Two new AlTiN coated cemented carbide drills with Al content of 40% and 55% in weight are developed for high efficiency dry drilling of 40Cr. By studying tool durability, machined hole quality, tool wear mechanism, ch...Two new AlTiN coated cemented carbide drills with Al content of 40% and 55% in weight are developed for high efficiency dry drilling of 40Cr. By studying tool durability, machined hole quality, tool wear mechanism, chip deformation, and lubrication, the dry drilling performance of the two kinds of coated drills is analyzed. Experimental results show that the AlTiN coated drills are suitable for high efficiency dry drilling and can obtain higher quality of machined holes. The tool durability of the drill with 55% Al content is 1. 3 times of that of the drill with 40% Al content at the cutting speed of 90 m/min. The wear mechanism of two AlTiN coatings are studied in experiments. During dry drilling process, oxidative wear appears in both two kinds of drills. The oxide film is formed on the top of the coated drill containing Al content of 55%. And the oxide film helps to increase its high temperature resistance and decrease the coating flaking, thus the drill is failed because of coating subsidence. The drill with less Al content is failed due to peeling and breakage. The lubricated condition in dry drilling is improved by the high Al content coating. It helps to reduce the cutting deformation and benefits to improve the quality of machined holes. The AlTiN coating with higher Al content shows longer tool life and higher quality of machined holes in high efficiency dry drilling. Its tool life increases by 30% compared with that of the coating with less Al content.展开更多
In this study, AlTiN coatings were deposited on YT14 cemented carbide balls by arc ion plating technique. The friction and wear behavior of the AlTiN-coated balls against SKD11 hardened steel was investigated by slidi...In this study, AlTiN coatings were deposited on YT14 cemented carbide balls by arc ion plating technique. The friction and wear behavior of the AlTiN-coated balls against SKD11 hardened steel was investigated by sliding tests using a ball-ondisk tribometer at various temperatures from 25 to 700 ℃ in air. The results showed that the friction and wear behavior was significantly influenced by the testing temperature. Obvious fluctuations were observed in the friction curves at elevated temperatures, which could be attributed to the formation and rupture of unstable Fe and Cr oxide layers. As the temperature increased from 25 to 500 ~C, the wear rate of the coated balls increased from the scale of 10-21-10-20 m3/ N m, and then decreased to 10-22 m3/N m as the temperature further increased to 700℃. It was also found that the friction and wear behavior of the coated balls was directly dependent on the counterpart materials. As the temperature increased, the main wear mechanism of the coated balls changed from mild abrasive wear and adhesive wear to abrasive wear failure at 500℃, and then transferred to adhesive wear and mild oxidation wear at 700℃. For SKD11 hardened steel, the primary wear mechanism changed from delamination wear to abrasive wear and then transferred to plastic deformation and fatigue wear, accompanied by adhesive wear and tribo-oxidation wear.展开更多
文摘Two new AlTiN coated cemented carbide drills with Al content of 40% and 55% in weight are developed for high efficiency dry drilling of 40Cr. By studying tool durability, machined hole quality, tool wear mechanism, chip deformation, and lubrication, the dry drilling performance of the two kinds of coated drills is analyzed. Experimental results show that the AlTiN coated drills are suitable for high efficiency dry drilling and can obtain higher quality of machined holes. The tool durability of the drill with 55% Al content is 1. 3 times of that of the drill with 40% Al content at the cutting speed of 90 m/min. The wear mechanism of two AlTiN coatings are studied in experiments. During dry drilling process, oxidative wear appears in both two kinds of drills. The oxide film is formed on the top of the coated drill containing Al content of 55%. And the oxide film helps to increase its high temperature resistance and decrease the coating flaking, thus the drill is failed because of coating subsidence. The drill with less Al content is failed due to peeling and breakage. The lubricated condition in dry drilling is improved by the high Al content coating. It helps to reduce the cutting deformation and benefits to improve the quality of machined holes. The AlTiN coating with higher Al content shows longer tool life and higher quality of machined holes in high efficiency dry drilling. Its tool life increases by 30% compared with that of the coating with less Al content.
基金supported in part by the projects of the National Natural Science Foundation of China(Grant No.51522502)the China Postdoctoral Science Foundation funded project(No.2016M600641)the Guangdong Natural Science Funds(Nos.2014A030311002 and 2016A050502056)
文摘In this study, AlTiN coatings were deposited on YT14 cemented carbide balls by arc ion plating technique. The friction and wear behavior of the AlTiN-coated balls against SKD11 hardened steel was investigated by sliding tests using a ball-ondisk tribometer at various temperatures from 25 to 700 ℃ in air. The results showed that the friction and wear behavior was significantly influenced by the testing temperature. Obvious fluctuations were observed in the friction curves at elevated temperatures, which could be attributed to the formation and rupture of unstable Fe and Cr oxide layers. As the temperature increased from 25 to 500 ~C, the wear rate of the coated balls increased from the scale of 10-21-10-20 m3/ N m, and then decreased to 10-22 m3/N m as the temperature further increased to 700℃. It was also found that the friction and wear behavior of the coated balls was directly dependent on the counterpart materials. As the temperature increased, the main wear mechanism of the coated balls changed from mild abrasive wear and adhesive wear to abrasive wear failure at 500℃, and then transferred to adhesive wear and mild oxidation wear at 700℃. For SKD11 hardened steel, the primary wear mechanism changed from delamination wear to abrasive wear and then transferred to plastic deformation and fatigue wear, accompanied by adhesive wear and tribo-oxidation wear.
