The quality control of coatings when selecting a powder material for the restoration of worn surfaces by gas-flame spraying is hampered by the lack of an operational method of non-destructive diagnostics. We present the results of studying coatings applied by gas-flame spraying using ultrasonic diagnostics. The powder coatings obtained using different technologies of gas-flame spraying were studied. Features of the structural state of coatings were evaluated using a model based on the effect of the structural inhomogeneities of the coating on the velocity and attenuation of ultrasonic waves. It is shown that the amplitude-time characteristics of the pulse of surface elastic waves when they pass along the coating are consistent with the data obtained from friction and hardness tests, the characteristics of the pulse being dependent on the quality of the coating material. The obtained results can be used to improve the quality control of coatings formed by gas-flame spraying.
On the example of the fingers of the scoop chain, a technique is proposed for the integral assessment of the quality of restoration of parts using elastic waves - ultrasound. The purpose of the work is to ensure the efficiency of measurements when assessing the quality of remanufactured parts in the conditions of a repair base. For this, data on the attenuation of elastic waves when they pass through the restored part were used. Unlike precision measurements of the velocity of elastic waves, the measurement of ultrasound attenuation does not require laboratory equipment, a conventional industrial flaw detector is sufficient. To assess the quality of the product, the transducer was alternately installed at points determined along the length of the finger, the probe beam was directed along the diameter and the first pulse of elastic vibrations reflected from the opposite side of the finger was recorded and the second, which passed two additional diameters of the finger. Found a quantitative indicator that allows you to assess the quality of restoration of the part. The proposed method to a certain extent solves the problem of integral assessment of the state of the restored finger of the scoop chain. To prevent premature failure of parts restored by welding with flux-cored wire, it is enough to introduce into practice an easy procedure for controlling sound attenuation.
The work presents a technique of diagnostics of fingers of a draw chain with the help of ultrasound, based on control of metal damage. The procedure of detection of fingers with maximum damaged metal is described. It is proposed to introduce in the practice of pre-repair diagnostics a non-burdensome procedure of sound attenuation control.
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