High-Chromium / High-Nickel Heat-Resistant Austenitic Stainless Steel
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UNS NUMBER
S31000
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ALLOY FAMILY
Austenitic (Heat-Resistant)
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STRUCTURE
100% Austenite
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UTS (MIN)
≥515 MPa
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MAX TEMP
~1150°C
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DENSITY
7.98 g/cm³
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Stainless Steel 310 (UNS S31000) is a 25Cr-20Ni heat-resistant austenitic grade with carbon up to 0.25%, built for furnace parts, radiant tubes, and petrochemical hardware operating to about 1150°C. It resists oxidation and sulfidation far better than 304 but has no molybdenum, so its aqueous pitting resistance is modest.
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Cr
24–26%
Oxidation resistance to 1150°C
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Ni
19–22%
Austenite + sulfidation resistance
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Mo
— (none)
Not added
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Si
≤1.50%
Oxidation aid
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UTS
≥515 MPa
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YS 0.2%
≥205 MPa
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Elong.
≥40%
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Service
up to 1150°C
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What is Stainless Steel 310?
310 is a fully austenitic, high-alloy heat-resistant steel. The 24–26% chromium gives excellent resistance to scaling in air up to roughly 1150°C, while the 19–22% nickel maintains the austenite and adds resistance to sulfur-bearing (sulfidizing) atmospheres that would attack lower-nickel grades. The higher carbon (up to 0.25%) supports strength at temperature.
Compared with 310S (carbon ≤ 0.08%), standard 310 is the stronger, more carburization-tolerant grade but is more prone to embrittlement and sensitisation in service. Neither grade contains molybdenum, so pitting resistance in liquid chlorides is poor — these are high-temperature materials, not seawater materials. For severe carburizing or higher temperatures, a nickel alloy is the next step.
Chemical Composition (Weight %)
| Element |
Min (%) |
Max (%) |
Role in Alloy |
| Chromium (Cr) |
24.0 |
26.0 |
Oxidation resistance to 1150°C |
| Nickel (Ni) |
19.0 |
22.0 |
Austenite; sulfidation resistance |
| Carbon (C) |
— |
0.25 |
Higher than 310S for strength |
| Manganese (Mn) |
— |
2.00 |
Deoxidizer |
| Silicon (Si) |
— |
1.50 |
Oxidation/surface stability |
| Phosphorus (P) |
— |
0.045 |
Impurity |
| Sulfur (S) |
— |
0.030 |
Impurity |
| Molybdenum (Mo) |
— |
0.75 |
Minor, not a design element |
| Iron (Fe) |
Balance |
— |
Matrix former |
★ 310 is the medium/high-carbon heat-resistant grade (C up to 0.25%); 310S is the low-carbon version (C ≤ 0.08%). The high chromium and nickel give oxidation and sulfidation resistance, but the absence of molybdenum keeps pitting resistance low.
Mechanical Properties
Values are for the annealed condition per ASTM A240, A182 (F310), and A312 (TP310).
| Condition / Form |
UTS (MPa) |
YS 0.2% (MPa) |
Elong. % (min) |
Hardness (max) |
| Minimum (ASTM A240 / A182 F310) |
≥515 |
≥205 |
40 |
225 HBW (95 HRB) |
| Typical annealed |
520–620 |
205–310 |
40–52 |
170–210 HBW |
Modulus of Elasticity 200 GPa. At elevated temperature the strength falls steadily; design uses ASME high-temperature allowable stresses. 310 is not hardenable by heat treatment.
Physical Properties
| Property |
Value |
Note |
| Density |
7.98 g/cm³ |
Slightly above 304 |
| Melting Range |
1400–1450°C |
Solidus ~1400°C |
| Thermal Conductivity (100°C) |
14.2 W/m·K |
Lower than carbon steel |
| Thermal Expansion (20–100°C) |
15.9 ×10⁻⁶ /K |
Lower than 304 |
| Specific Heat |
500 J/kg·K |
At 21°C |
| Electrical Resistivity |
0.78 µΩ·m |
At 21°C |
| Magnetic Property |
Non-magnetic |
Annealed |
| PREN (Pitting Resistance) |
~25 |
Cr 25, no Mo |
Corrosion Resistance
High-Temperature Oxidation
The 25% chromium forms a tenacious scale that protects to about 1150°C in continuous air and 1035°C in intermittent service. This is 310's primary advantage over 304/316.
