A high-performance austenitic stainless steel, Alloy 310S is engineered for superior oxidation resistance and structural stability in extreme high-temperature environments up to 1094°C.
Alloy 310S (also known as 310 stainless steel or UNS S31008) is a high chromium, high nickel austenitic stainless steel developed for use in elevated temperature environments where oxidation resistance and structural stability are critical. With chromium content of 24 to 26% and nickel content of 19 to 22%, it performs reliably in both continuous and intermittent high-temperature service, maintaining strength and resisting scaling under sustained thermal stress.
The alloy's high chromium content forms a stable, adherent oxide layer that protects against oxidation and hot corrosion, including sulphidation resistance. Its nickel content supports austenitic stability, toughness and low magnetic permeability across a wide temperature range, including at cryogenic temperatures where Alloy 310S also performs well.
Compared to standard Alloy 310, the lower carbon content in 310S (max 0.08%) improves weldability and reduces the risk of sensitisation and carbide precipitation during fabrication, making it the preferred grade for welded and fabricated components.
We stock Alloy 310S in a variety of product forms to suit different applications and fabrication requirements, including sheet, plate, round bar, pipe and tube. To view available sizes and submit an enquiry, use the dropdown selector below.
The following elements in Alloy 310S provide its distinctive balance of high-temperature oxidation resistance, sulphidation resistance and structural stability.
| % | Cr | Ni | C | Si | Mn | P | S | Mo | Cu | Fe |
|---|---|---|---|---|---|---|---|---|---|---|
| Min | 24 | 19 | - | - | - | - | - | - | - | - |
| Max | 26 | 22 | 0.08 | 0.75 | 2 | 0.045 | 0.03 | 0.75 | 0.5 | Balance |
Alloy 310S is built for service in extreme heat environments involving oxidising atmospheres, thermal cycling and prolonged mechanical load. Key physical and thermal properties include:
Alloy 310S (UNS S31008) is an industry standard for high-temperature service in oxidising and corrosive environments, widely specified across petrochemical, power generation, furnace manufacturing and industrial processing sectors.
It was developed to balance four things that are rarely found together in a single grade:
The grain size and carbon content of Alloy 310S meets both 310S and 310H requirements, giving specifiers additional flexibility. Its high chromium content forms a stable oxide layer that resists attack in oxidising atmospheres, while its nickel content ensures austenitic stability and toughness across a broad temperature range.
The low carbon content, the defining difference between 310 and 310S, reduces the risk of sensitisation and carbide precipitation at grain boundaries during welding and heat treatment. This makes Alloy 310S the preferred choice over standard 310 for any application involving welded fabrication or post-weld service in corrosive environments. Welding can be carried out using GTAW (TIG) or GMAW (MIG) methods. Alloy 310S can be machined using standard techniques, though carbide tooling is recommended due to its work-hardening tendency. As a trusted Alloy 310S supplier, NeoNickel stocks sheet, plate, round bar, pipe and tube across the UK and Europe, with full certification and traceability. Our stock range and processing capabilities support both standard supply and project-specific requirements.
| Mechanical & Physical Properties | 21.1 °C | 537.8 °C | 648.9 °C | 760 °C | 871.1 °C | 982 °C | 1093 °C |
|---|---|---|---|---|---|---|---|
| Ultimate Tensile Strength/ MPa | 551.6 | 467.5 | 373 | 242 | 131.7 | - | - |
| 0.2% Yield Strength/ MPa | 241.3 | 143.4 | 142.7 | 133.1 | 84.1 | - | - |
| Elongation % | 52 | 47 | 43 | 46 | 48 | - | - |
| Minimum Creep 0.0001% per hr/ MPa | - | - | 102.7 | 22.8 | 7.6 | 1.9 | - |
| 10,000 hr Rupture Strength / MPa | - | - | 99.3 | 31 | 10.3 | 4.6 | - |
| Coefficient of Thermal Expansion µm/m⁰C | - | 17.1 | 17.6 | 18.1 | 18.3 | 18.5 | 19.1 |
| Thermal Conductivity/kcal/(hr.m.°C) | 11.3 | 20.2 | 22.6 | 25 | 27.4 | 29.8 | - |
| Modulus of Elasticity/ x105 MPa | 2 | 1.59 | 1.5 | 1.41 | 1.32 | - | - |
Due to its oxidation resistance, thermal stability, sulphidation resistance and high-temperature strength, Alloy 310S is used across industries where materials must perform reliably under sustained heat and corrosive conditions. It is also specified for cryogenic structures where toughness and low magnetic permeability are required.
