INVESTIGATION OF SURFACE STRUCTURE, CRYSTALLOGRAPHIC TEXTURE, MICROTOPOGRAPHY OF FUNCTIONAL COATINGS DEPOSITED USING FLEXIBLE TOOL AND SOME APPLICATIONS. PART 2. INVESTIGATION OF THE EFFECT OF FUNCTIONAL COATINGS APPLIED USING FLEXIBLE TOOL ON SOME PROPERTIES OF MATERIALS AND APPLICATIONS

Abstract

Friction cladding as one of the simplest methods of surface modification with simultaneous coating application was used for surface nanostructuring. Intensive plastic deformation using a rotating wire brush (RWB) was performed during friction cladding. Brush fibers had an impulse-friction effect on the work surface with simultaneous coating application. Normalized steel samples (diameter 45 mm, width 10 mm) made of Grade 45 steel were tested for wear resistance. A copper-containing coating was applied at a circular grinder. Samples treated by various operating modes were tested at the SMC-2 friction machine using a disk-to-disk friction drive scheme. The tests showed that samples with a copper coating (C1) and a brass coating (B63) feature 2–10 times higher wear resistance in comparison than reference ones depending on the treatment mode. Samples with a brass coating (coating thickness 10–15 μm) applied in 6 passes with 2 mm interference (RWB feed on the work piece) at a sliding speed of 25 m/s demonstrated the highest strength. Smooth specimens (four series, a total of 60 pieces) made of 20CN steel were tested according to GOST 25502-82 «Fatigue Test Methods» to study the effect of friction cladding modes on endurance. Test results showed that the most effective way is surface plastic deformation with brass coating application. The endurance limit increase factor was Kυ = 1,41. It was found that steel mechanical properties (σв, σт, δ10) are not affected by coating application using friction cladding. Copper coating applied on coupling rods and plungers in hydraulic systems ensured 1,4–3,0 times longer service life, and up to 6 times longer life when applied on wave gear teeth in edge version.