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The Membrane Domain

BESTWELD INCORPORATED
40 Robinson Street
Pottstown, PA 19464
 TEL (610) 718-9700   FAX (610) 718-9800
E-mail fittings@bestweld.com

BELLED END SOCKET WELDING FITTINGS,
STAINLESS STEEL AND COPPER NICKEL
1. SCOPE

1.1 GENERAL
This Standard covers 1/4 through 12 NPS stainless steel and copper-nickel belled end socket welding fittings including dimensions, tolerances, materials, socket end preparation for welding, heat treating and market requirements for use with the following pipe standards.

  1. ANSI/ASME B36.19 (Sch 5S and IOS)
  2. ASTM B466
  3. ASTM B467
  4. MIL-T-16420 (C1 50 and C1 200 pipe)
2. SPECIAL CONSIDERATIONS

2.1 PARTIAL COMPLIANCE FITTINGS
Fittings may be made to special dimensions, sizes, shapes, tolerances, or of wrought materials other than those covered by this Standard Practice by agreement between the manufacturer and the purchaser. When such fittings meet all other stipulations of this Standard Practice, they shau be considered as being in partial compliance therewith, provided as they are appropriately marked.

2.2 FABRICATED FITTINGS
Fabricated laterals and fittingss employing intersecting welds are considered pipe fabrications and shall be manufactured in accordance with ANSI/ASME B31, Code for Pressure Piping.

3. DEFINITIONS

4. PRESSURE RATINGS

The allowable pressure ratings for fittings designed in accordance with this Standard Practice may be calculated as for straight seamless pipe in accordance with the rules established in the applicable sections of ANSI/ASME B31, Code for Pressure Piping. The pipe wall thickness and material type shall be that with which the fittings have been ordered to be used; their identity on the fittings is in lieu of pressure rating markings. The pipe fitting manufacturer certifies that his pipe fitting complies with this Standard Practice when his name or trademark is marked on the body of the fitting.

5. PROOF TESTING

5.1 PROOF OF FITTING DESIGN
The design of fittings may be established by mathematical analyses contained in nationally recognized pressure vessel or piping codes or, at the manufacturer's option, by design proof testing in accordance with applicable section herein. The design of fittings that cannot be qualified by such analyses shall be established by design proof testing.

5.2 Proof of Fitting Manufacturing Process
The validity of each tee and elbow manufacturing process must be periodically re-established by pressure proof testing. Each manufacturer shall perform a hydrostatic pressure proof test on the largest representative tee and elbow of each manufacturing process. As an example: A manufacturer intends to supply elbows in sizes 3 NPS to 12 NPS: and those 3 NPS to 6 NPS are seamless and those 8 NPS to 12 NPS are welded formed pieces. That vendor must test one 6 NPS and one 12 NPS elbow. This qualification will allow the vendor to fabricate a 6 NPS elbow but will not allow the vendor to make a seamless 8 NPS elbow without further tests. Retesting will be required for a change in manufacturing process, a change in corporate ownership, a change in factory location, a lapse of 5 years or a change in basic materials or a change in alloys sufficient to require a different heat treatment for annealing. Tests shall be conducted and certified by an independent laboratory and the results kept on file by the fitting manufacturer. Straight pieces of pipe shall be welded on to the other end of each fitting and these pieces shall be capped. The pipe pieces shall be no shorter than twice the pipe outside diameter. The pipe shall have the same rating as the fitting. Hydrostatic pressure shall be applied until the fitting ruptures. The test pressure prior to rupture shall be at least equal to the minimum manufacturing proof pressure defined as follows:

P(min) = 2St/D, where:
"S" is the minimum specified material tensile strength,
"I" is the minimum allowable pipe wall thickness. and
"D" is the nominal pipe diameter.

6. SIZE

The sizes of fittings, excepting only short radius elbows and thermometer well tees shall be from 1/4 NPS through 12 NPS. Short radius elbows shall be from 1 NPS through 12 NPS. Thermometer well tees shall have a body size of no larger than 2 NPS.

