ISO 7689:2025

Aerospace series - Bolts, with MJ threads, made of alloy steel, strength class 1 100 MPa - Procurement specification

This document specifies the characteristics and quality assurance requirements for MJ thread bolts made of alloy steel, of strength class 1 100 MPa, for aerospace construction. It is applicable whenever it is referenced in a definition document.

Série aérospatiale — Vis à filetages MJ, en acier allié, de classe de résistance 1 100 MPa — Spécification d'approvisionnement

General Information

• Status: Published
• Publication Date: 25-May-2025
• ICS: 49.030.20 - Bolts, screws, studs
• Technical Committee: ISO/TC 20/SC 4 - Aerospace fastener systems
• Drafting Committee: ISO/TC 20/SC 4/WG 3 - Supporting documents
• Current Stage: 6060 - International Standard published
• Start Date: 26-May-2025
• Due Date: 31-Oct-2025
• Completion Date: 26-May-2025

Relations

• Revises: ISO 7689:2008 - Aerospace - Bolts, with MJ threads, made of alloy steel, strength class 1 100 MPa - Procurement specification
• Effective Date: 23-Apr-2020

Overview

ISO 7689:2025 - "Aerospace series - Bolts, with MJ threads, made of alloy steel, strength class 1100 MPa - Procurement specification" - is the third edition international standard that defines characteristics and quality‑assurance requirements for MJ‑thread alloy‑steel bolts (strength class 1100 MPa) used in aerospace construction. It applies whenever referenced in a definition document (for example an in‑house standard, drawing or other specification) and replaces the 2008 edition with updated sampling tables and additional mechanical and dimensional requirements.

Key topics and technical requirements

• Scope and applicability: Requirements apply to bolts ready for use at ambient temperature and complement any requirements in the referenced definition document.
• Material and strength class: Bolts of alloy steel, strength class 1100 MPa; material verification follows the referenced material standard.
• Manufacturing controls:
  • Heads formed by hot or cold forging prior to heat treatment.
  • Forged blanks heat‑treated to achieve properties in the definition document (blanks shall not be heat‑treated more than twice).
  • Threads formed by single rolling after final heat treatment.
• Quality assurance and inspection:
  • Manufacturer responsibility for continuous compliance and maintenance of quality records for 10 years.
  • Qualification inspection: typically 25 bolts selected by simple random sampling for each type/diameter.
  • Acceptance inspection: sampling of production batches/inspection lots per AS/EN 9138; destructive and nondestructive tests specified in Table 1.
  • Use of statistical process control (SPC) is permitted when formally justified and validated; SPC is not applicable to destructive tests.
• Mechanical and test requirements: Table 1 in the standard lists mandatory inspections (dimensions per ISO 5855‑2, tensile strength per ISO 7961, hardness per ISO 6506/6507/6508, surface texture per ISO 21920‑3, surface coating standards, recess removal torque, etc.). Annex A and B provide formulae for tensile and double shear load calculations.
• Definitions and sampling concepts: Clear definitions for production batch, inspection lot, AQL/LQ, major/minor defects and sampling plans are provided.

Practical applications and users

ISO 7689:2025 is intended for:

• Aerospace OEMs and suppliers specifying MJ‑thread bolts in procurement documents and drawings.
• Fastener manufacturers who must qualify production routes, perform acceptance testing and retain traceable quality records.
• Quality engineers and procurement specialists implementing inspection plans, sampling, SPC and supplier surveillance.
• Design and structural engineers who require standard test methods, tensile/double‑shear formulae (Annex A/B) and minimum mechanical requirements for bolt selection.

Practical uses include supplier qualification, batch acceptance, manufacturing process validation, and contractual procurement requirements for flight‑critical or structural fastening systems.

Related standards

Key normative references cited in ISO 7689:2025:

• ISO 5855‑2 - MJ threads limit dimensions for bolts and nuts
• ISO 7961 - Aerospace bolts - Test methods (tensile/double shear)
• ISO 21920‑3 - Surface texture (profile)
• ISO 6506 / 6507 / 6508 - Brinell, Vickers, Rockwell hardness tests
• AS/EN 9138 - Aerospace quality management - statistical product acceptance requirements

Keywords: ISO 7689:2025, aerospace bolts, MJ threads, alloy steel bolts, 1100 MPa, procurement specification, quality assurance, sampling plan, tensile strength, SPC, acceptance inspection.

