Alloy 253MA

253MA is an alloy that combines excellent high-temperature performance with good workability. It withstands temperatures up to 1150°C and can outperform Grade 310 in atmospheres containing carbon, nitrogen, and sulfur. 253MA has a relatively low nickel content, offering some advantage in reducing sulfurous environments compared to high-nickel alloys and Grade 310. Its high content of silicon, nitrogen, and cerium provides good oxidation stability, high-temperature strength, and excellent resistance to sigma phase precipitation.

The austenitic structure gives this grade excellent strength, even at cryogenic temperatures.

Corrosion Resistance

Although not specifically designed for resistance to aqueous corrosion, its high chromium and nitrogen content gives it corrosion resistance comparable to Grade 316. However, due to its high carbon content, 253MA is highly susceptible to sensitization after welding or processing.

Physical Properties

Mechanical Properties

Welding

Weldability is excellent using all standard techniques with suitable filler materials.

AS 1554.6 prequalifies welding of 253MA with Grade 22.12HT rods or electrodes. Grade 309 filler materials can be used if slightly lower creep resistance is acceptable. Pure argon should be used as the shielding gas.

Heat Treatment

Heat to 1050–1150°C, then cool rapidly. It is recommended to perform solution treatment after 10–20% cold working to achieve maximum creep strength in service.