May 2010
Document updated in in July/August, 2011

Suggested definitions of some MT terms left out of EN 1330-7:2005 standard

In our paper titled ‘‘MT Lexicon (English/French)’’ published in March 2010 on our Website, we gave a translation in French of many terms used in MT. 

Definition of some of them is given in the EN 1330-7:2005 standard.

Due to technical improvements of MT, such as new magnetisation techniques or new devices to make MT a more reliable method, we think it useful to introduce new terms.

Readers may find underneath definitions we suggest for some entries “forgotten” in the standard.

Some terms are used for both PT and MT, especially those relating to lighting and viewing conditions.

Blue haze

Term in French
Brouillard bleu

Definition
Shady view due to the fluorescence emitted by organic molecules in the vitreous humour of the eye under the influence of UV-A if UV blocking goggles are not worn.

Combined radiometer/luxmeter

Term in French
Combiné radiomètre/luxmètre

Definition
Digital meter used to measure both the (UV-A or blue light) irradiance and the (visible light) illuminance.

Contrast

Term in French
Contraste

Definition
Ratio between the illuminance given by a discontinuity indication and that by the surrounding background.

Cut-off

Term in French
Coupure

Definition
Wavelengths at which the irradiance or the illuminance (as appropriate) is at 50% (generally chosen value) of the peak value.

Demagnetizing unit

Term in French
Démagnétiseur

Definition
Equipment used to set the residual magnetization to an acceptable figure.

Digital luxmeter

Term in French
Luxmètre numérique

Definition
Digital meter used to measure the (visible light) illuminance.

Digital radiometer

Term in French
Radiomètre numérique

Definition
Digital meter used to measure the (UV-A or blue light) irradiance.

Dry powder dispenser

Term in French
Pulvérisateur de poudre sèche

Definition
Hand-held item used to spray dry powders.

Dual purpose detection media

Term in French
Produit indicateur mixte

Definition
Detection media visible both under UV-A radiation and white light.

Fluorescent transparent comparator

Term in French
Comparateur d’indications fluorescentes

Definition
Transparent stiff plastic ruler containing drawings of geometrical shapes (lines, circles, etc.) of generally green colour in visible light and fluorescent under UV-A radiation allowing for assessing the dimensions of indications.

Full width spectral at half maximum (FWSHM)

Term in French
Largeur spectrale à mi-hauteur (LSMH)

Definition
Band width of wavelengths for which the irradiance or the illuminance (as appropriate) is at 50% of the peak value.

Headstock

Term in French
Épanouissement polaire fixe

Definition
Mass in full or laminated ferromagnetic material being a part of the magnetic circuit (or electromagnet) of a magnetic bench and which is used as interface with the part under inspection to provide an adequate magnetic flux circuit. A bench comes with two stocks, generally one fixed (headstock) and one mobile (tailstock: see this term).

Induced light source

Term in French
Lampe à induction

Definition
UV-A radiation or white light source fitted on portable electromagnets which lights on by induction.

Lift test bar

Term in French
Barreau pour test de soulèvement

Definition
Ferromagnetic parallelepipedic steel block, whose mass is 4.5 kg (for AC magnetic fields) or 18 kg (for DC or AC rectified magnetic fields), used to carry out the periodic functional test of permanent magnets and portable electromagnets.

Longitudinal magnetization

Term in French
Aimantation longitudinale

Definition
Magnetization where the magnetic field lines are essentially parallel to the longitudinal axis of a part under inspection, allowing for detecting transverse discontinuities.

Magnetic flux density indicator

Term in French
Indicateur d’induction magnétique

Definition
Compass-like item with a pointer or an analog or digital display to measure residual magnetisation. The pointer-equipped version cannot be calibrated.

Non-contact technique by induced current flow

Term in French
Technique d’aimantation sans contact par passage de courant induit

Definition
Technique in which the part (ring or pipe-shaped part for instance) is considered as the secondary of a transformer. The primary circuit is a cable, going through the hole of the part.  The primary of the transformer is generally the magnetic circuit or the electromagnet of the magnetic bench.

