機(jī)械專業(yè)外文及翻譯---在快速點(diǎn)磨削中磨削液供給參數(shù)對(duì)表面完整性影響的研究

1、<p><b>　　畢業(yè)設(shè)計(jì)論文</b></p><p><b>　　外文資料及譯文</b></p><p>　　學(xué) 院： 機(jī)械工程學(xué)院 </p><p>　　專 業(yè)： 機(jī)械設(shè)計(jì)制造及其自動(dòng)化</p><p>　　學(xué)生姓名：

2、 </p><p>　　學(xué) 號(hào)： </p><p>　　指導(dǎo)教師： </p><p><b>　　2011年 6月</b></p><p>　　Study on Effect of Grinding Fluid Supply Paramet

3、ers on Surface Integrity in Quick-point Grinding for Green Manufacturing</p><p>　　Abstract. </p><p>　　In high and super-high speed grinding process, there is an airflow layer with high speed aro

4、und the circle edge of the grinding wheel that hinders the grinding fluid into contact layer, namely, the air barrier effect. The speed of airflow layer is directly proportional to the square of the wheel speed. Quick-po

5、int grinding is a new type of high and super-high speed grinding process with a point contact zone and less grinding power. The edge effect of the air barrier is weakened because the thin </p><p>　　Introduct

6、ion</p><p>　　Grinding is the machining process that has heavy effect on both environment and resource. The heavy effect results from the grinding powder and grinding fluid that is used in grinding process la

7、rgely for cooling, washing and lubricating functions mainly. Especially for high and super-high grinding speed process, there is the airflow layer with high rotary speed around the circle edge of the grinding wheel that

8、hinders the grinding fluid into the contact layer [1], namely the airflow barrier effe</p><p>　　Analysis of Pressure and Velocity of Airflow Layer around Wheel</p><p>　　Grinding heat is generate

9、d from the deformation and friction of materials during the grinding process and makes the grinding temperature rise, which can result in the thermal surface damage of workpiece. Therefore, a reliable grinding fluid syst

10、em is necessary for the most grinding process to keep cooling, washing and lubricating functions. For high and super-high speed grinding process, the grinding fluid supply parameters and jet way must be designed reasonab

11、ly to overcome the airflow barrier </p><p>　　Fig. 1 Principle of quick-point grinding</p><p>　　The thickness and pressure of the airflow layer with high rotary speed around the circle edge of gr

12、inding wheel is the main factors to influence the fluid effect in high speed grinding, the higher the wheel speed, the thicker the airflow layer is and the higher the pressure of the airflow layer is. According to Bernou

13、lli Equation [2], the dynamic pressure of the airflow layer is given by</p><p>　　where va is the airflow speed [m/s], ρa(bǔ) is the air density [kg/m3]. If the dynamic pressure pa of the airflow layer is measure

14、d on the different wheel position, the airflow speed at same position can be calculated. Table1 gives the experiment values of dynamic pressure and speed of air layer. If the diameter of wheel is 600mm and the wheel spee

15、d is 30m/s and 60m/s respectively, the measured values of the dynamic pressure and the airflow speed are shown in Table1. It is visible that the dynamic p</p><p>　　Table 1 Measured values of dynamic pressure

16、 and speed of airflow layer</p><p>　　Fig. 2 shows the distribution of the speed of airflow layer with the distance t between the airflow layer and the wheel edge [3]. The airflow speed is decreased with the

17、increase of the distance between the airflow layer and the wheel, and increased with the increase of wheel speed. The maximum speed of airflow is generated on the circle of the wheel edge and approaches the maximum perip

18、heral wheel speed. But there are the sharper grads of the airflow speed along the radial direction of the whee</p><p>　　Calculation of Grinding Fluid Flow</p><p>　　In general, the work of 85%~90

19、% to be absorbed for deformation and friction of materials converts into heat energy at normal temperature [4, 5], namely the thermal effect. For grinding process, the deformation and friction of materials as the main wo

20、rk is generated through the whole process.Therefore, it can be concluded that the most non-elasticity work convert into heat in grinding process. Based on the heat-work balance equation, the flow of grinding fluid is giv

