Residual stress has a great influence on the metal, but it is difficult to measure at small area using a general method. Residual stress calculations using the Vickers indentation can solve this problem. In this paper, a numerical simulation has been made for the residual stress measurement method of metal material deformed by high-speed impact. Then, the stress-strain curve at the high-speed deformation was confirmed through actual experiments, and the residual stresses generated thereafter were calculated by the Vickers indenter method. A Vickers indentation analysis under the same conditions was performed at the position where a residual stress of about 169.39 MPa was generated. Experiments were carried out and high speed impact was applied to the specimen to generate residual stress. The obtained results indicate that it is possible to identify residual stresses in various metals with various shapes through Vickers indentation measurements, and to use them for process and quality control.
The small artificial surface defects in the coarse-grain steel are studied. The size of the used defects is smaller than the most relevant microstructural unit of steel, i.e. the average grain size. The samples of coarse-grain steel are prepared using a welding thermal-cycle simulator and a laboratory furnace. The defects are made by indenting with a Vickers pyramid. One of the final results of the defect making is the existence of local residual stresses. The influence of residual stresses on the crack initiation from those artificial defects is discussed in the article.