FIELD: machine building.
SUBSTANCE: invention relates to machine building and can be used for determination of hardness of strengthened surfaces of articles, in surface layers of which there are residual stresses, in particular in thin solid coatings deposited on solid substrates and having different purpose (wear-resistant, corrosion-resistant, protective, etc.). Method of determining true hardness of coating, comprising that article, on surface of which there is coating of known thickness, is placed in device – hardness meter, through which loading (introduction) of diamond pyramidal tip into surface of article with coating, load values and penetration depth are measured, from which hardness value is determined. Prior to measurement, dimension of diagonal of pyramidal indenter is calculated at penetration depth equal to -0.1 of coating thickness, from indenter tip cut in the coating perpendicularly to the surface two slots identical in width and length and parallel to each other with depth equal to not less than the thickness of the coating at the local surface of the analyzed surface of the coated article, wherein the distance between the slots should be not less than a triple value of the calculated diagonal, but not more than four times higher, orienting the coated article in the hardness meter so that when the indenter is further loaded, its tip falls into the center of the analyzed local area between two slots, inserts the diamond pyramid indenter into the coating at a depth of ~0.1 of the coating thickness, accurate values of load and penetration depth are measured, value of true hardness of coating material is calculated at depth of 0.1 of coating thickness by formula.
EFFECT: present invention increases accuracy of determination of hardness of coating, in which residual stresses are present.
1 cl, 3 dwg
