低温微量润滑条件下涂层刀具车削不锈钢的试验研究

发布时间：2018-06-28 00:21

本文选题：涂层刀具 + 低温微量润滑　；参考：《西安理工大学》2017年硕士论文

【摘要】：在传统的切削加工中,为提高加工质量,延长刀具寿命,通常会使用大量的切削液,这样不仅会造成资源浪费,还会带来环境污染问题。21世纪,人们开始倡导“绿色制造”不使用切削液的干式切削技术备受青睐,尤其是刀具涂层技术的发展使得干式切削的应用范围正在不断扩大。但实践证明在难加工材料(如耐热钢、不锈钢钛合金等)和难加工工序(如钻孔、攻丝、切槽,尤其深孔加工等)的切削加工中,即使使用涂层刀具进行干切削加工仍有一定困难,因此,必须研制开发新的冷却润滑方式。本课题将涂层刀具与微小量润滑(Minimum Quantity Lubrication, MQL)和冷风切削技术结合,进行奥氏体不锈钢的车削试验研究具有重要的现实意义。本次研究针对奥氏体不锈钢ICr8Ni9Ti材料,用前刀面和后刀面分别涂覆TiCN+Al_2O_3和TiCN+Al_2O_3+TiN涂层的硬质合金金刀片,通过进行车削试验,分析在干切削、不同供液方位的MQL、低温冷风、及低温MQL条件下切削力的变化规律,在此基础上,选择合适冷却润滑条件,进行刀具磨损试验,着重分析了刀具的磨损特性和磨损机理,试验后观察切屑形态,分析断屑的机理。试验结果表明:①低温MQL切削相比于干切削和MQL切削,确实能够降低切削区域的温度,改善切削加工条件,降低加工过程中的切削力。②随冷风温度的降低切削力呈现先减小后增大的趋势,在切削用量vc=150m/min,f=0.2mm/r,ap=1.5mm,空气压力和MQL的流量分别为0.6MPa和33ml/h情况下,冷风温度为-30℃时切削力最小。③在相同的切削参数下,切削相同长度的工件,低温MQL切削能减小涂层刀具前刀面月牙洼磨损宽度和深度,减小主后刀面边界磨损和沟槽亘磨损。④从涂层刀具主后刀面的磨损曲线可以直观的看出,初期磨损阶段,三者磨损曲线相差不大,但正常磨损阶段,低温MQL条件下曲线变化平缓,较MQL切削又有所延长,而且从曲线的走势看,低温MQL切削条件下,,刀具的磨钝标准值可能要大一些。可见,低温MQL条件可以减缓刀具的磨损速率。⑤ 低温MQL的冷却润滑作用可以有效降低切削区域的温度,改善切削条件,明显减小磨粒磨损,减小与温度密切相关的粘结磨损,提高刀具寿命。⑥低温MQL切削条件下切屑为锯齿形,与干切削和MQL切削相比,塑性流动带最窄,向齿顶扩展的面积最小;涂层刀具的断屑机理为绝热剪切。
[Abstract]:In the traditional cutting process, in order to improve the processing quality and prolong the tool life, a large number of cutting fluids are usually used. This will not only cause waste of resources, but also bring about environmental pollution problems in the.21 century. People begin to advocate "green manufacturing" dry cutting technology which does not use cutting fluid, especially the development of tool coating technology. The application scope of dry cutting is expanding. But it has been proved that it is difficult to use coating tools in the cutting process, such as heat-resistant steel, stainless steel, titanium alloy, etc. and difficult machining processes, such as drilling, tapping, cutting, especially deep hole processing. It is of great practical significance to combine the coating tool with the micro lubrication (Minimum Quantity Lubrication, MQL) and the cold air cutting technology in this subject. This study is of great practical significance to the research of the austenitic stainless steel turning test. This study was applied to the austenitic stainless steel ICr8Ni9Ti materials, and the TiCN+Al_ was coated with the front and rear surfaces respectively. 2O_3 and TiCN+Al_2O_3+TiN coated cemented carbide gold blade, through turning test, analyzed the changing law of cutting force in dry cutting, different azimuth of MQL, cold air, and low temperature MQL. On this basis, the suitable cooling condition was selected and the tool wear test was carried out. The wear characteristics and wear of the tool were emphatically analyzed. The mechanism is that the chip morphology is observed after the test and the mechanism of chip breaking is analyzed. The experimental results show that: 1. Compared with dry cutting and MQL cutting, the low temperature MQL cutting can reduce the temperature of the cutting area, improve the cutting conditions and reduce the cutting force in the machining process. The cutting capacity vc=150m/min, f=0.2mm/r, ap=1.5mm, air pressure and MQL flow are 0.6MPa and 33ml/h respectively, and the cold wind temperature is -30 C cutting force minimum. 3. Under the same cutting parameters, cutting the same length of workpiece, low temperature MQL cutting can reduce the wear width and depth of the crescent face of the coated tool face and reduce the main blade surface. It can be seen from the wear curve of the main cutter surface of the coated tool that the three wear curves in the initial stage of wear and tear have little difference, but the normal wear stage, the curve of the low temperature MQL is slow, and the MQL cutting is prolonged, and from the trend of the curve, under the low temperature MQL cutting condition, the cutting tool The standard value of grinding blunt may be larger. It can be seen that the low temperature MQL condition can slow down the wear rate of the tool. 5. The cooling and lubrication of low temperature MQL can effectively reduce the temperature of the cutting area, improve the cutting conditions, reduce the abrasive wear, reduce the bond wear loss closely related to the temperature, and improve the tool life. 6. Under the low temperature MQL cutting condition The chip is zigzag. Compared with dry cutting and MQL cutting, the plastic flow belt is the narrowest and the area extending to the top of the tooth is the smallest. The chip breaking mechanism of the coated tool is adiabatic shearing.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG51;TG142.71

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