ISO 7500-2:2006

Overview

ISO 7500-2:2006 - "Metallic materials - Verification of static uniaxial testing machines - Part 2: Tension creep testing machines - Verification of the applied force" defines procedures for verifying the applied force of tension creep testing machines used for uniaxial creep testing in accordance with ISO 204. The standard covers a general machine inspection plus a formal verification of force for machines that apply load by dead weights, lever systems or direct spring loading. Machines that use an integral force‑measuring system are verified under ISO 7500-1.

Key topics and requirements

• Scope and machine types: Applies to dead‑weight machines, lever‑type creep testing machines and direct‑spring‑loading machines; excludes machines with load cells (see ISO 7500-1).
• Normative references: ISO 204 (creep testing method) and ISO 376 (calibration of force‑proving instruments).
• General inspection: Ensure machine is in good working order before force verification (see Annex A in standard).
• Force verification method: Uses tension force‑proving instruments compliant with ISO 376; instrument class must be equal or better than the machine class being verified.
• Masses and calibration: Use known masses (accuracy ±0.1 %, re‑verified at least every 5 years) or dedicated machine masses.
• Discrimination threshold: Determine the smallest detectable force increment (d) at 20 %, 60 % and 100 % of the force range (and at the lower limit when applicable).
• Lower limit of verification: Defined relative to the discrimination threshold and machine class (specified in the standard).
• Test procedure essentials:
  • Align and self‑align loading train and proving device.
  • Balance levers (overslung/underslung specifics included).
  • Temperature compensation and stabilization; apply temperature corrections per ISO 376.
  • Conditioning: exercise machine three times between zero and maximum force and reset to zero.
  • Apply at least five approximately equispaced forces from 20 % (or lower limit) upward; repeat series three times, rotating the proving device about 120° between series.
  • For spring‑loaded systems, calibrate the spring in a spring‑force calibration device using identical interfaces.
• Assessment and reporting: Calculate relative accuracy error and repeatability, assign machine class, and produce a verification report. Verification intervals are specified.

Applications and users

• Test laboratories performing uniaxial creep tests on metallic materials.
• Quality managers and materials engineers ensuring traceable force application for long‑term creep studies.
• Calibration laboratories and equipment manufacturers that supply or certify creep testing machines.
• R&D groups in metallurgy, aerospace, power generation and component life‑prediction where accurate creep load control is critical.

Related standards

• ISO 7500-1 - Tension/compression testing machines: verification and calibration of force‑measuring systems
• ISO 204 - Uniaxial creep testing in tension - Method of test
• ISO 376 - Calibration of force‑proving instruments

Keywords: ISO 7500-2:2006, tension creep testing machines, verification of applied force, discrimination threshold, force‑proving instruments, dead‑weight machines, lever‑type machines, spring‑loading machines, ISO 376, ISO 204.