Papers by Author: Yue Zhang

Abstract: The machining process of titanium alloys always need special control by using coolant and lubricant as it is one of the difficult-to-cut materials. The cutting experiments are carried out based on green cooling and lubricating technology. To achieve green cutting of titanium alloy Ti-6Al-4V with water vapor cooling and lubricating, a minitype generator is developed. Compared to dry and wet cutting, the using of water vapor decreases the cutting force and the cutting temperature respectively; enhances the machined surface. And it can help to chip forming and breaking. Water vapor application also improves Ti-6Al-4V machinability. The excellent cooling and lubricating action of water vapor 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 vapor has the potential to attain the green cutting of titanium alloy.

Abstract: Green cutting is one of the developing tends in the industry field. Water vapor can be introduced in metal cutting as coolant and lubricant due to its pollution-free, generating easily and unneeded disposal. Therefore, a special generating system is developed to produce suitable water vapor, and a simulation to the velocity of water vapor jet flow is presented. Then tool wear was investigated and a new capillary model is proposed, based on the experimental results. According to the boundary-layer theory, the kinetics equations of flow were solute. The velocity and flux of molecule are presented. In the capillary, the adsorption of tool-chip interface results in boundary lubricating film; the conical shape of capillary limits the depth of coolant and lubricant penetrating; and the negative press is the motility for coolant and lubricant penetrating. The study results show water vapor can decrease tool wear about 10% times and 20% comparing to cutting fluids and dry cutting, and water vapor could be a potential solution of green cutting.

Abstract: The gases of nitrogen, oxygen, argon and carbon dioxide were employed as coolant and lubricant in metal cutting. Therefore, the smaller kinetic diameter of gas, the lower cutting forces can be obtained. A conical capillary model is proposed, based on the experimental results and the theory analysis of stress distributions at the tool-chip interface. According to the boundary-layer theory, the kinetics equations of gas flow were solute. The velocity and flux of gas molecule are presented. In the capillary, the adsorption of tool-chip interface results in boundary lubricating film; the conical shape of capillary limits the depth of coolant and lubricant penetrating; and the negative press is the motility for coolant and lubricant penetrating. The study results show the molecule size of the coolant and lubricant could effect on its performances, and the coolant and lubricant with a relatively small molecule may have the particularly effective nature, in metal cutting.

Abstract: The copper - aluminum pipe has been widely used in the refrigeration industry. And the welding quality becomes the focus. A PLC control system was developed to accurately control the resistance welding process of the Cu-Al pipe. The welding voltage was adjusted by a couple of silicon controlled rectifiers (SCR). To restrain the effect of network voltage fluctuation on the welding heat generation, it was obtained that the experimental relationship of the angle of flow and the network voltage, and fitted to a quadratic polynomial equation. Therefore, the control system can calculate the exactly the angle of flow value according to the current network voltage. The experiment results show that the error of the welding heat generation is limited in 5% when the network voltage fluctuates in the range of 380V ±10%. And the SEM and EDS analyzing results suggests that the welding seam length is more than 5mm, and there is hardly eutectic composition.

Abstract: The machining process of titanium alloys always need special control by using coolant and lubricant as it is one of the difficult-to-cut materials. To achieve green cutting of titanium alloy Ti-6Al-4V with water vapor cooling and lubricating, a minitype generator is developed. Compared to dry and wet cutting, the using of water vapor decreases the cutting force and the cutting temperature respectively; enhances the machined surface appearance. Water vapor application also improves Ti-6Al-4V machinability. The excellent cooling and lubricating action of water vapor 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 vapor has the potential to attain the green cutting of titanium alloy instead of cutting floods.

Abstract: To investigate the effects of gases as coolant and lubricant on machined surface, the micrograph and roughness value were obtained face to green cutting. Under the experiment conditions, water vapor and nitrogen gas may give a better restrain action to nubs adhibiting on the machined surface. And water vapor gave the lowest roughness value, while nitrogen gas has hardly help to lower roughness value. Other gases, only at a certain extent, can restrain nubs adhibiting and lower roughness value. Common characters of these gases are widely source, out of pollution, needless to disposing and so forth. With the view point of environment friendly, these gases may achieve green cutting.

Abstract: To achieve green machining 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 improves Ti-6Al-4V machinability and prolongs the tool life about 1 time and 0.5 times. And if the same tool life was selected, it would be easy to obtain that as water steam applied the cutting speed can increase about 15% and 10%. As a result, the productivity can be increased. The excellent cooling and lubricating action of water steam could be summarized that water molecule has a small diameter and high speed, can be easily and rapidly to penetrate the capillaries and proceed adsorption in the cutting zone. The results indicate that the using of water steam has the potential to attain the green machining of titanium alloy Ti-6Al-4V.

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: 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.