ASTM A234 / A234M

This specification covers wrought carbon steel and alloy steel fittings of seamless and welded construction. These fittings are for use in pressure piping and in pressure vessel fabrication for service at moderate and elevated temperatures. The material for fittings shall consist of killed steel, forgings, bars, plates, seamless or fusion-welded tubular products with filler metal added. Forging or shaping operations may be performed by hammering, pressing, piercing, extruding, upsetting, rolling, bending, fusion welding, machining, or by a combination of two or more of these operations. The forming procedure shall be so applied that it will not produce injurious imperfections in the fittings. Fittings, after forming at an elevated temperature, shall be cooled to a temperature below the critical range under suitable conditions to prevent injurious defects caused by too rapid cooling, but in no case more rapidly than the cooling rate in still air. The fittings shall be subjected to tension test, hardness test, and hydrostatic test.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

1. Scope

1.1 This specification covers wrought carbon steel and alloy steel fittings of seamless and welded construction covered by the latest revision of ASME B16.9, B16.11, MSS-SP-79, MSS-SP-83, and MSS-SP-95. These fittings are for use in pressure piping and in pressure vessel fabrication for service at moderate and elevated temperatures. Fittings differing from these ASME and MSS standards shall be furnished in accordance with Supplementary Requirement S58 of Specification A 960/A 960M.

1.2 Optional supplementary requirements are provided for fittings where a greater degree of examination is desired. When desired, one or more of these supplementary requirements may be specified in the order.

1.3 This specification does not cover cast welding fittings or fittings machined from castings. Cast steel welding fittings are governed by Specifications A 216/A 216M and A 217/A 217M.

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.

2. Referenced Documents

A216/A216M Specification for Steel Castings, Carbon, Suitable for Fusion Welding, for High-Temperature Service
A217/A217M Specification for Steel Castings, Martensitic Stainless and Alloy, for Pressure-Containing Parts, Suitable for High-Temperature Service
A960/A960M Specification for Common Requirements for Wrought Steel Piping Fittings
B16.11 Forged Steel Fittings, Socket Welding and Threaded
B16.9 Steel Butt-Welding Fittings
MSS-SP-25 Standard Marking System for Valves, Fittings, Flanges, and Unions
MSS-SP-79 Socket Welding Reducer Inserts
MSS-SP-83 Steel Pipe Unions, Socket-Welding and Threaded
MSS-SP-95 Swage(d) Nipples and Bull Plugs
Section IX Welding Qualifications
Section V Nondestructive Examination
Section VIII, Division 1, Pressure Vessels
SNT-TC-1A Recommended Practice for Nondestructive Testing Personnel Qualification and Certification

Index Terms

pipe fittings—steel; piping applications; pressure containing parts; pressure vessel service; temperature service applications—elevated; ICS Number Code 23.040.40; 23.040.40

Citing ASTM Standards

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