310/310S Stainless steel are austenitic stainless steel grades with high nickel and high chromium contents, 310 and 310S grades contain 25% chromium and 20% nickel, making them superior corrosion resistance, resistance to oxidation and heat resistance.
310S stainless steel is austenitic chromium-nickel stainless steel (0.08% max carbon) with good oxidation resistance and strength at high temperatures. It resists oxidation in continuous service up to 2000ºF gave decreasing sulphur gasses are not present. It is additionally utilized for intermittent service at temperatures up to 1900°F because it resists rescaling and has a low coefficient of expansion. This factor reduces the tendency of the steel to warp in heat service.
310/310S Stainless Steel Chemical Composition
| Standard | Grade | C | Mn | Cr | Ni | Si | N | Other |
|---|---|---|---|---|---|---|---|---|
| ASTM A240 | 310 | ≤0.25 | ≤2.00 | 24.0-26.0 | 19.0-22.0 | 1.50 | ||
| ASTM A240 | 310H | 0.04-0.10 | ≤2.00 | 24.0-26.0 | 19.0-22.0 | 0.75 | ||
| ASTM A240 | 310S | ≤0.08 | ≤2.00 | 24.0-26.0 | 19.0-22.0 | 1.50 | ||
| EN 10095 | 1.4845 | ≤0.10 | ≤2.00 | 24.00-26.00 | 19.00-22.00 | 1.50 | ≤0.11 |
310/310S Stainless Steel Mechanical Properties
| Standard | Grade | Tensile Strength, Mpa (ksi) | 0.2% Yield Strength, Mpa (ksi) | Elongation in 2 in. (50 mm), % | Rockwell | HB |
|---|---|---|---|---|---|---|
| ASTM A240 | 310 | ≥ 205 (30) | ≥ 515 (75) | 40 | ≤ 95HRB | ≤ 217 |
| ASTM A240 | 310H | ≥ 205 (30) | ≥ 515 (75) | 40 | ≤ 95HRB | ≤ 217 |
| ASTM A240 | 310S | ≥ 205 (30) | ≥ 515 (75) | 40 | ≤ 95HRB | ≤ 217 |
310/310S Stainless Steel Physical Properties
| Physical Properties | 310 | 310S | Temperature In °C |
|---|---|---|---|
| Density | 8.0 G/Cm³ | 8.01 G/Cm³ | Room |
| Specific Heat | 0.12 Kcal/Kg.C | 0.12 Kcal/Kg.C | 22° |
| Melting Range | 1400 – 1455 °C | 1399 – 1454 °C | – |
| Modulus Of Elasticity | 193 – 200 KN/Mm² | 200 KN/Mm² | 22° |
| Electrical Resistivity | 77 ΜΩ.Cm | 94 ΜΩ.Cm | Room |
| Coefficient Of Expansion | 15.8 Μm/M °C | 14.4 Μm/M °C | 20 – 100° |
| Thermal Conductivity | 16.2 W/M -°K | 13.8 W/M -°K | 20° |
310S Stainless Steel Equivalent
- UNS S31808
- JIS 310S
- GB 1Cr25Ni20Si2
- EN X8CrNi25-21
- GOST 10KH23N1820KH23N18
Forms
Corrosion Resistance
The high chromium content – intended to increase high-temperature properties – also gives these grades good aqueous corrosion resistance. The PRE is approximately 25, and seawater resistance is about 22°C, similar to that of Grade 316. In high-temperature service, they exhibit good resistance to oxidising and carburising atmospheres. Resist fuming nitric acid at room temperature and fused nitrates up to 425°C.
The high carbon contents of all except 310L do make these grades susceptible to sensitisation and hence intergranular corrosion after elevated temperature exposure or welding. 310 is subject to stress corrosion cracking but more resistant than Grades 304 or 316.
Heat Resistance
Grades 310/310S have good resistance to oxidation in intermittent service in air up to 1035°Cand 1050°Cin continuous service. The grades are resistant to oxidation, sulfidation and carburisation.
Heat Treatment
Solution Treatment (Annealing)
Heat to 1040-1150°C and cool rapidly for maximum corrosion resistance. This treatment is also recommended to restore ductility after every 1000 hours of service above 650°C, due to long-term precipitation of brittle sigma phase.
These grades cannot be hardened by thermal treatment.
Welding
Good characteristics suited to all standard methods. Grade 310S electrodes are generally recommended for fusion welding. AS 1554.6 pre-qualifies welding of 310 with Grade 310 rods or electrodes.
Typical Applications
310/310S Stainless Steel is capable of applications in reducing sulphur atmospheres containing H2S. They are widely used in moderately carburising atmospheres, as encountered in petrochemical environments. For more severe carburising atmospheres other heat-resisting alloys should be selected. Grade 310 is not recommended for frequent liquid quenching as it suffers from thermal shock. The grade is often used in cryogenic applications, due to its toughness and low magnetic permeability.
- Industrial furnace equipment
- Oil industry equipment
- Heat treatment baskets
- Heat exchanges
- Steam boilers and thermowell
- Iron, steel, and non-ferrous industries
- Engineering industry
- Energy conversion plants
- Cement industry
Dual Certification
310H and 310S are often produced in “Dual Certified” form – mainly in plate and pipe. These items have chemical and mechanical properties complying with both 310H and 310S specifications. Products complying with 310 only or dual-certified 310 and 310S may have a carbon content below 0.04% which will not be acceptable for some high temperature applications.
310, 310S, 310H Chemical Composition Comparison
| Grade | C | Si | P | S | Cr | Mn | Ni | Fe |
|---|---|---|---|---|---|---|---|---|
| 310 | 0.25 Max | 1.50 Max | 0.045 Max | 0.03 Max | 24.0 – 26.0 | 2.0 Max | 19.0-22.0 | Balance |
| 310S | 0.08 Max | 1.50 Max | 0.045 Max | 0.03 Max | 24.0 – 26.0 | 2.0 Max | 19.0-22.0 | Balance |
| 310H | 0.04 0.10 | 0.75 Max | 0.045 Max | 0.03 Max | 24.0 – 26.0 | 2.0 Max | 19.0-22.0 | Balance |
310H has good resistance to oxidation in intermittent service in air at temperatures up to 1040°C and 1150°C in continuous service. Good resistance to thermal fatigue and cyclic heating. Widely used where sulphur dioxide gas is encountered at elevated temperatures. Continuous use in 425-860°C range is not recommended due to carbide precipitation if subsequent aqueous corrosion resistance is needed, but it often performs well in temperatures fluctuating above and below this range. Prone to sigma phase embrittlement in the temperature range 650 – 900°C.
Grade 310H is generally used at temperatures starting from about 800 or 900°C above the temperatures at which 304H and 321 are effective.
Related References
- ASTM A240/ASME SB240, Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
- ASTM A480, Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip
- EN 10088-2, Stainless steels. Technical delivery conditions for sheet/plate and strip of corrosion-resisting steels for general purposes
- EN 10088-3, Stainless steels. Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion-resisting steels for general purposes
- EN 10088-4, Stainless steels. Technical delivery conditions for sheet/plate and strip of corrosion-resisting steels for construction purposes
- EN 10088-5, Stainless steels. Technical delivery conditions for bars, rods, wire, sections and bright products of corrosion-resisting steels for construction purposes
- ASTM A249, Standard Specification for Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes
- ASTM A213, Standard Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes
- ASTM A312, Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes