Abstract： ASME B16.4:2021 pdf download.Gray Iron Threaded Fittings Classes 125 and 250. (c) For the purpose of easier entrance in making a joint and for protection of the thread, all threads shall be countersunk a distance of not less than one-half t...

ASME B16.4:2021 pdf download.Gray Iron Threaded Fittings Classes 125 and 250.

(c) For the purpose of easier entrance in making a joint and for protection of the thread, all threads shall be

countersunk a distance of not less than one-half the pitch of the thread at an angle olapproximately 45 deg with

the axis of the thread. Countersinking shall be concentric with the threads.

(d) The length of the threads specified in all tables shall be measured to Include the counter sink.

The maximum allowable variation in the alignment of threads of all openings of threaded fittings shall be 5.0 mm/m (0.06 in./ft) (0.5% slope).

9 RIBS

(a) The addition of ribs or lugs is permitted on threaded fittings. Where ribs are used, it is recommended that

their thickness be the same as specified [or metal thickness 01 the fitting.

(b) Right-hand couplings shall have not more than two ribs.

(c) Right- and left-hand couplings shall have four or more ribs unless the left-hand opening is clearly marked, in which case the use of ribs Is at the discretion of the manufacturer.

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 B16.14.

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 Al 53/Al 53M or have an electrodeposited zinc coating conforming to ASTM B633, Type I, Service Condition 4. Hot-dipped coatings shall

have a minimum thickness of 0.0864 mm (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.

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