ASME B16.4:2021 pdf free download

ASME B16.4:2021 pdf free download.Gray lron Threaded Fittings Classes 125 and 250.
7.2.2 The transition m wall thickness from one end size to another shall be in a manner that minimizes the addidon of stress caused by sudden changes in direction or wall thickness.
7.2.3 Proof of design shall be venlied by a hydrostatic pressure test made at ambient temperature in which pressure is applied continuously for no less th.in 1 mm and at no less than 5 times the pressure rating of the Largest size of end connection in the reducing fitting. Testing is considered successful only when no evidence of cracking. fracturing, or leakage is exhibited after holding for at least the minimum time at or above the required pressure.
7.3 ToLerances
The following tolerances shall be permitted:
frJ Metal Thickness Tolerances. At no point In the castrngs shall the metal thickness be less than 90% of the value given In Table 7.1-1, 7.1-4, or 7.1-5.
(b) Ce,ger-to-End Tolerances. Permitted tolerances on the center-to-end dimensions of the fittings are shown in Table 7.3-1. Tolerances for end-to-end dimensions and lengths of couplings and reducers shall be twice those given. The largest opening in a reducing fitting governs the tolerances to be applied to all openings. These tolerances do not apply to return bonds and caps.
8 THREADING
(a) All fittings shall be threaded according to ASME B 1.20.1. and the variations in threading shall be limited to one turn large or one turn small from the gaging notch on the plug when using working gages.
(bJ The reference point for gaging Internal fittings threads depends on the chamfer diameter. When the Inernal chamfer diameter exceeds the major diameter of the Internal thread, the reference point Is the last thread scratch on the chamfer cone. When the Internal chamfer diameter does not exceed the major diameter of the internal thread, the reference point is the end of the fitting (see Figure 8-1).
10 PLUGS, BUSHINGS, AND LOCKNUTS
For dimensions of plugs, bushings, and locknuts to be used in connection with Classes 125 and 250 gray iron threaded fittings, see ASME 816.14.
11 FACE BEVEL
A bevel not exceeding 5 deg is permitted on the faces of fitting openings. Center-to-end, end-to-end, and width-of- band dimensions may include or exclude the bevel.
12 COATINGS
When gray Iron fittings are zinc coated, they shall be hot dipped in accordance with ASTM A153/A1 53M or have an electrodeposited zinc coating conforming to ASTM 0633. Type I, Service Condition 4. Hot-thpped coatings shall have a minimum thickness of 0.0864mm (0.0034 in.) and shall be applied before threading. Electrodeposited zinc shall have a minimum thickness of 0.025 mm (0.001 in.) and may be applied either before or after threading.