Weldcore® Background
Materials exposed to mechanical stresses, below the yield point of the material, over prolonged periods of time, tend to deform permanently, due to the phenomenon known as creep. This phenomenon is more severe at elevated temperatures. Creep is typically experienced by high temperature and pressure components such as steam bearing structures found in thermal power generation plants.
The safe operating lifetimes of materials utilised in steam bearing structures of thermal power generation plants are calculated according to the envisaged exposure to certain elevated temperatures and pressure, as expected high margins of safety are built into the lifetime calculations. This invariably leads to structures prematurely reaching the perceived end of lifetime (EOL) and requiring replacement with huge cost implications both from a structural point of view and down time.
To determine the actual state of the material and predict remaining life requires continuous removal of metallurgical samples from the areas of concern; methods currently employed by the power generation industry generate data from the surface or shallow sub-surface samples which do not generate data with increasing depth into the side wall of the steam bearing pipe work. It follows that in attempting to operate these power generation plants beyond design life a reliable and accurate assessment needs to be done of the actual material state in areas of concern and therefore data with increasing depth into the side wall is of paramount importance.
The Weldcore® process was developed from this requirement.
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