Austenitic Stainless Steel
300-series stainless steels
Stainalloy is specialized in the 300-series stainless steels, classified as austenitic steels. These material austenitic grades have chromium (approx. 18 to 30%) and nickel (approx. 6 to 20%) as their major alloying additions. Austenitic stainless steel alloys exhibit excellent corrosion resistance, have a high ease of fabrication, outstanding formability, and maintain useful mechanical strength at elevated temperatures and pressures. Austenitic stainless steel is a type of steel alloy which is composed of chromium, nickel, other minor alloys, iron and carbon.
Due to its controlled carbon content of 0.04% to 0.10%, stainless steel 304H (UNS S30409) provides improved high-temperature strength and is typically used in applications up to about 1500°F (816°C).
Key Characteristics
- Chromium content: approx. 18 to 30%
- Nickel content: approx. 6 to 20%
- Excellent corrosion resistance
- High ease of fabrication
- Outstanding formability
- Useful mechanical strength at elevated temperatures and pressures
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Product Details
Application: By Service and Function
Austenitic stainless steels are used where elevated temperature and pressure performance and corrosion resistance are required, including:
- High-temperature and high-pressure chemical processes
- Furnaces of petrochemical cracker units, where high temperature and high-pressure resistant materials are essential
Application: By Industry
Stainalloy has extensive experience supplying these materials for:
- Petroleum refineries
- Electric generation plants
- Fertilizer and chemical plants
- Paper and pulp handling equipment
- Heat exchangers and cooling towers
Material grades
Stainless Steel 304H – UNS S30409
Due to its controlled carbon content of 0.04% to 0.10%, stainless steel 304H (UNS S30409) provides improved high-temperature strength and is typically used in applications up to about 1500°F (816°C).
Stainless Steel 317L – UNS S31703
Stainless Steel 317L (UNS S31703) is a molybdenum-containing, low carbon austenitic stainless steel with increased additions of chromium, nickel and molybdenum for better corrosion resistance and increased resistance to chemical attack from sulfurous, acetic, formic, citric, and tartaric acids.
Due to its low carbon content, 317L also provides:
- Resistance to sensitization when welded
- Higher creep, stress to rupture, and tensile strength at elevated temperatures
- Non-magnetic in the annealed condition but may become slightly magnetic after welding
Stainless Steel 321 – UNS S32100
Stainless Steel 321 (UNS S32100) is a titanium stabilized austenitic stainless steel with good general resistance to corrosion.
It has excellent resistance to intergranular corrosion after exposure to temperatures in the chromium carbide precipitation wide range of 800 – 1500°F.
It also possesses good low temperature toughness.
Material grades
Stainless Steel 321H – UNS S32109
Stainless Steel 321H (UNS S32109) is the higher carbon (0.04% to 0.10%) version of the alloy.
It was developed for enhanced creep resistance and for higher strength at temperatures above 1000°F.
Stainless Steel 347 / 347H – UNS S34700 / UNS S34709
Stainless Steel 347 (UNS S34700) is an austenitic, chromium steel containing Niobium (Nb) (formerly known as Columbium (Cb)) which allows for the elimination of carbide precipitation, and, consequently, intergranular corrosion.
347 is stabilized by the addition of niobium (columbium), with tantalum as an associated element, which limits chromium carbide precipitation at grain boundaries.
Alloy 347 generally offers somewhat better resistance than 321 in strongly oxidizing environments, while maintaining excellent intergranular corrosion resistance between 800–1500°F.
Stainless Steel 347H (UNS S34709) is the higher carbon composition form of Alloy 347 and demonstrates improved high temperature and creep properties.
Stabilizing heat treatment is used to reduce susceptibility to intergranular stress corrosion and embrittlement, and to increase high temperature creep strength.
Standards and Specifications
| Product type | Applicable standard | Specification / notes |
|---|---|---|
| Seamless pipes (½” up to and including 48”) | ASTM A312 / ASME SA312 | Manufactured by only the most reputable mills. Subject to additional testing that exceeds both industry and client-specific standards such as Shell. |
| Seamless and welded pipes | ASTM A358 | Available in addition to ASTM A312 / ASME SA312 seamless pipes. |
| Seamless & welded fittings | ASTM A403 | — |
| Fittings, flanges & forgings | ASTM A182 | — |
Stainalloy Capabilities
Stainalloy has extensive experience in supplying these materials for petroleum refineries, heat exchangers, cooling towers, electric generation plants, fertilizer and chemical plants, paper and pulp handling equipment, and high temperature and high-pressure chemical processes.
Stainalloy has a special focus on the furnaces of petrochemical cracker units for which high temperature and high-pressure resistant materials are essential.
Stainalloy supplies ½” up to and including 48” seamless ASTM A312 300-series stainless steels, manufactured by only the most reputable mills. The pipes are manufactured in accordance with ASTM A312/ASME SA312 and are subject to additional testing that exceeds both industry and client-specific standards such as Shell.
In addition to seamless and welded pipes that adhere to ASTM A358, Stainalloy is also able to supply:
- Seamless & welded fittings in accordance with ASTM A403
- Fittings, flanges & forgings in accordance with ASTM A182
Rowan de Visser
Senior Sales Engineer Stock
Germán Gómez
Head of Stock Sales
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