【国外标准】 Standard Specification for Heat-Treated Carbon Steel Fittings for Low-Temperature and Corrosive Service

This specification covers heat-treated wrought carbon steel piping fittings with lowered carbon content of seamless and electric fusion-welded construction for low-temperature and corrosive service applications. These fittings are for use in pressure components where inherent notch toughness and optimum sulfide-cracking resistance are required, such as oil and gas industry piping and distribution systems. The materials shall be manufactured by forging and shaping methods which involves hammering, pressing, piercing, extruding, upsetting, rolling, bending, fusion welding, machining, or by a combination of these operations. Fittings shall be heat treated by normalizing, quenching, and tempering or stress-relieving. Product analyses shall be performed wherein specimens shall conform to required chemical composition of carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, and copper. The fittings shall undergo tension and impact tests, and shall conform to the following mechanical requirements: yield strength, tensile strength, elongation, and notch toughness.1.1 This specification covers heat-treated wrought carbon steel piping fittings with lowered carbon content of seamless and electric fusion-welded construction covered by the latest revisions in ASME B16.9, ASME B16.11, MSS SP-75, MSS SP-79, MSS SP-83, MSS SP-95, or MSS SP-97. Fittings differing from these ASME and MSS standards shall be furnished in accordance with Supplementary Requirement S58 of Specification A960/A960M. These fittings are for use in pressure components where inherent notch toughness and optimum sulfide-cracking resistance are required, such as oil and gas industry piping and distribution systems.1.2 Optional supplementary requirements are provided for fittings when a greater degree of examination is desired. One or more of the supplementary requirements may be specified in the order.1.3 This specification does not cover cast-welding fittings or fittings machined from castings.1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. 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. Unless the other specifies the applicable “M” specification designation (SI units), the material shall be furnished to inch-pound units.1.5 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.