ISO 14577-2:2015

Overview

ISO 14577-2:2015 - "Metallic materials - Instrumented indentation test for hardness and materials parameters - Part 2: Verification and calibration of testing machines" - defines how to verify and calibrate machines used for instrumented indentation testing (IIT). It complements ISO 14577-1 (test method) by specifying both direct and indirect verification procedures to ensure accurate measurement of force, displacement, indenter geometry and machine compliance. The standard also applies to transportable testing machines and requires routine and method‑specific checks for reliable hardness and material-parameter data.

Key topics and technical requirements

• Direct verification and calibration (performed at stable temperature, typically 10–35 °C; preferably 23 ± 5 °C):
  • Test force calibration: Each force range must be calibrated over its full range with a minimum of 16 evenly distributed points during both application and removal; procedures repeated at least three times. Tolerances: typically ±1 % for forces ≥0.001 N (nano range ±1 % recommended) and ±2.5 % for forces <0.001 N.
  • Displacement measuring device calibration: Calibrate on-machine for each travel range at ≥16 points, repeated three times. Resolution requirements depend on range (micro-range reference depth h = 0.2 µm; macro typically ≥2 µm).
  • Machine compliance calibration: Procedures to determine and correct the machine’s elastic response are specified (see Annex D for normative procedure).
  • Indenter verification and area function: Verification of indenter geometry (Vickers, Berkovich, spherical, ball, etc.) and calibration/verification of the indenter area function, required especially when indentation depth is less than 6 µm.
  • Verification of test cycle: Confirm correct force application, dwell and removal without shock or vibration.
• Indirect verification: Used to determine machine repeatability and required for routine periodic checks; must be carried out independently for each test method.
• Environmental and installation requirements: Protection from vibration, air currents and temperature fluctuations; traceability of calibration instruments to national standards.
• Documentation: Requirement for verification reports and calibration certificates.

Practical applications

• Ensures traceable, repeatable IIT measurements for hardness, indentation modulus and elasto-plastic properties.
• Supports calibration labs, materials testing laboratories, quality assurance, research & development, and manufacturers of indentation equipment.
• Useful for routine service checks, initial machine commissioning and validation of transportable IIT units used in field testing.

Who should use ISO 14577-2:2015

• Calibration and metrology laboratories
• Mechanical testing labs and material scientists
• Equipment manufacturers and service engineers
• Quality managers requiring traceable hardness and modulus data

Related standards

• ISO 14577-1:2015 - Instrumented indentation test - Test method
• ISO 14577-3 - Calibration of reference blocks
• ISO 376 - Calibration of force-proving instruments

Keywords: ISO 14577-2:2015, instrumented indentation test, verification and calibration, testing machines, indenter area function, machine compliance, displacement calibration, force calibration.