Cone indentation experiments

Abstract Indentations were made in three cold-worked metals, namely mild steel, copper and aluminium, using indenting tools of cone angles between 10° and 140°. The indenting tools were lubricated to reduce the coefficient of friction to a low value. Minimum permissible sizes of indentation specimens were determined. The shear yield stress of the materials was found from torsion tests. Precautions were taken that non-uniformity and anisotropy should not vitiate the results. The ratio between mean indentation pressure and shear yield stress was found to be approximately the same for the three materials, and the variation of indentation pressure with cone angle is shown. Measurements of the volume of the raised lip and shape of the impression are given. The possible influence of plastic-elastic effects on the observed indentation pressures is discussed.