Stainless Steel 309 Sheet/Plates
Great Steel & Metals offers high quality stainless steel 309 sheet/plates to all its customers across the world that is appreciated for the applications with elevated temperature. It offers comparable resistance to corrosion, excellent oxidation resistance and retention of large fraction of strength at room temperature a compared to the common austenitic alloy 304 on account of high content of nickel and chromium present in it.
In the applications where high temperature corrosion resistance is required, alloy 309 (UNS S30900) is extensively used. Under the non-cyclic conditioners, oxidation up to 1900°F is resisted by the alloy.
The alloy 309 contain high content of chromium and low content of nickel on account of which it could be used in the atmosphere containing sulfur at up to 1832°F. The alloy offers moderate resistance to absorption of carbon and therefore is not recommended highly carburizing atmospheres.
The alloy is subject to sigma phase precipitation when it is heated between 1202-1742°F. A degree of toughness is restores by the solution annealing treatment at 2012-2102°F.
- Furnaces — burners, doors, fans, piping and recuperators
- Fluidized Bed Furnaces — grids, piping, wind boxes
- Paper Mill Equipment
- Petroleum Refining — catalytic recovery systems, recuperators
- Power Generation — pulverized coal burners, tube hangers
- Thermal Processing — annealing covers and boxes, burners grids, doors, fans, lead pans and neutral salt pots, muffles and retorts, recuperators, walking beams
- Waste Treatment — incinerators, rotary kilns and calciners
Alloy 309 is not designed for service in wet corrosive environments. The high carbon content, which is present to enhance creep properties, has a detrimental effect on aqueous corrosion resistance. The alloy is prone to intergranular corrosion after long term exposure at high temperatures. However, due to its high chromium content (23%), Alloy 309 is more corrosion resistant than most heat resistant alloys.
High Temperature Corrosion
Alloy 309 resists high temperature corrosion in most in-service conditions. Operating temperatures are as follows:
Oxidizing conditions (max. sulfur content – 2 g/m3)
1922°F (1050°C) continuous service
2012°F (1100°C) peak temperature
Oxidizing conditions (max. sulfur greater than 2 g/m3)
1742°F (950°C) maximum temperature
Low oxygen atmosphere (max. sulfur content – 2 g/m3)
1832°F (1000°C) maximum temperature
Nitriding or carburizing atmospheres
1562 –1742°F (850 – 950°C) maximum
The alloy does not perform as well as Alloy 600 (UNS N06600) or Alloy 800 (UNS N08800) in reducing, nitriding or carburizing atmospheres, but it does outperform most heat resistant stainless steels in these conditions.
Typical Creep Properties
Weight % (all values are maximum unless a range is otherwise indicated)
0.12 BTU/lb-°F (32 – 212°F)
502 J/kg-°K (0 – 100°C)
Modulus of Elasticity
28.5 x 106 psi
Thermal Conductivity 212°F (100°C)
2500 – 2590°F
1480 – 1530°C
30.7 Microhm-in at 68°C
78 Microhm-cm at 20°C
Typical Values at 68°F (20°C)
Alloy 309 can be easily welded and processed by standard shop fabrication practices.
Heat uniformly at 1742 – 2192°F (950 – 1200°C). After hot forming a final anneal at 1832 – 2101°F (1000 – 1150°C) followed by rapid quenching is recommended.
The alloy is quite ductile and forms in a manner very similar to 316. Cold forming of pieces with long-term exposure to high temperatures is not recommended since the alloy is subject to carbide precipitation and sigma phase precipitants.
Alloy 309 can be readily welded by most standard processes including TIG, PLASMA, MIG, SMAW, SAW and FCAW.