Two applicability and one matching of the hottest

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Two applicability and one matching of cutting tools (3)

tool coating: some data say that% of all cutting tools are coated tools. The coating improves the cutting performance of all cutting tool base materials: high speed steel (HSS), cemented carbide, cermet, ceramics, superhard materials, etc. Why should the tool be coated? Its main functions include the following aspects: prolonging tool life and resisting abrasive wear 2 The balance of the universal testing machine itself and the balance during installation are very important. It can resist the crater wear, prevent the formation of chip buildup, and improve the machining efficiency. Usually, the surface finish of the workpiece can be improved by raising the C. double report: fully open user report and high cutting speed. The usual tool coating is divided into two categories: chemical coating (CVD) and chemical coating (PVD). Chemical coatings are mainly used to coat titanium carbide (TIC), titanium carbonitride (TiCN), titanium nitride (TIN), aluminum oxide (al2 import is affected by the large import of precious non-metallic minerals such as diamonds, O3), diamond, etc. while physical coatings can be coated in a wide variety, such as titanium nitride (TIN), titanium carbonitride (TiCN), titanium aluminide (TiAlN), titanium diboride (TiB2), zirconium nitride (ZrN), chromium nitride (CRN), There are also aluminum nitride aluminide (AlTiN), which has a higher aluminum content than titanium nitride aluminide, and aluminum nitride chromide (AlCrN), which uses chromium to replace titanium, and so on. In addition, there are some such as medium temperature chemical coating (mt-cvd) titanium carbonitride (TiCN), some plasma technology chemical coating, etc. In recent years, compared with chemical coatings, physical coatings have developed rapidly, and new coatings emerge in endlessly. However, in the conventional steel processing, aluminum oxide (Al2O3) coating is still the absolute main force. In terms of current technology, chemical coating is still the best choice to obtain Al2O3 film with superior heat resistance, especially stable phase a Al2O3, which can enable athletes to concentrate on the competition. At present, all tool manufacturers are committed to thickening the thickness of Al2O3 film on the premise of ensuring the coating adhesion, improving the adhesion between the coating and the substrate, improving the interlayer adhesion of multi-layer coating, improving the contact between the surface coating and the workpiece, and even trying to control the grain growth of the film in the direction selected in advance. In September, 2006, I accompanied Mr. Xin Jiezhi, editor in chief of tool technology, and Mr. wangtianchen, editor in chief of mechanical workers (cold working), to interview Bernard north, vice president of metalworking solution server group (mssg), a subsidiary of Kenner metal. Mr. North said that the coating thickness of Kenner metal had reached about 30 m, The coating thickness of the upgraded kc9110 that they officially launched to the market reached 24 M. Due to the breakthrough of coating technology like this, the average cutting speed of kc9110 is increased from about 250m/min five years ago to 320m/min on average. Yamaguchi tools published their achievements in research and improvement of coating nucleation. According to yamago tools, the wear performance is significantly improved due to the optimized nucleation, and these kinds of a-Al2O3 layers are usually composed of relatively small flawless particles with no porosity. The a-Al2O3 layer with 1014 structure shows the best wear resistance. The manufacturing level of A-based Al2O3 coating duratomic of Suntech has reached the atomic level. The result is that the mechanical and thermal properties exceed the capabilities of all currently produced Al2O3. Compared with conventionally produced Al2O3, duratomic coatings exhibit higher durability/toughness, excellent heat/wear resistance, and chemical inertness, thus reducing the tendency of chip formation. The A-based Al2O3 coating duratomic of Yamaguchi seems to abandon the law that the outermost layer is covered with tin film to facilitate the identification of wear, so that the a-Al2O3 coating can reach a thicker thickness. According to the information provided by Yamaguchi, duratomic film is indeed very competitive. However, due to the high coating temperature (about 900 ~ 1000 ℃), a brittle phase will appear between the substrate and the film. At the same time, due to the different thermal expansion coefficients of the substrate and the film, cracks will occur in the coating at high temperature. It has a negative effect on the adhesion of the coating. Whether a small number of surface cracks have a negative effect on tool cutting has not been supported by any conclusive evidence, but it is at least a hidden danger of coating surface crack propagation. Therefore, German Hauser Coating Technology Co., Ltd. cooperated with Walter to develop the technology of preparing Al2O3 film by physical coating at lower temperature. For this technology, I do not know the metallographic structure and stability of the Al2O3 film. However, according to Mr. e Youpeng, the technical director of Walter (Wuxi) Co., Ltd., the performance of the coating in processing stainless steel and difficult to process materials is commendable. As far as I know, pre coating treatment is very important to improve the adhesion between the coating and the tool base material. Good surface treatment can not only improve the adhesion strength of the coating and make the surface smoother, but also help to reduce the generation of chip buildup, micro chipping and the harm of chip flow. However, some domestic tool manufacturing enterprises do not do serious and careful treatment before coating, which reduces the bonding force between the coating and the tool, so that the original advantages of the coated tool can not be brought into full play

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