ISO/TR 12391-3:2002
(Main)Gas cylinders — Refillable seamless steel — Performance tests — Part 3: Fracture performance tests — Cyclical burst tests
Gas cylinders — Refillable seamless steel — Performance tests — Part 3: Fracture performance tests — Cyclical burst tests
ISO/TR 12391-3 applies to seamless refillable cylinders of all sizes from 0,5 l up to and including 150 l water capacity produced of steel with tensile strength 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. ISO/TR 12391-3 is a summary and compilation of the test results obtained during the development of the Flawed-cylinder Cyclical-burst Test. The test is an alternate test method to the flawed-cylinder burst test with monotonic pressurization and is used to evaluate the fracture performance of steel cylinders which are used to transport high-pressure compressed gases. In ISO/TR 12391-3 test results are reported for more than one hundred flawed-cylinder cyclical burst tests that were conducted on seamless steel cylinders that ranged in tensile strength from 750 MPa to 1 210 MPa. The test method is intended to be used both for the selection of materials and to establish design parameters in the development of new cylinders as well as for an efficient quality control test to be used during the production of cylinders.
Bouteilles à gaz — Rechargeables en acier sans soudure — Essais de performance — Partie 3: Essais de mode de rupture — Essais de rupture cyclique
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Standards Content (Sample)
TECHNICAL ISO/TR
REPORT 12391-3
First edition
2002-12-15
Gas cylinders — Refillable seamless
steel — Performance tests —
Part 3:
Fracture performance tests — Cyclical
burst tests
Bouteilles à gaz — Rechargeables en acier sans soudure — Essais de
performance —
Partie 3: Essais de mode de rupture — Essais de rupture cyclique
Reference number
©
ISO 2002
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ii © ISO 2002 — All rights reserved
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 References. 1
3 Symbols . 2
4 Background information . 2
5 Experimental test programme . 4
5.1 Types of cylinder tested. 4
5.2 Material properties tests. 5
5.3 Description of the flawed-cylinder cyclical burst test. 6
6 Flawed-cylinder cyclical burst test results. 8
6.1 Flawed-cylinder burst test procedure. 8
6.2 Flawed-cylinder cyclical burst test results for group B materials. 9
6.3 Flawed-cylinder cyclical burst test results for group C materials. 10
6.4 Flawed-cylinder cyclical burst test results for group D materials. 11
7 Discussion . 13
7.1 Background . 13
7.2 ISO 9809-2 flawed-cylinder cyclical burst test procedures and acceptance criteria. 13
7.3 Comparison of the flawed-cylinder cyclical burst test with the flawed-cylinder burst test
with monotonic pressurization to evaluate fracture performance. 14
8 Summary and conclusions . 15
Bibliography . 47
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, Part 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 part of ISO/TR 12391 may be the subject
of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TR 12391-3 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
iv © ISO 2002 — All rights reserved
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 and 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 monotonic, flawed-cylinder burst tests
that were conducted in order to evaluate the fracture performance of cylinders ranging in tensile strength from
less 750 MPa to greater than 1 210 MPa.
TECHNICAL REPORT ISO/TR 12391-3:2002(E)
Gas cylinders — Refillable seamless steel — Performance
tests —
Part 3:
Fracture performance tests — Cyclical burst tests
1 Scope
This part of ISO/TR 12391 applies to seamless refillable cylinders of all sizes from 0,5 l up to and including
150 l water capacity produced of steel with tensile strength (R ) greater than 1 100 MPa.
m
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 cyclical burst test”. The test is an alternate test method to the flawed-cylinder burst test
with monotonic pressurization and is used to evaluate the fracture performance of steel cylinders which are
used to transport high-pressure compressed gases.
The concept and development of the flawed-cylinder cyclical burst test is described in ISO/TR 12391-1. The
details of the test method and the criteria for acceptable fracture performance of steel cylinders are given in
9.2.5.3.2 of ISO 9809-2:2000. In this part of ISO/TR 12391, test results are reported for more than one
hundred flawed-cylinder cyclical burst tests that were conducted on seamless steel cylinders that ranged in
tensile strength from 750 MPa to 1 210 MPa. The test method is intended to be used both for the selection of
materials and to establish design parameters in the development of new cylinders as well as for an efficient
quality control test to be used during the production of cylinders.
