IS 1501 : 2019Method for Vickers Hardness Test for Metallic Materials

IS 1501:2019 specifies the Vickers hardness test for metallic materials — the diamond-pyramid indentation hardness test (HV), usable across the full hardness range and especially for thin sections, coatings, weld zones, case-hardened layers and micro-hardness. It is the most versatile of the hardness methods (Brinell/Rockwell/Vickers) on fabrication and QC work.

It is read with the metals-testing stack:

• IS 1500 — Brinell hardness · IS 1586 — Rockwell hardness (the sister methods)
• IS 1608 Part 1 — tensile testing · IS 1786 / IS 2062 — rebar / structural steel
• IS 1367 Part 3 — fastener mechanical properties · IS 9595 — welding (HAZ hardness)

A square-based diamond pyramid is pressed at a defined force; the two diagonals of the impression are measured optically and HV = constant × F / d². Its advantages drive where it is used:

• One continuous scale across all hardness (soft to very hard) — no scale-changing as with Rockwell
• Geometrically similar indentations — HV is (largely) load-independent in the macro range, so results compare across forces
• Micro to macro: micro-Vickers (e.g. HV0.01–HV1) for thin coatings, case depth, individual weld phases and metallographic structures; macro-Vickers (HV5–HV100) for general components
• Weld HAZ hardness traverse: the standard way to check that welding hasn't produced brittle, over-hard zones (IS 9595) — a key weld-procedure-qualification measurement
• Case-hardening depth profiling

Report format: HV with the load (e.g. *320 HV10*) — a number without the load/scale is meaningless. Needs a flat, polished, well-supported surface; thin specimens must be thick enough for the indentation.

Scenario: verifying a structural steel weld procedure — the heat-affected zone must not be over-hard (brittle/crack-prone) per IS 9595.

Step 1 — method: Vickers (HV) — chosen because it can traverse parent metal → HAZ → weld metal on one continuous scale with small, closely-spaced indentations.

Step 2 — prep: section, polish and lightly etch the weld macro; ensure adequate thickness/support.

Step 3 — traverse: take a line of HV (e.g. HV5/HV10) indentations across parent → HAZ → weld → HAZ → parent at the specified spacing.

Step 4 — assess: the peak HAZ hardness must stay below the acceptance limit (commonly ~350 HV for many structural steels) — exceeding it indicates too-fast cooling / insufficient preheat → brittle, crack-susceptible HAZ.

Step 5 — action: if over-hard, the welding procedure (preheat, heat input, consumable) is revised and re-qualified — the hardness traverse is a *procedure-qualification* gate, not just a number. Report each as 'NNN HV10'.

1. Reporting HV without the load. '320 hardness' is meaningless — it must be e.g. 320 HV10; mixing loads/methods invalidates comparison.

2. Wrong load for the feature. Macro load on a thin coating punches through to the substrate; too-small load on coarse structure lands on one phase — match load to the feature scale (micro vs macro).

3. Poor surface prep / thin unsupported specimen. Vickers needs a flat, polished, properly supported surface and adequate thickness, or the optically-measured diagonals are wrong.

4. Treating hardness as the acceptance test. It correlates with strength and screens HAZ embrittlement, but final acceptance of steel/fasteners is the specified tensile/proof tests — hardness is a (powerful) screen.

5. Single indentation. Take several / a proper traverse and assess the peak (esp. for HAZ) — one reading can miss the hard zone.

• IS 1500 — Brinell hardness · IS 1586 — Rockwell hardness
• IS 1608 Part 1 — tensile testing of metals
• IS 9595 — metal-arc welding (HAZ hardness limits) · IS 814 — electrodes
• IS 1367 Part 3 — fastener mechanical properties
• IS 1786 / IS 2062 — rebar / structural steel

IS 1501:2019 is a current revision, harmonised in method with ISO 6507, so manufacturer/lab certificates quoting ISO 6507 HV are directly comparable. On construction and fabrication work, Vickers earns its place as the most versatile hardness method — and specifically as the weld-HAZ and case-depth tool, because a single continuous scale and small indentations let you traverse a weld and catch a brittle, over-hard HAZ that a procedure produced.

The practitioner discipline: use it as a screen and a procedure-qualification gate, not a verdict — an over-hard HAZ means *fix and re-qualify the welding procedure* (preheat/heat input), an in-band reading lets fabrication proceed to the definitive tensile/proof tests. Always report HV with the load, match the load to the feature scale, prepare the surface properly, and traverse rather than spot-check critical zones. Keep the machine calibrated against reference blocks — an out-of-cal tester quietly passes brittle welds and fails sound steel.