Residual Stress Measurement Using a Miniaturised Deep Hole Drilling Method
One of the significant advantages of the deep hole drilling (DHD) technique over others is that being a semi-invasive technique the experiment may be conducted ‘on-site’, allowing a component or structure to be withdrawn for testing and subsequent repair. This paper presents the details and recent developments of the deep hole drilling technique and then goes on to present recent research directed towards reducing the overall size of the existing measurement equipment. Using our existing experimental arrangement, which has been extensively developed over recent years [1, 2, 3, 4], it was possible to undertake residual stress measurements to depths in excess of 500mm, although this deep through-thickness capability meant that the rig had an overall length of about one meter, which limited its use in confined spaces. It was decided to miniaturise the machine to allow residual stress measurements to be made in environments that were hitherto not amenable to such measurements, e.g. on the inside of a pipe. The trade-off to the miniaturisation process was a reduced measurement depth capability of approximately 50mm. In addition to permitting residual stress measurements to be made in confined spaces, the miniaturisation process also provides improved transportability which, in turn, means that measurements made be made more readily away from the laboratory. The paper will begin by describing in detail the new, miniaturised deep hole drilling system and then go on to use the rig to make a residual stress measurement in a stainless steel component.
KeywordsWelding Total Heat Europe Tungsten Drilling
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