Abstract

Specifies dimensions, performance requirements and test procedures for heavy-duty (S series), light-duty (L series) and extra-light-duty (LL series) stud ends with ISO 261 threads and metal-to-metal sealing. It also specifies the designation of these stud ends.

Status
Published
Publication Date
31-Oct-2001
Technical Committee
IFEK - Ferrous metals
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Nov-2001
Due Date
01-Nov-2001
Completion Date
01-Nov-2001

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SIST EN ISO 9974-3:2001

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SIST EN ISO 9974-3:2001 is a SIST standard for connections for general use and fluid power. It specifies dimensions, performance requirements, test procedures and designation for stud ends with ISO 261 threads and metal-to-metal sealing (type B) in the heavy-duty (S series), light-duty (L series) and extra-light-duty (LL series) ranges.

These stud ends are used with threaded ports on fluid conductor fittings for tubes, pipes, hose fittings and hoses. In practice, the document tells manufacturers, buyers and test laboratories what to make, how to test it, and how to name it.

What does SIST EN ISO 9974-3:2001 specify?

SIST EN ISO 9974-3:2001 specifies the dimensions, performance requirements and test procedures for stud ends with ISO 261 threads and metal-to-metal sealing. It also specifies the designation of these stud ends.

The standard is organized into clauses covering scope, normative references, definitions, dimensions, requirements, metal-to-metal sealing, test methods, designation and an identification statement. That structure helps a reader move from product definition to testing and marking without having to cross-check several documents.

AnnexWhat it covers
Annex ANormative test data form for ISO 9974-3 stud ends
Annex BInformative bibliography

What are the key requirements of SIST EN ISO 9974-3:2001?

SIST EN ISO 9974-3:2001 sets out the design limits, pressure ratings and qualification tests for stud ends with metal-to-metal sealing. The most important points are the pressure classes, the sealing behavior, and the test evidence needed to show conformance.

Pressure ratings and series

Clause 1 states that the stud ends are for heavy-duty (S series), light-duty (L series) and extra-light-duty (LL series) use. The working pressure depends on the series and on size, material, design, working conditions and application, so the standard is not a one-pressure-fits-all rule.

For low carbon steel stud ends, the stated working pressures are up to 10 MPa for LL, 25 MPa for L and 40 MPa for S. For a purchaser or designer, that means the series choice is part of the engineering decision, not just a catalog preference.

Reuse and sealing behavior

Clause 6 explains that the machined seal edge is compressed during assembly and damages the sealing face of the port. Safe re-assembly is not possible, and high surface pressure is needed or leakage may occur. In practice, this is a critical warning for maintenance and replacement planning.

Clause 1 also states that these stud ends should not be used for leak-free hydraulic fluid power applications because they may leak if re-used. That matters when a system must stay tight after servicing.

Dimensions and construction

Clause 4 requires the stud ends to match the dimensions in Figure 1 and Table 1. Hex tolerances across flats are linked to ISO 4759-1 product grade C. For users, this is the basis for interchangeability and fit with matching parts.

Performance qualification

Clause 5 requires stud ends made of low carbon steel to meet at least the burst and impulse pressures in Table 2 when tested to Clause 7. Clause 1 adds that dimensional compliance alone does not guarantee rated performance, so manufacturers must test their components.

Test methods

Clause 7 sets out two main qualification tests: a burst pressure test and a cyclic endurance (impulse) test. The burst test uses at least three samples, while the cyclic endurance test uses six samples at the stated impulse pressures. The impulse cycling uses a uniform rate between 0.5 Hz and 1.3 Hz and follows the wave pattern in ISO 6803.

Test conditions and reporting

Clause 7 also gives practical test conditions: threads and contact surfaces are lubricated with hydraulic oil of viscosity VG 32, test blocks are unplated and hardened to 45 HRC to 50 HRC, and stud ends are made from low carbon steel and plated. Annex A provides the test data form, so test results and conditions are documented in a consistent way.

Designation and identification

Clause 8 defines the designation format as the words “Stud end”, the reference to this part, the thread size and the series. Clause 9 gives the identification statement to use in reports, catalogues and sales literature when claiming conformance.

What terms does SIST EN ISO 9974-3:2001 define?