As an initiative to reduce the numbers of combinations of reducing tees, the following sizing format is established:

7. MATERIALS

Stainless steel fittings except caps shall be made from stainless steel pipe, ASTM Designation A 312, of a material grade listed in Table 1 therein or from stainless steel sheet to ASTM Designation A 240. Caps, all sizes, shall be made from stainless steel sheet to ASTM Designation A 240.

Copper nickel fittings except caps shall be made from copper nickel pipe, either Military Specification MIL-T-16420, Type I (seamless), of a material composition allowed by paragraph 1.2 therein or ASTM Designation B 466 or B 467 of an alloy listed in Table I therein or from copper nickel sheet to either MIL-C-15726 or ASTM Designation B 122. Caps, all sizes, shall be made from copper nickel sheet to either MIL-C-15726 or ASTM Designation B 122.

8. FORMING AND FABRICATING

Whenever practicable, fittings shall be formed in one piece from pipe or sheet. Fittings may be fabricated from ASME/ANSI B 16.9 wrought fittings on to which a tangent end has been welded. The length of the tangent end shall be equal to the socket depth plus the transition length. The tangent end may be belled either before or after attachment.

Thermometer well tees utilizing extruded branch connections shall be fabricated in accordance with ASME B31.1 requirements for extruded outlets, integrally reinforced. The radius of curvature of the external contoured portion of the branch outlet measured in the plane containing the axes of the run and the branch shall not be less than 0.05 times the outside diameter of the branch. The nominal pipe size of the bodies of these fittings shall not exceed 2 NPS.

Fittings fabricated from mirror image halves which are longitudinally welded shall have the interior and exterior crowns of the longitudinal welds ground flush for a distance of the socket and the transition prior to the belling operation in order that the socket wall will expand uniformly.

The following requirements pertain to all fitting fabrication welds:

Each fitting shall be heat treated after completion irrespective of forming or fabrication process. Hydrostatic testing is not required. All fittings shall be capable of withstanding a hydrostatic test pressure of the pipe with which they identify without leakage and without impairing their serviceability.

9. FITTING DIMENSIONS

Dimensions for fittings and sockets are given in Tables 2 through 13.

10. TOLERANCES

Dimensional tolerances are given in Table 1.
Distances shown in the fitting sketches from the center of fittings to a pipe piece are pipe fabrication assembly design dimensions, thus are not assigned fitting manufacturing tolerances.
Squareness, vis., off angle and off plane, tolerances are the same values and are as follows:

NPS range
1/4 to 1 1/2
2 to 6
8 to 12		 VIZ Tolerance, inches
1/16
1/8
3/16
11. SOCKET FACE FILLET WELDING PREPARATIONS

The socket end face shall be flat and of a height no less than the minimum wall thickness for the pipe with which the fitting identifies. The socket end face serves as a guide for fillet weld height.

The choice of materials and/or the forrning process may produce a heavy socket wall thickness. When the socket wall thickness will result in a weld height of more than 150% of the minimum, a 15 degree chamfer shall be made on the OD of the socket wall to reduce the weld preparation height to within limits.

12. JOINT FILLET WELD

The height of the joint fillet weld shall equal the fitting socket face height and shall extend 1.75 times that distance along the length of the pipe. The slope of the weld face when measured from the horizontal (pipe sur- face) shall not exceed 30 degrees.

13. FINISH

Fittings supplied under this Standard Practice shall be examined visually. Surface discontinuities shall be explored for depth. Surface discontinuities deeper than 5% of the minimum wall thickness or surface checks (fish scale) deeper than 1/64 inch (0.4 mm) or mechanical marks deeper than 1/16 inch (1.6 mm) shall be removed by machining or grinding to sound metal and the repaired areas shall be well faired. The welding repair of cracks or of any surface discontinuities is not allowable. The reconstitution of minimum wall thickness by welding is not allowable. The removal of a weid discontinuity and re-welding is part of the welding process and is allowable if done before final heat treatment. Dents may be re-formed. When the removal of a surface discontinuity reduces the wall thickness below the minimum wall limits, the fitting shall be rejected.

