Stainless 309/309S
Stainless 309
It is an austenitic stainless steel developed for use in high temperature corrosion resistance. The alloy resists oxidation up to 1900°F (1038°C) under non-cyclic conditions. Regular heat cycling reduces oxidation resistance by approximately 1850°F (1010°C).
Due to its high chromium and low nickel content, Alloy 309 can be used in sulfur containing atmospheres up to 1832°F (1000°C). The alloy is not recommended for use in environments with high carbon deposition due to its moderate resistance. To carbon adsorption, Alloy 309 can be used in slight oxidizing, nitriding, adhesion and heat cycling applications, although maximum service temperature reduction is required.
When heated between 1202 - 1742°F (650 - 950°C), the alloy precipitates the sigma phase. A annealing treatment at 2012 - 2102°F (1100 - 1150°C) will restore some degree of toughness.
Stainless 309S
It is a low carbon alloy. It is used to facilitate production. 309H (UNS S30909) is a carbon modification developed to increase creep resistance. For most samples, the plate's grain size and carbon content can meet both the 309S and 309H requirements.
Alloy 309 can be easily welded and processed by standard shop fabrication practices.
feature
Applications
Furnaces - stoves, doors, fans, pipes and recuperators.
Fluidized Bed Furnaces - Airbox Duct Grids
paper mill equipment
Petroleum Refining - Catalyst Recovery System, Rehabilitation
Power Generation - Crushed Coal Burners, Lamp Hangers
Thermal processing - annealing covers and boxes, stove grids, doors, fans, neutral lead pans and salt pots, muffins and counters, recuperators, walking beams.
Waste Treatment - Waste Incinerators, Rotary Incinerators and Incinerators
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corrosion resistance
wet corrosion
Alloy 309 is not designed for service in wet corrosive environments. The high carbon content, which exists to enhance creep properties, has a detrimental effect on water corrosion resistance. The alloy is prone to long-term intergranular corrosion 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 is resistant to high temperature corrosion in most service conditions. The working temperature is as follows:
oxidizing condition (maximum sulfur content - 2 g / m3)
1922°F (1050°C) continuous service
Maximum temperature 2012 °F (1100°C).
oxidizing condition (Maximum sulfur greater than 2 g/m3)
Maximum temperature 1742°F (950°C)
low oxygen atmosphere (maximum sulfur content - 2 g / m3)
Maximum temperature 1832°F (1000°C).
Nitriding or carburizing atmosphere
Maximum 1562 –1742°F (850 - 950°C)
The alloy does not perform as well as Alloy 600 (UNS N06600) or Alloy 800 (UNS N08800) in reducing nitriding or atmospheric decomposition. But it is more efficient than most heat resistant stainless steels.
