RESEARCH OF MICRORELIEF AND STRUCTURE OF THE SURFACE LAYER BY LASER AND ULTRASONIC THERMO-STRAINING TREATMENT OF TOOL STEEL
DOI:
https://doi.org/10.20535/2305-9001.2016.78.83492Keywords:
laser heat treatment, ultrasonic strain treatment, steel W8, surface layer, microrelief, roughness, structure, hardnessAbstract
In this article, to improve the microrelief and structure of the surface layer of tool steel by combined method of the laser heat hardening and subsequent ultrasonic strain hardening and finishing was suggested. The results of experimental studies the formation of the microrelief on the surface, as well as the patterns of changes in the structure and microhardness of the surface layer of tool steel W8 using a CO2 laser and one-pin ultrasonic tip, are presented. The influence of technological regimes of the laser heat treatment (power of a laser beam and feed rate) on the structure, microhardness and size of the heat affected zone were established. It is shown that the microhardness of the surface layers increased more than 3.5 times at the laser heat treatment and at the ultrasonic strain treatment by 30...40% in comparison with the initial state. Using the combined method of thermo-strain hardening and finishing provided improving in 2 times in the surface roughness and increasing in 4.5 times of the surface layer microhardness as compared with untreated surface. It will allow increasing the wear resistance of the working surfaces of tools.References
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