2 References
ISO 148:1983, Steel — Charpy impact test (V-notch)
ISO 6892:1998, Metallic materials — Tensile testing at ambient temperature
ISO 9809-1:1999, Gas cylinders — Refillable seamless steel gas cylinders — Design, construction and
testing — Part 1: Quenched and tempered steel cylinders with tensile strength less than 1 100 MPa
ISO 9809-2:2000, Gas cylinders — Refillable seamless steel gas cylinders — Design, construction and
testing – Part 2: Quenched and tempered steel cylinders with tensile strength greater than or equal to
1 100 MPa
ISO/TR 12391-1, Gas cylinders — Refillable seamless steel — Performance tests — Part 1: Philosophy,
background and conclusions
ISO/TR 12391-2, Gas cylinders — Refillable seamless steel — Performance tests — Part 2: Fracture
performance tests — Monotonic burst tests
3 Symbols
A is the elongation, expressed as a percentage (= d/t );
d
d is the flaw depth, expressed in millimetres (= A × t );
d
D is the outside diameter of the cylinder, expressed in millimetres;
l is the flaw length, expressed in millimetres (= n × t );
o d
n represents multiples of t (= l /t );
d o d
P is the failure pressure measured in the flawed-cylinder burst test expressed in bar.
f
P is the calculated design test pressure for the cylinder, expressed in bar;
h
P is the calculated design service pressure for the cylinder, expressed in bar;
s
R is the guaranteed minimum yield strength;
e
R is the actual measured value of yield strength, expressed in megapascals;
ea
R is the maximum value of tensile strength guaranteed by the manufacturer, expressed in megapascals;
g, max
R is the minimum value of tensile strength guaranteed by the manufacturer, expressed in megapascals;
g, min
R is the actual measured value of tensile strength, expressed in megapascals;
m
t is the actual measured wall thickness at the location of the flaw, expressed in millimetres;
a
t is the calculated minimum design wall thickness, expressed in millimetres.
d
4 Background information
High-pressure industrial gases (such as oxygen, nitrogen, argon, hydrogen, helium, etc.) are stored and
transported in portable steel cylinders. These cylinders are designed, manufactured, and maintained in
accordance with ISO 9809-1 and ISO 9809-2. The cylinders are constructed from specified alloy steels that
[1]
are generally modified versions of steel alloys such as AISI 4130 or 34 Cr Mo 4 and AISI 4140 or equivalent
steels made to other national specifications. The cylinders are of seamless construction and are manufactured
by either a forging process, a tube-drawing process, or by a plate-drawing process. The required mechanical
properties are obtained by using an austenitizing, quenching and tempering heat treatment. Typical sizes of
these cylinders are 100 mm to 250 mm in diameter, 500 mm to 2 000 mm in length, and 3 mm to 20 mm in
wall thickness. Typical working pressure ranges from 100 bar to 400 bar.
Until recently, the tensile strength of the steels used in the construction of such cylinders has been limited to a
maximum of about 1 100 MPa. This limitation for the maximum tensile strength occurs because the fracture
toughness of the steels decreases with increase in the tensile strength and above a tensile strength of about
1 100 MPa the fracture toughness was not adequate to prevent fracture of the cylinders. Recently developed
new alloy steels, which are modifications of the AISI 4130 and AISI 4140 steels, which have both high tensile
strength and high fracture toughness make it possible to construct lighter cylinders with higher tensile strength
steels. This permits the use of cylinder designs in which the stress in the cylinder wall is increased for a
constant wall thickness. The use of higher strength steels will therefore achieve a lower ratio of steel weight to
gas weight that reduces shipping and handling costs.
2 © ISO 2002 — All rights reserved
A major concern in using higher strength steels for cylinder construction and correspondingly higher design
wall stress is the ability to maintain the same level of safety throughout the life of the cylinder. In particular,
increasing th
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