Method and Adaptability
GIS-MIC masters surface control and density procedures in its performance along with its evaluation.
- Control methods
- Codes / Norms
Definition of NDT different methods
Magnetic particle inspection:
Magnetic particle inspection consists in subjecting a piece to be checked to an effective magnetic field. In case a discontinuity appears, the magnetic field lines undergo a distortion which generates magnetic field « leaks », also called magnetic flux leakage.
An indicator product is applied during the magnetization (simultaneous technique) or after magnetization (residual technique) on the surface to be examined. The indications are notable by the black coloured and/or fluorescent product indicator drowns to the right sight of the defect.
In accordance to indicator product used, these indications are observed either in artificial white light or daylight or under ultraviolet radiation (UV-A).
The indications detection is improved when they are perpendicularly located in the magnetic field lines of force.
Penetrant testing also called liquid penetrant inspection is used to locate surface-breaking defects in all non-porous materials. It holds four phases of which the first one consists in a perfect cleaning of the piece to be controlled. During the second phase, a coloured and/or fluorescent liquid, called « penetrating » is applied to the surface to be checked. The liquid penetrates by capillarity inside the discontinuities, requiring a moment before the next step.
During the third phase, the excess of « penetrating » should be removed from the surface.
At this point, the surface can be covered by a thin « revealer »layer. This product owns its designation to its properties. Indeed it absorbs the « penetrating » contained in the discontinuities. During this fourth phase, the « revealer makes the penetrating sweat » which lead the discontinuities to appear on-surface.
The indications observation will be done under artificial white light (or in day light) or under ultraviolet radiation (UV-A) depending of the « penetrating » used.
In the most common configuration called reflection, an ultrasonic translator is used and acts as a transmitter and a receiver. The supervision of a particular piece consists in placing the ultrasonic translator on or above it and analyse the collected signals.
Contact control can be distinguished from submerged controls.
During a contact control, the ultrasonic translator is placed on the piece surface with use of a coupling. While submerged control requires moving the ultrasonic translator a certain distance away from the piece in a liquid environment, generally in water. We also distinguish manual controls in which the moves of the translator are led by an operator and automated controls.
The ultrasonic beam transmitted in the piece and therefore the sensitivity and control spatial resolution are characterised by the translator used, its dimensions, the waves frequencies and specifics adjustments (delay law for phased array).
Radiography is a non-destructive control procedure obtaining an image by electromagnetic radiation X or gamma of a non-uniformly composed and opaque object. The image is produced by a detector which is:
A silver film
A stored-value photostimulable screen
A set of digital detectors.
This method principle is based on the differential absorption of the environment ruled by its atoms atomic number and its density. A lower absorption is inducted by local lacks of material and identifiable by a higher optical density on the silver film or a level of grey more intense on the digital images.
In industrial radiology, X-rays are produced either by X-ray tubes (most of the time) or by a particle accelerator in case of high energy applications. The gamma radiation sources used in industry are the followings ones; iridium 192, cobalt 60 and selenium 75.
Radiography is an imaging technique which allows visualizing the material volume lacks of the object to be checked in two dimensions. There exists another technique based also on the electromagnetic radiations absorption which allows studying the material density by volume elements: the tomography.
Because of X-rays and Gamma ionizing properties, a strict radioprotection regulation must be applied.
We perform/verify your control procedures.
Indeed, we have certified experts level 2 and 3 according to NF IN ISO 9712-COFREND.
These procedures can be effectuates according to the following construction codes: CODAP, CODETI, in 1090, Standarts and ISO, RCC-M, ASME, AWS, API, BS…
We furnish our specialists CND certified levels 2 and 3 (COFREND/ASNT) the right equipment to operate their quality services in France and abroad.
GIS-MIC personnel works along with conventional methods as ultrasounds, radiography, penetrant testing and magnetic particle inspection and new methods as phase array, TOFD or ACFM.
Competences and trades:
Engineers, RT/UT/MT/PT Technicians level 2 and 3.
Phased array, ACFM, AUT and TOFD.