ISO 18338-2021 PDF

Full title and description

ISO 18338:2021 — Metallic materials — Torsion test at room temperature. This International Standard specifies the apparatus, specimen preparation, test procedure and required measurements for performing torsion tests on metallic materials at ambient temperature to determine torsional properties such as shear yield, ultimate shear and shear modulus.

Abstract

ISO 18338:2021 defines a standardized method for carrying out torsion tests on metallic specimens at room temperature. The standard covers specimen types and dimensions, calibration and verification of test equipment, test execution (application of torque and measurement of angle of twist), calculation of torsional properties and minimum reporting requirements to ensure repeatable, comparable results between laboratories.

General information

• Status: Published
• Publication date: December 2021
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 77.040.10 (Mechanical testing of metals)
• Edition / version: Edition 2 (2021)
• Number of pages: 17

Key bibliographic and lifecycle details (status, edition, pages and replacement of the previous 2015 edition) are recorded on the ISO bibliographic entry and in commercial standards catalogues.

Scope

This standard applies to torsion testing of metallic materials at ambient (room) temperature. It is intended for laboratory tests on specimen geometries addressed in the document (solid and tubular test pieces where applicable) and covers the measurement of torque and angle of twist, data processing to derive shear modulus and shear strengths, and the format of test reports. It replaces ISO 18338:2015 and is intended to improve inter-laboratory comparability of torsional property data.

Key topics and requirements

• Specification of specimen types, dimensions and tolerances for torsion tests.
• Apparatus and fixture requirements (torque application, clamps/chucks, alignment and angular measurement devices).
• Calibration, verification and classification of torque/angle measuring systems and verification intervals.
• Test procedure: preconditioning, loading rates, measurement of torque and angle of twist, test end points (proof torque or fracture).
• Calculations and data reduction: torque–twist curves, determination of shear modulus, shear yield/ultimate shear and reporting conventions.
• Minimum required information in test reports for traceability and reproducibility.

Typical use and users

ISO 18338:2021 is used by materials testing laboratories, quality and R&D departments in metal production and fabrication industries, mechanical and structural engineers, and certification bodies needing torsional material properties for design, verification, failure analysis and material specification. Laboratories performing torsion tests as part of product qualification, material characterization or when specifying fasteners, shafts and springs will commonly apply this standard.

Related standards

Standards commonly used alongside ISO 18338 include tensile test standards for complementary mechanical properties (for example the ISO 6892 series for tensile testing) and calibration/verification standards for test machines (for example ISO 7500‑1). National and industry standards for torsion-related measurements such as ASTM E143 (shear modulus at room temperature) may also be referenced when comparing methods or historic data.

Keywords

torsion test, torsional properties, shear modulus, shear strength, metallic materials, torque–twist, specimen geometry, test method, ISO 18338

FAQ

Q: What is this standard?

A: ISO 18338:2021 is an International Standard that specifies the method for performing torsion tests on metallic materials at room temperature to determine torsional properties such as shear yield, ultimate shear and shear modulus.

Q: What does it cover?

A: It covers specimen preparation and dimensions, required test apparatus and fixtures, calibration and verification of torque/angle measurement systems, detailed test procedures (loading, measurement and termination), calculations for deriving torsional properties, and reporting requirements to ensure reproducibility and comparability of results.

Q: Who typically uses it?

A: Materials testing laboratories, manufacturers of metal products (shafts, springs, fasteners), R&D and quality engineers, and certification bodies use this standard when torsional properties are required for design, verification or material specification.

Q: Is it current or superseded?

A: ISO 18338:2021 is the current published edition (second edition) that replaced ISO 18338:2015.

Q: Is it part of a series?

A: ISO 18338 is a standalone test method in the family of metallic materials testing standards; it is often used together with other mechanical test standards (for example the ISO 6892 series for tensile testing and ISO 7500‑1 for machine calibration) to provide a complete mechanical property dataset.

Q: What are the key keywords?

A: Torsion test, torque, angle of twist, shear modulus, shear yield, shear strength, metallic materials, test method, ISO 18338.