ASTM A928 Duplex Stainless Steel Welded Pipes

High-Strength Welded Solutions for Corrosive Environments

As a leading manufacturer of advanced piping systems, Ganyeah Group specializes in providing corrosion-resistant and high-strength solutions for demanding industries worldwide. Our ASTM A928 Duplex Stainless Steel Pipes represent the pinnacle of strength, durability, and performance in harsh service conditions, particularly in oil and gas, petrochemical, and offshore applications.

Duplex Pipe Sizes and Availability

We supply ASTM A928 Duplex Stainless Steel Pipes in the following ranges:

Outside Diameter: 1/2” to 48” (DN15 – DN1200)

Wall Thickness: SCH 10 to SCH 80 and customized

Length: Up to 12 meters or custom

Ends: Plain end, beveled end, grooved, or as per request

Customized specifications are available upon request, including special testing requirements (HIC/NACE), third-party inspections (SGS, BV, DNV), and marine export packaging.

What is ASTM A928?

ASTM A928/A928M is the American standard specification for electric-fusion-welded austenitic-ferritic (duplex) stainless steel pipe with added filler metal. These pipes are engineered for service in highly corrosive environments where high mechanical strength and excellent resistance to chloride-induced stress corrosion cracking are critical.

The current active version of this standard is ASTM A928/A928M–14 (2021).

Duplex Stainless Steel: The Ideal Balance of Strength and Corrosion Resistance

Duplex stainless steels are dual-phase alloys containing roughly equal proportions of austenite and ferrite. This balanced microstructure gives them:

Twice the yield strength of conventional austenitic stainless steels (e.g., 304/316)

Superior resistance to chloride corrosion, pitting, and stress corrosion cracking

Excellent toughness and weldability

Common Grades of ASTM A928 Pipes:

UNS No.	Common Name	Key Elements (% wt)	Recommended Application
S31803	2205	Cr: 21–23, Ni: 4.5–6.5, Mo: 2.5–3.5, N: 0.08–0.20	General-purpose duplex steel for seawater and process fluids
S32205	Enhanced 2205	Cr: 22–23, Ni: 4.5–6.5, Mo: 3.0–3.5, N: 0.14–0.20	Improved pitting and SCC resistance
S32750	2507	Cr: 24–26, Ni: 6–8, Mo: 3.0–5.0, N: 0.24–0.32	Super duplex for extreme environments
S32304	2304	Cr: 21.5–24.5, Ni: 3.0–5.5, Mo: 0.05–0.60, N: 0.05–0.20	Moderate corrosion, cost-effective option

All grades contain nitrogen as an alloying element to increase strength and improve resistance to localized corrosion.

Key Mechanical and Corrosion Properties

ASTM A928 pipes are built to meet strict mechanical performance metrics. Using UNS S32205 as a reference:

Tensile Strength: ≥ 620 MPa

Yield Strength (0.2% offset): ≥ 450 MPa

Elongation: ≥ 25%

Hardness: ≤ 290 HB (Brinell)

Corrosion Resistance:

Ganyeah’s duplex pipes are tested according to international corrosion standards:

ASTM G48: Pitting resistance test

ASTM G28 / A262: Intergranular corrosion resistance

Excellent resistance to chloride-induced stress corrosion cracking, outperforming 316L stainless steel in high-chloride, acidic, and seawater conditions.

Manufacturing and Quality Control

Welding Process Classification

ASTM A928 specifies five weld classes, from Class 1 to Class 5. Each class defines welding and inspection rigor:

Class	Welding Type	Radiographic Inspection
Class 1	Double-side welding	100% radiographic testing (RT)
Class 2	Single-side welding with backing	100% RT
Class 3	Single-side welding	100% RT
Class 4 & 5	Varying degrees of partial inspection	Spot or random RT

Ganyeah manufactures pipes primarily to Class 1 and Class 3, ensuring comprehensive testing and weld quality.

Heat Treatment:

All duplex pipes undergo solution annealing between 1020–1120°C, followed by rapid quenching to maintain a balanced duplex structure (typically 40–60% ferrite). This step is essential to maximize mechanical performance and corrosion resistance.

Surface Finish:

Pipes are treated with acid pickling and passivation to remove welding scale and oxidation, resulting in a clean, smooth internal surface that enhances flow efficiency and resists corrosion.

Applications of ASTM A928 Duplex Pipes

Due to their outstanding performance profile, these pipes are ideal for:

Oil & gas pipelines in offshore and onshore environments

Chemical and petrochemical process lines

Desalination and water treatment plants

Fire-fighting systems in coastal zones

Structural applications requiring high strength and corrosion resistance

Advantages of Choosing Ganyeah Group

With over 20 years of experience in the stainless steel piping industry, Ganyeah Group ensures that every ASTM A928 duplex pipe we deliver is:

Manufactured under strict ISO & ASTM quality controls

100% traceable with EN 10204 3.1 certification

Available in custom lengths, thicknesses, and end connections

Professionally packed for export to Europe, the Middle East, and Southeast Asia

We operate advanced welding and testing lines, enabling us to meet high-volume production demands without compromising quality.

Why Choose Duplex Over Austenitic Grades?

Compared to conventional 304 or 316 pipes, duplex stainless steels provide:

Up to twice the yield strength

Lower alloy content for similar or better corrosion resistance

Reduced weight for the same pressure rating

Higher cost-efficiency in the long run

Request a Quote or Technical Consultation

Ready to upgrade your system with ASTM A928 Duplex Stainless Steel Pipe? Contact Ganyeah Group today to discuss your technical requirements. Our engineers will help you select the most suitable grade, welding class, and delivery option.