Papers by Author: Yan Li Tang

Abstract: It is examined that the effects of water vapor as green coolant and lubricant on the cutting of austenitic stainless steel. Compared to nitrogen, oxygen, argon and carbon dioxide gas applied and dry cutting, water vapor produced the lowest cutting force and deformation coefficients, improved the machined surface appearance and helped to chip forming and breaking. And the lubricating actions of water vapor and gases may have the relation with the molecule polarity and the capacity of adsorption in the cutting zone. All these gases and water vapor have the green characteristic without pollutions. Comparably, water vapor may be a good selection for the green machining of austenitic stainless steel.

Abstract: In recent years, environmental concerns call for the reduced of cutting fluids in metal machining. The green cutting techniques are to be studied to achieve this objective. In this paper, application of ozone gas in metal cutting was investigated, compared with oxygen gas, cutting fluids and dry cutting. The effects of ozone on cutting force, cutting temperature and chip deformation have been examined in turning of C45 steel with carbide tool YT14. The results of experiments indicated that the cutting force and cutting temperature application of ozone were reduced about 7 percent and 10 percent respectively compared with dry cutting, both of them were less than oxygen gas and cutting fluids condition. The chip deformation coefficient was also less than oxygen, wet and dry cutting conditions. The research results showed that ozone had positive effects in metal machining and it was probable to be a clean and eco-friendly coolant and lubricant under specific conditions.

Abstract: The machinability of Nickel-based superalloy GH4169 is poor, the traditional methods to machining is application of cutting fluids with the active additives which will cause environmental and health problems. In recent years, environmental concerns call for the reduced of cutting fluids in metal machining. The green manufacturing techniques are to be investigated to achieve this objective. In this paper, the ionized air was applied instead of cutting fluids for the aim of green cutting. The effects of ionized air on cutting force, cutting temperature and chip formation have been examined in turning of GH4169 with carbide tools K20. The results of experiments indicated that application of ionized air produced lower cutting force and cutting temperature, the values were reduced about 7 percent and 9 percent compared to dry cutting respectively, and it is advantage in forming acceptable chips. The research results show that clean production was achieved in metal cutting associated with ionized air cooling and lubricating.

Abstract: To achieve green cutting of titanium alloy Ti-6Al-4V with water steam cooling and lubricating, a 600-800w minitype generator is developed. Compared to dry and water-based emulsion, the using of water steam decreases the main cutting force and the cutting temperature respectively; enhances the machined surface appearance. And it can help to chip forming and breaking. Water steam application also improves Ti-6Al-4V machinability and prolongs the tool life. The excellent cooling and lubricating action of water steam could be summarized that water molecule has polarity, small diameter and high speed, can be easily and rapidly to proceed adsorption in the cutting zone. The results indicate that the using of water steam has the potential to attain the green cutting of titanium alloy.

Abstract: Based on the theoretical principle of tapping formation and simulation with modified-tooth tap, the relationship among the different geometric parameters of the tap was further analyzed. A series of modified-tooth taps and standard ones with a cutting cone angle of 7°30´and a outer diameter of M6, which were made from high-speed steel W9, were taken to do the comparative tapping test on nickel-based high-temperature alloy GH4169, titanium alloy TC4 and 45 steel. The test results indicated that the leading cause of difficult tapping in GH4169 and TC4 was the largeness of their friction torques which were about 35 % and 62 % of tapping torque respectively, where the frictional wear was a fundamental reason for tough tapping GH4169 and the spring back of machined surface for TC4.The obvious decreases of friction torque with the modified-tooth tap approximately 70% and 50% respectively for GH4169 and TC4 were attributed to its unique tapping formation principle of generating broaching but no remarkable effects on 45 steel in comparison with standard tap.