A device for simultaneous determination of the impact resistance and hardness of insulating coatings of pipelines

We propose a hand-operated device for simultaneous determination of the impact resistance and hardness of anticorrosive insulating coatings, which completely models the work of a U-1 standard vertical impact testing machine. The proposed device is a prototype of the Poldi impact hardness gauge, however, unlike the latter, our device is used with a hammer of mass 1 kg, which equates it to the U-1 impact testing machine and enables one to determine simultaneously the hardness and impact resistance of protective coatings. When the hammer strikes, the indenter contacts simultaneously with the coating and indicator metal (a square bar), which has been calibrated on the U-1 impact testing machine and a stationary hardness gauge. This calibration results in a relation between the diameter of indentation and the energy of impact with a one-kilogram weight. Striking upon our device with a one-kilogram weight, measuring the diameter of indentation on the bar, and using the relation mentioned above, we can find the impact resistance, and the ratio between the diameters of indentations on the bar and coating enables us to determine its hardness according to GOST 18661-73.