ASTM A815 WP446
ASTM A815 WP446 – Ferritic Stainless Steel Pipe Fittings
ASTM A815 WP446 pipe fittings are manufactured from high-performance ferritic stainless steel Grade 446 (UNS S44600), engineered for superior resistance to oxidation, sulfidation, and high-temperature corrosion. These wrought stainless steel fittings are designed for demanding industrial environments involving elevated temperatures, high pressure, and aggressive media exposure.
With high chromium content (up to 27%), WP446 fittings provide exceptional stability in extreme heat and corrosive environments such as furnaces, petrochemical processing systems, heat exchangers, and industrial exhaust applications. Their excellent thermal resistance, scaling resistance, and durability make them a preferred choice in the power generation, chemical processing, and metallurgical industries.
Key Features
High-chromium ferritic stainless steel (UNS S44600)
Outstanding resistance to high-temperature oxidation & scaling
Excellent corrosion resistance in acidic & sulfur-rich environments
Superior performance in high-temperature service conditions
Strong resistance to chloride stress-corrosion cracking
High thermal conductivity & dimensional stability
Suitable for furnace, combustion, and heat-exchanger systems
Specifications
| Specification | Details |
|---|---|
| Standard | ASTM A815 / A815M |
| Grade | WP446 |
| UNS Number | S44600 |
| Material | Ferritic stainless steel |
| Manufacturing | Seamless / Welded wrought fittings |
| Standard Compliance | ASME B16.9 / MSS SP-43 / B16.28 (as applicable) |
| Form | Butt-weld pipe fittings |
Equivalent Grades
| Standard | Grade |
|---|---|
| UNS | S44600 |
| AISI | 446 |
| EN / DIN | 1.4762 / 1.4763 (approx.) |
| JIS | SUS 446 |
Equivalence values are approximate.
Available Sizes
Size Range: ½” – 48” NPS
Schedules: SCH 10S to XXS
Form: Seamless & Welded
Chemical Composition
| Element | % |
|---|---|
| Chromium (Cr) | 23.0 – 27.0 |
| Carbon (C) | ≤ 0.20 |
| Manganese (Mn) | ≤ 1.50 |
| Silicon (Si) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Iron (Fe) | Balance |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥ 485 MPa |
| Yield Strength | ≥ 275 MPa |
| Elongation | ≥ 20% |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.70 g/cm³ |
| Melting Point | ~1500°C |
| Modulus of Elasticity | 200 GPa approx. |
| Thermal Conductivity | Higher than austenitic grades |
Types of ASTM A815 WP446 Fittings
ASTM A815 WP446 Elbow
ASTM A815 WP446 Tee
ASTM A815 WP446 Reducers
ASTM A815 WP446 Caps
ASTM A815 WP446 Cross Fittings
ASTM A815 WP446 Nipples
ASTM A815 WP446 Couplings
ASTM A815 WP446 Stub Ends
Corrosion Resistance
Excellent resistance to:
High-temperature oxidation
Sulfidation & carburization
Chlorides & industrial atmospheres
Hot gases and combustion environments
Suitable for highly corrosive & elevated temperature applications
Heat Resistance
Designed for high-temperature service up to ~1100°C
Exceptional scaling & thermal fatigue resistance
Ideal for furnace components & heat-exchanger systems
Heat Treatment
| Type | Process |
|---|---|
| Annealing | 800°C – 900°C, air cooldown |
| Stress-relieving | Recommended after heavy forming |
| Hardening | Not hardenable by heat treatment (only cold work increases strength) |
Welding
Fair weldability (ferritic grade considerations apply)
Suitable welding methods: TIG / MIG / SMAW
Pre-heat & post-heat treatment recommended to avoid grain growth
Use ferritic stainless steel filler metals for best results
Fabrication
Good machinability with proper tooling
Suitable for forming & cold-working (moderate)
Avoid severe hot-working without controlled heat treatment
Applications
Furnace components & burners
Heat exchangers & superheaters
Petrochemical & refinery equipment
Industrial exhaust & flue gas systems
Thermal processing plants
Metallurgical & furnace engineering
Power generation & boiler systems