Study On Test Of The Coated Tool Cutting Stainless Under Cryogenic Minimal Quantity Lubrication

In the traditional cutting process, in order to improve the quality of processing and prolong the tool life, we usually use a lot of cutting fluid, which will not only lead to waste of resources,but also bring about environmental pollution problems. In 21st Century, people began to advocate green manufacturing", and the dry cutting technology without using cutting fluid becomes more and more popular. Especially the development of cutting tool coating technology makes the application range of dry cutting expand. But in practice for machining materials（such as heat resistant steel, stainless steel, titanium alloy） and difficult machining process （such as drilling, tapping, cutting, especially deep hole processing etc.）, even if the coated tool used in dry machining still has certain difficulty, therefore, must develop new ways of cooling and lubrication. In this paper, the application of Minimum Quantity Lubrication （MQL） and cold air cutting technology to austenitic stainless steel turning experiment research has important practical significance.The research studies turning test on austenitic stainless steel 1Cr18Ni9Ti material by using the rake face and flank respectively TiCN+Al₂O₃ coating and TiCN+Al₂O₃+TiN coating of the carbide blade, analyzing the change rule of cutting force of dry cutting and different direction and position range of MQL, low temperature air, and CMQL. On the basis of this, the tool wear test is carried out by choosing suitable cooling and lubrication conditions, and the wear characteristics and wear mechanism of the tool are analyzed.Test results show that:① Compared with dry cutting and MQL cutting,CMQL cutting can reduce the temperature of cutting area, improve cutting conditions and reduce cutting force during machining.② With the cold air temperature reducing cutting force decreased first and then increased,when cutting parameters are vc=15m/min,f=0.2mm/r,ap=1.5mm,air pressure is 0.6MPa,flow rate of MQL is 33ml/h and cooling air temperature is -30℃, respectively, the cutting force is minimum.③ Under the same cutting parameters, the MQL cutting at the same length can reduce the wear depth and depth of the crater in the rake face of the coated tool, and reduce the wear of the main flank and the groove wear.④ From the main coating tool flank wear curve can be seen directly, the initial wear stage,the wear curves of three or less, but the normal wear stage, low temperature change curve under the condition of MQL, which is flat, cutting and extended, but also from the curve trend,CMQL cutting conditions, tool wear standard the value may be greater. It can be seen that the CMQL condition can slow down the tool wear rate.⑤ Low temperature MQL cooling lubrication can effectively reduce the cutting area temperature, improve cutting conditions, significantly reduce abrasive wear, reduce the temperature and closely related to adhesive wear, improve tool life.⑥ The low temperature MQL cutting conditions for serrated chip, and compared to dry cutting and MQL cutting, plastic flow with the most narrow, to expand the area of minimum addendum; chip breaking mechanism of coated tool is adiabatic shear.