Stud end - The male connector covered by the standard, designed to seal in a port by metal-to-metal contact.

Metal-to-metal sealing (type B) - A sealing method where the machined seal edge compresses against the port face, rather than using an elastomeric seal.

Working pressure - The pressure the stud end is designed to carry in service, which varies by series and application.

Burst pressure - The pressure level used in qualification testing to prove resistance to rupture.

Cyclic endurance (impulse) test - A repeated-pressure test used to show that the stud end can withstand pressure cycling over time.

S series, L series, LL series - The heavy-duty, light-duty and extra-light-duty series used to classify stud ends by duty level and pressure capability.

Who uses SIST EN ISO 9974-3:2001?

SIST EN ISO 9974-3:2001 is used by manufacturers of fluid power connectors, quality and test laboratories, and designers of hydraulic and general fluid systems. Buyers and engineers use it to select a stud end series, check pressure capability, and confirm how the part must be tested and designated.

Which standards are used with SIST EN ISO 9974-3:2001?

Clause 2 names the standards that provide the supporting rules for this part:

  • ISO 261 - general-purpose metric screw threads, used for the thread system.
  • ISO 3448 - viscosity classification for the hydraulic oil used in testing.
  • ISO 4759-1 - fastener tolerances, used for hex dimensions.
  • ISO 5598 - fluid power vocabulary, used for definitions.
  • ISO 6508 - Rockwell hardness testing, used for test block hardness.
  • ISO 6803 - hydraulic pressure impulse test without flexing, used for the impulse test wave pattern.

The foreword also links this part to ISO 9974-1, ISO 9974-2, ISO 8434-1 and ISO 8434-4, which helps place it within the wider family of fluid power connections.

What does the SIST EN ISO 9974-3:2001 document contain?

The document includes one figure showing the stud end shape, and three main data tables: dimensions, pressures and qualification torques. Table 1 gives the dimensional envelope, Table 2 gives the working, burst and impulse pressures, and Table 3 gives the torques used during qualification testing.

Annex A provides a ready-to-use report form for burst and cyclic endurance testing, including sample results, failure type, hardness and final conclusions. Annex B lists related standards for background and further reference.

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SIST EN ISO 9974-3:2001

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Frequently Asked Questions

SIST EN ISO 9974-3:2001 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Connections for general use and fluid power - Ports and stud ends with ISO 261 threads with elastomeric or metal-to-metal sealing - Part 3: Stud ends with metal-to-metal sealing (type B) (ISO 9974-3:1996)". This standard covers: Specifies dimensions, performance requirements and test procedures for heavy-duty (S series), light-duty (L series) and extra-light-duty (LL series) stud ends with ISO 261 threads and metal-to-metal sealing. It also specifies the designation of these stud ends.

Specifies dimensions, performance requirements and test procedures for heavy-duty (S series), light-duty (L series) and extra-light-duty (LL series) stud ends with ISO 261 threads and metal-to-metal sealing. It also specifies the designation of these stud ends.

SIST EN ISO 9974-3:2001 is classified under the following ICS (International Classification for Standards) categories: 23.100.60 - Filters, seals and contamination of fluids. The ICS classification helps identify the subject area and facilitates finding related standards.

SIST EN ISO 9974-3:2001 has the following relationships with other standards: It is inter standard links to SIST ISO 6508:1995, SIST ISO 4759-1:1996, SIST ISO 5598:1998, SIST EN 12101-6:2005, SIST EN 572-7:2004, SIST EN ISO 780:2000, SIST EN 14730-2:2007, SIST EN 12514:2020. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

SIST EN ISO 9974-3:2001 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.

