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2000#, 3000#, 6000#, 9000#
Threaded and socket weld
All sizes of swages, nipples and outlets available
Chrome moly, ferritic alloy, creep and heat resistant
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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, MSS-SP-95, and MSS-SP-97. These fittings are for use in pressure piping and in pressure vessel fabrication for service at moderate and elevated temperatures. The M in the designation stands for metric.
The starting material for fittings shall be fully killed steel, consisting of forgings, bars, plates, sheet, and seamless or fusion-welded tubular products with filler metal added and shall conform to the chemical requirements. Unless otherwise specified for carbon steel plates and sheet, the steel may be made to either coarse grain or fine grain practice. Grade WP9 shall be made to fine grain practice.
NOTE 1: All requirements are maximum unless otherwise indicated.
NOTE 2: Where an ellipsis (...) appears in this table, there is no requirement and analysis for the element need not be determined or reported.
|WPB B, C , D ,E , F||0.30 max||0.29–1.06||0.050||0.058||0.10 min||0.40 max||0.15 max||0.40 max||0.40 max||Vanadium 0.08 max|
|WPC C , D ,E , F||0.35 max||0.29–1.06||0.050||0.058||0.10 min||0.40 max||0.15 max||0.40 max||0.40 max||Vanadium 0.08 max|
|0.15 max||0.30–0.60||0.040||0.030||0.50 max||4.0–6.0||0.44–0.65||...||...||...|
|0.15 max||0.30–0.60||0.030||0.030||1.00 max||8.0–10.0||0.90–1.10||...||...||...|
Aluminum 0.02 maxG
Titanium 0.01 maxG
Zirconium 0.01 maxG
(A) When fittings are of welded construction, the grade and marking symbol shown above shall be supplemented by letter “W”.
(B) Fittings made from bar or plate may have 0.35 max carbon.
(C) Fittings made from forgings may have 0.35 max carbon and 0.35 max silicon with no minimum.
(D) For each reduction of 0.01 % below the specified carbon maximum, an increase of 0.06 % manganese above the specified maximum will be permitted, up to a maximum of 1.65 %.
(E) The sum of Copper, Nickel, Chromium, and Molybdenum shall not exceed 1.00 %.
(F) Applies both to heat and product analyses.
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 NPS-4 and under may be machined from hot-forged or rolled, cold-sized, and straightened bar stock having the chemical composition of the Grade in the Chemical Requirements above & the mechanical properties of the Grade in the Tensile Requirements.
NOTE 1: Where an ellipsis (...) appears in this table, there is no requirement.
|Tensile strength, minimum unless a range is given ksi [MPa]||60 ||70 ||
|75 ||85 ||90 ||
Yield strength, min, ksi [MPa]
(0.2 % offset or 0.5 % extension-under-load)
|35 ||40 ||30 ||30 ||46 ||45 ||60 ||60 ||64 ||32 |
All Grades except WPR,
WP91, and WP911
|WPR and WP24||
|Standard round specimen, or small proportional specimen, min % in 4 D||22||14||20||...||20||13|
|Rectangular specimen for wall thickness 5/16 in. [7.94 mm] and over, and for all small sizes tested in full section; min % in 2 in. [50 mm]||30||20A||28||...||...||...|
|Rectangular specimen for wall thickness less than 5/16 ;in. [7.94 mm]; min % in 2 in. [50 mm] (1/2-in. [12.7-mm] wide specimen)||B||B||B||...||...||...|
(A) WPB and WPC fittings manufactured from plate shall have a minimum elongation of 17 %.
(B) For each 1/32 in. [0.79 mm] decrease in wall thickness below 5/16 in. [7.94 mm], a deduction of 1.5 % for longitudinal and 1.0 % for transverse from the values shown above is permitted. The following table gives the minimum value for various wall thicknesses.
|All Grades except WPR, WP91 and WP911||WPR||WP91, WP92, and WP911|
|7/32||-0.219||5.56||25.5||. . .||23.5||17|
|3/16||-0.188||4.76||24||. . .||22||16|
|5/32||-0.156||3.97||22.5||. . .||20.5||15|
|1/8||-0.125||3.17||21||. . .||19||14|
|3/32||-0.094||2.38||19.5||. . .||17.5||13|
|1/16||-0.062||1.59||18||. . .||16||12|
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 chemical composition of each cast or heat used shall be determined and shall conform to the requirements of the chemical composition for the respective materials listed in the Chemical Requirements. The ranges as shown have been expanded to include variations of the chemical analysis requirements that are listed in the various specifications for the starting materials (pipe, tube, plate, bar, and forgings) normally used in the manufacturing of fittings to this specification.
Butt-welding fittings and butt-welding short radius elbows and returns purchased in accordance with this specification shall conform to the dimensions and tolerances given in the latest revision of ASME B16.9. Steel socket-welding and threaded fittings purchased in accordance with this specification shall conform to the sizes, shapes, dimensions, and tolerances specified in the latest revision of ASME B16.11, MSS-SP-79, or MSS-SP-83. Swage (d) Nipples, Bull Plugs, and Integrally Reinforced Forged Branch Outlet Fittings purchased in accordance with this specification shall conform to the sizes, shapes, dimensions, and tolerances specified in the latest revision of MSS-SP-95 or MSS-SP-97.
All fittings shall have the prescribed information stamped or otherwise suitably marked on each fitting in accordance with the Standard Marking System for Valves, Fittings, Flanges and Unions (MSS-SP-25, latest edition).
The prescribed information for butt-welding fittings shall be: The manufacturer's name or trademark, schedule number or nominal wall thickness designation, size, fitting designation and the heat number or manufacturer's heat identification.
Fitting Designation for Marking Purposes
|WPB||W (Welded construction)||WPBWA|
|S (Seamless construction)||WPB|
|WPC||W (Welded construction)||WPCWA|
|S (Seamless construction)||WPC|
|WP1||W (Welded construction)||WP1WA|
|S (Seamless construction)||WP1|
|WP12||CL1||W (Welded construction)||WP12 CL1WA|
|S (Seamless construction)||WP12 CL1|
|CL2||W (Welded construction)||WP12 CL2WA|
|S (Seamless construction)||WP12 CL2|
|WP11||CL1||W (Welded construction)||WP11 CL1WA|
|S (Seamless construction)||WP11 CL1|
|CL2||W (Welded construction)||WP11 CL2WA|
|S (Seamless construction)||WP11 CL2|
|CL3||W (Welded construction)||WP11 CL3WA|
|S (Seamless construction)||WP11 CL3|
|WP22||CL1||W (Welded construction)||WP22 CL1WA|
|S (Seamless construction)||WP22 CL1|
|CL3||W (Welded construction)||WP22 CL3WA|
|S (Seamless construction)||WP22 CL3|
|WP5||CL1||W (Welded construction)||WP5 CL1WA|
|S (Seamless construction)||WP5 CL1|
|CL3||W (Welded construction)||WP5 CL3 WA|
|S (Seamless construction)||WP5 CL3|
|WP9||CL1||W (Welded construction)||WP9 CL1 WA|
|S (Seamless construction)||WP9 CL1|
|CL3||W (Welded construction)||WP9 CL3 WA|
|S (Seamless construction)||WP9 CL3|
|WPR||W (Welded construction)||WPR WA|
|S (Seamless construction)||WPR|
|WP91||W (Welded construction)||WP91WA|
|S (Seamless construction)||WP91|
(A) Add “U” to marking if welds are ultrasonic inspected in lieu of radiography.
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