Sulfidation & Carburization
High nickel gives 310 good resistance to sulfur-bearing gases (H₂S) in oxidizing atmospheres — better than leaner grades. In strongly carburizing atmospheres other heat-resistant alloys may be needed.
Pitting & Aqueous Corrosion
No molybdenum means PREN ~25 and poor pitting/crevice resistance in chlorides. 310 is not a seawater or process-liquid grade; it is chosen for dry heat.
Sensitization & Thermal Shock
Service in the 550–800°C range sensitizes 310 to intergranular attack. It also suffers thermal-shock cracking under repeated liquid quenching, so avoid frequent quench cycles.
Stainless Steel 310 vs Similar Grades — Selection Guide
| If you need... |
Choose... |
Why |
| Furnace parts to 1150°C, dry |
310 / 310S |
High Cr/Ni oxidation resistance |
| Welded furnace fabrication |
310S |
Low carbon, less sensitization |
| Severe carburizing / >1150°C |
Nickel alloy (e.g. 800H) |
Higher temperature capability |
| Chloride liquid service |
316L / 904L |
Need molybdenum |
| Lean, cheaper heat part to ~900°C |
253MA |
Less nickel, good creep strength |
Applicable Standards
HT PIPE Supply — Stainless Steel 310 Product Forms
| Product Form |
Specifications |
HT PIPE Supply |
| Seamless Pipe |
ASTM A312 TP310 |
✅ Available |
| Forged Flanges |
ASTM A182 F310, ASME B16.5 |
✅ In stock |
| Butt-Weld Fittings |
ASTM A403 WP310 |
✅ Available |
| Plate / Sheet |
ASTM A240 |
✅ Available |
| Bar / Rod |
ASTM A276 / A479 |
✅ Available |
| Radiant Tube / Custom |
Made to drawing |
✅ On request |
HT PIPE supplies 310 (and 310S) in pipe, flanges, fittings, plate, and bar for furnace and petrochemical high-temperature service, with MTRs.
Project Experience — Stainless Steel 310
HT PIPE supplies 310 for furnace, radiant-tube, and petrochemical high-temperature components.
| Project |
Product |
Specification |
| Petrochemical Furnace Radiant Tubes (Middle East) |
310 Pipe + Fittings |
A312, A403 |
| Heat-Treatment Furnace Rolls (China) |
310 Bar + Plate |
A276, A240 |
| Kiln & Burner Hardware (Europe) |
310 Flanges + Forgings |
A182 F310 |
We advise 310 vs 310S selection based on welding and service-temperature profile.
| FREQUENTLY ASKED QUESTIONS |
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FAQ — Stainless Steel 310
| What is the difference between 310 and 310S? |
| 310 allows carbon up to 0.25%; 310S caps it at 0.08%. 310 is stronger and more carburization-tolerant but more prone to sensitization; 310S is the better choice for welded furnace fabrications. |
| What temperature can 310 withstand? |
| Continuous service to about 1150°C in air, intermittent to 1035°C. It is one of the highest oxidation-resistant standard austenitic grades before stepping to nickel alloys. |
| Is 310 good in seawater or chlorides? |
| No. It has no molybdenum (PREN ~25) and is not a pitting-resistant grade. It is selected for dry high-temperature service, not aqueous corrosion. |
| What filler is used for 310? |
| ER310 or ER309 (over-alloyed) for matching/over-matching deposits. Avoid low-alloy fillers that lack the chromium-nickel level. |
| Does 310 resist sulfur atmospheres? |
| Yes, better than leaner grades because of its high nickel. In oxidizing sulfur-bearing gases it resists sulfidation well; strongly reducing (low-oxygen) sulfur environments still need caution. |
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Need Stainless Steel 310 for High-Temperature Service?
HT PIPE supplies 310 (UNS S31000) pipe, flanges, fittings, plate, and bar for furnace and petrochemical applications to 1150°C. Contact our technical team for grade and welding advice.
Request a Quote |
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