Mining Pick Structural Material Analysis And Cutter Head Performance Study

Cutting pick is the sharp tool in shearer used to cutting cools during mining applications.It has always been the focus for researchers in the world to improve the service performance and the service life of cutting pick since its emergence. As the deepening studies of domestic researchers on cutting pick, product quality and service life of cutting pick has been increased greatly. But at present, as to the conical pick applied widely at home and abroad, there still exists a large gap on the service performance of the cutting pick between domestic product and foreign product. Due to the properties of cutting pick are mainly dominated by material compositions and structures, therefore, based on the actual usage of the same cutting picks foreign and domestic in mining applications, it has been analyzed systematically on some cutting pick with excellent mechanical behaviors in chemical composition and microstructure distribution in this paper. Further, the effects of additives(TiC/TaC) on the microstructures and mechanical properties of gradient cemented carbide were explored. This will facilitate the fabrication of better cemented carbide cutting head and the improvement of service life of domestic cutting pick.It was analyzed on microstructures and material compositions of some cutting pick with excellent properties through optical microscope, scanning electron microscope(SEM) and X-X-ray photoelectron spectroscopy(XPS) in the paper, results indicated that the cutting head was WC-Co based cemented carbide, pick matrix was medium steel with low alloy elements content, and cutting head was brazed on pick matrix. The wear resistant layer on the surface of cutting head was Fe-based alloy powders, which has superior wear resistance compared to pick matrix. Hardness measurements suggested that the studied cutting pick could satisfy the requirements of mining application on hardness and wear resistance well.It was explored on the effects of TiC/TaC on the microstructures and composition gradient distributions of the gradient cemented carbide fabricated based on carburization.According to XPS results, the thickness of carburized layer of gradient cemented carbide was about 400 um and the C content decreased gradually along the gradient direction. The Co phase migration phenomenon was not apparent in gradient direction of the sample. In the organizations more than 100 um from the surface of gradient cemented carbide, the content of(Ti+Ta) and Co present regular changes relatively. Metallographic images present great amount of solid solutions of(TiW)C,(TaW)C and(TiWTa)C in the surface layer of gradient cemented carbide. These solid solutions distributed as clusters and decreased gradually along gradient direction. While in the subsurface layer, only a little solid solutions were observed and distributed sporadically. Inner surface layer of gradient cemented carbide, WC grains were coarse, even present aggregation phenomenon of WC grains somewhere. While WC grains were finer in the subsurface layer relatively, and distributed evenly. Hardness on surface layer was obviously higher than that on subsurface, due to the present of great amount of WC grains and solid solutions. Both the hardness and the fracture toughness were stable roughly on cemented carbide surface layer, while changed as undulates on subsurface layer along the gradient direction. This was not consistent with the traditional WC-Co gradient cemented carbide processed by carburization, which was related with the distributions of Co phase and TiC, TaC.