ASTM A860 WPHY butt-welding fittings are wrought high-strength ferritic steel butt-welding fittings of seamless and electric-fusion welded construction. These fittings are for use in high-pressure gas and oil transmission and distribution systems, including pipelines, compressor stations, metering and regulating stations and mains. Six steel grades are specified according to its minimum yield strength: WPHY 42, WPHY 46, WPHY 52, WPHY 60, WPHY 65, WPHY 70. The term “WPHY” denotes “wrought pipe high yield”. The fittings shall be made by one or a combination of several hot- and cold- working operations in the factory. Proper heat treatments shall be done to achieve the high-yield requirements. ASTM A860 WPHY butt-welding fittings are designed to match API 5L pipes of various steel grades, as well as ASTM A694 forgings for high-pressure transmission service. “Butt welding” is the joining method by which the fittings are attached to the pipeline or piping.
ASTM A860 WPHY butt-welding fittings shall be manufactured in accordance with the dimensional requirements of ASME B16.9 and MSS SP 75: (1)Dimensional requirements for NPS 14 and smaller butt-welding fittings are provided in ASME B16.9; (2)Dimensional requirements for butt-welding fittings larger than NPS 14 through NPS 60 are provided in MSS SP 75; (3)Special custom-design fittings shall be furnished in accordance with supplementary requirements S58 of ASTM A960 (4)The wall thickness at all points shall be at least 93.5% of the specified nominal wall thickness. These butt-welding fittings include 90° & 45° elbows, 180° return bends, reducers (straight or reducing), tees (straight or reducing), cross (straight or reducing), and end caps. The application of WPHY grades of ASTM A860 butt-welding fittings in pressure piping are governed by ASME B31.3 Process Piping. The lower temperature limit and the higher temperature limit as specified by B31.3 are -50°F and 500°F, respectively.
|ASTM A860||Yield Strength|
min. MPa [ksi]
2", min. %
|WPHY 42||290 ||415-585|
|WPHY 46||315 ||435-605|
|WPHY 52||360 ||455-625|
|WPHY 60||415 ||515-690|
|WPHY 65||450 ||530-705|
|WPHY 70||485 ||550-725|
One set of Charpy V-notch impact tests shall be performed on three specimens sized of 10mm x 10mm at test temperature -50°F [-46°C]. If the fitting is made by an electric fusion welding process, both the base metal and the weld metal shall be tested respectively. The minimum average energy absorption of 3 specimens and the minimum energy absorption of each specimen shall be 40J and 34J, respectively.
The material for ASTM A860 butt welding fittings of all WPHY grades shall be fully killed fine-grain material made by a melting process that is intended to produce rounded, well dispersed, fine sulphide inclusions, that promote good notch toughness, assists in the resistance to hydrogen induced cracking, and for weldability for field welding. Starting materials shall consist of plate, sheet, forging, forging quality bar, seamless or fusion-welded tubular products with filler metal added. The fittings shall be manufactured by one or a combination of these forming operations such as hammering, pressing, upsetting, piercing, extruding, rolling, bending, fusion welding, and machining.
For large size EFW fittings made to ASTM A860, the welders, welding operators, and welding procedures shall be qualified under Section IX of ASME BPVC. Radiographic examination throughout the entire length of each weld shall be performed in accordance with Section V and Section VIII of ASME BPVC. ASTM A860 butt welding fittings of all WPHY grades, either seamless or electric fusion welded, shall be furnished in the heat-treated conditions. Usually the heat treatments applied are normalizing and tempering, or quenching and tempering.
The fittings shall be sandblasted internally and externally. Black coating, anti-rust oil coating, zinc-plated, or hot dipped galvanization is at buyer’s discretion. The butt-welding ends will be covered with plastic protection caps and the fittings will be packaged in sea-worthy firm plywood cases or pallets.