Products Features

Excellent resistance to chloride stress corrosion cracking (core advantage)

One of the core advantages of S32950 is its excellent resistance to chloride stress corrosion cracking (SCC) brought about by its duplex microstructure. Austenitic stainless steels (such as 304L and 316L) are highly susceptible to SCC failure in chloride-containing environments under the combined influence of temperature, stress, and chloride ions. In contrast, the duplex structure of S32950 provides it with an inherent immunity to chloride-induced SCC. This characteristic makes it an ideal material choice for applications where chloride ions and stress coexist, such as offshore platforms, oil and gas processing equipment, and chemical plants.

High strength matched with good ductility

The yield strength of S32950 (≥ 485 MPa) is approximately twice that of 316L, with a tensile strength ≥ 690 MPa and an elongation ≥ 15%, along with good reduction of area. Its strength level is comparable to or even exceeds that of some low-alloy steels, while its ductility is far superior to that of ferritic stainless steels. At equivalent design strength, S32950 can achieve thinner wall thicknesses and lighter structural designs, thereby reducing material costs and manufacturing expenses.

Excellent pitting and crevice corrosion resistance

The high chromium (26-29%), high molybdenum (1.0-2.5%), and high nitrogen (0.15-0.35%) content of S32950 endows it with exceptional resistance to pitting corrosion and crevice corrosion. Its PREN value is approximately 34-37, significantly higher than that of 316L (≈25). In harsh environments such as seawater, chloride solutions, and acidic chloride media, S32950 can form a stable passive film, resisting the initiation and propagation of pitting. Its critical pitting temperature (CPT) and critical crevice corrosion temperature (CCT) are notably higher than those of 316L and 317L.

Good welding performance

S32950 exhibits good weldability. Compared to the first-generation duplex stainless steels, second-generation duplex steels have significantly reduced sensitivity to welding thermal cycles. Various welding methods such as TIG, MIG, SMAW, and SAW can be used for joining. During welding, heat input and interpass temperature (typically ≤ 150°C) should be controlled to prevent the precipitation of harmful intermetallic phases (e.g., sigma phase). Post-weld solution annealing is generally not required, but pickling or passivation is recommended to restore corrosion resistance. The welded joints of S32950 maintain good resistance to stress corrosion cracking (SCC) in hot chloride environments, but additional corrosion assessment at the weld location is advised.

Good hot working and cold working properties

S32950 exhibits excellent hot working properties and can be formed through hot forging, hot rolling, hot extrusion, and other hot working processes within a temperature range of 950-1150°C. After hot working, solution treatment (approximately 1010-1150°C) is required to achieve the optimal duplex microstructure and mechanical properties. The alloy's cold working performance is superior to that of ferritic stainless steels, allowing for cold bending, cold rolling, stamping, and other forming operations. However, its tendency to work harden is higher than that of austenitic stainless steels.

Technical Specifications

Chemical Composition(ASTM A240 / UNS S32950)

Element	Standard Requirements	Notes
Cr	26.0 - 29.0%	Core elements that form a dense passivation film to provide corrosion resistance; ferrite-forming elements
Ni	3.5 - 5.2%	Austenite stabilizing elements promote the formation of duplex microstructure and enhance toughness
Mo	1.0 - 2.5%	Improves resistance to pitting and crevice corrosion, with an effect approximately three times that of chromium
N	0.15 - 0.35%	Strong austenite-forming elements, solid solution strengthening, improve pitting corrosion resistance
Mn	≤ 2.0%	Deoxidizer, added in small amounts
Si	≤ 0.60%	Deoxidizer, strictly controlled
C	≤ 0.030%	Strictly control to prevent the precipitation of carbides from impairing corrosion resistance
P	≤ 0.035%	Deoxidizer, strictly controlled
S	≤ 0.010%	Impurity elements, strictly controlled to prevent hot brittleness
Fe	Remaining quantity (≈ 63.5%)	Matrix element

Physical Properties

Property	Value/Range	Test Conditions
Density	7.80 g/cm³	Room Temperature (20°C)
Melting Point	≈ 1450°C	-
Thermal Conductivity	≈ 17 W/(m·K)(100°C)	Superior to austenitic stainless steel
Coefficient of thermal expansion (20-100°C)	≈ 11 × 10⁻⁶ /K	Superior to austenitic stainless steel
Resistivity	≈ 0.80 μΩ·m	Room Temperature
Elastic modulus (Young's modulus)	192 - 200 GPa	Room Temperature
Poisson's ratio	0.25 - 0.29	Room Temperature
Magnetism	Ferromagnetism	The duplex structure is magnetic

Mechanical Properties (Solution Annealed Condition, Typical Values, ASTM A240)

Property	Typical Value	Specification
Tensile Strength	≥ 690 MPa	ASTM A240
Yield Strength (0.2% Offset)	≥ 485 MPa	ASTM A240
Elongation	≥ 15%	ASTM A240
Hardness	≈ 31 HRC	-

Note: The yield strength of S32950 is approximately twice that of 316L, which can significantly reduce wall thickness, achieving structural lightweighting and cost optimization.