21、en by</p><p>　　where ρ is the fluid density [kg/m3], N is the grinding power [kW], c is the specific heat [J/kg·K], G is the cooling coefficient that rests with the contact area between wheel and workpi

22、ece and the ratio of the effective fluid to enter grinding zone, generally, G is selected in range of 1.0~2.0, Δt is the increment of temperature and selected in range of 5 ~15 ℃. For the grinding fluid supply system (Fi

23、g. 3) in quick-point grinding, the larger G can be selected due to the better cooling conditi</p><p>　　Analysis of Fluid Jet Pressure</p><p>　　To overcome the airflow barrier effect and make the

24、 fluid enter contact zone, the grinding fluid jet pressure must fit for the following inequation</p><p>　　where v0 is the fluid jet speed [m/s]. Given the diameter of the fluid jet nozzle, the fluid flow Q i

25、s increased with the increase of the fluid jet pressure. On the other hand, the higher the jet pressure of fluid, the heavier the splash and spray of the fluid are, and the more the consumed power is. Therefore, the jet

26、pressure is usually 0.3~3 MPa in high and super-high speed grinding process. In quick-point grinding process, it is the point contact between the wheel and the workpiece in theory</p><p>　　In addition, the t

27、hin CBN wheel makes the airflow barrier effect weaken. </p><p>　　Therefore, given the fluid jet pressure, the flow can be lessened by reducing the diameter of the jet nozzle to weaken the influence of grindi

28、ng fluid on environment and improve the greenness of the grinding process.</p><p>　　Calculation of Jet Nozzle Diameter</p><p>　　The fluid flux through the jet nozzle is calculated by</p>

29、<p>　　where d0 is the jet nozzle diameter [mm]. Combined Eq.3 with Eq.4, the maximum diameter of jet nozzle is given by</p><p>　　For improving the fluid effect, double nozzles are applied in quick-point

30、 grinding process (Fig. 3). Given the fluid flux, the maximum diameter of the primary and secondary jet nozzle is calculated by</p><p>　　In quick-point grinding process, provided that the local area near the

31、 contact point was considered only and the curvature effect of the contact arc on the workpiece was omitted, the real contact length may be less than 0.5mm [6], therefore the larger G can be selected due to the better co

32、oling conditions.</p><p>　　Experiment for Effect of Grinding Fluid on Surface Integrity</p><p>　　Experiment Conditions. The experiment conditions are shown in Table 2.</p><p>　　The

33、grinding wheel and fluid system are shown in Fig. 4 and ground workpiece is shown in Fig. 5。The hardness is measured with TH550 Rockwell Hardness Tester at the depth 0.1 mm from the surface.</p><p>　　Analysi

34、s of Experiment Results. </p><p>　　Given the fluid jet pressure 2 MPa, the ground surface roughness presents a decline trend appreciably with increase of fluid flow at the range of 0~20 L/min, but the declin

35、e extent is very less. So the grinding fluid flux is not a main factor to influence the surface roughness under certain fluid jet pressure. Given the fluid jet pressure 2MPa, the ground surface hardness presents a declin

36、e trend appreciably with decrease of the fluid flux at the range of 0~20 L/min. Especially in dry grinding, </p><p>　　Conclusions</p><p>　　(1) In high and super-high grinding speed process, ther

37、e is the airflow layer with high rotary speed around the circle edge of grinding wheel that hinders the grinding fluid into contact layer. The pressure of the airflow layer increases with raise of the rotary speed of gri

38、nding wheel. There are the sharper speed grads in the airflow layer along the radial direction of the wheel. </p><p>　　(2) The less contact area in quick-point grinding makes the grinding heat and force lowe

39、r observably, and the cooling performance and the grinding fluid effect increase. Due to the thin CBN wheel used, the airflow barrier effect is weakened. Therefore, it is possible to lower the fluid supply parameters in

40、quick-point grinding process for weakening the influence of grinding fluid on environment and improving the greenness of the grinding process.</p><p>　　(3) The grinding fluid flow is not main factor to affec