Standards Content (Sample)


SLOVENSKI STANDARD
01-november-2001
3ULNOMXþHYDQMD]DVSORãQRXSRUDERLQ]DIOXLGQRWHKQLNR2GSUWLQHLQSULNOMXþNL]
QDYRMLSR,62LQ]HODVWRPHUQLPDOLNRYLQVNLPWHVQMHQMHPGHO3ULNOMXþNLV
NRYLQVNLPWHVQMHQMHP WLS%  ,62
Connections for general use and fluid power - Ports and stud ends with ISO 261 threads
with elastomeric or metal-to-metal sealing - Part 3: Stud ends with metal-to-metal sealing
(type B) (ISO 9974-3:1996)
Leitungsanschlüsse für Fluidtechnik und allgemeine Anwendung - Einschraublöcher und
Einschraubzapfen mit Gewinde nach ISO 261 und Elastomerdichtung oder metallener
Dichtkante - Teil 3: Einschraubzapfen mit metallener Dichtkante (Typ B) (ISO 9974-
3:1996)
Raccordements pour applications générales et transmissions hydrauliques et
pneumatiques - Orifices et éléments mâles a filetage ISO 261 et joint en élastomere ou
étanchéité métal sur métal - Partie 3: Eléments mâles avec étanchéité métal sur métal
(type B) (ISO 9974-3:1996)
Ta slovenski standard je istoveten z: EN ISO 9974-3:2000
ICS:
23.100.60 )LOWULWHVQLODLQ Filters, seals and
RQHVQDåHYDQMHWHNRþLQ contamination of fluids
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL
STANDARD
First edition
1996-04-15
Connections for general use and fluid
power - Ports and stud ends with IS0 261
threads with elastomeric or metal-to-metal
sealing -
Part 3:
Stud ends with metal-to-metal sealing (type B)
Raccordemen ts pour applications g&&ales et transmissions h ydrauliques
et pneumatiques - Orifices et &men ts msles ;i filetage IS0 26 1 et joint
en blastomkre ou 6tanchbit4 m&al sur m&al -
Partie 3: i%ments males avec 6tanchMG m&al sur m&al (type B)
Reference number
IS0 9974-3:1996(E)
IS0 9974=3:1996(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide fed-
eration of national standards bodies ( IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for
which a technical committee has been established has the right to be rep-
resented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. IS0 col-
laborates closely with the International Electrotechnical Commission (IEC)
on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are cir-
culated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 9974-3 was prepared jointly by Technical
Committees lSO/TC 5, ferrous metal pipes and metallic fittings, Sub-
committee SC 5, Threaded or plain end butt-we/ding fittings, threads,
gauging of threads, and ISO/TC 131, Fluid power systems, Subcommittee
SC 4, Connectors and similar products and components.
IS0 9974 consists of the following parts, under the general title Connec-
tions for general use and fluid power - Ports and stud ends with IS0 261
threads with elastomeric or metal-to-metal sealing.
- Part I: Threaded ports
Part 2: Stud ends with elastomeric sealing (type E)
Part 3: Stud ends with metal-to-metal sealing (type B)
The performance requirements, dimensions and designs are defined for
port and stud end connections for the L and S series in IS0 9974-Z and for
the LL, L and S series in IS0 9974-3. Significant testing over more than
30 years of use has confirmed the performance requirements of these
port and stud end connections.
Stud ends conforming to IS0 9974-2 and 9974-3 are identical to those
conforming to DIN 3852-l. IS0 9974-2 stud ends are used on IS0 8434-l
and IS0 8434-4 fittings, and IS0 9974-3 stud ends are used on IS0 8434-l
fittings.
Annex A forms an integral part of this part of IS0 9974. Annex B is for
information only.
0 IS0 1996
All rights reserved. Unless otherwise specified, no part of this publication may be
reproduced or utilized in any form or by any means, electronic or mechanical, including
photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
IS0 9974=3:1996(E)
0 IS0
Introduction
In fluid power systems, power is transmitted and controlled through a fluid
(liquid or gas) under pressure within an enclosed circuit. In general appli-
cations, a fluid may be conveyed under pressure.
Components are co nnected through their th readed ports by stud ends on
fluid conductor fittin gs to tubes and pipes or to hose fittings a nd hoses.

