This specification covers standards for iron-chromium and iron-chromium-nickel alloy castings of general purpose grades (Grades HF, HH, HI, HK, HE, HT, HU, HW, HX, HC, HD, HL, HN, and HN) applicable in heat-resistant services. Alloys shall be produced through electric arc, electric-induction, or other approved processes. Heat-treatment shall be conducted when agreed upon by the manufacturer and purchaser. The material shall conform to carbon, manganese, silicon, phosphorus, sulfur, chromium, nickel, and molybdenum contents. Tensile requirements including tensile strength, yield point, and elongation shall apply when specified in the purchase order. Guidelines for repair by welding are also given.

1.1 This specification covers iron-chromium and iron-chromium-nickel alloy castings for heat-resistant service. The grades covered by this specification are general purpose alloys and no attempt has been made to include heat-resisting alloys used for special production application.

Note 1: For heat-resisting alloys used for special product application, reference should be made to Specifications A351/A351M, A217/A217M, and A447/A447M.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.