The hole-drilling strain-gage method has been standardized by the ASTM E 837-13 “Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method”.

High-speed drilling is very powerful and has the merit of not changing the state of stresses in the material: it allows to drill holes without inducing new stresses, that's a very important point during a test.

The high-speed drilling system comprises:

  • A high speed air turbine, 400000 rpm
  • A tungsten carbide inverted cone

The main operations involved in performing a residual stress measurement by the HOLE-DRILLING METHOD are:

  • install a three-element strain gage rosette,
  • center the drilling device with the center of the rosette,
  • establish the initial contact between the workpiece and drilling device (zero setting),
  • drill a through hole or blind hole in hole depth steps,
  • record strains released through residual stress relaxation by each grid of the rosette ,
  • measure the actual hole diameter,
  • calculate residual stresses from recorded strains by the method considered most appropriate (ASTM E837-13, Integral method, Kockelmann method).

In terms of cost, accuracy and versatility, this is one of the more efficient non-destructive mode of relief of residual stresses. Due to this process it is also called the "method of the hole".

ASTM E837 Excerpt