Determination of corosion in carbon steel pipes by using digital radiography

The pipes which are the widespread and important components of industrial plants such as oil and chemistry industries and power plants, are so important for reliability and safety of these plants. In these plants, the conditions of critic components can be observed by appropriate non-destructive testing methods even the plant operates. Consequently, operations such as fixing changing of these components and moving the deopsits can be performed delibarately without affecting the production, environment and workers seriously. The inspections done before the operation and at the time of operation can protect the public and environment from the risks of industrial plants which can be disaster. In steel pipes used in industry, deposit, abrasion, corrosion or decomposition can be formed by various chemical or physical effects by the time. Because of these effects wall thickness of steel pipes can be changed within a time. Because of the fact that steel pipes are used in such areas where the safety comes first like oil, gas, waterworks, chemical substance carrying pipe lines, the determination of wall tickness of the pipes has a big importence. The aim of this study is to measure the wall tickness to determine the corrosion in steel pipes by using computed radiography (CR). The wall tickness of pipe materials was measured by tangential radiography technic. In experimantal studies, VMI brand 5100MS model digital image plate scaning system was used. The sistem operates with Starrview 8 image processing software. Spacial materials with different diameters and wall thicknesses having holes with different diameters and depth were used. The exposures were interpreted by changing source-imaging plate distance, exposure time that are exposure parameters. The wall thicknesses were read directly on the digital images obtained and determination of thickness was made by using pixel intensity change profile simultaneously. It was examined that the holes having of what depth and diameters can be determined in what wall thickness.