ISO 7-1:1994 pdf download.Pipe threads where pressure-tight joints are made on the threads
1 Scope
This part of ISO 7 specifies the requirements for thread form, dimensions, tolerances and designation for jointing pipe threads, sizes 1116 to 6 inclusive, for joints made pressure-tight by the mating of the threads. These threads are taper external, parallel internal or taper internal and are intended for use with pipes suitable for threading and for valves, fittings or other pipeline equipment interconnected by threaded joints.
An appropriate jointing medium should be used on the thread to ensure pressure-tight joints.
NOTES
1 Parallel external pipe threads are not suitable as jointing
threads.
2 For pipe threads where pressure-tight joints are not
made on the threads, see ISO 228-1.
3 ISO 7-2 gives details of methods of verification of jointing thread dimensions and form and recommended gauging systems.
2 Normative reference
The following standard contains provisions which, through reference in this text, constitute provisions of this part of ISO 7. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this part of ISO 7 are encouraged to investigate the possibility of applying the most recent edilion of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
ISO 7-2:1982.Pipe threads where pressure-tight joints are made on the threads - Part 2: Verification by means of limit gauges.
3.3 gauge plane: Plane, perpendicular to the axis of the taper thread, at which the major cone has the gauge diameter.
NOTE 4 For external threads the gauge plane is located at a distance equal to the nominal gauge length from the small end of the thread. For internal threads the gauge plane is located at a distance of half-pitch behind the face of the threaded part. This is in order to give consideration to the start of the thread that has been removed by chamfering.
3.4 gauge length: On an external thread, the dis-tance from the gauge plane to the small end of the thread.
7.1.1 Parallel thread
The basic form of the parallel pipe thread shall be as shown in figure1. The angle between the flanks,measured in an axial plane section, is 55°. The thread profiles are rounded equally at crests and roots by circular arcs blending tangentially with the flanks.
7.1.2 Taper thread
The basic form of the taper pipe thread shall be as shown in figure2. The taper is 1 to 16, measured on the diameter. The angle between the flanks, meas-ured in an axial plane section, is 55°，the flanks making equal angles with the axis.ISO 7-1 pdf download.