High potential new tool material - ceramic tool material

       With the development of modern science and technology and production, a variety of new and difficult materials in a large number of applications, the traditional carbide tool has been difficult to meet the production needs, and ceramic tools with its excellent heat resistance, wear resistance , Good chemical stability and cost-effective and by the people of all ages. Especially in the field of high-speed cutting and difficult to process materials, showing the traditional tool can not match the advantages.

   The use of ceramic cutting tools for ordinary steel, cast iron, hardened steel, high manganese steel, nickel-based superalloys, powder metallurgy sintered parts, glass steel and various engineering plastics and other difficult materials, the tool life can be several times higher than carbide tools Ten times. In the production it can not only be used for general car, boring and milling, and has been successfully used in hole machining tools; in addition to the use of ordinary machine tools, but also can be effectively used for CNC machine tools and machining centers and other efficient Equipment, is internationally recognized as the most efficient production efficiency of a kind of tool. In addition, compared with diamonds such as diamond and cubic boron nitride, the price of ceramic cutting tools is relatively low (the main raw material of ceramic cutting tools, alumina, silicon oxide is the most abundant components of the crust, inexhaustible "With the continuous improvement of the performance of modern ceramic tool materials, in the future it will be with the coated carbide cutting tools, diamond and cubic boron nitride and other super-hard tool together to become high-speed cutting, dry cutting and Hard cutting of the three main cutting tools. "Figure 1 shows the use of ceramic cutting tools to hard-cut instead of grinding out of the carburizing hardened transmission gear (57HRC-59HRC) synchronous cone part, the hole and the back of the application Example.

   Ceramic tool material performance advantages and disadvantages

   Compared with carbide cutting tools, ceramic tool hardness up to 92-95HRA, good wear resistance, the same conditions in the processing of steel, it is only P10 (YT15) carbide cutting tool 1/15, tool life long. At the same time, ceramic cutting tools and steel and other metal materials, the affinity of small, low coefficient of friction, anti-adhesion and anti-proliferation ability, cutting is not easy to stick knife and produce BUE, processing surface quality. Ceramic tool heat resistance is also very good, at 1,200 ℃ can still maintain about 80HRA high hardness, so suitable for high temperature cutting and cutting at high temperatures, and the price is far below the cutting performance and similar to the diamond and cubic Boron nitride tool. Table 1 lists the ceramic and commonly used cemented carbide two kinds of material performance comparison.

  The main drawbacks of ceramic cutting tools are bending strength, fracture toughness and low elastic modulus, brittle. For a long time mainly as a finishing tool, accounting for the proportion of various types of tool materials is very small. But over the past decade, due to advances in materials science and manufacturing technology, by controlling the purity of raw materials and grain size, the use of hot and hot isostatic pressing sintering process and other methods (made by hot pressing sintered ceramics, its strength and Hardness is better than the past cold pressure method; and made by hot isostatic pressing ceramic, its organization is dense, higher strength, anti-chipping performance), add a variety of carbides, nitrides, borides and oxides, etc. Can improve the performance of ceramics, and through the particles, crystal repair, phase change, micro-cracks and several toughening mechanism synergies to improve its fracture toughness and strength, not only the ceramic bending strength increased to 0.9-1.0GPa (highest Up to 1.3-1.5GPa, has been equivalent to carbide), and its impact resistance is also greatly improved, increasing the scope of application, in addition to general finishing and semi-finishing, but also for the impact of the load roughing.