41、t the surface roughness under certain fluid jet pressure. Although the dry grinding can be applied in quick-point grinding process for high greenness, it is necessary to design the proper grinding fluid parameters agains

42、t the thermal damages in grinding some quenched steels.</p><p>　　Acknowledgments</p><p>　　This research was financially supported by the Science and Technology Foundation of Liaoning Province of

43、 China under granted No. 20072030 and the National Natural Science Foundation of China under granted No. 50775032.</p><p>　　References</p><p>　　[1] E. Brinksmeier, M. Heinzel. Annals of the CIRP

44、, 1999, Vol. 2:48 (1999), p. 581-598</p><p>　　[2] M.T. Tan: Microcosmic Investigation on Metal Cutting (Shanghai Science and Technology Press, China 1988)</p><p>　　[3] G. L. Song: Basic Study on

45、 Super-high Speed Grinding Technology. (Ph.D. Northeastern University, Shenyang, 1997)</p><p>　　[4] S. C. Chen, Q. R. Ye: Principle of Plasticity Process for Metal. (Tsinghua University Press, Beijing, 1991)

46、</p><p>　　[5] J. X. Ren, and D. A. Hua: Grinding Principle. ( Northwest Technical University Press, Xian, 1988), p. 234-238</p><p>　　[6] S. C. Xiu, G. Q. Cai and Y. D. Gong. Diamond and Abrasive

47、s Engineering, No.4 (2005), p.33-35</p><p>　　Grinding at Very Low Speed</p><p>　　Abstract. </p><p>　　Grinding is a very complex machining process. Single grain grinding methods are

48、useful to study complex grinding action. Very low speed single-grain grinding tests were carried out for 45 steel and 20Cr alloy with 14# ZA grain. The grinding groove width and depth, the grinding force ratio, specific

49、grinding forces, and grain wear and fracture are studied. The plowing decreases with the grinding section area or grinding depth increase. The average tangential force at grain fracture in the experim</p><p>

50、;　　Introduction</p><p>　　Grinding is a machining process which utilizes a grinding wheel consisting of abrasive grains. It is a very complex process with many variations. In scientific research, complex phen

51、omena are usually abstracted to simple models. The single grain grinding is an important method to study complex grinding action [1-6]. Single grain grinding experiments are useful because with the application of a large

52、 load, the extent of damage can be amplified for interpretation while unaffected by interactionswi</p><p>　　Experimental Condition and Procedure</p><p>　　The experiments have been done on a mach

53、ine tool in Northeastern University. A single grain is adhered to a bolt. The bolt is installed on the dynamometer device. The device is shown in Fig. 1. The tangential and normal grinding forces are measured by Y82-7 p

54、iezoelectricity crystalloid force-sensor (sensitive degree: 4.08pc/N, intrinsic frequency: 30KHZ) and FDH-2T electricity amplifier. The signal is output to CS2092 dynamic testing instrument to note and deal with the data

55、 after amplified. I</p><p>　　The grain used in the experiments is 14# ZA Aluminum Oxide (10~15%ZrO2). The materials of work is 45 steel (HV hardness, 222 kg/mm2) and 20Cr alloy (HV hardness, 162 kg/mm2).The

56、 experimental conditions of single grain grinding is shown in Table 1. The experiments were carried out in atmospheric condition of room temperature 20℃; relative humidity, 40-60%.</p><p>　　Fig. 1 Configurat

57、ion of single grain grinding test</p><p>　　Table 1 Conditions of test</p><p>　　Results and Discussion</p><p>　　Grinding Groove Morphology. The groove cross section is shown in Fig.

