ATI 20-25+Nb™ alloy is an austenitic stainless steel intended primarily for elevated temperature service. This alloy fills a performance gap between conventional heat-resistant stainless steels and nickel-base superalloys, providing high performance with an economical composition. The chromium, nickel, and manganese levels result in superior resistance to high temperature oxidation in air and steam-bearing atmospheres. Additions of nitrogen and molybdenum provide solid-solution-strengthening, resulting in superior room and elevated temperature strength. Control of niobium (columbium) and carbon additions, along with advanced thermo-mechanical processing (TMP) results in the formation of a very fine dispersion of carbides and carbonitride particles with particle size ranging down to the nanoscale. This results in excellent resistance to elevated temperature creep and stress-rupture, while exhibiting austenite phase stability superior to many heat and corrosion-resistant alloys, which allows for retention of mechanical properties after elevated temperature exposures.

ATI 20-25+Nb™ alloy is available in Precision Rolled Strip®, standard strip, sheet and plate product forms in a wide range of sizes and finishes. The properties of this alloy make it a suitable candidate for a variety of applications, including heat exchangers and recuperators, high temperature structural components, vessels, retorts, calciners, piping, tubing and heat-treatment fixtures.