Finishing plasma strengthening of tools, dies and molds

Аuthors

Bologov D. V.^*, Prokopenko A. V.^**, Sutormin A. Y.^***, Fetisov G. P.^****

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

*e-mail: bdv12@inbox.ru
**e-mail: 7298887@mail.ru
***e-mail: alexeysj1@gmail.com
****e-mail: fetisov901@mail.ru

Abstract

This work investigates the possibility of strengthening of production tooling, used for aircraft engine parts production, and cutting tools by diamond-like coating. We have developed diamond-like thin-film coating technique for the finishing plasma strengthening based on disintegration of liquid technologic agents vapors, ins erted into an arc plasma gun followed by plasma- chemical reactions and formation of product coating. We used metal-organic and organic compounds in liquid state as parent substances for providing diamond-like coating based on silicon oxycarbonitride. We choose argon as an orifice gas, used in arc plasma gun.

The applied coating duplicates the substrate profile, and strengthening coating herewith is formed as an optically transparent film.

We investigated comparison characteristics of adhesive properties of diamond-like coating and titanium nitride coating applied by ion-plasma sputtering in vacuum. As a result of our investigations we found that the val ue of critical load initiating first chips and delaminations equals to 35N for titanium nitride coating and 65N for coatings applied by diamond-like thin-film coating technique.

We found that being a dielectric itself the applied diamond-like coating forms a film barrier preventing stiffening of conjugated surfaces. Besides, this coating possesses higher corrosion stability and heat resistance. This fact is confirmed by numerous long-term atmospheric corrosion tests of samples under temperatures up to 1000 — 2000 °C.

For friction and wearout tests we used samples 38 mm in diameter and 12 mm thick made of steel P6M5 coated by means of diamond-like thin-film coating and titanium nitride coating applied by ion-plasma sputtering in vacuum techniques. As a counterbody we selected samples made of steel SHH15 heat-treated to the hardness of HCR 63. Contact conditions were as follows — rolling friction with 20% sliding with lubrication. The tests were carried out at 1000 min-1 rotation frequency and 1650 N load. For comparison, we also used a sample made of heat-treated steel P6M5.

In the course of the experiment, the values of friction torque and mass wear of the samples were registered, and friction coefficients and wear rate were calculated.

Based on tests results we determined that the friction coefficient of the surfaces with diamond-like coating is two times smaller, compared to reference surface of steel P6M5 and 17% less than for the surface with titanium nitride coating applied in vacuum. The wear rate is reduced by 46% and 16% correspondingly.

Due to the obtained data we came to a conclusion of the expediency of application of the developed technique for strengthening of production tooling and cutting tools in various industries, and for aircraft gas- turbine engines parts manufacturing in particular. The developed technique was tested at the number of enterprises, and its application showed 3-6 times increase in production tooling and cutting tools durability.

Keywords:

strengthening, diamond-like coating, test, surface, friction factor, wear rate

References

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2. Tibrin G.S. Teplovye osnovy tekhnologicheskikh protsessov (Thermal basics of technological processes), Moscow, MAI, 2008, 148 p.

3. Goncharenko I.A. Osnovy tekhnologii termicheskoi obrabotki stali (Basics of steel heat treatment technology), Tula, Grif i K, 2006, 326 p.