ASTM A182 F6a
ASTM A182 F6A Flanges & Fittings
ASTM A182 F6a is a martensitic stainless steel grade containing 12% chromium and low carbon, manufactured by forging and heat treatment for high-strength applications. It offers excellent wear resistance, moderate corrosion resistance, and outstanding hardness after heat treatment.
F6a stainless steel is widely used in turbine parts, valve trims, pump shafts, engineering components, and petrochemical applications where strength, erosion resistance, and temperature durability are crucial.
This grade is commonly supplied in the quenched and tempered or normalized and tempered condition to achieve required mechanical properties.
Key Features
High strength and hardness after heat treatment
Good resistance to erosion, abrasion, and mild corrosion
Excellent performance in steam, oil, and mildly corrosive media
Suitable for high-temperature and high-pressure service
Magnetic martensitic structure
Good machinability in annealed condition
Excellent dimensional stability
Technical Specification
| Property | Details |
|---|---|
| Standard | ASTM A182 / ASME SA182 |
| Grade | F6a |
| UNS | S41000 (Equivalent Grade) |
| Type | Martensitic Stainless Steel (12% Cr) |
| Product Forms | Forged flanges, fittings, shafts, valve bodies, pump parts |
| Delivery Condition | Annealed / Quenched & Tempered / Normalized & Tempered |
ASTM A182 F6A Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| UNS | S41000 |
| ASTM | A182 F6a |
| ASME | SA182 F6a |
| AISI | 410 (approx) |
| EN | X12Cr13 (1.4006) |
| JIS | SUS410 |
Available Sizes
| Product | Size Range |
|---|---|
| Forged Fittings | ½″ – 4″ (DN 15–DN 100) |
| Flanges | ½″ – 48″ (DN 15–DN 1200) |
| Pressure Class | 150#, 300#, 600#, 900#, 1500#, 2500# |
| Wall Thickness | SCH 10 – XXS |
| Custom shapes | Shafts, Bars, Machined Components |
Chemical Composition (%)
| Element | Min | Max |
|---|---|---|
| Carbon (C) | — | 0.08 |
| Chromium (Cr) | 11.5 | 13.5 |
| Nickel (Ni) | — | 0.75 |
| Manganese (Mn) | — | 1.00 |
| Silicon (Si) | — | 1.00 |
| Phosphorus (P) | — | 0.040 |
| Sulfur (S) | — | 0.030 |
| Iron (Fe) | Balance | Balance |
Mechanical Properties
| Property | Requirement |
|---|---|
| Tensile Strength | 485 MPa (Min) |
| Yield Strength | 275 MPa (Min) |
| Elongation | 20% Min |
| Hardness | 190 HB Max (Annealed), up to 300 HB when tempered |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.75 g/cm³ |
| Melting Range | 1480 – 1530°C |
| Modulus of Elasticity | 200 GPa |
| Thermal Expansion | 10.1 µm/m°C |
| Thermal Conductivity | 24.9 W/m-K |
Type ASTM A182 F6A Flanges & Fittings
Corrosion Resistance
Moderate corrosion resistance in fresh water, steam, mild acids, and alkalis
Good resistance to erosion and abrasion
Not recommended for high-chloride or highly acidic environments unless surface-hardened or coated
Heat Resistance
Good strength and scaling resistance up to 650°C
Short-term exposure up to 815°C possible
Maintains hardness at elevated temperatures
Heat Treatment
| Process | Temperature Range | Notes |
|---|---|---|
| Annealing | 815–900°C, slow cool | Improves machinability |
| Hardening (Q&T) | 950–1050°C + oil/air quench | Produces martensitic hardness |
| Tempering | 610–760°C | Achieves desired strength & toughness |
Welding
Weldable with pre-heat & post-heat treatment
Preheat: 150–260°C
Post-weld tempering required to prevent cracking
Recommended filler metals: 410, 410NiMo
Fabrication
Good machinability in annealed condition
Hard after heat treatment — requires carbide tooling
Suitable for forging & machining into precision parts
Magnetic and can be surface hardened
Applications
Steam & Turbine Components
Pump & Valve Trim
Shafts, Spindles & Pins
Petrochemical Plants
Oilfield Tools & Drilling Equipment
Hydroelectric & Thermal Power Plants
High-pressure industrial fittings
Boiler feed systems