Surfaces shall be free of black oxide and have roughness values not exceeding 125 RMS.

14. HEAT TREATMENT

All welding must be done prior to the final heat treatment.
Stainless steel fittings: All fittings shall be fumished in the heat-treated condition. The heat-treat procedure, except for those grades listed below, shall consist of solution annealing the fittings at a minimum temperature of 1900 degrees F (1040 degrees C) until the chromium carbides go into solution, and then cooling at a sufficient rate to prevent re-precipitation. Grades 321H, 347H and 348H shall be solution annealed at 1925 degrees F (1050 degrees C minimum). S31254 shall be solution annealed at 2100 degrees F (1150 degrees C) minimum. S33228 shall be solution annealed at 2050 degrees F (1120 degrees C) minimum. S34565 shall be solution annealed in the range of 2050 degrees F (1120 delrees C) to 2140 degrees F (1170 degrees C). The maximum temperature for solution annealing grades 321, 321H, 347 and 347H shall be 2100 degrees F (1150 degrees C).

Copper nickel fittings: All fittin2s shall be furnished in the fully annealed condition. Annealing, shall be performed at 1300 +/- 50 F per hour per inch of thickness. Cooling shall be effected in still air.

Annealing shall not reduce the material below minimum mechanical strength requirements.

15. MARKING

All fittings shall be permanently marked by electro-etch or engraving pencil. The electrolyte shall not contain harmful amounts of chlorides, metals or metallic salts, such as zinc or copper, that would cause corrosive attack on heating. No metal impression stamps shall be used.

All fittings shall be marked with the prescribed information in accordance with MSS SP-25.

The prescribed information shall be as follows:

The Method of Manufacture shall be described by the following symbols:
  • WP-S indicates fittings formed from a seamless product using only seamless methods of manufacture.
  • WP-W indicates fittings formed from welded product using only seamless methods of manufacture or fittings forrned from a seamless product using only seamless methods of manufacture on to which seamless tangents for sockets are circumferentially welded or fittings fabricated from seamless product using only circumferential welds and those welds proven crack free by dye penetrant test.
  • WP-WX indicates fittings formed and fabricated from either seamless or welded product using either seamless or welded methods of manufacture in which all welds have been radiographically examined throughout their entire length in accordance with Appendix 12 of Section VIII, Division I of the ASME Boiler and Pressure Vessel Code.
  • WP-WU indicates fittings formed and fabricated from either seamless or welded product using either seamless or welded methods of manufacture in which all welds have been ultrasonically examined throughout their entire length in accordance with Appendix 12 of Section VIII, Division I of the ASME Boiler and Pressure Vessel Code.
  • -PC used as a suffix to the foregoing notation shall be used to denote partial compliance fittings.
The following are examples of fitting markings:

    (A stainless steel fitting)  	(A copper nickel fitting)
    Manufacturer                 	Manufacturer
    6 NPS SIO                    	6 NPS Class 200
    WP 304L-W                    	WP 90/1 O-S CU-N]
    MSS-SP-TBD                   	MSS-SP-TBD
    MFR-PROD #                   	MFR. PROD #
    07/04/95                     	07/04/95

In those cases where the size of the fitting will not pennit the complete marking, the size of the marking may be reduced. If complete marking is not possible, then lines of identification may be omitted in the following order.

Stainless steel fittings meeting the chemical and mechanical property requirements of Tables 1 and 2 of ASTM Designation A312 for more than one class or gtade may be marked with more than one class or grade designation, such as WP304/304L or WP304/304L/304N or WP304/304H, etc.

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