Pear shaped centrifuge tube

Term in French
Poire/tube de sédimentation/ampoule à décanter

Definition
Graduated tube to measure the solid content of a liquid. It DOES NOT measure the magnetic particle content of a magnetic ink. . It is designed only to check that the content of solid particles of a brand-new magnetic ink meets the supplier's or prime's specification.

Permanent magnet

Term in French
Aimant permanent

Definition
Set of two magnetic (North and South) poles which, spaced out one from the other one and applied on the test surface, induce a true DC magnetic field in the area of the part between both poles.

Residual or remanent magnetization

Term in French
Aimantation résiduelle ou rémanente

Definition
Magnetization remaining in a part after the shut-off of the magnetising field/current.

Swinging field technique

Term in French
Technique d’aimantation par champ tournant

Definition
Technique in which the magnetization vector turns very quickly to allow for the detecting of all defects (regardless of their direction) in a single shot. This is generally achieved by using 2 phases of a 3-phase main power source. A phase gives the longitudinal magnetization while the second phase gives the transverse magnetization. Both magnetizations shall be balanced. Due to the delay between phases, the magnetization vector scans all the directions on 360°. Equipment may be either a magnetic bench with the current flow technique for the transverse magnetization and with the magnetic flow technique for the longitudinal magnetization, or a non-contact unit (multidirectional magnetization chamber or an inspection equipment by induced current).

Tailstock

Term in French
Épanouissement polaire mobile

Definition
The mobile stock of a magnetic bench, allowing for fitting parts of a large range of lengths. See the “headstock” entry.

Transverse magnetization

Term in French
Aimantation transversale

Definition
Magnetization where magnetic field lines are essentially perpendicular to the longitudinal axis of the part under inspection. If the part is cylinder-like, this magnetisation is also called circular magnetisation. It allows for detecting longitudinal discontinuities.

UV-A or blue light source

Term in French
Projecteur UV-A ou de lumière bleue

Definition
Source of UV-A radiation or of blue light.

(UV-A or blue light) irradiance

Term in French
Éclairement énergétique (UV-A ou lumière bleue)

Definition
Power of (UV-A or blue light) electromagnetic radiation received per surface area unit to be inspected.

UV-A overhead Source

Term in French
Plafonnier UV-A

Definition
UV-A source secured to the ceiling or overhanging the inspection area.

(Visible light) illuminance

Term in French
Éclairement lumineux (lumière visible)

Definition
Quantity of (visible light) luminous flux received per surface area unit of the area to be inspected.

Woods glass filter

Term in French
Filtre de Wood

Definition
UV-B and UV–C blocking filter letting violet and infrared radiations pass through along with UV-A radiation.

Of course this list is not all-comprehensive and it will be updated when needed.

We hope that the Technical Group in charge of the EN 1330-7:2005 standard revision will eventually consider our suggestions.

Reference

• EN 1330-7:2005 Non-destructive testing Terminology Part 7: Terms used in magnetic particle testing, European Committee for Standardization, Brussels, Belgium, 2005.

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We, Pierre CHEMIN and Patrick DUBOSC, welcome any comment, any idea. If you have some examples you would like to see discussed here, please give us all the useful indications. If you require confidentially, we would modify locations, names and some parameters to prevent any traceability.
Nevertheless, we are convinced that our site may be a kind of surge-valve: the topic is NOT to target this company, or that auditor; but it is always to make users think, to make them ask themselves, or others, the right questions.

We may also give advice, once again on a confidential basis if needed: please, feel free to ask questions, to document our data basis: about Material Safety Data Sheets (MSDS), about environment, a chemical name you don't understand, a Penetrant process you have heard about, etc.
We have plenty of examples, some being out of all the specifications/standards, which led to the discontinuities detection, when the "current, normal, processes" prevented discontinuity finding.