Актуальные проблемы в машиностроении том 4 №4

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Актуальные проблемы в машиностроении. Том 4. № 4. 2017 Инновационные технологии
в машиностроении
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INFLUENCE OF BORIDING ON DIMENSIONAL ACCURACY AND FRAGILITY
OF SURFACE PRECISION PARTS MADE OF COLD WORK TOOL STEELS
Konstantinov V.M., (Engineering), Professor, e-mail:
Dashkevich V.G., Ph.D. (Engineering), Associate Professor, e-mail:
Kovalchuk A.V., Post-graduate Student, e-mail:
Belorussian National Technical University, ave. Nezavisimosty, 65, Minsk, 220013, the Republic of
Belarus
Abstract
The estimation of factor of the fragility of the two-phase boride layers obtained on steels «У8А»
and «9XC», depending on the saturation temperature and exposure time. The regression equations
that allowed to define more efficient modes boriding process and provide a measure of phase
boundary at the interface FeB / Fe2B at 120 ... 140 MPa. Refined data on changes in the geometric
characteristics of the surface of the product resulting in a powder boriding environment.
Constructed a nomogram for determining the gain of the linear dimensions of parts of cold work
tool steels «У8А» and «9XC» the holding time at boriding in the temperature range 930 ... 950 ° C.
To study the value of growth options boriding linear dimensions were as follows: steel «У8А» – 14
... 25% of the thickness of the boride layer on the side, for steel «9XC» – 10 ... 21%.
Keywords
thermochemical treatment, boriding, diffusion layer, fragility, precision details, dimensional
accuracy