Strengthening the cutter body of a road milling machine by applying an electrospark coating based on VK8 hard alloy

The purpose of the study. Development of a technological process for strengthening the body of a road milling cutter by applying an electric spark coating based on VK8 alloy.

Methods. Modern techniques and equipment were used to achieve the set goal. The coatings were applied to pre-prepared samples made from the cutter of the KZTS A6/20 road milling machine using the UR-121 electric spark alloying unit.

Technological parameters: anode - cutter tip (VK8 hard alloy); cathode - cutter body (structural alloy steel); sparking voltage 70 V; operating temperature 18-20°C; NORMA process mode 100 Hz; vibration amplitude of the vibrator VIBRATION 11; electric processing mode MODE 3.

To study the elemental composition and microstructure of the hardening coating, images were taken using an EDAX energy-dispersive X-ray analyzer built into a Quanta 600 FEG scanning electron microscope.

Vickers microhardness testing of samples before and after hardening was performed using an AFFRI DM-8 microhardness tester.

A Revetest scratch tester was used to test strength, scratch resistance, and determine the mechanism of sample failure.

Results. As a result of the experiment, electrospark hardening coatings based on VK8 alloy were obtained on the cutter body of a road milling machine. Recycling of cutter tip waste was carried out by applying wear-resistant coatings to the cutter body of the KZTS A6/20 by the electrospark alloying method. It was found that the hardening coating does not have pores, cracks and other defects, its main elements are Fe, W, Mn, Cr, O. The microhardness of the coating is 1.6 times higher than the microhardness of the substrate. When scratched, the coating on the samples wears off, but there are no delaminations, that is, it is destroyed by the cohesive mechanism.

Conclusion. The completed study will allow developing recommendations for the practical application of resource-saving technologies for the restoration and strengthening of road milling cutter bodies and implementing the recycling process.

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