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ASME B16.50-2018 pdf download

ASME B16.50-2018 pdf download.Wrought Copper and Copper Alloy Braze-Joint Pressure Fittings.
5 MARKING Each fitting shall be permanently marked with the manufacturer’s name or trademark in accordance with MSS SP-25 and the letters “BZ” in uppercase. Marking on fittings less than size 1 ∕ 2 or on any fitting where it would damage the brazing surfaces is not required. 6 ð18Þ MATERIAL (a) FittingsshallbemadefromcopperUNSNo.C10200, C12000, or C12200 or copper alloy UNS No. C23000, for which allowable stresses are found in ASME B31.1, ASME B31.9,orASMEBoilerandPressureVesselCode,SectionII, Part D. (b) Other coppers and copper alloys are permitted, provided (1) they meet the chemical requirements of 84% minimum copper and 16% maximum zinc (2) the fittings produced from the copper alloy meet all the mechanical and corrosion-resistant properties for the end purposes of the fittings Thecompositionofthecopperalloys shallcontainnothing that will inhibit joining to the tube or to other fittings. 7 LAYING LENGTHS Due to widely varying manufacturing processes, mean- ingful laying length requirements of fittings cannot be established. Consult the manufacturer for these dimensions. 8 TUBE STOPS Except for repair couplings, fittings shall be manufac- turedwithatubestop. Repaircouplings shallnotrequirea tube stop. The tube stop shall control joint length, even with an external (FTG) end having the minimum outside diameter shown in Table 3.1-1. Examples ofvarious tube stop configurations are shown in Figure 8-1. 9 INSPECTION TOLERANCE 9.1 Convention For determining conformance with this Standard, the convention for fixing significant digits where limits (maximum and minimum values) are specified shall be as defined in ASTM E29. This requires that an observed orcalculatedvalueberoundedofftothenearestunitinthe last right-hand digit used for expressing the limit. Decimal values and tolerances do notimplya particular method of measurement. 9.2 Linear Dimensions An inspection tolerance, as shown in Table 9.2-1, shall be allowed on center-to-shoulder, center-to-center, center-to-threaded-end, and shoulder-to-threaded-end dimensions on all fittings having internal (C) braze ends, as well as on center-to-braze-end and braze-end- to-threaded-enddimensionsonallfittingshavingexternal (FTG) braze ends. Couplinginspection limits forshoulder- to-shoulder and shoulder-to-end dimensions shall be double those shown in Table 9.2-1, except that the minus tolerance applied to dimension L (Figure 4.1-1) shall not result in a dimension less than 1.5 mm (0.06 in.). The largest opening in the fitting shall govern the tolerance to be applied to all openings. 9.3 Ovality of Fitting End (C or FTG) Maximum ovality ofthe fitting braze-jointend shall not exceed1% ofthemaximumdiameters showninTable 3.1- 1. The average ofthe maximum and minimum diameters shall be within the dimensions shown in the table. 9.4 Inside Diameter of Fitting The minimum cross-sectional area of the inside diameter through the fitting body shall not be less than the theoretical minimum area defined by diameter O in Table 3.1-1. The out-of-roundness condition of the cross-sectional area shall not exceed the value shown in Table 3.1-1. For reducer or adapter fittings, the smallest end diameter shall apply, provided that this diameter does not restrict the other outlets. 9.5 Wall Thickness The minimum wall thickness shall not be less than shown in Table 3.1-1. 10 THREADED ENDS Fittingthreads shall be right-hand, conformingto ASME B1.20.1. They shall be taper threads (NPT). 10.1 Countersink or Chamfer All internal threads shall be countersunk a distance no less than one-half the pitch of the thread, at an angle of approximately 45 deg with the axis of the thread. All external threads shall be chamfered at an angle of 30 deg to 45 deg from the axis. Countersinking and cham- fering shall be concentric with the threads. The length ofthreads shall be measured to include the countersink or chamfer.
10.2 Threading Tolerances Tapered pipe threads (NPT) shall be checked by use of plug or ring gages in either standard or limit types. When gaging internal taper threads, the plug gage shall be screwed hand-tight into the fitting. The reference point for gaging internal product threads depends on the chamfer diameter. When the internal chamfer diameter exceeds the major diameter of the internal thread, the reference point shall be the last thread scratch on the chamfer cone. Otherwise, when the internal chamfer diameter does not exceed the major diameter of the internal thread, the reference point shall be the end of the fitting. In gaging external taper threads, the ring gage shall be screwed hand-tight on the external thread. On the external thread, the ring gage shall be flush with the end of the thread. Tolerance for an internally threaded end having an internal shoulder shall be from the gage reference point(notch) to oneturnsmall. Toleranceforaninternally threaded end without a shoulder, and for an externally threaded end, shall be from one turn small to one turn large. 10.3 Design of Threaded Ends The wrenchingsection ofinternallythreaded ends shall be polygonal, and the wrenching section of externally threaded ends shall be furnished with either polygon or flats, at the manufacturer’s option. 11 ALIGNMENT The maximum allowable deviation in the angular align- mentofanyendfromthespecifiedaxis positionshall be 1 ∕ 2 deg (1 deg total) (see Figure 11-1). 12 GAGING 12.1 Preferred Gaging Method ofBraze-Joint Ends Thepreferredmethodofgagingthediametertolerances for external and internal ends shall be by the use ofplain plug and ring gages designed to hold the product within the limits established in Table 3.1-1. Gage tolerances shall be Class ZM, as defined in ANSI B4.4M. 12.2 Optional Gaging Method of Braze-Joint Ends For gaging the diameter tolerance of external and internal ends, the use of direct reading instruments instead of ring and plug gages as specified in para. 12.1 shall be permitted. When gaging the diameters of external and internal ends using direct reading instru- ments, refer to para. 9.3. 12.3 Standard Gaging Method of Threaded Ends The standard method of gaging the externally and internally threaded ends shall be in accordance with the requirements of ASME B1.20.1. NOTE: In gagingpipe threads, itis acceptable and common prac- tice to rap or tap the part to ensure proper seating of the gage. However, itis firstnecessary to clean both the gage and product threads to ensure that they are free ofchips, burrs, abrasives, or other foreign materials.

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