58、2. w is groove width, and d groove depth. The relationships between groove width and depth under different conditions are shown in Fig. 3. Those relations reflect conditions of grains cutting blade and elastic comeback o

59、f groove.</p><p>　　Fig. 2 Cross section of grinding groove</p><p>　　Force Ratio ε. Force ratio can be defined as ε=Ft/Fn, where Ft is tangential force, Fn normal force. Force ratio ε is very use

60、ful to study the friction between grain and work, to evaluate grain cutting conditions. For sharp grains, tangential force Ft is mainly used to form chips, Force ratio ε is larger than that for blunt grain. The relations

61、hip between force ratio ε and groove cross section area is shown in Fig. 4. As shown in Fig. 4, force ratio ε increase with groove cross section area. Thi</p><p>　　Fig. 3 Scheme of the grind width versus the

62、 grind depth of grooves</p><p>　　Fig. 4 Relation between ratio of tangential-to-normal force and groove section area</p><p>　　Specific Grinding Force. Specific grinding force definite as σ’= Fgt

63、/A. Specific grinding force σ’ may reflect characteristic of work material and grain tartness degree. Specific grinding force has the similar physics meaning and the same dimension with specific energy. The specific melt

64、ing energy of steels is 10.35J/mm3.The specific force for single grain grinding 45 carbon steel and 20Cr alloy is about 12×103N/mm2 at v=2.8cm/s with the cross section area of undeformed chip increase. That value<

65、;/p><p>　　Fracture of Grain. The actual cutting points on abrasive grains at wheel surface are micro-cutting tools which interact with the work material. The grain fracture can produce new abrade on the grain.

66、That is the foundation of the characteristic of wheel self-sharpen. The ratio of tangential-to-normal force ε varies along the groove in a single pass grinding is shown in Fig. 5. The value of force ratio ε stabilizes in

67、 the middle part of the groove. In this period the chips were formed. The force </p><p>　　Fig. 5 Ratio of tangential-to-normal force along the groove</p><p>　　Conclusions</p><p>　　G

68、rinding is a very complex machining process with many variations, which utilizes a grinding wheel consisting of abrasive grain. Single grain grinding experiments are useful to study complex grinding action. In this inves

69、tigation, single-grain grinding tests were carried out for 45 steel and 20Cr alloy with 14# ZA grain. The tangential-to-normal grinding force ratio increase with groove cross section area. The plowing decreases with the

70、grinding section area increase. The tangential-to-normal gr</p><p>　　Acknowledgment</p><p>　　The research is supported by the innovation fund No.2004J003 of young science and technology talent o

71、f Fujian province in China, the innovation team fund of Ludong University in China, and the science and technology development fund No.LY20064302 of Ludong University in China.</p><p>　　References</p>

72、<p>　　[1] B. F. Feng and G. Q. Cai: Key Engineering Materials, Vol. 202-203(2001):115.</p><p>　　[2] O. Desa and S. Bahadur: Wear, 225-229(1999), p.1264.</p><p>　　[3] Y. Ohbuchi and T. Mats

73、uo: Annals of CIRP. Vol. 40 (1991), p.327.</p><p>　　[4] B. F. Feng; H. H. Zhao; G.Q. Cai and T. Jin: Journal of Northeastern University (Natural</p><p>　　Science), Vol.23 (2002), 5: 470-473(In C

74、hinese).</p><p>　　[5] B. F. Feng and G. Q. Cai: Key Engineering Materials, Vol.304-305(2006):196.</p><p>　　[6] G. Q. Cai and H. W. Zheng: Grinder and Grinding, No.5 (1985):1.</p><p>

75、;　　在快速點(diǎn)磨削中磨削液供給參數(shù)對(duì)表面完整性影響的研究</p><p><b>　　摘要：</b></p><p>　　在高速和超高速磨削過(guò)程中，有一個(gè)高速氣流圈環(huán)繞在砂輪周圍，阻礙磨削液進(jìn)入接觸層，此即空氣屏障作用。氣流層的速度與砂輪速度的平方成正比?？焖冱c(diǎn)磨削是一種新型的高速、超高速磨削過(guò)程，此過(guò)程是點(diǎn)接觸，需要更少的磨削力。因?yàn)镃BN砂輪的應(yīng)用，空氣的屏障作用

