Non-Destructive testing (NDT) Services
X-Ray Radiography
X-Ray radiography is an NDT method used to inspect material and components using the concept of differential absorption of penetrating radiation. Each specimen under evaluation will have difference in density, thickness, shapes, size, or absorption characteristics, thus absorbing different amounts of radiation. The unabsorbed radiating that passes through the part is recorded on the films. Indication of internal and external conditions will appear as variants of black / white/ gray constraints on exposed film.
Gamma Ray Radiography
The apparatus necessary for gamma-ray radiography is vey simple. most cabalt-60 source are cylindrical, with dimension of 3 by 3 to 6 mm and sealed in appropriate container or capsule. Unlike X-ray, Gamma- ray from its source are emitted in all directions; therefore a number of separate welded objects having cassette containing film, fastened to the back of each object, are disposed in a circle around the source placed in a central position. This way many welded objects can be radiographed simultaneously and overnight exposures may be taken without continuous supervision.
Magnetic particle Inspecting
This method of non- destructive testing tend to supplement rather than displace radiography. For example, radiography ordinarily cannot detect small crack, especially when they are too small be seen with human eye. This method of inspection is used on magnetic ferrous weldments for detecting invisible surface or slightly subsurface defect. Deeper subsurface defects are not satisfactorily detected because the influence of the distorted lines of magnetic flux (owing to discontinuity) on the magnetic particles spread over the job surface become weaker with the distance, so that sensitivity falls away rapidly with the depth. The defects commonly revealed by magnetic particle inspecting are quenching cracks, thermal cracks, seams lap, grinding cracks, overlaps, non-metallic inclusion, fatigue crack, hot tears, etc. magnetic particle inspection is a relatively simple and easy technique
Dye Penetrant Testing
A liquid penetrant test is non-destructive type. It detect flaws that are open to the surface e.g. Crack , seams, la[, lack of bond, porosity, cold shuts etc. it can be effectively used not only in the inspection of ferrous metals but is especially useful for non-ferrous metal product and on non-porous, non-metallic materials such as ceramics, plastic and glass. The principle of liquid penetrate test is that the liquids used enter small openings such as crack or porosities by capillary action the rate and extent of this actin are dependent upon properties such as surface tension, cohesion, adhesion and viscosity
Ultrasonic testing
Ultrasonic inspection is employed to detect and locate internal defects such as cracks, porosity, inclusions, lack of fusion and incomplete penetration. Wall thickness can be measured in close vessels or in case where such measurement cannot otherwise be made. Ultrasonic vibrations can be used locate defects in ferrous and non- ferrous metallic objects as well as in plastics and ceramic.
Ultrasonic inspection for flaw detection makes use of acoustic waves with frequencies in the range between 20kHz and 20kHz, which can be transmitted through solids (even liquid as well) and get reflected by the subsurface defects. Ultrasonic waves from a basis for detecting, location and size, estimation of defects
Hardness testing
The hardness test gives and idea of the resistance to wear of the weld metal. This is important with the respect of the components which have been built up and have to withstand abrasive wear. Hardness value can give information about the metallurgical change cause by welding. In case of premium and high carbon steels and cast iron, the heat effected zone or weld junction may become hard and brittle because of the formation of the marten site. Hardness value in a welding joint are usually sensitive to such conditions of weld, as The process used electrode composition heat input Plate thickness preheat or interposes temperature Hardness values indicate whether the correct welding technique (pre and post) heat treatment have been carried out. The hardness of weld is particularly important if the weld must be machined