1. IMPROVEMENT OF WEAR-RESISTANT QUALITIES OF ALUMINUM ALLOY BY GAS-THERMAL SPRAYING OF HIGH- THICK COATINGS Developed by student of 632AM Alexandra Krivtsova Scientific Supervisor – Fedor Vashkevich English Supervisor – Victoria Kuzmenko

2. The general tendency in mechanical engineering is the reduction of metal consumption. It dictates the replacement of steel basic caterpillar wheels by more light ones, for example, made of aluminum alloys. In consequence it is necessary to reinforce the sections that are most of all exposed to the wear by more hard materials.

3. The sketch of track wheels

4. This is a complex problem and its solution should be found in three directions:  choosing of the form of groove;  choosing of the wear-resistant coating;  choosing of technology of application of coating.

5. Distribution of forces during the basic wheel movement upon the chain track

6. Groove configuration with symmetrical cross section and screw gear

7. Determination of wear-resistant coating  mechanical-and-physical properties of sprayed coatings

8. The elaboration of application technology of wear-resistant coating. Nowadays the gas-thermal spraying of coatings is the most multiple-purposed and it allows to spread wear- resistant materials in the form of powder and wire. If to compare electric arc, gas-oxygen and plasma spraying, electric arc spraying is the most competitive. The working conditions of electric arc metallizing gun has a great influence on the final hardness of the 40Cr13 steel coating because of carbon burning in coating. Especially the arc voltage influences on the carbon content and hardness. The voltage increase on the arc more than 35 V leads to significant decreasing of the carbon content and hardness. That is why metallization of coatings is conducted with 30 V and current= 200 – 220 A. This mode allows to save the hardness of the metallised coating near 60-65 HPA.

9. The general view of stand for application of protection coatings on wheel rims

10. Micro-structure of metallized coating on aluminum alloy in the groove with straight gears

11. Mechanized infantry combat vehicle

12. Tracked military car

13. Semitracked quad

14. Conclusions 1. The conducted analysis of methods of getting protective coatings showed the preference of electric arc metallization as the most efficient and easy method. 2. 40Cr13 has been chosen as a suitable material for metallization. 3. Groove configuration with symmetrical cross section and screw gear has been chosen due to the distribution of forces during the basic wheel movement upon the chain track. 4. The stand for application of protection coatings on wheel rims was made by plasma technology laboratory in PSACEA.

15. Thank you for your attention!