ISO/TR 12391-4:2002 ガスボンベ — 詰め替え可能なシームレス鋼 — 性能試験 — Part 4: 欠陥のあるボンベサイクル試験 | 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, 2.

The main task of technical committees is to prepare International Standards. 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.

In exceptional circumstances, when a technical committee has collected data of a different kind from that which is normally published as an International Standard (“state of the art”, for example), it may decide by a simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely informative in nature and does not have to be reviewed until the data it provides are considered to be no longer valid or useful.

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

ISO/TR 12391-4 was prepared by Technical Committee ISO/TC 58, Gas cylinders, Subcommittee SC 3, Cylinder design.

ISO/TR 12391 consists of the following parts, under the general title Gas cylinders — Refillable seamless steel — Performance tests:

• Part 1: Philosophy, background and conclusions
• Part 2: Fracture performance tests — Monotonic burst tests
• Part 3: Fracture performance tests — Cyclical burst tests
• Part 4: Flawed-cylinder cycle test

Introduction

Gas cylinders as specified in ISO 9809-1 have been constructed of steel with a maximum tensile strength of less than 1 100 MPa. With the technical changes in steel-making using a two-stage process, referred to as ladle metallurgy or secondary refining, significant improvement in mechanical properties have been achieved. These improved mechanical properties provide the opportunity of producing gas cylinders with higher tensile strength, which achieve a lower ratio of steel to gas weight. The major concern in using steels of higher tensile strength with correspondingly higher design wall stress is safety throughout the life of the gas cylinder.

When ISO/TC 58/SC 3 began drafting ISO 9809-2, Working Group 14 was formed to study the need for additional controls for the manufacture of steel gas cylinders having a tensile strength greater than 1 100 MPa.

This part of ISO/TR 12391 presents all of the specific test results of the flawed-cylinder cycle tests that were conducted to evaluate the fatigue performance of cylinders ranging in tensile strength from less 800 MPa to greater than 1 350 MPa.

1 Scope

This part of ISO/TR 12391 applies to seamless steel refillable cylinders of all sizes from 0,5 l up to and including 150 l water capacity produced of steel with tensile strength, R_m, greater than 1 100 MPa.

It can also be applied to cylinders produced from steels used at lower tensile strengths. In particular, it provides the technical rationale and background to guide future alterations of existing ISO standards or for developing advanced design standards.

This part of ISO/TR 12391 is a summary and compilation of the test results obtained during the development of the"flawed-cylinder cycle test". The"flawed-cylinder cycle test" was developed as part of a co-operative project under the direction of ISO/TC 58/SC 3/WG 14. The"flawed-cylinder cycle test" is a test method to evaluate the fatigue performance of steel cylinders that are used to transport high pressure, compressed gases.

The concept and development of the flawed-cylinder cycle test is described in ISO/TR 12391-1. The details of the test method and the criteria for acceptable fatigue performance of steel cylinders are given in 9.2.6 of ISO 9809-2:2000,"flawed-cylinder cycle test". In this part of ISO/TR 12391, test results are reported for more than a hundred flawed-cylinder cycle tests that were conducted on seamless steel cylinders ranging in measured tensile strength from less than 800 MPa to greater than 1 350 MPa. The test method is intended to be used for the selection of materials and design parameters in the development of new cylinder designs.

2 References

3 Terms and definitions