Mole toe bionics and surface heat treatment improving resistance reduction and abrasion resistance performance of toothed ditching blade

Abstract: In the process of agricultural ditching machinery operation, the ditching blade contacts directly with soil. The quality and efficiency of ditching operation are closely related to the performance of ditching blade. Among them, resistance reduction and abrasion resistance performance are the most important. Improving the resistance reduction and abrasion resistance ditching blade can reduce trenching power consumption and improve operation quality, which is beneficial to increasing the service life of the blade, improving operation efficiency and saving economic costs. Moles live underground in most time of their life and have amazing soil-ditching skills. The studys show that third toe of mole's front paw is the most critical tool to ditching soil. In this paper, the third toe of mole's fore paw is taken as an object, and the whole tooth of the toothed ditching blade is replaced by the bionic model of the third toe of mole's fore paw. Firstly, the point cloud data of the third toe of the mole fore paw are obtained by 3D laser scanner. Then, the point cloud data are sparsely processed, spliced and encapsulated, smoothed and denoised by Geomagic studio 2017 software, and the bionic model of the third toe of the mole fore paw is obtained. Then the bionic cutter tooth is used to replace all the teeth of toothed ditching blade. Bionic ditching blades are manufactured using a 3D metal printer. The simulation of ditching process is achieved using EDEM software. Power consumptions of bionic ditching blade are 9.68%, 10.44%, 10.22%, 10.70% and 10.95% less than that of toothed blade separately when ditch depths are 150, 200, 250, 300 and 350 mm. In order to improve the abrasion resistance of bionic ditching blade, five surface heat treatment methods are selected to strengthen the surface of bionic ditching blade: quenching tempering at medium temperature(Blades I), chromizing quenching at high temperature(Blades Ⅱ), carburizing quenching at low temperature(Blades Ⅲ), laser cladding WC/Ni60A powder alloy (WC mass fraction 40%, BladesⅣ) and oxygen-acetylene flame surfacing casting WC electrode (WC mass fraction 60%, Blades V). Abrasion weight of 5 kinds of blades are measured by bench abrasion test. Abrasion weight of Blades II to Blade V are 14.17%, 42.05%, 66.98% and 75.96% less than that of Blade I separately. Hardened layer microstructure of Blades I to Blade III are all martensite, and that of Blades IV and Blasé V are both WC hard phase. Aerage microhardness of Blades I to Blade V are 558, 700, 888, 1 195 and 1 441 HV0.1 respectivly. And average microhardness of Blade II to Blade V are 25.41%, 59.11%, 114.08% and 158.17% higher than that of Blade I. Abrasion types of Blade I and Blade II are both adhesive abrasion, and average friction factors are 0.67 and 0.57 respectivly. Abrasion types of Blade III and Blade V are abrasive abrasion, and average friction factors are 0.26, 0.25 and 0.22. Field test is completed to compare differences between resistance reduction and abrasion resistance performance of 3 blades. Power consumption of Blade III and Blade V are 11.45% and 5.41% lower than that of toothed blade. Average abrasion weight of Blade III and Blade V are 28.26% and 82.63% less than that of toothed blade. The results can provide references for improving resistance reduction and abrasion resistance performance of ditching blades.