1.1 This specification2 covers austenitic steel castings for valves, flanges, fittings, and other pressure-containing parts (Note 1). Note 1: Carbon steel castings for pressure-containing parts are covered by Specification A216/A216M, low-alloy steel castings by Specification A217/A217M, and duplex stainless steel castings by Specification A995/A995M. 1.2 A number of grades of austenitic steel castings are included in this specification. Since these grades possess varying degrees of suitability for service at high temperatures or in corrosive environments, it is the responsibility of the purchaser to determine which grade shall be furnished. Selection will depend on design and service conditions, mechanical properties, and high-temperature or corrosion-resistant characteristics, or both. 1.2.1 Because of thermal instability, Grades CE20N, CF3A, CF3MA, and CF8A are not recommended for service at temperatures above 800 °F [425 °C]. 1.3 Supplementary requirements of an optional nature are provided for use at the option of the purchaser. The Supplementary requirements shall apply only when specified individually by the purchaser in the purchase order or con