilises the protective film under high velocity, sand-laden and partly deaerated brine, which is exactly the duty inside MSF evaporator heat recovery and reject sections. Where 70/30 tubes thin at the inlet ends, C71640 holds.

Nickel-chromium-molybdenum alloy strengthened by niobium. Exceptional strength and corrosion resistance from cryogenic temperatures to 980 C without heat treatment.

Nickel-molybdenum-chromium alloy with tungsten, regarded as the most universally corrosion resistant alloy available for both oxidising and reducing media.

Iron-nickel-chromium alloy for high temperature strength with oxidation and carburisation resistance. The 32Ni-21Cr balance resists chloride stress corrosion cracking that austenitic stainless suffers, which is why it is standard for process heater and reformer tubing.

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.

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.

Titanium and niobium stabilised austenitic grades. The stabilising addition ties up carbon so the steel resists intergranular corrosion after prolonged exposure in the 425-815 C sensitisation range.

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.

A molybdenum-up step on 316L. Raising Mo to 3 - 4% lifts PREN to around 30, which buys real margin against pitting and crevice attack in pulp, scrubber and chloride service where 316L is borderline but duplex is more than the duty needs.

Titanium-stabilised 316. The titanium ties up carbon so the steel keeps its intergranular corrosion resistance after long exposure in the 425 - 815 C sensitisation range, and it holds higher creep strength than 316L in hot service.