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5LM-P-8
LASER-MATTER INTERACTION
Laser creation of samples to reveal hidden defects in steel products
E. Surmenko, T. Sokolova, D. Bessonov, Yu. Chebotarevskiy, A. Klushev, N. Kulikov
Saratov State Technical University, 77 Polytechnicheskaya st., 410054, Saratov, Russia
surmenko@yandex.ru
In the manufacture of various products, in particular, rolling bearings, hidden surface defects occur that are not detected by visual inspection. Existing methods for detecting such defects, such as the eddy current method, require "standard samples" to identify defects. In the present work, we propose a method for creating such samples by the method of surface modification by laser radiation.
The modification of the surface of stainless steel samples by laser radiation was carried out, followed by a study of the area of laser action ("burns") by the eddy current method and hardness tester.
To create modified layers on the metal surface in order to obtain "standard samples of the defective layer", defocused millisecond radiation was used.
Burns were applied to the sample using various modes. During the experiment, the focal length 110 mm to the treated surface and the duration of laser radiation pulses 4 ms acted as unchangeable modes; the operating voltage of the drives was the variable parameters^ Then the hardness was measured and the eddy current method was applied in the center of burns and in the area of the sample without surface defects.
Fig.1. Dependence of microhardness on energy in center of the burn
The eddy current method confirmed the change in the signal in the area of laser action in the absence of visible damage. Based on the data obtained, it can be concluded that the determination of structural changes without external signs is possible using the eddy current method, and samples with laser surface modification can be used as "standard samples".
