UNS S31500 Pipes and Tubes

What Is UNS S31500 Duplex Stainless Steel? 

The microstructure that consists of two phases for UNS S31500 reveals the equal presence of both ferrite and austenite, which ensures yield strength characteristic values that exceed the relevant values for austenitic alloys (304, 316) by a factor of two.

In addition, it has a composition of silicon, chromium, and molybdenum, which guarantees exceptional resistance to pitting, crevice corrosion, and clogging. Due to all those properties, this alloy stands out as a perfect material for making construction components in conditions of aggressive environments containing high temperatures and chemicals.

Standards Chemical Composition Mechanical Strengths Configurations S31500 vs 316L

Global Material Standards and Equivalents

UNS S31500 pipes and tubes can be manufactured or supplied following the relevant specification, dimensions, and project needs. 

Designation	S31500 Reference
UNS	S31500
W.Nr.	1.4417
EN Number	1.4424
EN Material Name	X2CrNiMoSi18-5-3
DIN Material Designation	X2CrNiMoSi 19 5
Industry / Trade Name	3RE60
ASTM Tube Specification	ASTM A789/A789M
ASTM Pipe Specification	ASTM A790/A790M

UNS S31500 Chemical Composition

The specific elemental composition of UNS S31500 guarantees the structural stability in applications. An elevated level of silicon serves as an effective deoxidizer and results in the formation of a protective layer on the surface against corrosive chemicals.

Element	Minimum Percent	Maximum Percent
Carbon	0.000	0.030
Chromium	18.00	19.00
Nickel	4.20	5.20
Molybdenum	2.50	3.50
Silicon	1.40	2.00
Manganese	1.20	2.00
Nitrogen	0.05	0.10
Phosphorus	0.000	0.030
Sulfur	0.000	0.015
Iron	Balance	Balance

Mechanical and Physical Strengths

UNS S31500 provides a reliable carrying capacity. The added alloy strength allows thinner pipe walls to be used while maintaining the pressure ratings, thus reducing the system weight and transportation costs.

Property	Metric Reading	Imperial Reading
Tensile Strength Minimum	630 MPa	92 ksi
Yield Strength Minimum	440 MPa	64 ksi
Elongation in 2 Inches	30 Percent	30 Percent
Brinell Hardness Maximum	290 HBW	290 HBW
Rockwell C Hardness Maximum	30 HRC	30 HRC

Need Custom Sizing or Technical Specifications for S31500?

We maintain an active inventory of standard and non-standard schedules ready for fast worldwide dispatch. Request a quote or S31500 directly from our sales team. 

Available Product Configurations

We stock and manufacture UNS S31500 tubular products to match specific line pressures and physical sizes.

• Seamless Pipes and Tubes: Produced via hot extrusion or cold drawing for high-pressure systems, including chemical reactors and heavy vessels.
• Welded Pipes and Tubes: Formed using modern TIG or automated fusion welding methods for large-diameter lines and cooling circuits.
• Bright Annealed Tubing: Finished with a smooth interior surface to minimize fluid drag in hydraulic lines and instruments.
• U-Bend Heat Exchanger Tubes: Bent to custom radiuses, stress relieved, and pressure tested for direct mounting inside condensers and boilers.

Nominal Pipe Size (NPS)	Outside Diameter (OD)	Available Schedules	Manufacturing Standard
1/2" to 2"	21.3mm – 60.3mm	SCH 10S, SCH 40S, SCH 80S	ASTM A789 / A790
2-1/2" to 8"	73.0mm – 219.1mm	SCH 5S, SCH 10S, SCH 40S, SCH 80S	ASTM A790 / EN 10216-5
10" to 24"	273.0mm – 610.0mm	SCH 10S, SCH 40S, SCH XS	ASTM A790 (Welded/Seamless)

S31500 vs 316L Stainless Steel

S31500 and 316L are both used in corrosion-resistant applications, but their metallurgy and mechanical properties are different.

Property	UNS S31500	316L Stainless Steel
Metallurgical Structure	Duplex ferritic-austenitic	Austenitic
Yield Strength	Higher	Lower
Chloride Stress Corrosion Resistance	Generally higher	More susceptible under severe chloride conditions
Nickel Content	Relatively low	Higher
Mechanical Strength	High	Moderate
Typical Application	Aggressive chloride/process environments	General corrosion-resistant applications

Key Industrial Applications

Pipes and tubes made from UNS S31500 perform vital functions across several primary sectors:

• Chemical Industry: Involved in transporting organic and mineral acids and saline solutions, a scenario where basic 316L is prone to corrosion.
• Oil and Gas: Implemented in flow lines, unit heaters, and gas treatment systems utilizing sour gas and brine.
• Paper and Pulp Industries: Used as digester heating equipment, bleaching machines, and piping for continuously exposed chemical infrastructure.
• Marine and Desalination Industries: Found in high-pressure pipes, seawater purification devices, and equipment located near the coast.

Processing, Welding, and Heat Treatment

Working with UNS S31500 is straightforward when following basic duplex fabrication procedures.

• Welding Procedures: Formulated to preserve a proper ferrite-to-austenite ratio in the weld zone. Arc welding methods like SMAW, GTAW, and GMAW yield solid results when paired with matching filler metals.
• Heat Treatment: Full solution annealing takes place between 1020 degrees Celsius and 1100 degrees Celsius, followed by immediate water quenching. This step preserves the dual-phase structure and stops unwanted phase precipitation.
• Machining: The material work-hardens quickly due to its high yield point. Machinists should use rigid setups, heavy feed rates, low speeds, and generous cutting fluids.

Why Select USA Piping Solutions

USA Piping Solutions enforces strict quality control across every run. Our inspection team runs non-destructive checks on all orders, including hydrostatic tests, eddy current scans, ultrasonic tests, and positive material identification. We issue full EN 10204 3.1 test certificates alongside every shipment to prove compliance with your engineering rules.

If you are weighing different construction options for your layout, read our detailed guide onSeamless vs Welded Pipe and Tubes. For help selecting alloys for corrosive service, read our resource onCorrosion Resistant Alloy Selection. You can also review our full inventory on the mainStainless Steel Pipes and Tubes page.