【国外标准】 Standard Specification for Steel Castings, Martensitic Stainless and Alloy, for Pressure-Containing Parts, Suitable for High-Temperature Service

This specification covers steel castings, martensitic stainless steel and alloys steel castings for valves, flanges, fittings, and other pressure-containing parts intended primarily for high-temperature and corrosive service. The grades of steels covered here are: Grade WC1, Grade WC4, Grade WC5, Grade WC6, Grade WC9, Grade WC11, Grade C5, Grade C12, Grade C12A, and Grade CA15. Heat treatment shall consist of normalizing and tempering for Grade C12A and tempering for all other grades. Heat treatments shall be performed after castings have been allowed to cool. Heat and product analyses shall be performed wherein specimens shall conform to required chemical composition of carbon, molybdenum, chromium, nickel, vanadium, manganese, phosphorus, sulfur, silicon, columbium, nitrogen, aluminum, copper, titanium, tungsten, and zirconium. The surface of the casting shall be examined visually and shall be free of adhering sand, scale, cracks and hot tears. Steels shall undergo tension test, and shall conform to the following mechanical requirements: tensile strength, yield strength, elongation, and reduction of area.1.1 This specification2 covers martensitic stainless steel and alloy steel castings for valves, flanges, fittings, and other pressure-containing parts (Note 1) intended primarily for high-temperature and corrosive service (Note 2).1.2 One grade of martensitic stainless steel and nine grades of ferritic alloy steel are covered. Selection will depend on design and service conditions, mechanical properties, and the high-temperature and corrosion-resistant characteristics (Note 3).NOTE 1: Carbon steel castings for pressure-containing parts are covered by Specification A216/A216M. Low alloy quench-and-tempered grades equivalent to Specification A217/A217M grades may be found in both Specifications A352/A352M and A487/A487M.NOTE 2: The grades covered by this specification represent materials that are generally suitable for assembly with other castings or wrought steel parts by fusion welding. It is not intended to imply that these grades possess equal degrees of weldability; therefore, it is the responsibility of the purchaser to establish for himself a suitable welding technique. Since these grades possess varying degrees of suitability for high-temperature and corrosion-resistant service, it is also the responsibility of the purchaser to determine which grade shall be furnished, due consideration being given to the requirements of the applicable construction codes.NOTE 3: The committee formulating this specification has included nine grades of materials that are considered to represent basic types of ferritic alloy steels suitable for valves, flanges, fittings, and other pressure-containing parts. Additional alloy steels that may better fulfill certain types of service will be considered for inclusion in this specification by the committee as the need becomes apparent.1.3 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.1.4 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.