Few alloys perform reliably at both extremes. Alloy 310S is one of them, which is why it is specified for demanding applications where long service life matters. Note that for severely carburising atmospheres, RA330 or RA333 may be more appropriate. Alloy 310S is also not recommended for applications involving repeated liquid quenching due to severe thermal shock.
Alloy 310S is used in high-temperature applications including radiant tubes, furnace linings, heat treatment equipment, flare tips, coal gasifier components, petrochemical refining and cryogenic structures. It is selected wherever materials face sustained exposure to heat, oxidising atmospheres, sulphidation or repeated thermal cycling. For severely carburising environments, RA330 or RA333 may offer better performance.
The key difference is carbon content. Alloy 310S has a maximum carbon of 0.08%, compared to 0.25% in standard Alloy 310. This lower carbon level significantly reduces the risk of sensitisation and carbide precipitation at grain boundaries during welding and heat treatment, making 310S the preferred choice for fabricated and welded components. Both grades share the same high chromium-nickel base composition and perform well in similar high-temperature environments.
Alloy 310S offers oxidation resistance in continuous service up to approximately 1094°C (2000°F). Under cyclic or intermittent service conditions, performance can vary depending on the thermal profile and atmosphere. The alloy is not recommended for applications involving repeated liquid quenching due to the severity of thermal shock involved.
Yes. In addition to its high-temperature performance, Alloy 310S is also used in cryogenic structures due to its excellent toughness and low magnetic permeability at sub-zero temperatures, making it one of the few stainless grades specified for both ends of the temperature spectrum.
Yes. Alloy 310S provides good resistance to oxidation, sulphidation and hot corrosion at elevated temperatures, particularly in oxidising atmospheres. It performs well in moderately carburising environments such as those found in petrochemical processing. For severely carburising atmospheres or strongly reducing conditions, RA330 or RA333 should be considered.
Yes. Alloy 310S is readily weldable using TIG (GTAW) and MIG (GMAW) processes. Its low carbon content makes it particularly well suited to welded fabrications compared to standard Alloy 310, significantly reducing the risk of sensitisation in the heat-affected zone. Post-weld annealing is recommended for optimum performance in corrosive or high-temperature service environments.
NeoNickel supplies Alloy 310S in sheet, plate, round bar, seamless pipe and welding wire. Contact our team to discuss available sizes, certifications and lead times.
Alloy 310S and 310H share similar chemistries, but 310H has a higher minimum carbon content (0.04 to 0.10%) and a controlled grain size, optimised specifically for high-temperature creep resistance. The grain size and carbon content of NeoNickel's Alloy 310S meets both 310S and 310H requirements. If your application requires confirmed 310H compliance, please contact our technical team.
NeoNickel stocks Alloy 310S in the UK and Europe, with the ability to support both urgent requirements and longer-term project schedules. All material is supplied with full mill certification and traceability, meeting ASTM, AMS and other relevant international standards. No minimum order restrictions apply to standard stock items. Our technical team can support material selection, confirm compliance requirements and advise on sizing, processing and lead times. For non-standard or cut-to-length requirements, contact us directly for availability. As a trusted Alloy 310S supplier across the UK and Europe, NeoNickel combines technical expertise with reliable stock and fast turnaround. Fill out our enquiry form to discuss your requirements and a member of the team will be in touch.
Can't find the information you need? Please contact us directly.
Proud members of the British Valve & Actuator Association