ASME B16.51-2018 pdf free download.Copper and Copper Alloy Press-Connect Pressure Fittings
9.2 Out-of-Roundness of Fitting End (P or FTG) Maximum out-of-roundness ofthe press-connectfitting ends, dimensions A and F, shall not exceed 1% of the maximum corresponding diameters shown in Table 9.1-1. The average of the maximum and minimum diameters shall be within the dimensions shown in Table 9.1-1.
9.3 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 9.1-1. The out-of-roundness condition of the cross-sectional area shall not exceed 10% of the minimum diameter shown in Table 9.1-1. For reducer or adapter fittings, the smallest end diameter shall apply, provided that this diameter does not restrict the other outlets.
9.4 Wall Thickness Theminimumwallthicknesstakenatanylocationofthe fitting shall not be less than shown in Table 9.1-1.
10 THREADED ENDS The threaded ends shall have right-hand nominal pipe taper (NPT) threads conforming to ASME B1.20.1.
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 of threads shall be measured to include the countersink or chamfer.
10.2 Threading Tolerances NPT threads shall be checked by use of a plug or ring gage 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 internal 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 of Press-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 9.1-1. Gage tolerances shall be Class ZM, as defined in ANSI B4.4M. 12.2 Optional Gaging Method of Press-Connect Pressure Fittings 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. 9.2.
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 practice to rap or tap the part to ensure proper seating of the gage. However, it is first necessary to clean both the gage and the productthreads to ensure thattheyare free ofchips, burrs, abra- sives, or other foreign materials. ASME B16.51 pdf download.ASME B16.51-2018 pdf free download
