The surface of cemented carbide conical end mills is prone to burns and cracks after sharpening, which seriously affects the performance of the tool and its tool life. For this reason, we found through production practice that the choice of grinding wheel with what size and line speed can really effectively avoid the cracks and burns on the surface of cemented carbide tools and ensure the improvement of the quality of sharpening.
(1) Classification, composition and use of commonly used cemented carbide
The classification, chemical composition, performance and application of commonly used cemented carbides in my country are shown in Table 1. The cemented carbide produced in my country is divided into two categories: YT and YG. YT type is composed of titanium carbide, tungsten carbide and cobalt. The main components are WC, TiC and Co. They are mostly used to make tools for cutting steel. YG is an alloy of tungsten carbide and cobalt. The main components are WC and Co. They are mostly used to make cutting tools for iron castings, hardened steel, stainless steel, etc., as well as to make various cemented carbide measuring tools, molds, geological mining and oil drilling. Used mining tools, etc. In addition, there are YW-type titanium-tungsten-cobalt carbides with a small amount of precious metal carbides such as tantalum carbide or niobium carbide, which are used as tools for cutting special heat-resistant alloy materials.
(2) Cemented carbide for various tools
Another classification method is to divide the various types of cemented carbide used for cutting, mining and other purposes into two types: cermet cemented carbide and steel bonded cemented carbide.
① Cermet cemented carbide is a powder metallurgical material made by mixing refractory metal carbide powders (such as WC, TiC, etc.) and binders (such as Co, Ni, etc.), forming it under pressure, and sintering. For example, tungsten-cobalt cemented carbide (YG3, YG6, YG8, etc.) and tungsten-cobalt-titanium cemented carbide (YT5, YT15, YT30, etc.) are the most widely used in production. This kind of cemented carbide tools are resistant to high temperature and wear, and are widely used in the manufacture of measuring tools and molds, as well as drill bits and drill bits.
② Steel-bonded cemented carbide uses one or several carbides (such as TiC, WC, etc.) as the hardening phase, and alloy steel (such as high-speed steel, chromium-molybdenum steel, etc.) powder as a binder, after batching, mixing, and pressing And sintered powder metallurgy materials. This is a new type of tool material, which can be divided into the following two types.
a. The proportion of high-speed steel bonded cemented carbide containing TiC is 35%, and the proportion of mass containing high-speed steel is 65%. The hardness after quenching and tempering is HRC69-73.
b. The proportion of WC in chromium-molybdenum steel-bonded cemented carbide is 50%, and the proportion of mass of chromium-molybdenum steel is 50%.
The above is the sharing of tips on reducing the surface roughness of cemented carbide milling cutters, and I hope it will be helpful to everyone.
