Design and Field Testing of Laser Cladding Coatings with Surface Textures on Rotary Tiller Blades
Rotary tiller blades suffer continuous abrasive wear from soil, sand, and crop residues, causing premature failure and high replacement costs. Conventional overlapping laser cladding consumes excessive powder and generates interfacial defects. This study designed and fabricated four non-overlapping textured Ni60A-WC (20%) composite coatings with grooves on 245-type 65Mn steel blades: perpendicular to blade edge, parallel to blade edge, vertical cross (90° intersection), and oblique cross (45° intersection). Grooves enable soil self-filling to form a protective layer. Discrete element method (EDEM) simulations identified stress concentration at the forward cutting edge, side cutting edge, and their junction. Field tests compared textured, untextured, and ordinary blades. The vertical cross texture exhibited the best wear resistance, with a wear rate of only 2.33%, an 80% reduction versus ordinary blades, while reducing cladding powder consumption by 67% (4.1 g vs. 18.6 g for traditional overlapping). Wear data correlated with simulated cumulative contact force. Laser confocal microscopy showed the wear area of the vertical cross texture (852.559 μm²) was only 18% of that of the perpendicular texture. The wear mechanism involves soil and sand filling the grooves to form a soft-hard alternating self-filling wear-resistant coating parallel to the cutting direction, enabling a fill-wear-refill dynamic cycle. This approach reduces powder usage while enhancing wear resistance.