Pitting Resistance Equivalent Number (PREN) Comparison

Material grade	PREN(Cr+3.3Mo+16N)	Chloride resistance
S32950	≈ 34 - 37	Excellent
316L	≈ 25	General
317L	≈ 28	Good
2205 (S31803)	≈ 33 - 35	Excellent

Corrosion Resistance (Typical Value)

Medium	Concentration	Temperature	Corrosion rate	Rating
Seawater	-	Room temperature to high temperature	Ignored	Excellent
Chloride solution (salt water)	-	High Temperature	Ignored	Excellent
Nitric acid (HNO₃)	≤ 40%	Room Temperature	＜0.05	Excellent
Sulfuric acid (H₂SO₄)	≤ 40%	Room Temperature	＜0.1	Good
Hydrochloric acid (HCl)	Low concentration	Room Temperature	＜0.1	Good
Sodium hydroxide (NaOH)	-	Room Temperature	Ignored	Excellent
Organic acids (such as acetic acid, citric acid, etc.)	-	Room Temperature	Ignored	Excellent
Wet Chlorine Gas	-	Room Temperature	Ignored	Excellent

Note: The corrosion resistance of S32950 is superior to that of 316L and 317L in most environments. It exhibits excellent resistance to stress corrosion cracking (SCC) in chloride-containing environments, but its corrosion resistance is limited in strongly reducing media such as high-temperature, high-concentration hydrochloric acid and hydrofluoric acid. In hydrogen-containing environments, duplex stainless steels are susceptible to hydrogen embrittlement and require careful evaluation.

High-temperature performance

High-temperature strength retention:

S32950 maintains high strength at moderate temperatures:

Temperature	Tensile Strength (MPa)	Performance retention rate
Room temperature (20°C)	≥ 690	100%
200°C	≈ 620	≥ 90%
300°C	≈ 560	≥ 81%
400°C	≈ 500	≥ 72%

Long-term thermal stability and organizational stability:

S32950 exhibits good microstructural stability during long-term service at temperatures ≤ 300°C

Note that prolonged exposure at temperatures between 300-500°C may lead to 475°C embrittlement (spinodal decomposition of the ferrite phase), resulting in reduced toughness. Therefore, long-term use within this temperature range is not recommended.

Prolonged exposure in the 600-900°C range may lead to the precipitation of the sigma phase (an intermetallic compound), significantly reducing corrosion resistance and toughness.

S32950 is less sensitive to harmful phase precipitation than first-generation duplex stainless steels, but strict control of cooling rate is still required during heat treatment and welding to quickly pass through the sensitive temperature range.

Antioxidant performance:

S32950 can form a protective oxide film below 800°C, and its oxidation resistance is better than that of austenitic stainless steel.

For long-term service at higher temperatures, it is recommended to evaluate oxidation weight gain.

Heat treatment system

The heat treatment of S32950 has a decisive impact on the final microstructure and properties, with common specifications as follows:

1. Solution treatment (for obtaining the optimal duplex microstructure and comprehensive properties):

Heat to 1010-1150°C, hold for a sufficient time (approximately 2-4 minutes per inch of thickness), then water quench or rapid air cool. This will yield an ideal duplex microstructure consisting of approximately 50% ferrite and 50% austenite, providing optimal corrosion resistance.

2. Stress Relief Treatment (After Welding/Cold Working):

Heat to 650-750°C, hold for 1-2 hours, then air cool. Used for relieving residual stresses,

However, note that sigma phase precipitation may occur in this temperature range; it is recommended to carefully evaluate its impact on corrosion resistance.

Note:

1. Heat treatment should quickly pass through the sensitive temperature range of 600-900°C to avoid precipitation of σ phase and χ phase.

2. The solution treatment temperature should not be too high (> 1150°C), otherwise excessive ferrite content will affect toughness and corrosion resistance.

3. It is recommended to perform pickling or passivation after heat treatment to remove surface scale.

Welding Performance and Process Key Points

S32950 has good welding properties, which is an important feature of the second-generation duplex stainless steel:

1. Recommended welding methods:

TIG (GTAW), MIG (GMAW), SMAW, SAW, FCAW.

2. Heat input control:

It is recommended that the heat input be 0.5-2.5 kJ/mm, and the interpass temperature be ≤ 150°C to avoid grain coarsening in the heat-affected zone and precipitation of harmful phases.

3. Protective gas:

It is recommended to use a mixed gas of Ar + 1-2% N₂, which can increase the austenite content in the weld metal, thereby improving the toughness and corrosion resistance of the weld.

