UNS S41500 is Equivalent to ASTM A182 F6NM?

UNS S41500 Equivalent to ASTM A182 F6NM

UNS S41500 is fully equivalent to ASTM A182 F6NM. F6NM is the common designation used in ASTM A182 for forgings, while UNS S41500 is the unified numbering system grade. Both refer to the same soft martensitic stainless steel (also known as 1.4313 / X3CrNiMo13-4 or AISI 415 / CA6-NM).

This grade combines high strength, excellent toughness, good weldability, and moderate corrosion resistance, especially in environments containing chlorides or mild sour service (NACE MR0175 compliant when properly heat treated).

Gangsteel supplies UNS S41500 / ASTM A182 F6NM in various forms including plates, forgings, bars, and flanges from our stainless steel stock, with full certification and fast delivery.

What Is UNS S41500 / F6NM?

UNS S41500 (F6NM) is a low-carbon, chromium-nickel-molybdenum martensitic stainless steel. The addition of 3.5–5.5% nickel softens the martensite structure, significantly improving toughness compared to standard 13% Cr grades like 410 or 420. Molybdenum (0.5–1.0%) enhances pitting and crevice corrosion resistance, while the very low carbon content (max 0.05%) ensures excellent weldability and reduces the risk of sensitization.

This material is widely recognized for its balanced properties in quenched and tempered condition, offering high yield strength combined with good impact toughness even at low temperatures (down to -60°C).

Chemical Composition of UNS S41500 / ASTM A182 F6NM

Typical chemical composition (weight %):

• Carbon (C): 0.05 max
• Manganese (Mn): 0.50 – 1.00
• Silicon (Si): 0.60 max
• Phosphorus (P): 0.030 max
• Sulfur (S): 0.030 max
• Chromium (Cr): 11.5 – 14.0
• Nickel (Ni): 3.5 – 5.5
• Molybdenum (Mo): 0.50 – 1.00
• Nitrogen (N): 0.10 max (optional in some specs)
• Iron (Fe): Balance

The low carbon and balanced alloying elements result in a PREN (Pitting Resistance Equivalent Number) of approximately 18–22, providing better chloride resistance than basic 13Cr martensitic steels.

Mechanical Properties (Quenched and Tempered)

In the typical QT (quenched and tempered) condition per ASTM A182 F6NM:

• Tensile Strength: 790 – 1150 MPa (115 ksi min)
• Yield Strength (0.2% offset): 620 MPa min (90 ksi min)
• Elongation: 15% min
• Hardness: Usually limited to 23 HRC max for sour service (NACE)
• Impact Toughness: Good CVN values, often ≥27J at -18°C or lower depending on heat treatment

Different tempering temperatures allow adjustment of strength vs. toughness to meet specific project requirements (e.g., QT760 or QT840 conditions).

Key Equivalents

• UNS: S41500
• ASTM: A182 F6NM (forgings), A240 (plates), A479 (bars)
• EN / DIN: 1.4313, X3CrNiMo13-4
• AISI / SAE: 415 / CA6-NM
• Other: JIS SCS5, AFNOR Z6CND13-04, BS 425C11

UNS S41500 and ASTM A182 F6NM are interchangeable in most applications. The “F6NM” designation is primarily used for forged products under A182, but the material chemistry and properties are identical.

Main Applications of UNS S41500 / F6NM

Thanks to its combination of high strength, toughness, and moderate corrosion resistance, this grade is popular in critical industries:

• Oil & Gas / Petrochemical: Valve bodies, flanges, pump shafts, wellhead components, Christmas trees, subsea manifolds, and sour service equipment (when hardness is controlled per NACE MR0175/ISO 15156).
• Power Generation & Hydropower: Turbine runners, blades, casings, and compressor discs.
• Chemical Processing: Reactors, heat exchangers, and piping exposed to mild acids or chlorides.
• Marine & Offshore: Subsea connectors, actuators, and components in seawater environments.
• General Engineering: High-pressure valves, centrifuges, and structural parts requiring weldability and impact toughness.

It performs well in temperatures from -60°C up to approximately 300–350°C.

Processing and Fabrication

UNS S41500 / F6NM offers good weldability due to its low carbon content. Preheating is usually minimal, and post-weld heat treatment can often be avoided or simplified compared to higher-carbon martensitic grades. It can be machined, forged, and formed in the annealed condition, then heat treated to final properties.

Gangsteel provides value-added services including cutting, machining, heat treatment, and testing to meet your exact specifications.

Why Choose Gangsteel for UNS S41500 / ASTM A182 F6NM?

• Large inventory of plates, forgings, and bars in our stainless steel stock
• Full traceability with mill test certificates (EN 10204 3.1 or 3.2)
• Compliance with ASTM A182, NACE MR0175, and other international standards
• Competitive pricing and fast delivery
• Technical support for material selection, heat treatment, and welding procedures

Whether you need small trial quantities or large project volumes, Gangsteel ensures reliable supply of high-quality UNS S41500 equivalent to ASTM A182 F6NM.

Conclusion

UNS S41500 is directly equivalent to ASTM A182 F6NM and serves as a high-performance martensitic stainless steel that bridges the gap between standard 13Cr grades and more expensive duplex or austenitic alloys. Its excellent toughness, weldability, and balanced corrosion resistance make it a preferred choice for valves, turbines, pumps, and offshore equipment worldwide.

Contact Gangsteel today for current stock availability, detailed datasheets, or a quotation for UNS S41500 / ASTM A182 F6NM plates, forgings, or custom components.