AS 2331.1.4-2001 PDF

Full title and description

Methods of test for metallic and related coatings — Method 1.4: Local thickness tests — Magnetic induction and eddy current methods. Specifies requirements for two non‑destructive local thickness testing methods: (a) magnetic induction (low frequency) for non‑magnetic and organic coatings on magnetic substrates; and (b) eddy‑current (high frequency) for non‑conductive coatings on non‑magnetic substrates and certain metallic coating/substrate combinations.

Abstract

This Standard defines procedures, apparatus, calibration and reporting for magnetic induction and eddy‑current dry film thickness measurement of metallic and related coatings. It summarises application limits, accuracy expectations and factors affecting measurement (surface roughness, curvature, probe pressure and edge effects) and is intended for routine quality control and inspection.

General information

• Status: Current (reconfirmed 2017).
• Publication date: 17 July 2001.
• Publisher: Standards Australia.
• ICS / categories: Surface treatment and coating (ICS 25.220 — metallic and organic coatings / coating inspection).
• Edition / version: 2001 edition (third edition reported in catalogues).
• Number of pages: 7 (standard publication PDF/print length as listed by Standards Australia distributors).

Key bibliographic and status details above are based on the Standards Australia publication record and standard distributors.

Scope

This Standard sets out requirements for two non‑destructive local thickness methods: the magnetic induction (low frequency) method for non‑magnetic/organic coatings on magnetic substrates, and the eddy‑current (high frequency) method for non‑conductive coatings on non‑magnetic substrates or coatings/substrate combinations with appreciably different conductivities. It applies to coating thicknesses not less than 2 µm and includes calibration, measurement procedure, preparation of test pieces and reporting requirements. The Standard also identifies factors that affect accuracy (see Appendix A).

Key topics and requirements

• Definitions and measurement principles for magnetic induction and eddy‑current methods.
• Apparatus and probe types, including recommended calibration foils and coated standards.
• Calibration procedures and use of basis‑metal standards to ensure traceable, repeatable readings.
• Measurement limits and expected accuracy: under best conditions accuracy is approximately ±0.7 µm or ±10%, whichever is greater.
• Preparation of test pieces, probe application considerations (pressure, temperature), surface roughness, curvature and edge effects (guidance in Appendix A).
• Reporting requirements: instrument identification, calibration data, measurement positions and statistical presentation of results.
• Not suitable for chemical conversion coatings (note in Standard).

The above topics are drawn from the Standard text and official product descriptions.

Typical use and users

Used by coating inspection teams, quality control laboratories, metal finishers, galvanizers, anodisers, manufacturers of plated or painted parts, and third‑party inspection agencies for acceptance testing and process control. Typical applications include verification of electroplated layers, tin/lead/silver plating, anodic oxide layers on aluminium and organic coating thickness checks on steel. Portable coating‑thickness gauges and inspection kits are commonly used to perform the tests in the field or production line.

Related standards

Part of the AS 2331 series (Methods of test for metallic and related coatings). Closely related and cross‑referenced standards include AS 2331.1.1 (micrographic cross‑section thickness measurement), AS 2331.2.1 (average coating mass/thickness by dissolution methods) and international standards covering similar methods (ISO 2178, ISO 2360, ISO 2808 and relevant ASTM methods such as ASTM B499/ASTM D1186). Users should consult referenced documents for complementary or alternative measurement procedures.

Keywords

coating thickness; dry film thickness (DFT); magnetic induction; eddy current; non‑destructive testing; calibration; metallic coatings; anodic coatings; Standards Australia; AS 2331.1.4.

FAQ

Q: What is this standard?

A: AS 2331.1.4-2001 is an Australian Standard that specifies methods, apparatus and procedures for local thickness measurement of metallic and related coatings using magnetic induction and eddy‑current techniques.

Q: What does it cover?

A: It covers the principle, required apparatus, calibration (including use of calibration foils and coated/basis‑metal standards), test piece preparation, measurement procedure, factors affecting accuracy and reporting for both magnetic induction and eddy‑current local thickness tests. It applies to coating thicknesses ≥ 2 µm and notes limitations such as unsuitability for chemical conversion coatings.

Q: Who typically uses it?

A: Coating inspectors, QC laboratories, metal finishing and plating shops, galvanizers, anodisers, OEM quality engineers and third‑party inspection bodies for routine acceptance testing and process control. Portable thickness gauges and inspection kits reference this Standard in product specifications.

Q: Is it current or superseded?

A: The 2001 edition is listed as current and was formally reconfirmed in 2017 (reconfirmation notice). Users should check for any later revisions or replacement documents before applying the Standard in regulated procurement.

Q: Is it part of a series?

A: Yes — it is part of the AS 2331 series, which groups methods of test for metallic and related coatings (local thickness, average mass/thickness, corrosion tests and physical tests). See AS 2331.0 for series guidance and cross‑references.

Q: What are the key keywords?

A: Coating thickness, magnetic induction, eddy current, DFT, non‑destructive measurement, calibration foils, metallic coatings, anodising.