4. Filler metal:

It is recommended to use duplex stainless steel filler metals such as 2209 or 2594 that are matched or over-matched to the base metal to ensure that the corrosion resistance of the weld is not lower than that of the base metal.

5. Post-weld treatment:

It is recommended to perform pickling or passivation to restore the corrosion resistance of the heat-affected zone and remove welding oxidation discoloration. Pickling is more effective than mechanical cleaning in removing chromium-depleted layers.

Comparison of Magnetic Properties and Application Selection

Performance indicators	S32950 (Duplex stainless steel)	316L (Duplex stainless steel)	2205 (Duplex stainless steel)
Yield strength (MPa)	≥ 485	≈ 220	≥ 450
Tensile Strength (MPa)	≥ 690	≈ 520	≥ 620
Elongation (%)	≥ 15	≥ 40	≥ 25
PREN (Pitting Corrosion Equivalent)	34 - 37	≈ 25	33 - 35
Resistance to SCC (Chlorides)	Excellent	Difference (Highly Sensitive)	Excellent
Magnetism	Ferromagnetism	Non-magnetic	Ferromagnetism
Thermal Conductivity	Higher (≈17 W/m·K)	Lower (≈14 W/m·K)	Higher
Price	Medium	Lower	Medium
Selection suggestions	Primarily used in high-strength, chlorine-resistant, and moderately corrosive environments: oil and gas, offshore platforms, seawater desalination, heat exchangers, high-pressure pipelines	Primarily used in general corrosion-resistant environments with requirements for chlorine-free, low-temperature, low-strength, and non-magnetic properties	It is primarily used for applications with higher strength and corrosion resistance requirements. Its PREN is similar to that of S32950, but it has a higher nickel content.

Applicable Media

1. Seawater and chloride solutions: Excellent resistance to pitting corrosion, crevice corrosion, and stress corrosion cracking.

2. Oxidizing acids: Such as nitric acid (≤40%), with excellent corrosion resistance.

3. Moderately concentrated reducing acids: Such as sulfuric acid (≤40%).

4. Organic acids: Acetic acid, citric acid, formic acid, etc.

5. Alkaline solutions: Sodium hydroxide, potassium hydroxide, etc.

6. Chlorine-containing oil and gas media: Petroleum and natural gas exploration and processing environments.

7. High-temperature water vapor (temperature limitations should be noted).

Note:

S32950 is not resistant to strongly reducing media such as hydrofluoric acid and high-temperature concentrated hydrochloric acid. In hydrogen-containing environments, duplex stainless steels are susceptible to hydrogen embrittlement and require careful evaluation. Long-term use conditions should avoid 475°C embrittlement and sigma phase precipitation.

S32950 (UNS S32950) is suitable for applications with comprehensive requirements for high strength, chlorine resistance, and moderate corrosion. It is recommended for use in the following fields:

Application Fields

Oil and Natural Gas Industry (Core Applications)
● Oil and gas field pipeline systems, gathering and transportation pipelines, submarine pipelines
● Downhole tools, wellhead equipment, valves, pipe fittings, flanges
● Separator, heat exchanger, pump and valve components
● Drilling platform modules, fire protection systems
Chemical Processing and Petrochemical Engineering
● Pressure vessels, high-pressure tanks, reactors
● Heat exchangers, condensers, evaporators
● Pipeline system for conveying corrosive media (including chloride environments)
● Distillation column, absorption tower, separator
Ocean Engineering and Seawater Desalination
● Desalination plant pipelines, high-pressure reverse osmosis (RO) units
● Offshore platform structural components, seawater heat exchangers
● Ship ballast water system, fire water system
Pulp and Paper Industry
● Steaming vessels, bleaching equipment, washers, and storage processing systems
Electric power industry
● FGD flue gas desulfurization system, absorber tower, pipelines and flue gas ducts
● Nuclear power secondary cooling water circuit pipeline
Environmental Protection and Wastewater Treatment
● Wastewater treatment system, exhaust gas scrubber tower, wastewater treatment equipment
Machinery and Structural Components
● High-pressure rotating shafts, pressing rolls, blades, impellers, fasteners, and mechanical and structural components for high-strength and corrosion-resistant environments

Delivery and Customization

We offer flexible and reliable supply chain solutions to ensure you receive S32950 materials that perfectly match your project requirements.

