Weld testing is an essential service, and one that needs to be carried out on any weld, no matter where it is or what it supports. However, the idea behind weld testing is subject to a number of different factors. The main aspect to decide upon before weld testing is carried out is the nature of the application and therefore what the weld is required to do. Once this has been established, the testing can proceed and will be successful if carried out with care. In order to test welds in a non-destructive way, portable x-rays are needed.
The Nature of Non-Destructive Testing
The overall look and appearance, as assessed by the welder looking over the workmanship after it has been completed, is often regarded as enough to ascertain whether the weld is of good quality or poor quality. While this cursory test may be all that is needed in non-essential welding situations, it is not always good enough for other applications, and is certainly not going to make the grade when essential structures are considered; for example, buildings or bridges. The surface quality of a weld does not say anything about the internal quality of the same weld – and this is the most important factor to test.
For this reason, non-destructive testing is essential. Non-destructive examinations make it possible to check that what looks fine on the surface is also passing the grade beneath the surface. There are five basic methods for carrying out a non-destructive examination of a weld: visual, magnetic particle, ultrasound, liquid penetrant, and x-ray.
X-ray weld inspection is an important and accurate way to carry out non-destructive testing. X-rays are used to ascertain the internal quality and soundness of welds. X-rays can pass through the join being inspected in order to provide an image that can be used to ascertain whether the weld is good for the task. X-rays are generated by high-voltage machines which are applied to a tube, whereby the x-ray wavelength becomes shorter and has more penetrating power. X-rays test welds effectively because not all the emission from the x-ray passes through the material being tested. Depending on the density, different materials will absorb different wavelengths. The image that is given by the x-ray examination is developed on a screen, or today is more widely generated as a digital image.
Advantages of Mobile X-Ray
Inspection welding tasks are made easier when using portable x-ray machines. The reliability of the technology is a distinct advantage, particularly when the testing takes place under difficult conditions or in extreme environments. The non-destructive testing principle often has to be carried out in the field in order to prevent damage to the structure under test. The task of detecting flaws is easier because the image shows up immediately, and decisions can be made at the site about what to do. Welds, being highly important components of any structure, can be swiftly checked and quickly fixed if needed.
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