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ASTM A350

Standard Specification for Carbon and Low-Alloy Steel Forgings, Requiring Notch Toughness Testing for Piping Components

This specification covers several grades of carbon and low alloy steel forged or ring-rolled flanges, forged fittings and Valves for low-temperature service. The steel specimens shall be melt processed using open-hearth, basic oxygen, electric furnace or vacuum-induction melting. A sufficient discard shall be made to secure freedom from injurious piping and undue segregation. The materials shall be forged and shall undergo heat treatment such as normalizing, tempering, quenching and precipitation heat treatment. Heat analysis and product analysis shall be performed wherein the steel materials shall conform to the required chemical compositions of carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, copper, columbium, vanadium, and nitrogen. The materials shall also undergo tension tests and shall conform to the required values of tensile strength, yield strength and elongation. Impact tests shall also be performed and the steel materials shall conform to the required values of minimum impact energy, temperature, and minimum equivalent absorbed energy. Hardness and hydrostatic tests shall also be performed.
1. Scope
1.1 This specification covers several grades of carbon and low-alloy steel forged or ring-rolled flanges, forged fittings and Valves intended primarily for low-temperature service and requiring notch toughness testing. They are made to specified dimensions, or to dimensional standards, such as the ASME and API Specifications referenced in Section . Although this specification covers some piping components machined from rolled bar and seamless tubular materials (see ), it does not cover raw material produced in these product forms.
1.2 No limitation on size is intended beyond the ability of the manufacturer to obtain the specified requirements. However, Class 3 of Grade LF787 is only available in the quenched-and-precipitation heat treated condition.
1.3 Supplementary requirements are provided for use when additional testing or inspection is desired. These shall apply only when specified by the purchaser in the order.
1.4 This specification is expressed in both inch-pound units and in SI units. However, unless the order specifies the applicable "M" specification designation (SI units), the material shall be furnished to inch-pound units.
1.5 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. Note 1Refer to Test Methods and Definitions A 370 for notes on significance of notched-bar impact testing.

2. Referenced Documents
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A788/A788M Specification for Steel Forgings, General Requirements
A961/A961M Specification for Common Requirements for Steel Flanges, Forged Fittings, Valves, and Parts for Piping Applications
600 Steel Gate Valves with Flanged or Butt-Welding Ends
602 Compact Design Carbon Steel Gate Valves for Refinery Use
605 Large Diameter Carbon Steel Flanges
A5.1 Mild Steel Covered Arc-Welding Electrodes
A5.5 Low-Alloy Steel Covered Arc-Welding Electrodes
B16.10 Face-to-Face and End-to-End Dimensions of Ferrous Valves
B16.11 Forged Steel Fittings, Socket Welding and Threaded
B16.30 Unfired Pressure Vessel Flange Dimensions
B16.34 Valves-Flanged, Threaded, and Welding End
B16.47 Large Diameter Steel Flanges
B16.5 Steel Pipe Flanges and Flanged Fittings
B16.9 Factory-Made Wrought Steel Butt-Welding Fittings
Section IX Welding Qualifications

Reference: ASTM

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