Form	Sheet/Plate	Bar/Rod	Pipe / Tube	Strip/Sheet Coil	Wire/Wire Rod
Conventional Range	Thickness: 0.5 - 100 mm Width: ≤ 1500 mm	Diameter Φ6-500mm	Outer diameter Φ10-300mm	Thickness: 0.1 – 3.0 mm Width: 10 – 600 mm	Diameter Φ0.5-10mm
Customization Capability	Hot-rolled or cold-rolled plates, ultra-thin plates (starting from 0.1mm), stamped parts, length-cutting to specified dimensions, special surface treatments (pickling, polishing)	Forged bars, hot-rolled bars, polished bars, shaped bars, and different heat treatment conditions (solution-treated condition)	Seamless Tubes / Welded Tubes (Compliant with ASTM A789), Fixed Length Cutting, U-Tubes	Precision strip materials, stamping coil stock, laminated blanking, non-standard width, special protective film	Precision drawing, welding filler wire, special surface treatment

Why Choose Us? - Reliable Engineering Technology. Dependable Delivery.

We are not just a supplier, but a trusted materials partner for you in China.

Vertically Integrated Production

Own 20,000㎡ facility with 10+ automated lines (8,000+ tons/year). In-house tooling & die center enables rapid customization and effective cost control - no middleman markup.

Strict Quality Control at Every Stage

Full traceability across key QC checkpoints throughout production. 100% compliant with ASTM/ASME, EN, and GB standards. Material test reports available with every shipment.

Reliable Delivery & Export Packaging

10+ years exporting to Europe, North America, Southeast Asia & Middle East with waterproof and anti-rust protection, combined with flexible shipping options ensures safe and on-time arrival.

Sample Validation Before Mass Production

We provide free samples for quality verification, allowing you to place bulk orders only after approval. We ensure consistency from sample to mass production by accurate dimensional measurement and transparent manufacturing.

FAQ

Q: What are the main advantages of S32950?

Q: What is the difference between S32950 and 316L? How to choose between them?

Q: What is the difference between S32950 and 2205? How to choose between them?

Q: What is the maximum usage temperature for S32950?

Q: What is the welding performance of S32950?

Q: Can S32950 replace 316L?

It can partially replace, especially in chlorinated environments and under conditions requiring higher strength:
Scenarios suitable for substitution (S32950 has obvious advantages):
● In chloride-containing environments such as seawater, brine, and coastal atmosphere, the SCC resistance and pitting corrosion resistance of S32950 are far superior to that of 316L.
● High-pressure and high-stress structural components:
S32950 has twice the yield strength of 316L, allowing for a significant reduction in wall thickness.
● Heat Exchangers:
S32950 has higher thermal conductivity, lower thermal expansion coefficient, and better thermal efficiency
● Offshore platforms, oil and gas equipment:
S32950 is a mature application material for these industries

Scenarios where substitution is not suitable (316L remains the better choice):
● Chlorine-free, low-temperature, and mildly corrosive environments:
316L is more cost-effective and sufficient to meet the requirements.
● Non-magnetic requirement:
S32950 is magnetic (approximately 50% ferrite), while 316L is non-magnetic.
● Complex cold-formed parts (such as deep-drawn parts)：
316L has a lower work hardening rate and better formability
● Low temperature (below -40°C)：
The ductile-to-brittle transition temperature of duplex stainless steel is higher than that of austenitic stainless steel

Material Selection Recommendations:
Please provide detailed operating conditions (temperature range, chloride ion concentration, load type, welding requirements, and medium environment) for specific material selection. We can assist with technical and economic comparative analysis to help you make the optimal choice between S32950 and other stainless steel grades.

For quotations on specific specifications, material test reports, or technical parameter sheets, please contact our sales engineers. We support customizing dimensions, heat treatment conditions, and surface treatments as required, and provide a full set of internationally certified documents.

Hot Tags: s32950, China s32950 manufacturers, suppliers, factory

Comparison Item	S32950 (Duplex stainless steel)	316L (Austenitic stainless steel)
Organization Type	Biphasic (Ferrite + Austenite)	Austenite
Yield strength	≥ 485 MPa (Approximately twice that of 316L)	≈ 220 MPa
PREN (Pitting Corrosion Equivalent)	34 - 37(Excellent)	≈ 25(General)
Chloride SCC	Excellence (Natural Resistance)	Difference (Highly Sensitive)
Magnetism	Ferromagnetism	Non-magnetic
Price	Higher	Lower
Selection suggestions	Primarily used in chlorinated environments, high-stress, high-strength structural components	Primarily used in general corrosion-resistant environments such as chlorine-free, non-magnetic, and low-temperature conditions

Comparison Item	S32950	2205 (S31803/S32205)
Chromium content	26-29%	22-23%
Molybdenum content	1.0-2.5%	2.5-3.5%
Nickel content	3.5-5.2%	4.5-6.5%
PREN	34 - 37	33 - 35
Selection suggestions	Primarily used for applications with high Cr content, high corrosion resistance, and moderate Mo.	Preferred for more stringent operating conditions requiring higher Mo and Ni content, but at a higher cost

S32950

Products Features

Technical Specifications

Application Fields

Delivery and Customization

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