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 VashkevichEnglish Supervisor – Victoria Kuzmenko

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.

The sketch of track wheels

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.

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

Groove configuration with symmetrical cross section and screw gear

Determination of wear-resistant coating mechanical-and-physical properties of

sprayed coatings

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.

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

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

Mechanized infantry combat vehicle

Tracked military car

Semitracked quad

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.

Thank you for your attention!