This page intentionally left blank

INTERNATIONAL STANDARD @ IS0 IS0 9974=3:1996(E)
Connections for general use and fluid power - Ports and stud
ends with IS0 261 threads with elastomeric or metal-to-metal
sealing -
Part 3:
Stud ends with metal-to-metal sealing (type B)
1 Scope 2 Normative references
The following standards contain provisions which,
This part of IS0 9974 specifies dimensions, perform-
through reference in this text, constitute provisions of
ance requirements and test procedures for heavy-duty
this part of IS0 9974. At the time of publication, the
(S series), light-duty (L series) and extra-light-duty
editions indicated were valid. All standards are subject
(LL series) stud ends with IS0 261 threads and metal-
to-metal sealing. It also specifies the designation of to revision, and parties to agreements based on this
these stud ends. These stud ends should not be used part of IS0 9974 are encouraged to investigate the
for leak-free hydraulic fluid power applications be- possibility of applying the most recent editions of the
cause they may leak if re-used. standards indicated below. Members of IEC and IS0
maintain registers of currently valid International Stan-
dards.
Stud ends in accordance with this part of IS0 9974
may’ be used at working pressures up to IO MPa
IS0 261:- 21, IS0 general-purpose metric screw
(I 00 bar 1)) for the LL series, 25 MPa (250 bar) for the
threads - General plan.
L series and 40 MPa (400 bar) for the S series. The
permissible working pressure depends upon the stud
IS0 3448: 1992, Industrial liquid lubricants - IS0 vis-
end size, materials, design, working conditions, appli-
cosity classification.
cation, etc.
IS0 4759-l :I 978, Tolerances for fasteners - Part 1:
For threaded ports and stud ends specified in new Bolts, screws and nuts with thread diameters be-
designs in hydraulic fluid power applications, only
tween I,6 (inclusive) and 750 mm (inclusive) and
IS0 6149 is to be used. Threaded ports and stud
product grades A, B and C.
ends in accordance with IS0 1179, IS0 9974 and
IS0 11926 are not to be used for new designs in
IS0 5598: 1985, Fluid power systems and components
hydraulic fluid power applications.
- Vocabulary.
IS0 6508: 1986, Metallic materjals - Hardness test -
Conformance to the dimensional information in this
Rockwelltest(scalesA-B-C-D-E-F-G-H-K).
part of IS0 9974 does not guarantee rated perform-
ance. Each manufacturer should perform testing
according to the specification contained in this part of IS0 6803:1994, Rubber or plastics hoses and hose
IS0 9974 to assure that components comply with the assemblies
- Hydraulic pressure impulse test with-
performance ratings. out flexing.
I) 1 bar = 0,l MPa = 105 Pa; 1 MPa = 1 N/mm2
2) To be published. (Revision of IS0 261 :I 973)

0 IS0
IS0 9974=3:1996(E)
7.12 Materials
3 Definitions
Test blocks shall be unplated and hardened to 45 HRC
For the purposes of this part of IS0 9974, the defi-
to 50 HRC (see IS0 6508). Stud ends shall be made
nitions given in IS0 5598 apply.
from low carbon steel and plated.
7.1.3 Procedure
4 Dimensions
7.1.3.1 Thread lubrication
Stud ends shall conform to the dimensions shown in
For testing only, threads and contact surfaces shall be
figure 1 and given in table 1. Hex tolerances across
lubricated with hydraulic oil with a viscosity of VG 32
flats shall be in accordance with IS0 4759-1, product
in accordance with IS0 3448 prior to the application of
grade C.
torque.
7.1.3.2 Stud end torque
Test stud ends after application of the torques given in
5 Requirements
table 3.
7.1.3.3 Pressure rise rate
5.1 Working pressure
During the burst test, the rate of pressure rise shall
Stud ends made of low carbon steel shall be designed
not exceed 138 MPa/min (1 380 bar/min).
for use at the working pressures given in table 2.
7.1.4 Test report
5.2 Performance
Test results and conditions shall be reported on the
test data form given in annex A.
Stud ends made of low carbon steel shall meet at
least the burst and impulse pressures given in table 2,
when tested in accordance with clause 7.
7.2 Cyclic endurance (impulse) test
7.2.1 Principle
6 Metal-to-metal sealing
Test six samples at their respective impulse press-
ures.
The machined seal edge is compressed during as-
sembly. This causes damage to the sealing face of the
port. Safe re-assembly is not possible. A high surface
7.2.2 Materials
pressure shall also be obtained, otherwise leakage is
possible.
Use the same materials as those given in 7.12.
7.2.3 Procedures
7 Test methods
7.2.3.1 Thread lubrication
burs
...