ISO 7041:2012

Prevailing torque type hexagon nuts (with non-metallic insert), style 2 - Property classes 9 and 12

ISO 7041:2012 specifies the characteristics of prevailing torque type hexagon nuts (with non-metallic insert), style 2, with threads from M5 up to and including M36, in product grade A for threads up to and including M16, and product grade B for threads above M16, and with property classes 9 and 12.

Écrous hexagonaux autofreinés (à anneau non métallique), style 2 — Classes de qualité 9 et 12

General Information

• Status: Published
• Publication Date: 06-May-2012
• ICS: 21.060.20 - Nuts
• Technical Committee: ISO/TC 2/SC 12 - Fasteners with metric internal thread
• Drafting Committee: ISO/TC 2/SC 12 - Fasteners with metric internal thread
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 11-Jun-2025
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 7041:2025 - Fasteners - Prevailing torque hexagon nuts - High nuts (with non-metallic insert)
• Effective Date: 06-Jun-2022
• Revises: ISO 7041:2002 - Prevailing torque type hexagon nuts (with non-metallic insert), style 2 - Property classes 9 and 12
• Effective Date: 19-Jan-2012

Overview

ISO 7041:2012 is an international standard specifying the requirements for prevailing torque type hexagon nuts with non-metallic inserts, style 2, applicable to property classes 9 and 12. These nuts feature threads ranging from M5 to M36, classified under product grade A for threads up to M16, and product grade B for threads above M16. This standard ensures consistent mechanical and physical characteristics critical for fastening applications that demand reliable prevailing torque performance.

ISO 7041:2012 enhances fastener quality control by providing detailed dimensional, material, and performance parameters. It replaces the previous edition (ISO 7041:2002) with minor but vital revisions focusing on product uniformity and compliance with prevailing fastener demands.

Key Topics

• Scope and Dimensions:
  ISO 7041:2012 covers hexagon nuts with non-metallic inserts, designed to provide prevailing torque for secure locking. Dimensional details such as thread size (M5 to M36), heights, widths, and pitches align with related ISO standards like ISO 4033 and ISO 225.

• Material and Property Classes:
  Nuts are made of steel suitable for property classes 9 and 12, ensuring high-strength performance. Non-metallic inserts are typically polyamide, contributing to effective locking action and resistance to loosening under vibration.

• Tolerance and Thread Specifications:
  Threads follow ISO’s general metric thread standards (ISO 261, ISO 724, and ISO 965-2), with tolerance class 6H to maintain consistency. Product grades are defined as grade A for smaller nuts (up to M16) and grade B for larger sizes (above M16), fulfilling distinct tolerance and finish requirements.

• Mechanical and Performance Properties:
  The standard references ISO 898-2 and ISO 2320 for mechanical strength and prevailing torque performance. It mandates specific torque characteristics for reliability under dynamic conditions.

• Surface Treatments and Finishes:
  Surface coatings and finishes conform to ISO 4042 for electroplating and ISO 10683 for non-electrolytically applied zinc flake coatings. Surface integrity, including limits for discontinuities, follows ISO 6157-2.

• Inspection and Acceptance:
  Nuts are subject to acceptance inspection according to ISO 3269, assuring quality in manufacturing and compliance before delivery or installation.

Applications

ISO 7041:2012 prevailing torque hexagon nuts are widely utilized in industries requiring secure fastening where vibration resistance is critical. Typical applications include:

• Automotive and Transportation: Fastening components in engines and chassis requiring reliable locking nuts to prevent loosening.
• Industrial Machinery: Machines exposed to repeated motion and vibrations benefit from prevailing torque nuts to enhance safety and reduce maintenance needs.
• Construction and Engineering: Structural applications demanding high-strength fastening and secure joins.
• Electrical and Electronic Equipment: Securing components where non-metallic inserts prevent galvanic corrosion and ensure insulation.
• Renewable Energy Installations: Wind turbines and solar panels where vibration and dynamic loads necessitate locking nuts of consistent quality.

Choosing ISO 7041:2012 nuts ensures fastener reliability, long-term performance, and compliance with international mechanical property standards, catering to both routine and specialized engineering tasks.

Related Standards

ISO 7041:2012 references several key ISO standards to maintain interoperability and comprehensive quality coverage:

• ISO 4033: Hexagon nuts style 2, defining base dimensions and product grades.
• ISO 261, ISO 724, ISO 965-2: Metric screw thread standards governing thread profiles and tolerances.
• ISO 898-2: Mechanical properties of nuts, including strength and classification.
• ISO 2320: Mechanical and performance properties specific to prevailing torque steel nuts.
• ISO 3269: Procedures for acceptance inspection of fasteners.
• ISO 4042: Electroplating specifications for fasteners to enhance corrosion resistance.
• ISO 4759-1: Tolerance grades and limits applied to bolts, screws, studs, and nuts.
• ISO 6157-2: Limits for surface discontinuities to ensure product integrity.
• ISO 10683: Requirements for zinc flake coatings applied non-electrolytically.

Utilizing these coordinated standards allows manufacturers and users to ensure full compliance with international fastener quality, safety, and performance benchmarks.

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Keywords: ISO 7041:2012, prevailing torque hexagon nuts, non-metallic insert nuts, property classes 9 and 12, metric thread nuts, fastening standards, ISO hexagon nuts, vibration-resistant nuts, mechanical fasteners, ISO fastener standards.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 7041
Fourth edition
2012-05-15
Prevailing torque type hexagon nuts (with
non-metallic insert), style 2 — Property
classes 9 and 12
Écrous hexagonaux autofreinés (à anneau non métallique), style 2 —
Classes de qualité 9 et 12
Reference number
©
ISO 2012
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 either ISO at the address below or ISO’s
member body in the country of the requester.
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ii © ISO 2012 – All rights reserved

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.
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 7041 was prepared by Technical Committee ISO/TC 2, Fasteners, Subcommittee SC 12, Fasteners with
metric internal thread.
This fourth edition cancels and replaces the third edition (ISO 7041:2002), of which it constitutes a minor revision.
INTERNATIONAL STANDARD ISO 7041:2012(E)
Prevailing torque type hexagon nuts (with non-metallic insert),
style 2 — Property classes 9 and 12
1 Scope
This International Standard specifies the characteristics of prevailing torque type hexagon nuts (with non-
metallic insert), style 2, with threads from M5 up to and including M36, in product grade A for threads up to and
including M16, and product grade B for threads above M16, and with property classes 9 and 12.
NOTE The dimensions of the nuts correspond to those given in ISO 4033 plus prevailing torque feature.
If other specifications are required, they can be selected from existing International Standards, e.g. ISO 261,
ISO 724, ISO 898-2, ISO 965-2, ISO 2320 and ISO 4759-1.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
ISO 225, Fasteners — Bolts, screws, studs and nuts — Symbols and descriptions of dimensions
ISO 261, ISO general purpose metric screw threads — General plan
ISO 724, ISO general-purpose metric screw threads — Basic dimensions
ISO 89
...