ISO 20339:2017 pdf – Non-destructive testing — Equipment for eddy current examination — Array probe characteristics and verification.
1 Scope This document identifies the functional characteristics of eddy current array probes and their interconnecting elements and provides methods for their measurement and verification. The evaluation of these characteristics permits a well-defined description and comparability of eddy current array probes. Where relevant, this document gives recommendations for acceptance criteria for the characteristics. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 12718, Non-destructive testing — Eddy current testing — Vocabulary ISO 15548-1, Non-destructive testing — Equipment for eddy current examination — Part 1: Instrument characteristics and verification ISO 15548-2:2013, Non-destructive testing — Equipment for eddy current examination — Part 2: Probe characteristics and verification 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 12718 and the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at http:// www .iso .org/ obp — IEC Electropedia: available at http:// www .electropedia .org/
4.1.5 Safety The probe and its interconnecting elements shall meet the applicable safety regulations regarding electrical hazard, surface temperature, or explosion. Normal use of the probe should not create a hazard. 4.1.6 Environmental conditions The temperature and humidity for normal use, storage and transport should be specified for the probe and its interconnecting elements. The tolerance of the probe and its interconnecting elements to the effects of interference noise and electromagnetic radiation shall conform to electromagnetic compatibility (EMC) regulations. Materials used in the manufacture of the probe should be resistant to contaminants. 4.2 Electrical characteristics The electrical characteristics of a probe connected to a specified length and type of cable are the following: — recommended range of excitation voltage for safe operation; — recommended range of excitation frequencies. The electrical characteristics of any extension cable are the following: — resistance and capacitive reactance per length unit. 4.3 Functional characteristics The functional characteristics of an array probe shall be determined for a defined system. The measurement of the functional characteristics of a probe requires the use of reference blocks. The material used for the reference block is determined by the application. The functional characteristics of a probe are the following: — angular sensitivity; — response to elementary discontinuities or variations (hole, slot, deposit, etc.); — length and width of coverage for a given pattern; — area of coverage for a given pattern; — minimum dimensions of discontinuities for constant response; — penetration characteristics;4 Probe and interconnecting elements characteristics 4.1 General characteristics 4.1.1 Application Probes and interconnecting elements are selected to satisfy the requirements of the intended application. The design is influenced by the instrument with which they are used. 4.1.2 Probe types The probe is described by the following: — type of material to be examined, i.e. ferromagnetic, non-ferromagnetic with high or low conductivity; — the geometry of the examined zone; — whether it is conformable or not; — family, e.g. coaxial probe, surface probe; — the receiver type; — the number of elements (transmitters and/or receivers); — shape and assembly of elements and spacing; — purpose of the examination, e.g. detection of discontinuities, sorting or thickness measurement, etc.; — specific features, e.g. focused, shielded, etc.; — the function of the elements (transmission or reception) as well as the type of measurement (absolute or differential) may coexist in the same array probe depending on the patterns, the sequencing and the instrument software. 4.1.3 Interconnecting elements They may include the following: — active devices, e.g. multiplexer (built-in or external), amplifier; — cables and/or extensions; — connectors; — slip rings; — rotating heads; — polarizers. 4.1.4 Physical characteristics The following are to be stated among others: — external size and shape; — weight; — information for mechanical mounting;