ASTM A815 WP429
ASTM A815 WP429 Wrought Stainless Steel Pipe Fittings
ASTM A815 WP429 refers to wrought martensitic stainless steel butt-weld pipe fittings made from Grade 429 stainless steel. This steel grade offers excellent resistance to corrosion, oxidation, and scaling at elevated temperatures, along with good mechanical strength and moderate toughness.
With improved performance over standard ferritic grades and designed to withstand high-temperature exhaust, furnace, and industrial chemical environments, ASTM A815 WP429 fittings are widely used in chemical plants, power stations, heat treatment systems, and thermal processing equipment.
These pipe fittings offer excellent weldability, dimensional accuracy, and long-term durability, making them suitable for demanding industrial fluid-handling systems.
Key Features
Manufactured from martensitic stainless steel (Grade 429)
Excellent scaling and oxidation resistance at high temperatures
Good chloride stress corrosion resistance
Higher mechanical strength than ferritic grades
Suitable for high-temperature exhaust and furnace components
Good wear and abrasion resistance
Precise fit and dimensional stability for pressure pipelines
Specification
| Property | Details |
|---|---|
| Standard | ASTM A815 |
| Grade | WP429 |
| Material Type | Wrought Martensitic Stainless Steel |
| Form | Butt-Weld Pipe Fittings |
| Sizes | ½” to 48” (DN15–DN1200) |
| Schedule | SCH 10 to SCH XXS |
| Class | WP – Wrought Fittings |
| Surface Finish | Mill Finished / Pickled & Passivated |
| Manufacturing Method | Formed, Welded / Seamless |
Equivalent Grade
| Standard | Grade |
|---|---|
| UNS | S42900 |
| AISI | 429 |
| ASTM | A815 WP429 |
| EN / W.Nr | Equivalent to 1.4000 / Similar martensitic grade |
| JIS | Equivalent martensitic stainless grade reference |
Note: Grade matches UNS S42900 martensitic stainless steel.
Available Sizes
Size Range: ½” to 48”
Thickness: SCH 10 – XXS
End Type: Beveled ends (BW fittings)
Chemical Composition
| Element | Percentage (%) |
|---|---|
| Chromium (Cr) | 14.0 – 16.0 |
| Carbon (C) | ≤ 0.12 |
| Manganese (Mn) | ≤ 1.0 |
| Silicon (Si) | ≤ 1.0 |
| Nickel (Ni) | ≤ 0.5 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Iron (Fe) | Balance |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥ 450 MPa |
| Yield Strength | ≥ 275 MPa |
| Elongation | ≥ 20% |
| Hardness | ≤ 223 HBW |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.7 – 7.8 g/cm³ |
| Melting Range | 1420°C – 1510°C |
| Modulus of Elasticity | ~200 GPa |
| Thermal Conductivity | Higher than austenitic grades |
| Thermal Expansion | Lower than 300-series stainless steel |
Types of ASTM A815 WP429 Fittings
ASTM A815 WP429 Elbow
ASTM A815 WP429 Tee
ASTM A815 WP429 Reducers
ASTM A815 WP429 Caps
ASTM A815 WP429 Cross Fittings
ASTM A815 WP429 Nipples
ASTM A815 WP429 Couplings
ASTM A815 WP429 Stub Ends
Corrosion Resistance
ASTM A815 WP429 offers:
Good corrosion resistance in mild acids & organic compounds
Strong resistance to oxidation & scaling up to 850°C
Good performance in exhaust gas & heat-treating environments
Effective in mild chloride environments with proper design
Heat Resistance
Resistant to oxidation and scale formation up to ~850°C
Suitable for high-temperature exhaust, furnace tubes, heat treatment areas
Maintains structural integrity under thermal cycling
Heat Treatment
Typically supplied in annealed or tempered condition
Annealing: 820°C – 900°C
Air cool after annealing
Tempering may improve ductility and stress relief
Welding
Weldable using standard techniques for martensitic grades
Preheat recommended: 150°C – 300°C
Post-weld heat treatment advised to restore corrosion resistance & strength
Suggested filler: Matching 429 grade or similar martensitic filler
Fabrication
Machinable & formable with appropriate tooling
Recommended to avoid severe cold working without intermediate annealing
Better machinability than austenitic grades
Applications
Power Plants & Boiler Systems
Exhaust & Flue Gas Systems
Heat Treatment Furnaces
Petrochemical Equipment
Thermal Processing Units
Gas Turbine Components
Industrial Heaters & Burners
Automotive & Industrial Exhaust Systems
Chemical Processing Equipment