310S Stainless Steel (UNS S31008)
Austenitic (heat-resistant) · ASTM A240/A240M · Density 7.98 g/cm³
310S (UNS S31008) is a high-chromium, high-nickel austenitic stainless steel used for furnace components, radiant tubes, heat-treatment fixtures and other oxidation-controlled hot service. Its practical limit is not a universal temperature number: gas chemistry, cycling, load, creep duration, deposits and fabrication details must be checked for the equipment design.
Quotation brief
Quote 310S When
Quote 310S when high chromium and nickel are required for an austenitic component exposed to oxidizing furnace service, and the equipment designer has defined the gas chemistry, metal temperature, time, stress and cycling. It is a candidate for radiant tubes, muffles, burner parts and heat-treatment fixtures, not a blanket rating for every atmosphere. The decision must separate dry oxidation from carburization, sulfidation, molten deposits and wet shutdown corrosion.
Best fit
- Furnace muffles, radiant tubes and burner components evaluated for oxidizing gas, known metal temperature and controlled thermal cycling.
- Heat-treatment baskets and fixtures whose design accounts for section loss, distortion, creep exposure and repeated heating and cooling.
- Fabrications that require a high-chromium, high-nickel austenitic grade with traceable UNS S31008 chemistry and ordered flat-product condition.
Limits to check
- A maximum-temperature claim without atmosphere, load, time and cycle data is not an equipment rating and must not be used for design approval.
- Reducing, sulfur-bearing, carburizing, nitriding or molten-salt environments can change alloy ranking and require service-specific corrosion data.
- 310S does not gain molybdenum-based resistance to wet chloride pitting, so condensate and shutdown chemistry need a separate materials review.
Quoted product forms
Quoted product forms for 310S Stainless Steel (UNS S31008)
We quote 310S Stainless Steel as sheet / plate, coil / strip, pipe / tube, bar against the named product standard.
- Traceability: heat or lot identity plus the inspection document named in the RFQ (EN 10204 3.1 when that route supports it).
- Processing: decoiling, cutting, polishing, shearing and beveling as ordered.
- Next step: send product form, size and quantity; we quote the supply route.
Chemical Composition (wt%)
| C | Mn | Si | Cr | Ni | P | S |
|---|---|---|---|---|---|---|
| ≤0.08 | ≤2.00 | ≤1.50 | 24.0–26.0 | 19.0–22.0 | ≤0.045 | ≤0.030 |
Single values are maximums unless a range is shown. Balance: Fe. Per ASTM A240/A240M.
Mechanical Properties
| Tensile strength | ≥515 MPa (75 ksi) |
|---|---|
| Yield strength (0.2%) | ≥205 MPa (30 ksi) |
| Elongation (50 mm) | ≥40% |
| Hardness | ≤217 HBW |
Room-temperature minimum values are summarized for annealed flat product under ASTM A240/A240M unless a condition is named in the property label; product form and thickness can change the requirement.
Physical Properties & Structure
| Density | 7.98 g/cm³ |
|---|---|
| Magnetic response | Essentially non-magnetic after solution annealing; cold work can introduce a measurable magnetic response. |
| Microstructure | Austenitic (heat-resistant) |
Corrosion Resistance & Limits
- The high chromium content supports oxide-scale formation in oxidizing hot gases, while scale stability changes with temperature, oxygen potential, thermal cycling and contamination. Sulfur-bearing, reducing, carburizing or molten-salt conditions require separate alloy evaluation.
- 310S is not a molybdenum-bearing wet-corrosion grade. Condensate, chlorides and acidic deposits during startup or shutdown can create a different damage mechanism from dry oxidation and must be assessed independently.
