ISO 7481-2023 PDF

Full title and description

St ISO 7481-2023 — Aerospace — Nuts, self-locking, with maximum operating temperature less than or equal to 425 °C — Test methods. This international standard specifies test methods for metric self‑locking nuts (MJ threads) intended for aerospace use where the maximum operating temperature is ≤ 425 °C; it defines the test device and procedures for each specified test.

Abstract

This document gives the test methods applicable to self‑locking nuts intended for aerospace construction with maximum operating temperatures up to and including 425 °C. It describes the test apparatus and the step‑by‑step method for each test and applies when a dimensional standard, drawing or procurement specification for a nut refers to this document.

General information

• Status: Published
• Publication date: 2 November 2023
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 49.030.30 (fasteners)
• Edition / version: Edition 3 (2023)
• Number of pages: 19

Information based on the ISO catalogue entry for ISO 7481:2023.

Scope

ISO 7481:2023 applies to metric self‑locking nuts with MJ threads intended for aerospace applications where the nut's maximum operating temperature is less than or equal to 425 °C. The standard is limited to test methods (inspection and test procedures); it does not define dimensional requirements or procurement tolerances, which remain the responsibility of the relevant dimensional standard, drawing or procurement specification that references this document.

Key topics and requirements

• Definition of the test apparatus and fixtures used for self‑locking nut testing.
• Procedures for measuring locking performance and torque characteristics at specified temperatures (≤ 425 °C).
• Environmental and conditioning requirements prior to testing (temperature/time profiles where applicable).
• Pass/fail criteria and test reporting requirements to support procurement and quality control.
• References to dimensional standards and procurement documents that invoke these test methods.

Typical use and users

Used by aerospace manufacturers, fastener suppliers, quality and test laboratories, and procurement/specification engineers who need standardized test methods for qualifying self‑locking nuts (MJ threads) intended for high‑temperature aerospace service (up to 425 °C). Also used by certification bodies and design engineers when specifying fasteners for aircraft and space hardware.

Related standards

ISO 7481:2023 replaces earlier editions of the same standard (notably ISO 7481:2000 and the original ISO 7481:1984 withdrawn versions). Related documents include the dimensional standards or procurement specifications that define the nut geometry and material, and other ISO/TC 20/SC 4 standards covering aerospace fasteners and test methods.

Keywords

self‑locking nut, MJ thread, aerospace fasteners, test methods, high‑temperature nuts, locking performance, torque test, ISO 7481:2023

FAQ

Q: What is this standard?

A: ISO 7481:2023 is an international standard that specifies test methods for metric self‑locking nuts (MJ threads) intended for aerospace use at maximum operating temperatures ≤ 425 °C.

Q: What does it cover?

A: It covers the test equipment, conditioning, step‑by‑step test procedures, and reporting criteria used to evaluate the locking and torque characteristics of self‑locking nuts for aerospace applications; it does not define dimensional requirements (those are covered by separate dimensional standards or procurement documents).

Q: Who typically uses it?

A: Aerospace fastener manufacturers, test laboratories, procurement/specification engineers, design and structural engineers, and certification authorities involved in qualifying and verifying self‑locking nuts for aircraft and space hardware.

Q: Is it current or superseded?

A: ISO 7481:2023 is the current published edition (Edition 3, published 2 November 2023) and replaces earlier editions such as ISO 7481:2000 and the original 1984 edition.

Q: Is it part of a series?

A: It is part of the body of ISO standards maintained by ISO/TC 20/SC 4 on aerospace fasteners and test methods; while not a numbered series per se, it is closely associated with other ISO standards and procurement/dimensional documents that together govern aerospace fastener design, testing and acceptance.

Q: What are the key keywords?

A: Self‑locking nut, MJ thread, aerospace, test methods, high temperature (≤ 425 °C), torque, locking performance, ISO 7481:2023.