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China ASTM A403 B16.9 Butt-Welded Fittings | Trusted Suppliers & Quality Factory Partnerships
Introduction
ASTM A403 is a standard specification for wrought austenitic stainless steel pipe fittings, while ASME B16.9 defines the dimensions and tolerances for factory-made wrought butt-welding fittings. Together, "ASTM A403 B16.9" refers to stainless steel fittings (e.g., elbows, tees, reducers) that meet both material and dimensional requirements. These fittings are designed for high-pressure, high-temperature, and corrosive service in piping systems.
Key Features
Corrosion Resistance
Excellent resistance to oxidizing acids, chlorides (316/316L), and high-temperature scaling.
Heat Treatment
Solution-annealed for optimal corrosion resistance and ductility.
Dimensional Precision
Complies with ASME B16.9 for seamless integration into piping systems.
Product Specification
Standard
ASTM A403, ASME B16.9, ASME B16.28, ASTM A234, EN 10253
Type
Seamless and welded
Products Name
Elbows, Equal Tees, Cross, Reducers, End caps, Stub ends etc.
Grade
WP304, WP304L, WP316L, WP321, WP316Ti, WP310S, WPB, etc.
Sizes
From 1/2" to 48", Sch5s - XXH.
Surface
ANNEALED, SANDBLASTED
Inspection
100% PMI Tested
En10204.3.1b Mill Test Certificate
Third Party Inspection Accepted
Marking
All Fittings are marked as follows: Specifications, Standard, Grade, Heat NO. (or as per customers’ requirement)
Packing
Plywood cases or fumigated wooden case as per customer's requirement
A403 B16.9 Material Properties
| Grade | Chemical Composition (Typical %) | Mechanical Properties |
|---|---|---|
| WP304 | Cr: 18–20, Ni: 8–11, C: ≤0.08 | Tensile: ≥515 MPa, Yield: ≥205 MPa |
| WP316 | Cr: 16–18, Ni: 10–14, Mo: 2–3 | Tensile: ≥515 MPa, Yield: ≥205 MPa |
| WP321 | Ti: 5×C min (stabilized against sensitization) | Tensile: ≥515 MPa |
Frequently Asked Questions
What is the difference between ASTM A403 and ASME B16.9?
ASTM A403 specifies the material requirements (chemical composition, mechanical properties, and heat treatment) for wrought austenitic stainless steel pipe fittings. ASME B16.9 defines the physical dimensions, tolerances, and ratings for factory-made wrought butt-welding fittings.
Which stainless steel grades are covered under ASTM A403?
Common grades include WP304, WP304L, WP316, WP316L, WP321, WP316Ti, and WP310S. These grades offer various levels of corrosion resistance and mechanical strength.
What types of pipe fittings are manufactured to ASME B16.9 dimensions?
It covers standard butt-welding fittings including elbows (long and short radius), equal and reducing tees, crosses, concentric and eccentric reducers, end caps, and stub ends.
Why is solution annealing heat treatment necessary for ASTM A403 fittings?
Solution annealing helps relieve manufacturing stresses, restores ductility, and dissolves chromium carbides back into the stainless steel matrix, thereby optimizing the material's corrosion resistance.
What quality inspection standards do these fittings undergo?
Fittings undergo 100% Positive Material Identification (PMI) testing, are supplied with En10204.3.1b Mill Test Certificates, and are compatible with third-party inspections.