Fabrication & Heat Treatment
| Welding | Qualify filler, heat input, joint restraint and purge for the actual hot-service assembly. Weld geometry and dilution matter because local hot spots, sigma-phase exposure and cyclic strain can govern before base-metal oxidation data. |
|---|---|
| Forming | 310S is formable in the annealed condition but work hardens rapidly and needs higher force than lower-alloy austenitic sheet. Allow for springback, protect the surface from carbon-steel contamination and review intermediate annealing for severe reductions. |
| Machining | Use rigid setups, sharp tooling and continuous positive feed to avoid rubbing into a work-hardened surface. Control cutting heat and verify dimensional allowance for components that will later see thermal expansion. |
| Heat treatment | Solution treatment is used to establish the specified austenitic condition; 310S is not hardened by conventional quench-and-temper practice. Thermal processing after fabrication must be reviewed against grain growth, distortion and the final service requirement. |
Equivalent Grades
The closest international equivalents of 310S Stainless Steel are 1.4845 (X8CrNi25-21) in the EN system, SUS310S in the JIS system, 06Cr25Ni20 in the GB system.
These are common corresponding designations, not unconditional substitutes. Verify chemistry, mechanical properties, product standard, delivery condition, dimensions and project approval before changing designation.
| System | Designation |
|---|---|
| UNS | S31008 |
| EN | 1.4845 (X8CrNi25-21) |
| JIS | SUS310S |
| GB | 06Cr25Ni20 |
Ordering Checks for 310S
- Specify UNS S31008, governing product standard, form, dimensions, thickness, solution-treated condition and surface requirements.
- State maximum and normal metal temperature, dwell time, cycle frequency, gas composition, oxygen potential and known contaminants or deposits.
- Provide design-code, allowable-stress, creep-life, weld procedure and dimensional-stability requirements to the responsible equipment engineer.
- Define inspection documents, heat traceability, chemistry, mechanical tests, dimensional tolerances and any supplementary examination in the purchase order.
Reference Product Forms & Dimensional Ranges
Common reference product forms for 310s stainless steel: Sheet / Plate, Coil / Strip, Pipe / Tube, Bar.
| Finishes | No.1, 2B |
|---|---|
| Sheet / coil thickness | 0.5–6.0 mm |
| Plate thickness | 6–60 mm |
Common surface and delivery options
- No.1, 2B, BA or mechanically polished finish when supported by the product route
- Annealed and pickled, descaled or polished tube finish as specified
- Hot rolled, peeled, bright drawn, ground or polished bar condition according to tolerance
These published ranges are engineering references, not a live-stock or production-capability promise. Send the required product form, dimensions, condition and finish; we quote the matching supply route.
Browse related product hubs:Sheet & plate,Coil & strip,Pipe & tube,Bar & rod.
Typical Applications
- Furnace parts and muffles
- Heat treatment baskets and fixtures
- Radiant tubes and burner parts
- Kiln and boiler internals
310S Compared With Other Grades
Frequently Asked Questions
What temperature can 310S withstand?
310S is commonly selected for oxidation resistance at temperatures above the usual 304 range, but a page-level number cannot rate a component. Continuous or cyclic operation, oxygen potential, sulfur, carbon activity, design stress, creep time and section thickness all affect the allowable temperature.
310 vs 310S — what is the difference?
310S is the lower-carbon designation within the 310 family. That chemistry distinction can support fabrication and sensitization control, but 310 and 310S are separate ordered grades; use the exact UNS or standard designation and verify the heat chemistry on the inspection document.
Is 310S resistant to carburizing atmospheres?
Its nickel-rich austenitic structure can be useful in some carburizing environments, but carbon activity, oxygen potential, temperature, cycle length and deposits determine performance. Severe reducing or carburizing duty requires comparison with purpose-designed heat-resistant stainless or nickel alloys using service-specific data.
Published by Tsingshan (Shandong) Iron & Steel Co., Ltd..Sources, update policy and technical limitations.
Quote request
Get a 310S Stainless Steel Quotation
Send the product, grade and quantity you already have. We will complete the specification and quote the supply route.