ISO 6892-3:2015

Overview

ISO 6892-3:2015 - "Metallic materials - Tensile testing - Part 3: Method of test at low temperature" specifies a standardized method for tensile testing of metallic materials at temperatures between +10 °C and −196 °C. It is part of the ISO 6892 series for tensile testing and provides procedures, equipment requirements, and documentation rules for reliable, reproducible low-temperature tensile tests (cryogenic testing).

Key Topics and Requirements

• Scope and principle: Tensile testing to determine mechanical properties of metallic materials at low temperatures; stresses are calculated using original cross-sectional area measured at room temperature.
• Temperature range and control: Tests performed between +10 °C and −196 °C; includes requirements for cooling devices, temperature measurement, verification and soaking time (time to stabilize test-piece temperature).
• Test pieces and dimensions: Test-piece geometries and gauge lengths are specified; original gauge length (Lo) and extensometer gauge length (Le) are measured at room temperature unless otherwise agreed.
• Force measuring system: Must be calibrated per ISO 7500-1, class 1 or better.
• Extensometer requirements: Use ISO 9513 extensometers - class 1 for proof strength measurements, class 2 acceptable for larger extensions. Extensometer gauge length shall be ≥ 10 mm and correspond to the central portion of the parallel length.
• Testing methods and strain rates: Two methods are defined:
  • Method A - strain-rate-based testing with narrow tolerances (intended to minimize variability and measurement uncertainty).
  • Method B - conventional strain rate ranges (expanded ranges). Choice of method and strain rates aligns with ISO 6892-1 and ISO 6892-2 updates.
• Measurement and reporting: Procedures for determining tensile strength, yield/proof strength, percentage elongation, reduction of area, and reporting; includes guidance on measurement uncertainty and required test report content.
• Safety warning: Standard notes hazards associated with cryogens and procedures; users must establish safe work practices.

Practical Applications and Users

ISO 6892-3 is used by:

• Materials testing laboratories performing cryogenic tensile tests (e.g., liquid nitrogen).
• Manufacturers and suppliers of metals and alloys requiring low-temperature mechanical property verification (pipeline steels, aerospace alloys, cryogenic storage vessels).
• Design engineers, quality assurance teams, and certification bodies needing standardized test data for low-temperature performance, yield/tensile strength, and elongation.
• Research organizations studying temperature-dependent mechanical behavior of metallic materials.

Keywords: ISO 6892-3, tensile testing, low temperature, metallic materials, cryogenic testing, extensometer, ISO 7500-1, ISO 9513, strain rate.

Related Standards

• ISO 6892-1:2009 - Method of test at room temperature
• ISO 6892-2 - Method of test at elevated temperature
• ISO 6892-4 - Method of test in liquid helium
• ISO 7500-1 - Calibration of force-measuring systems
• ISO 9513 - Calibration of extensometer systems

This standard ensures consistent, comparable low-temperature tensile test results for materials selection, qualification, and research.