Disclosed is an austenitic stainless steel alloy that includes or consists of, by weight, about 20.0% to about 21.5% chromium, about 8.5% to about 10.0% nickel, about 4.0% to about 5.0% manganese, about 0.5% to about 2.0% silicon, about 0.4% to about 0.5% carbon, about 0.2% to about 0.3% nitrogen, and a balance of iron with inevitable/unavoidable impurities. The elements niobium, tungsten, and molybdenum are excluded beyond impurity levels. Turbocharger turbine housings made of the stainless steel alloy, and methods of making the same, are also disclosed. The stainless steel alloy is suitable for use in turbocharger turbine applications for temperatures up to about 1020° C.