76、減弱。通過(guò)對(duì)動(dòng)壓和砂輪周圍邊緣氣流層的速度分析，在磨削過(guò)程中建立有效磨削液流動(dòng)和噴嘴壓力的數(shù)學(xué)模型，以熱力學(xué)和快速點(diǎn)磨削過(guò)程中的技術(shù)特征為基礎(chǔ)優(yōu)化噴嘴直徑的計(jì)算過(guò)程。該快速點(diǎn)磨削實(shí)驗(yàn)中，表面完整性受磨削液供給參數(shù)影響。</p><p><b>　　引言</b></p><p>　　磨削加工過(guò)程受環(huán)境和材料影響很大。研磨劑和研磨液對(duì)磨削加工有很大影響，研磨液功能主要是冷

77、卻、沖洗、潤(rùn)滑。特別是在高速和超高速磨削加工過(guò)程中，有一個(gè)高速氣流圈環(huán)繞在砂輪周圍，阻礙磨削液進(jìn)入接觸層，此即空氣屏障作用。因此它必須增加磨削液供給參數(shù)保持在研磨過(guò)程流體作用。近年來(lái)，它一直是研究的重點(diǎn)工程，以改善和發(fā)展綠色磨削工藝?？焖冱c(diǎn)磨削是一種新型的高速和超高速磨削技術(shù)，它有一些很好的特點(diǎn)，如低磨削力、低溫、冷卻條件好、砂輪壽命長(zhǎng)等等。通過(guò)設(shè)計(jì)合理的磨削液系統(tǒng)和磨削液供給參數(shù)以及優(yōu)化綠色制造的磨削工藝參數(shù)，可以實(shí)現(xiàn)干磨削。<

78、/p><p>　　砂輪氣流層流速和壓力的分析</p><p>　　磨削熱產(chǎn)生于研磨過(guò)程中材料的變形和摩擦，使磨削溫度上升，從而導(dǎo)致熱的工件表面損傷。因此，一個(gè)可靠的磨削液系統(tǒng)是大多數(shù)磨削工藝所必需的，此系統(tǒng)可保持冷卻，清洗和潤(rùn)滑功能。對(duì)于高速和超高速磨削過(guò)程，為了克服空氣流的屏障作用，增加有效流動(dòng)比率，減少液體的飛濺和浪費(fèi)，必須設(shè)計(jì)合理的磨削液供給參數(shù)和噴射方式。在快速點(diǎn)磨削過(guò)程中，砂輪和工件

79、之間由于點(diǎn)磨削角度和CBN砂輪（圖1）點(diǎn)接觸，氣流層非常狹窄，氣流屏障作用減弱，流體作用大大提高，因此，研磨液供給參數(shù)可以降低。圖.1快速點(diǎn)磨削原理圖</p><p>　　在磨削加工過(guò)程中，砂輪周圍高速旋轉(zhuǎn)的氣流層的厚度和壓力是影響流動(dòng)速度的主要因素，砂輪速度越高，氣流層越厚，壓力越高。根據(jù)伯努利方程[2]，氣流層的壓力用下面公式計(jì)算</p><p>　　其中是氣流速度，是空氣密度[kg/

80、m3]</p><p>　　如果氣流層動(dòng)態(tài)壓力Pa是根據(jù)不同輪的位置來(lái)衡量，在相同位置的氣流速度可以計(jì)算出來(lái)。表1給出了動(dòng)態(tài)壓力和氣流層速度實(shí)驗(yàn)值。如果砂輪直徑為600mm,砂輪速度分別是30m/s和60m/s，動(dòng)態(tài)壓力和氣流速度的測(cè)量值在表1中列出。可以看出氣流層動(dòng)態(tài)壓力隨著砂輪速度增加而增加。</p><p>　　表1 動(dòng)態(tài)壓力和氣流層速度的測(cè)量值</p><p&

81、gt;　　圖2顯示了氣流速度隨氣流層和輪緣[3]之間的距離t的分布。氣流速度隨氣流層和砂輪之間的距離的增加而增加，同時(shí)隨著輪速的增加而增加。氣流最高速度產(chǎn)生于砂輪最外邊緣并且接近最大輪緣速度。但也有氣流層沿砂輪徑向方向急劇產(chǎn)生。因此，高壓旋氣流層阻擋磨削液進(jìn)入磨削區(qū)，由于失去了流體作用而降低了工件的完整性和砂輪壽命。在快速點(diǎn)磨削過(guò)程中，在理論上砂輪和工件之間是點(diǎn)接觸，由于車輪與工件的軸線不平行對(duì)方（圖1），它不同于傳統(tǒng)外圓磨，所以冷卻條

