Non-Destructive Testing Mechanical (overview)

The successful application of mechanical nondestructive testing inspection methods requires that

    1. The test system and procedure be suited to both inspection objectives and types of flaws.
    2. The operator has sufficient training, experience and is qualified.
    3. The standard for acceptance is defined.

The most commonly used non destructive testing methods used for the inspection of ferrous and non-ferrous steels on construction sites comprise the following:

Radiographic Testing

This inspection method is used for the inspection of carbon steel for the investigation of welding defects on the surface and sub surface. The advantages of this method is that there is a permanent record for as built purposes. Approval certification is required to use this equipment on site.

This inspection method can identify the following welding defects, pipe mismatch, lack of penetration lack of fill, undercut, cavities. burn through, slag inclusions, lack of fusion, porosity, cracking, tungsten inclusions.

Liquid-Penetrant Testing

This inspection method is used for the inspection of carbon steel for the investigation of welding surface and surface cracking.The advantages of this method is that it is easy to use and very portable. Operators are required to be certified.

This inspection method can identify the following defects, all type of surface cracks ,porosity, shrinkage areas, laminations.

Magnetic-Particle Testing

This inspection method is used for the inspection of carbon steel for the investigation of welding surface and surface cracking. The advantages of this method is that it is easy to use and very portable. This method is especially suitable for surface carbon steel microcracking. Operators are required to be certified.

This inspection method is can identify the following defects,subsurface defects.

Ultrasonic Inspection Testing

This inspection method is used for the inspection carbon steel for the investigation of welding defects. Operator approval certification is required in order to use this equipment on site.

This inspection method can identify the following defects, cracks laminations, cavities, flakes pores bonding faults, inclusions, internal flaws, measure thickness and corrosion.

Hardness Testing

This inspection method is used for checking the hardness of the heat effected zone after post weld heat treatment of welded connections.

It is normally stated in the contract specifications the hardness value this inspection method has to meet.