Grade dossier
310S Stainless Steel for Furnace and Hot-Gas Components
The low-carbon 25Cr-20Ni heat-resistant grade used for fabricated furnace equipment and oxidizing hot-gas service after atmosphere and loading review.
Identity before substitution
Define the grade, product and condition together
A familiar grade name is not a complete purchase specification. Product form, controlling standard, dimensions, condition, finish, certification and service environment determine whether the delivered material is suitable.
Composition control
ASTM A240/A240M flat-product chemistry
Limits are not heat analysis targets
The table summarizes grade limits commonly used for plate, sheet and strip. Pipe, tube, bar, forgings and cast products can be governed by different specifications. Always place the product standard and edition on the purchase order.
| C | 0.08 max |
|---|---|
| Mn | 2.00 max |
| Si | 1.50 max |
| P | 0.045 max |
| S | 0.030 max |
| Cr | 24.00-26.00 |
| Ni | 19.00-22.00 |
Properties with context
Minimums, typical indicators and delivered condition
Specified annealed flat-product values
| Tensile strength | 515 MPa min |
|---|---|
| 0.2% yield strength | 205 MPa min |
| Elongation | 40% min |
| Hardness | 95 HRBW max |
Selection indicators
| Density | about 7.8 g/cm3 |
|---|---|
| Producer air-temperature guidance | up to about 1050°C / 1920°F; not a design allowable |
| Thermal expansion | about 18.8 × 10⁻⁶/K from 20-600°C |
| Thermal conductivity | about 15 W/m·K at 20°C |
Values depend on product form, thickness, test orientation, condition and governing edition. Use the mill test certificate and the purchase specification for acceptance, not a web table alone.
Selection boundary
Where 310S belongs and where to escalate
Grade selection is an environmental decision, not a popularity contest. Review the complete medium, temperature, geometry, fabrication, cleaning and inspection requirements.
Good reasons to evaluate it
Furnace muffles, radiant tubes and fixtures
Burner parts and heat shields
Kiln and heat-treatment components
Oxidizing hot-gas service after atmosphere review
Reasons to stop and review
Carburizing, nitriding, sulfurous or reducing gas without data
Using maximum oxidation guidance for load-bearing design
Wet chloride service without corrosion evaluation
Confusing 310S with 310H
Fabrication route
Protect properties through cutting, forming and welding
Use creep and allowable-stress data at the actual temperature.
Allow for expansion, restrained thermal stress and cycling.
Qualify filler, heat input and joint geometry.
Design drainage to avoid corrosive shutdown condensate.
Supply definition
Product form changes the applicable requirements
Do not send an RFQ that names only the grade. State form, governing standard, dimensions, tolerances, finish, edge or end condition, quantity, certification and inspection.
Cold-rolled coil, strip and sheet
Hot-rolled coil, strip and plate
Quarto plate
Welded high-temperature assemblies
Certificate checkpoint
Request heat identity, chemical analysis, mechanical results and compliance to the exact product specification. Add PMI, corrosion testing or supplementary examination only when the application requires it.
Interactive selection check
Test 310S against the controlling question
Procurement FAQ
Questions to close before placing the order
Is 310S stainless steel magnetic?
Magnetic response depends on microstructure and delivered condition.
Can 310S replace another grade?
Only after checking the governing standard, composition, mechanical properties, corrosion exposure, fabrication route and certification. A commercial name is not a substitution approval.
Does the table apply to every product form?
Not automatically. The values shown use flat-product requirements as a reference. Other forms can use different product standards, dimensions and tests.
What should a 310S RFQ include?
Product form, standard and edition, UNS or EN designation, dimensions, tolerances, finish, quantity, service, fabrication, certificate and inspection requirements.
Sources, scope and RFQ
Use traceable grade data, then specify the actual product
ASTM A240/A240M requirements for UNS S31008 flat product
Outokumpu Therma 310S/4845 official datasheet
EN 10095 heat-resisting steel identity and guidance
Applicable ASME design-code allowables for the actual product and temperature