82、件較好。此外，由于CBN砂輪在此過(guò)程中使用，氣流層研磨液屏障作用減弱。</p><p>　　圖2氣流層速度分布 圖1磨削液供給系統(tǒng)</p><p><b>　　磨削液的流量計(jì)算</b></p><p>　　一般來(lái)說(shuō)，在常溫下[4，5]，85％?90％的功被吸收用于材料的變形和摩擦，轉(zhuǎn)換成熱能，即熱效應(yīng)。對(duì)于

83、磨削工藝，材料的變形和摩擦的主要工作是產(chǎn)生于整個(gè)過(guò)程.因此可以得出結(jié)論，大多數(shù)非彈性工作在磨削過(guò)程中轉(zhuǎn)換成熱能。在熱-工平衡方程基礎(chǔ)上，對(duì)磨削液流量由下式給出</p><p>　　其中ρ為流體密度[kg/m3的]，N是磨削功率[kW]，c是比熱研究[J/公斤?k]的，G為冷卻系數(shù)在于輪與工件之間的接觸面積和有效的液比進(jìn)入磨削區(qū)，一般，G是在1.0?2.0范圍內(nèi)選定，Δt是溫度升高，在5?15℃的范圍內(nèi)選擇。對(duì)于快

84、速點(diǎn)磨削的磨削液供給系統(tǒng)（圖3），接觸面積越小，G可以根據(jù)更好的冷卻條件選擇更大值。</p><p><b>　　分析流體射流壓力</b></p><p>　　為了克服氣流的屏障作用，使流體進(jìn)入接觸區(qū)，磨削液射流壓力必須符合以下不等式</p><p>　　其中V0為射流速度[米/秒]。鑒于流體噴嘴直徑，流體流量Q是隨流體噴射壓力增加。另一方面，

85、較高的流體噴射壓力，加重色斑和流體噴霧的，消耗更多的功率。因此，在高速和超高速磨削過(guò)程中，噴射壓力通常在0.3?3 MPa。在快速點(diǎn)磨削過(guò)程中，它不同于傳統(tǒng)的外圓磨，理論上它是連接砂輪與工件的接觸點(diǎn)，因?yàn)樯拜喤c工件的軸線不平行點(diǎn)接觸對(duì)方（圖1），所以接觸面積磨削熱降低，但磨削力變大，提高了冷卻性能和磨削液的作用。此外，CBN砂輪使氣流的屏障作用減弱，因此，考慮到流體噴射壓力，流量可通過(guò)減少噴嘴直徑削弱了磨削液對(duì)環(huán)境的影響，提高了磨削工藝

86、。</p><p><b>　　噴嘴直徑的計(jì)算</b></p><p>　　噴嘴液體流量通過(guò)以下公式計(jì)算</p><p>　　其中D0為噴嘴直徑[mm]。</p><p>　　結(jié)合Eq.4 Eq.3，最大的噴嘴直徑由下式給出</p><p>　　為了提高流體效應(yīng)，雙噴嘴適用于快速點(diǎn)磨削過(guò)程（圖3）

87、。</p><p>　　鑒于流體流量，主要和次要噴嘴最大直徑通過(guò)以下公式計(jì)算</p><p>　　在快速點(diǎn)磨削過(guò)程中，接觸點(diǎn)附近的局部區(qū)域被認(rèn)為遺漏了工件上的接觸弧曲率效應(yīng)，實(shí)際接觸長(zhǎng)度可能小于0.5mm[6]，因此G可以根據(jù)更好的散熱條件來(lái)選擇。</p><p>　　磨削液對(duì)表面完整性的影響實(shí)驗(yàn)</p><p><b>　　實(shí)驗(yàn)條

