Alloy 310S

Stainless steel is the generic name of different grades of steels (containing low carbon and iron), used primarily because of their corrosion resistance. All stainless steels share a minimum percentage of 10.5% chromium element. Chromium (Cr), usually a deciding factor, nickel and molybdenum are commonly added to steels to improve their corrosion resistant and make them ‘stainless’. Most of the stainless steel grades will have a UNS number that start off with letter ‘S’ such as UNS S32100 (Alloy 321) and UNS S31008/S31009 (Alloy 310/310S).

There are some stainless steel grades that are engineered to be used specifically for high temperature applications. Some can be used up to 1100°C. The choice of grade depends on the following factors:

• Maximum operating temperature
• Holding time and cyclic nature of process
• Type of atmosphere (oxidising, reducing, sulphidising, nitriding, carburising etc.)
• Required strength and creep rupture properties

Increasing amount of Chromium and Silicon contributes to greater oxidation resistance. For example, 310S with a nominal Chromium content of 25% can be used at temperatures up to 1100°C. Nickel, on the other hand, is added for greater carburisation resistance or lowered to enhance the resistance to sulphidation attack.

• Oxidation resistance to 1100°C
• Moderate high strength at elevated temperatures
• Resistance to hot corrosion
• Strength and toughness at cryogenic temperatures

• Flare tips
• Fluidized bed coal combustors
• Tube hangers for petroleum refining and steam boilers
• Coal gasifier internals & thermowells
• Radiant tubes
• Refractory anchor bolts
• Retorts, muffles and annealing covers
• Burners & combustion chambers
• Cryogenic structures