【作者】 赫青山；

【导师】 傅玉灿；

【作者基本信息】 南京航空航天大学 ， 机械制造及其自动化， 2013， 博士

【摘要】 目前强韧性材料（如钛合金、高温合金）在高效磨削加工中暴露出的主要问题之一是磨削弧区温度过高引起的工件烧伤。传统理论认为，尽可能多的将磨削液引入到磨削弧区是保证对其强化换热的有效手段，但实际上，随着砂轮线速度、磨削深度以及工件进给速度的不断提高，再加上磨削弧区又相对封闭，磨削液越来越难进入到弧区。另一方面，一旦在磨削过程中磨削弧区的热流密度输入达到成膜沸腾的临界值，由于工件表面形成汽膜层的阻挡，磨削液更是无法在磨削弧区起到正常的换热作用。本文提出利用热管技术实现强韧性难加工材料高效磨削的构想，并设计制作出基体中带有热管的新型磨具——热管砂轮，使积累在磨削弧区的热量能够经砂轮自身热管作用迅速的疏导出去，从而达到降低磨削弧区温度的目的。基于上述构想，本文主要完成了以下几个方面的工作：1、设计制作了一种热管砂轮结构，并对热管砂轮结构的密封性与结构强度进行了检测，结果表明，砂轮结构的密封效果能够保证热管后续的使用寿命，且砂轮结构强度可以满足高效磨削加工时的使用要求。利用建立的热管砂轮制作平台，制作出能够用于磨削的电镀CBN热管砂轮。2、建立了热管砂轮传热性能评价系统平台，并在该平台上进行热管砂轮与无热管砂轮的传热能力对比试验，证实了热管砂轮具有的传热优势。同时还进一步掌握了不同因素对热管砂轮传热能力与启动时间的影响规律，并对热管砂轮在工作状态时的传热机理进行了分析。此外，通过比较热管砂轮和普通实心砂轮的等效热阻，结果表明，由于热管的传热作用可以将砂轮传热能力提高一个量级的水平，这也进一步验证了热管砂轮具有对磨削弧区热量进行迅速疏导的潜力。3、利用FLUENT仿真软件建立了热管砂轮在平面磨削中的三维传热模型，并分析了砂轮转速、冷凝端冷却条件以及热端热流输入条件三个因素对磨削弧区温度的影响。仿真结果表明，热管砂轮在磨削中能够起到有效降低磨削弧区温度的作用。4、使用电镀CBN热管砂轮和无热管电镀CBN砂轮进行了钛合金和高温合金材料的磨削对比试验。试验结果表明，在相同试验条件下，热管砂轮在缓磨和高效深磨过程中能够有效疏导磨削弧区的热量，从而将磨削温度始终维持在较低水平，并防止工件烧伤。更多还原

【Abstract】 At present, one of the most problems exposed in the high efficiency grinding of strength andtoughness difficult-to-cut materials such as titanium alloy and superalloy is the workpiece burn causedby high grinding temperature in the grinding contact zone. The traditional theory considers thatmaking a large quantity of coolant into the grinding contact zone is an effective method to ensure itseffect of heat transfer enhancement. But actually, with the continuously increase of the grinding speed,grinding depth and workpiece feed-speed in the grinding, and superadd the grinding contact zone is arelatively closed area, it will be much more difficult to make coolant into the grinding contact zone.On the other hand, once the condition of heat flux input in the grinding contact zone exceeds thecritical value whose the coolant will occur to film boiling state, the coolant will loss the function ofheat exchange with the contact zone due to the obstruct of formed vapor film on the workpiecesurface.To solve the above trouble, one novel conceive about utilization of heat pipe technology to achievethe high efficiency grinding for strength and toughness difficult-to-cut materials is proposed in thispaper. Moreover, A new grinding wheel——heat pipe grinding wheel (HPGW) which owns a loopheat pipe in the wheel matrix is designed and manufactured. That new grinding wheel can rapidly takethe heat accumulating in the grinding contact zone away by means of its loop heat pipe in the grinding,and thus realize the purpose to further strengthen the heat transfer in the grinding contact zone as wellas reduce the grinding temperature. Based on the above mentioned conceive, some works have beencompleted in this paper:(1) Designed and manufactured one HPGW structure and then the sealing and structural strength ofHPGW were detected. The test results show that the sealing performance can guarantee HPGWhaving a long service life in future and the structural strength of HPGW is also able to satisfy the userequirements in the high efficiency grinding. After that, an electroplated CBN HPGW applied in thehigh efficiency grinding was developed through an established heat pipe making platform.(2) A heat transfer performance evaluation system platform for HPGW was developed. The heattransfer superiority of HPGW was verified obviously by comparing with the conventional grindingwheel without heat pipe and the influence of some factors on heat transfer capacity and start-up timeof HPGW were analyzed by the heat transfer experiments. According to the experiment results, heattransfer mechanism of HPGW in working condition was probed. Furthermore, the equivalent thermal resistances of HPGW and conventional grinding wheel without heat pipe were compared. The resultsprove that the heat transfer capacity of HPGW relative to conventional grinding wheel can beimproved by an order of magnitude due to the heat transfer effect of heat pipe, and thus further verifythe heat transfer potential of HPGW to take grinding heat away from the contact zone in the grinding.(3) Based on the Computational Fluid Dynamics software, a three-dimensional heat transfer modelof HPGW in the grinding was developed to analyze the influence of different parameters of thegrinding speed, cooling condition and heat flux input on the grinding temperature. The simulationresults show that the grinding temperature can be dramatically reduced by using HPGW in thegrinding.(4) Grinding contrast experiments using the electroplated CBN HPGW and conventionalelectroplated CBN grinding wheel without heat pipe were carried out in the grinding of Titaniumalloy Ti-6A1-6V and Inconel718under the same condition. Results suggest that using HPGW in thecreep feed grinding and high efficiency deep grinding can further take the grinding heat away fromthe grinding contact zone, and thus maintain the grinding temperature at a low level as well as preventthe burnout.更多还原