88、件見(jiàn)表2</b></p><p><b>　　表2實(shí)驗(yàn)條件</b></p><p>　　砂輪與流體系統(tǒng)如圖4所示。地面工件如圖5。從表面TH550洛氏硬度計(jì)，硬度測(cè)量的深度0.1毫米。</p><p>　　圖4 磨削輪和流體供給系統(tǒng) 圖5 地面工件</p><p>　　圖6

89、磨削淬火鋼工件的表面完整性試驗(yàn)結(jié)果</p><p>　　實(shí)驗(yàn)結(jié)果分析。由于射流壓力2 MPa時(shí)，流量在0?20升/分范圍內(nèi)增加時(shí)，地表粗糙度明顯呈現(xiàn)下降趨勢(shì)，但下降的幅度是非常少。因此，在某些液體噴射壓力下，磨削液流量不是表面粗糙度的主要影響因素。由于流體噴射壓力2MPa時(shí)，在0?20升/分范圍內(nèi)，地面表面硬度呈現(xiàn)與流體通量下降的趨勢(shì)明顯減少了。特別是在干磨削時(shí)，表面硬度明顯下降，這表明熱損壞是在一定程度上產(chǎn)生的

90、。因此，雖然干磨可應(yīng)用于快速點(diǎn)磨削過(guò)程中有時(shí)為了更加環(huán)保，需要設(shè)計(jì)一些適當(dāng)磨液供給參數(shù)來(lái)防止在磨削淬火鋼中的熱磨損。</p><p><b>　　結(jié)論</b></p><p>　　（1）在高速、超高速磨削速度的磨削過(guò)程中，氣流層在砂輪圈的邊緣高速旋轉(zhuǎn)，阻礙磨削液進(jìn)入接觸層。提高砂輪的轉(zhuǎn)速可提高氣流層的壓力。還有一些在沿徑向方向的砂輪氣流層速度梯度層清晰。</p&

91、gt;<p>　?。?）快速點(diǎn)磨削接觸面積減少，使磨削熱和力降低明顯，冷卻性能和磨削液的作用增加。由于CBN砂輪薄使用，氣流屏障作用減弱。因此，在快速點(diǎn)磨削過(guò)程，有可能降低流體提供參數(shù)降低磨削液影響，提高了綠色磨削工藝。</p><p>　　（3）在某些液體射流壓力下，磨削液流量不是表面粗糙度主要影響因素。雖然干磨可應(yīng)用于快速點(diǎn)磨削過(guò)程中有時(shí)為了更加環(huán)保，需要設(shè)計(jì)一些適當(dāng)磨液供給參數(shù)來(lái)防止在磨削淬火

92、鋼中的熱磨損。</p><p><b>　　致謝</b></p><p>　　此研究得到中國(guó)遼寧省科學(xué)與技術(shù)基金會(huì)的財(cái)政支持，批準(zhǔn)號(hào)20072030，國(guó)家自然科學(xué)基金委員會(huì)授予號(hào)50775032。</p><p><b>　　參考文獻(xiàn)</b></p><p>　　[1] E. Brinksmeier

93、, M. Heinzel. Annals of the CIRP, 1999, Vol. 2:48 (1999), p. 581-598</p><p>　　[2] M.T. Tan: Microcosmic Investigation on Metal Cutting (Shanghai Science and Technology Press, China 1988)</p><p>

94、　　[3] G. L. Song: Basic Study on Super-high Speed Grinding Technology. (Ph.D. Northeastern University, Shenyang, 1997)</p><p>　　[4] S. C. Chen, Q. R. Ye: Principle of Plasticity Process for Metal. (Tsinghua

95、University Press, Beijing, 1991)</p><p>　　[5] J. X. Ren, and D. A. Hua: Grinding Principle. ( Northwest Technical University Press, Xian, 1988), p. 234-238</p><p>　　[6] S. C. Xiu, G. Q. Cai and

96、Y. D. Gong. Diamond and Abrasives Engineering, No.4 (2005), p.33-35</p><p><b>　　低速磨削</b></p><p><b>　　摘要：</b></p><p>　　磨削是一個(gè)非常復(fù)雜的加工過(guò)程。單粒研磨方法對(duì)于研究復(fù)雜磨削運(yùn)動(dòng)非常有用。單顆粒

