What is p92 chemical composition

Feb 06, 2026

The main alloying elements of A335P92 alloy steel pipe include chromium, molybdenum, vanadium, niobium, and nitrogen. Chromium improves the steel's oxidation resistance and corrosion resistance, typically ranging from 8.5% to 9.5%; molybdenum helps enhance high-temperature strength, with a content of approximately 0.3% to 0.6%; the addition of vanadium and niobium refines the grain size, improving the material's toughness and creep resistance; and nitrogen stabilizes the austenitic structure.

This balanced ratio of elements allows A335P92 alloy steel pipe to maintain good mechanical properties even at high temperatures, such as high tensile strength and creep rupture strength above 600 degrees Celsius. The material also possesses good weldability and machinability, facilitating its use in practical engineering projects.

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Alloy Steel P92 Pipes Chemical Composition

C, %	Mn, %	P, %	S, %	Si, %	Cr, %	Mo, %
0.07 - 0.13	0.30-0.60	0.020 max	0.010 max	0.50 max	8.50 - 9.50	0.30 - 0.60

Carbon (C) 0.07–0.13% solid solution strengthening, improves strength, but needs to be controlled to avoid weld cracking.
Chromium (Cr) 8.50–9.50% forms a dense oxide film, improving oxidation resistance and corrosion resistance.
Molybdenum (Mo) 0.30–0.60% enhances high-temperature strength and creep resistance, but its content is lower than that of P91 steel.
Tungsten (W) 1.50–2.00% works synergistically with molybdenum, increasing the molybdenum equivalent (Mo+0.5W) to approximately 1.5%, significantly improving high-temperature strength.
Vanadium (V) 0.15–0.25% forms carbides with carbon, refines grains, and improves toughness.
Niobium (Nb) 0.04–0.09% inhibits grain growth and enhances high-temperature stability.
Nitrogen (N) 0.03–0.07% solid solution strengthening, improving creep strength.
Boron (B) 0.001–0.006 Trace addition significantly improves grain boundary strength and inhibits creep crack propagation.
Manganese (Mn) 0.30–0.60 Deoxidizer, improves hot working properties.
Silicon (Si) ≤0.50 Deoxidizer, improves strength.
Phosphorus (P) ≤0.020 Impurity element, requires strict control to avoid brittleness.
Sulfur (S) ≤0.010 Impurity element, requires strict control to avoid hot cracking.
Nickel (Ni) ≤0.40 Trace addition, improves toughness.
Aluminum (Al) ≤0.02 Deoxidizer, controls grain size.

A335 P92 Alloy Steel Pipes Application Scenarios

1. Power Industry: P92 pipes are widely used in the main steam pipelines and reheat systems of ultra-supercritical units. For example, in a 1000MW unit project in China, P92 pipes withstood parameters up to 31MPa/610℃ and had a service life exceeding 100,000 hours. Compared to P91, P92 allows for a 20% reduction in pipe wall thickness, significantly reducing thermal inertia and improving unit efficiency.

2. Petrochemical Industry: In the high-temperature reaction section (400-550℃) of hydrocracking units, P92 steel pipes are used to transport mixtures of hydrogen and hydrocarbons. Its resistance to hydrogen corrosion (passed NACE TM0177 standard test) prevents equipment embrittlement failure.

3. Nuclear Power Industry: P92 has been selected as a candidate material in the secondary loop systems of fourth-generation nuclear power plants. Experiments show that its impact toughness attenuation rate under irradiation is 40% lower than that of 316L stainless steel.