Technical knowledge
310S and 253MA: austenitic grades for elevated temperature service
Oxidation limits, creep strength, thermal fatigue and specification guidance for 310S and 253MA in furnace, kiln and exhaust applications where austenitic stainless is preferred to nickel alloys.
Composition and performance
| Item | 310S | 253MA |
|---|---|---|
| UNS number | S31008 | S30815 |
| Chromium | 24.0 - 26.0 % | 20.0 - 22.0 % |
| Nickel | 19.0 - 22.0 % | 10.0 - 12.0 % |
| Nitrogen | Not specified | 0.14 - 0.20 % |
| Silicon | 1.5 % maximum | 1.4 - 2.0 % |
| Rare earth additions | No | Yes, cerium bearing |
| Oxidation limit in air | About 1150 C | About 1150 C |
| Creep strength | Moderate | Higher for the same cost |
How to choose between them
- Load bearing at temperature. 253MA, because nitrogen and rare earth additions improve creep and oxidation behaviour together.
- Severe thermal cycling. 310S has excellent scale adhesion through its high chromium and nickel content.
- Reducing or sulphidising atmospheres. Neither grade is ideal; consult the atmosphere composition before selecting.
- Cost. 253MA uses less nickel and is usually more economical for the same duty.
Design and fabrication notes
Allow for the much higher thermal expansion of austenitic stainless compared with carbon steel, and design supports to accommodate growth. Sigma phase can form in 310S after long exposure around 600 to 900 C, causing embrittlement, so consider that risk for long life components in the intermediate range. For welded fabrication use a matched filler and control heat input.
Questions about this topic
Can 310S be used continuously at 1100 C?
Yes in oxidising atmospheres. In reducing, carburising or sulphidising atmospheres the limit is lower and the atmosphere composition must be assessed before selecting the grade.
Why does 310S become brittle after long service?
Sigma phase can precipitate after extended exposure in roughly the 600 to 900 C range, which removes toughness. This is a known limitation and should be considered for long life components operating in that band.
Is 253MA a direct replacement for 310S?
Often for load bearing components at temperature, yes, and at lower cost. Confirm the oxidation and creep data for the actual atmosphere and design life before substituting.
Questions about our products
What products does Hangbo Alloy supply?
Four product families, all available in nickel-based alloys, titanium, duplex and special stainless steel: flanges, butt weld pipe fittings, elbows, and seamless tube and pipe. Flanges cover weld neck, long weld neck, slip-on, blind, socket weld, threaded and lap joint patterns. Fittings and elbows cover concentric and eccentric reducers, equal and reducing tees, caps, stub ends, and 45°, 90° and 180° returns in both long and short radius, plus 3D and 5D bends for piggable lines. Seamless tube and pipe is supplied cold drawn or hot finished from 6 mm to 630 mm outside diameter.
Which alloy grades are available for these products?
More than 90 grades are published in our grade library. The most requested are Inconel 625, 718, 600 and X-750, Hastelloy C-276, C-22 and B-2, Monel 400 and K-500, Incoloy 800H, 825 and 925, duplex 2205 and super duplex 2507, 316L, 904L and 254SMO stainless steel, and titanium Grade 2 and Grade 5. Nickel-based grades can also be supplied with VIM plus ESR double melting where cleanliness or fatigue life is critical.
What sizes, wall thicknesses and pressure classes can you supply?
Flanges run from NPS ½ to NPS 24 to ASME B16.5 and from NPS 26 to NPS 60 to ASME B16.47 Series A or B, in pressure classes 150 through 2500. Butt weld fittings and elbows run from NPS ½ to NPS 48 (DN 15 to DN 1200) in wall thickness Schedule 5S through XXS. Seamless tube and pipe covers 6 mm to 630 mm outside diameter, in random lengths of about 5 to 7 metres or fixed lengths up to 12 metres. Non-standard and intermediate sizes are quoted on request.
Which material and dimensional standards do you work to?
Forged flanges to ASTM B564, B381 and A182 with dimensions to ASME B16.5 and ASME B16.47. Butt weld fittings and elbows to ASTM B366 and A403 with dimensions to ASME B16.9 and MSS SP-43. Seamless tube and pipe to ASTM B444, B423, B622, B163, B167, B861, A312, A213 and A790. Marking follows MSS SP-25 and the applicable product standard. If your project is governed by EN, DIN, JIS or a company specification, send the document and we will confirm equivalence before quoting.
Is there a minimum order quantity?
There is no minimum for standard sizes and grades held in stock, and prototypes, spares and small trial batches are accepted. Made-to-order melts and special forgings carry a minimum weight that depends on the alloy and the route, typically from about 500 kg for special grades.
What inspection and certification is issued with the goods?
Every shipment carries an EN 10204 3.1 mill test certificate quoting the actual chemical and mechanical results for the specific heat lot, together with dimensional records and heat treatment data where applicable. Testing is carried out in house by optical emission spectrometry, tensile, impact and hardness testing, plus ultrasonic and eddy current examination, with hydrostatic pressure and intergranular corrosion testing to ASTM G28 or A262 Practice E where the specification requires it. Third party inspection by SGS or another recognised agency can be arranged, and their report is issued alongside the shipment.
What are typical lead times?
Standard stock items ship within days. Common production grades such as Inconel 625 or duplex 2205 are typically a few weeks. Special chemistries, larger forgings and items that require third party inspection take longer and are quoted individually against the requirement.
How are the products packed for export?
Flanges and fittings receive a rust preventive coating, are individually wrapped and are packed in plywood cases secured with steel banding. Tube ends are capped and bundles are strapped. Packing lists quote heat numbers so every case can be cross-checked against the mill certificate on arrival. We quote EXW, FOB, CFR, CIF and DAP, and mixed-alloy orders can be consolidated into one shipment with a single documentation package.
How do I request a quotation or a sample?
Send the grade or UNS number, the dimensions including schedule or wall thickness, the governing material and dimensional standards, quantity, any heat treatment or NDT scope and the certificate type you need; a drawing is ideal for special flanges and fittings. Email demi@nickel-alloy.com or message us on WhatsApp +86 15618279078 and we normally issue a formal quotation within 24 hours on working days. Samples and previous test reports can be arranged before the first order.
Talk to an engineer
Share your duty conditions and we will shortlist candidate alloys within one working day.