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Delta Spec Rope Access Company

Inspection

At a time of rising operation costs and aging assets/infrastructure, integrity assurance and maximising life expectancy has never been more essential. Effective plant inspections, monitoring and testing are key contributors for verifying asset integrity and minimising downtime.

Non Destructive Testing is the branch of engineering concerned with all methods of detecting and evaluating flaws in materials. Flaws can affect the serviceability of the material or structure, so NDT is important in guaranteeing safe operation as well as quality control and assessing plant life.

DeltaSpec offer a range of Non Destructive Testing, our main Inspection techniques can be seen below. All our inspection personnel are certified by the British Institute of Non Destructive Testing and hold Personal Certification in Non Destructive Testing (PCN Level 2) to their relevant discipline.

Dye Penetrant Inspection (PT)

A low cost method of detecting surface breaking flaws, such as cracks, cold laps, porosity etc. The dye penetrant is drawn into the surface breaking flaw by capillary action and excess surface penetrant is then removed; a developer is then applied to the surface, to draw out the penetrant in the crack and produce a surface indication. The technique can be applied to any non-porous clean material, metallic or non-metallic, but is unsuitable for dirty or very rough surfaces.

Eddy Current Inspection (ET)

An electrical technique detecting surface breaking defects in all electrically conducting materials through paint and surface coatings. All electrical methods are indirect; a material property is measured as an electrical property variation. A coil carrying an AC current is placed on the specimen surface. This generates circulating eddy currents in the specimen close to the surface and these in turn affect the current in the coil by mutual induction. Flaws and material variations affect the strength of the eddy currents. The presence of flaws is therefore measured by electrical changes in the excitation coil. Applications range from crack detection to metal sorting and from tube, bar and weld inspection.

Magnetic Particle Inspection (MT)

An extremely cost effective method for the detection of surface and near surface flaws in ferromagnetic materials is primarily used for crack detection. Following magnetisation the specimen is covered with very fine iron particles either dry or suspended in a liquid. Surface breaking flaws distort the magnetic field causing local magnetic flux leakage that attract the iron particles producing a build-up that can be seen visually.

Ultrasonic Inspection (UT)

Ultrasonic methods of NDT use beams of mechanical waves (vibrations) of short wavelength and high frequency, transmitted from a small probe in contact with the specimen surface and detected by the same or other probes. Such mechanical vibrations have different forms depending on the direction of particle movement in the wave motion, so there are several forms of ultrasonic waves. The most common and widely used in NDT are compressional and transverse (shear) waves. They can travel large distances in fine-grain metal and an oscilloscope display (A-scan) shows the time that it takes for an ultrasonic pulse to travel to a reflector (flaw or back-surface). Applications include location of manufacturing defects in welds and castings through to Corrosion / Erosion monitoring and large scale corrosion mapping.