ISO 7-2:2000 ねじ山に耐圧継手が作られているパイプねじ山—パート2：限界ゲージによる検証 | ページ 2

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, 3.

Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this part of ISO 7 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

International Standard ISO 7-2 was prepared by Technical Committee ISO/TC 5, Ferrous metal pipes and metallic fittings, Subcommittee SC 5, Threaded or plain end butt-welding fittings, gauging of threads.

This second edition cancels and replaces the first edition (ISO 7-2:1982), which has been technically revised.

ISO 7 consists of the following parts, under the general title Pipe threads where pressure-tight joints are made on the threads:

• Part 1: Dimensions, tolerances and designation
• Part 2: Verification by means of limit gauges

Annex A forms a normative part of this part of ISO 7.

Introduction

This revision of ISO 7-2 has been undertaken with the aim of providing a unified gauging system which could be adopted worldwide and thus eliminate the differing gauging results obtained with the use of gauges in accordance with ISO 7-2:1982 and existing national practices. This revision also includes details of plain ring gauges to provide additional means of checking ISO 7-1 external threads and a parallel modified thread form check ring gauge for checking taper full form threaded plug gauges.

1 Scope

This part of ISO 7 specifies a process using limit gauges, for the validation of taper internal and external threads and parallel internal threads on piping systems components and other products, the dimensions and tolerances of which are detailed in ISO 7-1.

The gauging system described may not be suitable, without special precautions, for gauging of threads on injection moulded plastic workpieces.

This part of ISO 7 does not cover completely all the requirements necessary for full control of thread quality and dimensions. Additional control of tools and equipment and visual inspection during production are required to ensure complete compliance with ISO 7-1, for example the length of useful thread on internally threaded workpieces should be checked by direct measurement.

Annex A gives a summary of the gauges included in this part of ISO 7, together with details of the thread elements controlled by each gauge and gauge identification numbers.

In the event of a dispute over compliance with the requirements of ISO 7-1, the gauges in this part of ISO 7 are to be considered as decisive for the thread elements which they control on the workpiece.

2 Normative reference

The following normative document contains provisions which, through reference in this text, constitute provisions of this part of ISO 7. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 7 are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.

3 Terms and definitions

For the purposes of this part of ISO 7, the terms and definitions given in ISO 7-1 and the following apply.