97、的研磨試驗(yàn)在非常低的速度下對(duì)45鋼和20Cr合金進(jìn)行了測(cè)試，研究了磨削溝槽的寬度和深度，磨削力比率，特定磨削力，磨損和斷裂和紋理的影響。磨削溝槽隨截面積與磨削磨削深度增加而變淺。磨粒折斷平均實(shí)驗(yàn)切向力54.4N，平均晶斷裂正常力949.6N。當(dāng)磨粒斷裂時(shí)，該切向力對(duì)正常力的比率會(huì)突然變化。</p><p><b>　　引言</b></p><p>　　磨削是一種采用了

98、砂輪磨粒加工工藝的過(guò)程。這是一個(gè)非常復(fù)雜的過(guò)程，其中有許多變化。在一些科研中，復(fù)雜的現(xiàn)象通常被抽象為簡(jiǎn)單的模型。單粒研磨實(shí)驗(yàn)是一種來(lái)研究復(fù)雜的研磨作用[1-6]非常有用的方法 ，因?yàn)閼?yīng)用于大負(fù)載，同時(shí)不會(huì)被周邊地區(qū)發(fā)生的相互作用類似進(jìn)程的影響，產(chǎn)生的損害程度可能被放大。</p><p>　　該方法提供了一個(gè)磨削點(diǎn)的橫截面形狀的最詳細(xì)的圖片。許多學(xué)者，研究了磨粒磨損和碰撞和理想形狀的磨粒碎片和磨削力，并得到了一些有

99、益的結(jié)論。在本文中，已對(duì)單粒磨削45鋼和20Cr合金14＃ ZA磨粒（氧化鋁，氧化鋯10?15％）進(jìn)行了測(cè)試。討論了磨削力比，磨粒磨損和斷裂。</p><p><b>　　實(shí)驗(yàn)條件及程序</b></p><p>　　該實(shí)驗(yàn)已經(jīng)在東北大學(xué)的機(jī)床上完成。一個(gè)單磨粒附著在一個(gè)螺栓上，該螺栓安裝在測(cè)功機(jī)上。圖1 是此設(shè)備的示意圖。切向和正常的磨削力通過(guò)Y82- 7壓電晶體力傳

100、感器（敏感程度：4.08pc/氮，固有頻率：30kHz的）和外傭-2T的電力放大器測(cè)量。信號(hào)輸出到動(dòng)態(tài)測(cè)試儀CS2092對(duì)數(shù)據(jù)進(jìn)行說(shuō)明和處理放大處理。為了降低噪聲，提高精度，傳感器加預(yù)應(yīng)力。因?yàn)榇嬖陬A(yù)應(yīng)力，測(cè)試儀處于更好的狀態(tài)下。校準(zhǔn)完成后，測(cè)試儀是固定的。</p><p>　　在實(shí)驗(yàn)中使用的磨粒是氧化鋁14＃（10?15％氧化鋯）。工作材料為45鋼（高壓硬度，222 kg/mm2）和20Cr合金（高壓

101、硬度，162 kg/mm2）。單粒研磨的實(shí)驗(yàn)條件見(jiàn)表1。實(shí)驗(yàn)是在室溫20℃，相對(duì)濕度40-60％的條件下進(jìn)行的。</p><p>　　圖1單磨粒磨削試驗(yàn)裝置</p><p><b>　　表1測(cè)試條件</b></p><p><b>　　結(jié)果與討論</b></p><p>　　磨削溝槽形態(tài)。

102、溝槽截面如圖2所示。W是溝槽寬度，d是溝槽深度。不同條件下溝的寬度和深度之間的關(guān)系如圖3所示。這些關(guān)系反映的切削刃和溝槽彈性恢復(fù)的條件。</p><p><b>　　圖2磨溝斷面</b></p><p>　　力比ε。力比可以被定義為ε=，其中Ft為切向力，F(xiàn)n為正壓力。在研究磨粒和工件之間的摩擦，力比ε對(duì)于評(píng)估磨削條件是非常有用。對(duì)于鋒利的磨粒，切向力Ft主要用于形成