Standards Content (Sample)

International
Standard
ISO 7689
Third edition
Aerospace series — Bolts, with
2025-05
MJ threads, made of alloy steel,
strength class 1 100 MPa —
Procurement specification
Série aérospatiale — Vis à filetages MJ, en acier allié, de classe de
résistance 1 100 MPa — Spécification d'approvisionnement
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Quality assurance . 3
4.1 General .3
4.2 Qualification inspection conditions . . .3
4.3 Acceptance inspection conditions . .4
4.4 Use of "statistical process control (SPC)" .4
5 Requirements . 4
Annex A (informative) Cross sectional areas and formulae for tensile loads .18
Annex B (informative) Cross sectional areas and formulae for double shear loads .20
Bibliography .21

iii
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
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with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
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Any trade name used in this document is information given for the convenience of users and does not
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For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 4, Aerospace fastener systems.
This third edition cancels and replaces the second edition (ISO 7689:2008), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— new tables for sampling;
— additional requirements in Table 1, item no 2 "Dimensions";
— additional requirements in Table 1, item no .4-1 "Tensile strength";
— additional requirements in Table 1, item no 4-3 "Hardness";
— additional requirements in Table 1, item no 4-4 "Recess removal torque";
— additional values in Table 8 "Minimum loads for tensile and double shear tests" for protruding head;
— update of normative references.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 7689:2025(en)
Aerospace series — Bolts, with MJ threads, made of alloy
steel, strength class 1 100 MPa — Procurement specification
1 Scope
This document specifies the characteristics and quality assurance requirements for MJ thread bolts made of
alloy steel, of strength class 1 100 MPa, for aerospace construction.
It is applicable whenever it is referenced in a definition document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 5855-2, Aerospace — MJ threads — Part 2: Limit dimensions for bolts and nuts
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method
ISO 7961, Aerospace — Bolts — Test methods
ISO 21920-3, Geometrical product specifications (GPS) — Surface texture: Profile — Part 3: Specification
operators
AS/EN 9138, Aerospace Series - Quality Management Systems Statistical Product Acceptance Requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
production batch
quantity of finished bolts, manufactured using the same process, from a single material cast (single heat of
alloy), having the same number of definition document (3.3), same thread and diameter code, heat treated
together to the same specified condition and produced as one continuous run
3.2
inspection lot
quantity of bolts from a single production batch (3.1) having the same number of definition document (3.3)

3.3
definition document
document specifying directly or indirectly all the requirements for bolts
Note 1 to entry: The definition document can be an International Standard, an in-house standard or a drawing.
3.4
crack
rupture in the material which may extend in any direction and which may be intercrystalline or
transcrystalline in character
3.5
seam
open surface defect
3.6
lap
surface defect caused by folding over metal fins or sharp corners and then rolling or forging them into the surface
3.7
crevice
hollow area at thread crest
3.8
inclusions
non-metallic particles originating from the material manufacturing process
Note 1 to entry: These particles can be isolated or arranged in strings.
3.9
sampling plan
plan according to which one or more samples are taken in order to obtain information and possibly to reach
a decision
Note 1 to entry: In this document, each sampling plan specifies the number of bolts to be inspected as a function of the
size of the batch and the acceptance number [number of defective items acceptable (Ac)]. See ISO 2859-1.
3.10
simple random sampling
sampling of n items from a population of N items in such a way that all possible combinations of n items have
the same probability of being chosen
3.11
major defect
defect, other than critical, that is likely to result in a failure or to reduce materially the usability of the
considered product (bolt) for its intended purpose
3.12
minor defect
defect that is not likely to reduce materially the usability of the considered product (bolt) for its intended
purpose, or that is a departure from the established specification having little bearing on the effective use
or operation of this product
3.13
limiting quality
LQ
quality limit that corresponds to a specified and relatively low probability of
acceptance
Note 1 to entry: It is the limiting lot quality characteristic that the consumer is willing to accept with a low probability
that a lot of this quality would occur.

