253MA Stainless Steel Gains Traction in Hightemperature Industries

253MA, a specially designed austenitic heat-resistant stainless steel, stands out in high-temperature industrial applications due to its unique composition and exceptional performance. This article delves into the chemical makeup, physical and mechanical properties, corrosion resistance, heat treatment processes, and typical applications of 253MA stainless steel, offering insights for material selection.

253MA (UNS S30815) is an austenitic stainless steel with outstanding high-temperature performance and excellent workability. It exhibits superior oxidation resistance at temperatures up to 1150°C and outperforms Type 310 stainless steel in atmospheres containing carbon, nitrogen, and sulfur. Known alternatively as 2111HTR, 253MA features relatively low nickel content, giving it an edge over high-nickel alloys and Type 310 stainless steel in reducing sulfide environments. The addition of high silicon, nitrogen, and cerium content enhances oxide stability, high-temperature strength, and resistance to sigma phase precipitation. Its austenitic structure ensures remarkable toughness, even at low temperatures.

These properties are specified in ASTM A240/A240M for flat-rolled products (plates, sheets, and coils) of grade S30815. Similar, though not identical, characteristics are defined in respective standards for other products like pipes and bars.

The typical composition range of 253MA stainless steel is shown in Table 1.

• Chromium (Cr): At 20-22%, chromium forms a protective oxide layer, granting 253MA exceptional resistance to high-temperature oxidation.
• Nickel (Ni): Moderate nickel content stabilizes the austenitic structure while reducing costs and improving corrosion resistance in sulfur-rich environments.
• Silicon (Si): Enhances oxidation resistance and high-temperature strength by promoting stable oxide film formation.
• Nitrogen (N): A potent austenite stabilizer that boosts strength and resistance to intergranular corrosion.
• Cerium (Ce): A rare-earth element that improves oxide film adhesion and oxidation resistance.

The typical mechanical properties of 253MA stainless steel are listed in Table 2.

Table 3 outlines the typical physical properties of 253MA stainless steel.

253MA excels in high-temperature environments (500-900°C) due to its strength and oxidation resistance. It is widely used in furnace components, petrochemical equipment, and electrical heating elements. While not designed for aqueous corrosion resistance, its high chromium and nitrogen content provide pitting resistance comparable to 316 stainless steel.

Solution annealing at 1050-1150°C followed by rapid cooling is recommended. The steel cannot be hardened by heat treatment. It welds well with matching filler metals and requires sharp tools for machining due to its austenitic structure.