ISO 9015-2:2016

Overview - ISO 9015-2:2016 (Microhardness testing of welded joints)

ISO 9015-2:2016 specifies procedures for microhardness testing (Vickers) on transverse sections of welded joints in metallic materials where high hardness gradients exist. It covers low‑force Vickers tests in accordance with ISO 6507‑1, normally using test loads from 0.98 N to less than 49 N (HV 0.1 to < HV 5). The standard is intended to determine the highest and/or lowest hardness levels in the parent materials, heat‑affected zone (HAZ) and weld metal, and is tailored for applications where fine spatial resolution is required.

Key topics and technical requirements

• Test method: Vickers microhardness in accordance with ISO 6507‑1; two test forms - rows of indentations (R) and individual indentations (E).
• Load range: Normally HV 0.1 to < HV 5 (0.98 N to < 49 N). Tests at 49.03 N and above are covered by ISO 9015‑1.
• Specimen preparation: Transverse cross‑section, mechanically cut and metallographically prepared (polished, preferably etched) to avoid altering hardness.
• Environmental conditions: Ambient temperature typically (23 ± 5) °C.
• Indentation placement:
  • Rows (R) and individual (E) locations illustrated for parent metal, HAZ and weld metal.
  • Recommended centre‑to‑centre distances (L) in the HAZ vary by load and material (examples from the standard):
    • Ferrous metals: HV 0.1 → L ≈ 0.2 mm; HV 1 → L ≈ 0.5 mm; HV 5 → L ≈ 0.7 mm.
    • Aluminium/copper alloys: larger spacings (e.g. HV 0.1 → 0.6–2 mm, HV 1 → 1.5–4 mm, HV 5 → 2.5–5 mm).
  • For metals that harden in the HAZ, at least one indentation shall be ≤ 0.5 mm from the fusion line.
• Reporting: Test report shall include type of hardness test, machine identification, parent material, thickness, weld type and process, consumables, post‑weld heat treatment/ageing, notes, and a picture or drawing (see Annex A/B for example formats).
• Limitations: Not applicable to hardness testing of resistance spot/projection/seam welds (see ISO 14271), very narrow laser/electron‑beam welds (see ISO 22826), or macro‑hardness loads ≥ 49.03 N (ISO 9015‑1).

Applications and who uses it

ISO 9015‑2 is used by:

• Welding inspectors, metallurgists and materials laboratories for characterizing hardness gradients across welds.
• QA/QC engineers verifying weld integrity after welding or post‑weld heat treatment.
• Manufacturers and fabricators working with dissimilar materials where localized hardening or softening must be quantified. Practical uses include detecting hardened/softened HAZ regions, assessing weld metal properties, validating heat treatment, and supporting failure analysis.

Related standards

• ISO 6507‑1 - Vickers hardness test method (normative reference).
• ISO 9015‑1 - Hardness testing with higher loads (≥ 49.03 N).
• ISO 14271 - Vickers testing for resistance spot/projection/seam welds.
• ISO 22826 - Guidance for very narrow welds (laser/electron beam).

Keywords: ISO 9015‑2:2016, microhardness testing, Vickers hardness, welded joints, heat‑affected zone, HAZ, weld inspection, HV 0.1, ISO 6507‑1.