Tags: Radiographic

Radiographic Examination – Radiograph Quality

{0 Comments}

Radiographic Examination – Radiograph Quality

The acceptability of a radiograph for the detection of flaws is determined with a device, referred to as a “penetrameter,” that is placed upon the surface of the workpiece when the exposure is made. Penetrameters are relatively thin pieces of material with radiation attenuation characteristics similar to the workpiece that contain holes with diameters of […]

Read More…

Radiographic Examination – Exposure

{0 Comments}

The exposure of the photographic film by radiation passing through the workpiece is determined by the intensity of the radiation multiplied by the time of the exposure. The optical density of the developed negative increases with increasing exposure. ASME Code, Section V, requires a radiograph to have a density between 1.8 and 4.0 for proper […]

Read More…

Radiographic Examination – Photographic Film

{0 Comments}

The radiation which passes through the workpiece is recorded by photographic film. The radiographs are usually interpreted visually with the aid of a high intensity light source (light box), but optical densitometers or image analyzers are occasionally used. Two primary characteristics of the film can affect the sensitivity of RT for detecting flaws: gradient and […]

Read More…

Radiographic Examination – Radiation Sources

{0 Comments}

Both x-rays and gamma rays can be used as the incident radiation. Energy and intensity are the most important characteristics of the incident radiation. The energy of the incident radiation determines its ability to penetrate the workpiece. Higher energy radiation is required to penetrate thicker workpieces but it reduces the scatter of radiation passing through […]

Read More…

Radiographic Examination – Physical Principles

{0 Comments}

Radiographic Examination – Physical Principles

X-rays and gamma rays penetrate steel, but the intensity of the incident radiation will be attenuated as it passes through the material. The degree of attenuation depends on the thickness and density of the material. Flaws can have the effect of reducing the thickness of material through which the radiation must pass by interposing cavities […]

Read More…

Radiographic Examination (RT)

{0 Comments}

RT is very useful for detecting both surface and internal flaws, and it is the primary NDE procedure required by the ASME Code to verify the quality of welds during construction. However, the associated radiation hazard makes it difficult to use for inspection of pressure vessels during shutdowns, when other personnel are working on the […]

Read More…