Influence of TiCN/Fe metal ceramic coating by reaction nitrogen arc cladding on wear resistance of agricultural tools

Abstract: There is a current problem that agricultural tools easily get worn and frequently lose effectiveness. In order to solve this problem, the TiCN/Fe metal ceramic coating had been successfully prepared on a Q235 steel specimen surface by a reaction nitrogen arc cladding technique with a TXⅡ500 argon arc welding machine. In the coating preparation, the industrial titanium powder and the graphite powder (300 mesh, a purity of 98%) are mixed at the ratio of 47.9:12 in weight with 6 hours through the DQM type planetary ball mill, and precoated on the specimen surface. The precoated thickness is 2±0.2 mm, and the industrial N2 (purity 99.999%) is used as a reaction and protection gas. The coating was prepared on the surface of a specimen based on the high temperature of the nitrogen arc which made the N2 and precoated powder react in the course of welding. Effects of cladding speed (1.5, 2.0, 3.0 mm/s) on morphology, phase, and microhardness of the TiCN/Fe coating were analyzed by means of a scanning electronic microscope (SEM), X-ray diffractometer (XRD), and microhardness gauge, and contrast tests of wear were done between agricultural tools and coating. The results showed that the surface of the coating can obtain good morphology when the cladding speed is 1.5 mm/s, but when the coating contains less TiCN and the microhardness of coating is low; with the increase of the cladding speed(such as 3.0 mm/s), the coating morphology is worse off, but the microhardness and wear resistance have been increased obviously. The microhardness on the coating surface could reach up to HV0.5 1089, about 3 times as much as Q235 microhardness. Contrasted with common agricultural tools material (65 Mn), the wear loss is only 1/2 times as 65Mn, and the coating wear resistance is better. The coating can be used on agricultural tools for improving the service life of tools.