This paper studies Hadfield steel single crystals with the orientation of the normal load axis and friction axis . The chosen orientation implies that deformation develops by slip and twinning. Analysis of the crystallographic orientation and acting stresses has revealed stages of shear deformation development in slip systems. Consecutive tests of the same duration were conducted to study the evolution of the deformation relief. Using the fast Fourier transform, the median frequency and energy of acoustic emission signals generated at different stages of friction are analyzed. A correlation is established between changes in the acoustic emission parameters and wear of single crystals.