What is 1.4833 Stainless Steel?

1.4833 stainless steel, commonly known as 309S or UNS S30908, is a high-alloy austenitic stainless steel designed for excellent oxidation resistance and high-temperature strength. With its elevated chromium and nickel content, it is well-suited for continuous service at temperatures up to 1050°C, making it a reliable and cost-effective choice for furnace parts, heat exchangers, and industrial heating equipment where 310S would be over-specified.

 

This high-temperature resistant grade is standardized under major international systems.

Standard	Equivalent Grade
EN (Europe)	1.4833
ASTM/AISI (USA)	309S, UNS S30908
JIS (Japan)	SUS309S
KS (Korea)	STS309S

Its composition provides a robust balance of chromium and nickel for stability at high temperatures.

Element	C	Si	Mn	P	S	Cr	Ni
Content (%)	≤ 0.08	≤ 1.0	≤ 2.0	≤ 0.045	≤ 0.03	22.0 - 24.0	12.0 - 15.0

It maintains good mechanical properties across a range of temperatures, with excellent oxidation resistance.

Property	Yield Strength (Rp0.2)	Tensile Strength (Rm)	Elongation (A)	Hardness (HB)
Typical Value	≥ 205 MPa	500 - 750 MPa	≥ 40%	≤ 215

 

Key Characteristics and Applications of 1.4833 / 309S

Excellent High-Temperature Oxidation Resistance: Forms a stable chromium oxide layer that protects against scaling and oxidation in continuous service up to 1050°C, with good performance in intermittent service to 980°C.

Good Thermal Fatigue Resistance: Performs well under cyclic heating and cooling conditions due to its stable austenitic structure and good thermal conductivity.

Resistance to Sulfur Atmospheres: Holds up better than many other stainless steels in environments containing moderate levels of sulfur compounds.

Cost-Effective High-Temperature Solution: Provides excellent performance at a lower cost than higher-alloyed grades like 310S, making it ideal for applications where maximum temperature capability is not required.

 

Primary Applications:

Heat Treatment Furnaces: Radiant tubes, retorts, baskets, furnace linings, and annealing covers.

Chemical Processing: High-temperature reactors, reformer tubes, and pyrolysis equipment.

Power Generation: Boiler components, superheaters, and heat recovery units.

Welding Filler Metal: Widely used as an overlay or filler for joining dissimilar metals, particularly for cladding carbon steel with stainless steel.

Cement and Lime Kilns: Cyclones and ducting in preheater systems.

Ceramic Industry: Kiln furniture and car tops.

 

How does 309S (1.4833) compare to 310S (1.4845) in high-temperature applications?
Both are high-temperature grades, but 310S contains higher chromium and nickel (25% Cr, 20% Ni) compared to 309S (23% Cr, 13% Ni). This gives 310S superior oxidation resistance and a higher maximum continuous service temperature (1150°C vs. 1050°C). 309S is often used as a more cost-effective option for slightly less severe conditions, for applications where maximum temperature is below 1050°C, or where thermal cycling resistance is the primary concern. 309S is also frequently chosen as a welding filler metal due to its excellent performance in dissimilar metal joints.

 

Is 309S stainless steel suitable for welding dissimilar metals?
Yes, 309S is highly weldable and is specifically designed as a filler metal for joining dissimilar metals, particularly for welding austenitic stainless steels to carbon or low-alloy steels. Its high alloy content provides a buffer zone that accommodates the different thermal expansion coefficients and prevents carbon migration from the carbon steel to the stainless steel. It is also widely used for stainless steel cladding of carbon steel components in pressure vessels and process equipment. Its low carbon content minimizes carbide precipitation in the heat-affected zone, ensuring good corrosion resistance in the welded joint.

 

Looking for a Reliable Supplier of 1.4833 / 309S Stainless Steel?
GNEE Steel supplies high-temperature grade 309S (1.4833) stainless steel in plate, sheet, pipe, bar, and welding filler forms, suitable for demanding furnace, process, and dissimilar metal joining applications. We provide full material traceability and certification to relevant standards, and offer comprehensive processing services. If you have any requirements, please feel free to contact us.