Реферат

This specification covers steel castings, general requirements, for pressure-containing parts. The steel shall be made by open-hearth or electric-furnace process, with or without separate refining such as argon-oxygen-decarburization (AOD), unless otherwise designated by the individual specification. Ferritic and martensitic steel shall be cooled after pouring to provide substantially complete transformation of austenite prior to heat treatment to enhance mechanical properties. The material shall conform to the specified chemical composition requirements. An analysis of each heat shall be made by the manufacturer to determine the percentages of the elements specified. The mechanical test methods and definitions are presented in details. One tension test shall be made from each heat, and shall conform to the tensile requirements specified. Test coupons shall be cast from the same heat as the castings represented, except that for investment castings, the test coupons shall be cast in the same type of mold as the castings. After machining, each casting shall be tested under specified hydrostatic shell test pressures in the applicable steel rating for which the casting is designed.

Область применения

1.1 This specification covers a group of common requirements that, unless otherwise specified in an individual specification, shall apply to steel castings for pressure-containing parts under each of the following ASTM specifications:

Title of SpecificationASTM Designation Steel Castings, Carbon, Suitable for Fusion Welding,A 216/A 216M for High-Temperature Service Steel Castings, Martensitic Stainless and Alloy, forA 217/A 217M Pressure-Containing Parts, Suitable for High- Temperature Service Castings, Austenitic, Austenitic-Ferritic (Duplex),A 351/A 351M Pressure-Containing Parts Steel Castings, Ferritic and Martensitic, for Pressure-A 352/A 352M Containing Parts, Suitable for Low-Temperature Service Steel Castings, Alloy, Specially Heat-Treated, forA 389/A 389M Pressure-Containing Parts, Suitable for High- Temperature Service Steel Castings Suitable for Pressure ServiceA 487/A 487M Castings, Iron-Nickel-Chromium and Nickel Alloys, Specially Controlled for Pressure Retaining Parts for Corrosive ServiceA 990 Castings, Austenitic-Ferritic (Duplex) Stainless Steel, for Pressure-Containing PartsA 995/A 995M

1.2 This specification also covers a group of supplementary requirements which may be applied to the above specifications as indicated therein. These are provided for use when additional testing or inspection is desired and apply only when specified individually by the purchaser in the order.

1.3 In case of conflict between the requirements of the individual specification and this general specification, the former shall prevail.

1.4 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 non-conformance with the standard.