Note 2 to entry: For the purposes of this document, the limiting quality quoted in Table 4 to 7 corresponds to a
probability of acceptance of 10 %.
3.14
acceptable quality limit
AQL
maximum percent defective (or maximum number of defects per hundred units) that, for purposes of
sampling inspection, can be considered satisfactory as a process average
Note 1 to entry: Variant: quality limit which in a sampling plan (3.9) corresponds to a specified but relatively high
probability of acceptance.
3.15
grip length
shank length
dimension from top of head (flush head bolt) or underhead bearing surface (protruding head bolt) to the end
of full cylindrical portion of shank, excluding the thread radius at shank/slope transition
3.16
IRR
initial reliability requirement
inspection reliability requirement
minimum acceptable outgoing yield or probability of conformance
4 Quality assurance
4.1 General
The manufacturer shall be capable of continuous production of bolts complying with the quality
requirements specified in this document.
1)
The purpose of qualification inspections of bolts is to check that the design and manufacturing conditions
of a bolt allow it to satisfy the requirements of this document.
Quality documentation for parts produced in accordance to this document shall be maintained for a
minimum period of 10 years.
The purpose of production acceptance inspection of a bolt is to check, as simply as possible, using a method
which is inexpensive but the most representative of the actual conditions of use, with the uncertainty
inherent in statistical sampling, that the bolts satisfy the requirements of this document.
Production acceptance inspections shall be carried out by, or under the responsibility of, the manufacturer.
4.2 Qualification inspection conditions
Unless otherwise specified, the inspection shall be carried out on:
— each type and diameter of bolt;
— 25 bolts selected from a single inspection lot by simple random sampling.
The test programme can be reduced, or the qualification granted without inspection; any such decision
shall be based on the results obtained on similar types and diameters of bolt provided that the design and
manufacturing conditions are identical.
The inspections shall be repeated on any bolt if the manufacturing conditions have been modified.
Table 2 indicates the allocation of bolt samples for the inspections.
1) In order to simplify the text the term "inspections" used in this document also refers to "inspections and tests".

4.3 Acceptance inspection conditions
Inspections shall be carried out on each production batch or inspection lot. Bolts from the batch or lot to be
inspected shall be selected by simple random sampling.
Each bolt may be submitted to several inspections, provided that none of the characteristics to be verified
has been previously altered during any of these inspections.
Acceptance inspections and tests are specified in Table 1. They shall be carried out on each production batch
or inspection lot. Table 1 specifies the test methods and sampling tables to be used for each test. Fasteners
from the batch to be tested shall be selected by sampling in accordance with AS/EN 9138.
The bolts to be subjected to destructive inspections may be those on which non-destructive inspections
have been carried out.
If a more stringent inspection is deemed necessary, all or part of the qualification inspections may be
performed during the acceptance inspections. In this case, the number of bolts submitted is the same as that
submitted for qualification inspection.
Production batches or inspection lots declared unacceptable after the production acceptance inspections
shall be submitted for re-inspection only after all the defective units have been removed and/or defects
have been corrected. In this case, the attribute(s) that caused the rejection shall be verified using a sample
of twice the normal size but the maximum number of allowed defective items shall be the same as in the
original inspection.
4.4 Use of "statistical process control (SPC)"
When a characteristic is obtained by a controlled statistical process, in order to declare conformity of
the characteristic, the manufacturer has the possibility of refraining from the final systematic sampling
provided for in this document if he/she is capable of formally justifying this choice by using the standards
quoted in it as a basis.
This justification includes the following phases:
— analysis of the key characteristics of the product;
— analysis of the risks for each implemented process;
— determination of the parameters and/or characteristics to be respected under SPC;
— determination of the capabilities of each process;
— drawing up of an inspection plan and integration in the manufacturing process;
— drawing up of routes and control charts (e,g, ISO 7870-1);
— use of control charts for data consolidation;
— determination of the audits to be run and the control to be carried out to ensure reliability of the device.
To be usable in production, this process shall or should be validated beforehand by the qualifying body,
either during the qualification phase or a posteriori, according to the case, by analysing the justificatory file
and the results of the qualification inspections such as provided for in Clause 5. Such an SPC process is not
applicable to destructive tests.
5 Requirements
The requirements in Table 1, unless otherwise specified, shall apply to bolts ready for use. The test
temperature, unless otherwise specified, shall be the ambient temperature. These requirements complement
the requirements of all other standards or specifications referenced in the definition document.

Table 1 — Requirements and test methods
Inspection and test Designa-
Item no Characteristic Requirement Sample size
method tion
1 Material In accordance with the defini- See material standard. As required
tion document. by semi-fin-
ished prod-
uct
2 Dimensions In accordance with the defini- Standard gauging. Q 20
tion document.
ISO 5855-2 shall apply.
A See Table 3
Dimensions shall include the
and Table 4
chemical applied or electroplat-
to 7
ed finishes designated on the
detailed drawing. Dimensions
shall exclude paint and similar
coating, metallic dips and dry
film lubricants
...