灰铸铁仿生制备工艺及抗热疲劳性的研究
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摘要
本文以HT200灰铸铁为研究对象,在贝壳软硬交替结构具有优良抗热疲劳性的自然界非光滑现象的启发下,通过激光器在长方体薄块状灰铸铁试样表面加工出一条条平行等间距的单元体来提高灰铸铁的抗热疲劳性能。研究单元体横截面积的变化对试样热疲劳抗性的影响;以单元体横截面积的大小为指标对激光器的加工参数进行了优化;研究了不同参数对单元体横截面积大小的影响规律;并研究了预热和退火工艺对单元体中的孔洞、裂纹、拉应力的影响。研究表明:试样的热疲劳裂纹扩展速度随着单元体横截面积的增加而显著减小。激光脉宽是影响单元体横截面积的最显著因素,脉宽增加,单元体横截面积显著增加;激光功率增加单元体横截面积逐渐增大;扫描速度加快使单元体的横截面积逐渐减小;频率和离焦量对单元体尺寸影响不显著。各因素对指标的影响次序为:脉宽>功率>扫描速度>频率>离焦量。对脉宽进行扩大化试验,确定的激光加工参数的最优值为:脉宽13 ms,功率为1482W,扫描速度0.5 mm/s,频率10Hz,离焦量5.5mm。对试样整体预热温度提高到250℃后,再激光处理可消除单元体表面的裂纹和孔洞,处理后单元体的晶粒略有增大,硬度下降7.42%。在同样的激光加工参数下,250℃预热后的试样的热疲劳性能相对于未预热的试样略有提高。预热后加工单元体再退火工艺可以去除单元体处93.3%的拉应力,退火后的试样的热疲劳性能相对于仿生非光滑未预热试样和仿生非光滑预热试样提高38%。
Brake drum is the key part of truck braking system, the improvement of its performance can enhance the safety of vehicles and reduce maintenance cost. Modern society needs trucks having higher performance, such as higher speed, heavier load and some trucks have to more frequently work in variety harsh environments, these changes require brake drums having higher life. Gray cast iron HT200, is commonly used as the materials for brake drums in China. This kind cast iron has many excellent machining performances, which are why it can be widely used, but it contains a large number of graphite sheets having no strength, which is a kind of serious flaw. Brake drums are tore by braking force; the temperature of brake drums' surface reaches to very high temperature during braking while drop to room temperature after braking; cracks are generated between high temperature and low temperature and the expanding of cracks result in the ultimate failure of brake drums.
     Our team has improved the thermal fatigue resistance of gray cast iron more than twice from the view of bionics, using a laser to process some parallel units in the gray cast iron surface to simulate the alternate hard and soft structure of shells. However, the laws of laser system's five parameters impacting the thermal fatigue resistance of units have not been researched strictly. Some cracks, holes and biggish tensile stress would be generated in the surface of units, which seriously damaged the units' thermal fatigue resistance. In this paper, cracks and holes in units were eliminated through preheating process, tensile stress was reduced sharply by annealing process, and the laws of preheating and annealing process impacting the units' thermal fatigue properties were also studied.
     Through experiments and research analysis, the conclusions are as follows.
     1. By comparing the thermal fatigue property of samples whose units had different cross-sectional area, it was found that the thermal fatigue property of samples increased with the increased cross-sectional area of units.
     2. Through optimization test of laser parameters, the laws of laser system's five parameters impacting the thermal fatigue resistance of units had been researched strictly. It was found that the laser pulse width was the most important impact which affected the cross-sectional area of units. The cross-sectional area of units became larger obviously while the pulse width was increased; the cross-sectional area of units became larger with power increased; the cross-sectional area of units became smaller with scanning speed increased; the cross-sectional area of units was changed little while frequency and distance from the focused point changed. Factors are sorted as follows: pulse width> power> scanning speed> frequency> distance from the focused point. The optimal laser processing parameters are determined by the expansion test of the pulse width test. Minor other secondary factors are fixed and pulse width is changed only. The fixed final laser processing parameters are as follows: pulse width 13 ms, power of 1482W, scanning speed 0.5 mm / s, frequency of 10Hz, 5.5mm distance defocused.
     3. The cracks and holes in the surface of units could be eliminated by being preheated at 250℃firstly and then being scanned, moreover, the organization became a little bigger and hardness of units decreased 7.42%. Under the same laser processing parameters, compared with sample un-preheated, the thermal fatigue performance of preheated sample was increased very little. This was because although preheating process eliminated the cracks and holes, the higher tensile stress was not released. Tensile stress enhanced the growing of cracks and decreased the effect of the elimination of units' cracks and holes which could enhance resistance to thermal fatigue.
     4. The tensile stress was eliminated 93.3% by annealing process and the annealing. The thermal fatigue performance of bionic non-smooth preheated and annealed sample was increased 38% compared with bionic un-preheated sample and bionic non-smooth preheated sample.
引文
[1]熊坚.汽车制动过程的模拟分析[J].北京:汽车工程出版社,1995.
    [2]张庆云.汽车制动性能对稳定性和操纵性的影响[J].汽车技术,1991.
    [3]熊坚.汽车制动过程的计算机模拟分析[J].汽车技术,1995.
    [4]王文静.铁路列车制动鼓常用材料的热疲劳性能研究,机械工程材料,1998.
    [5]黄笑梅.低合金化灰铸铁汽车制动鼓的研制[J].汽车工艺与材料,2002(1):22224.
    [6]朱育全.制动鼓(盘)研究现状与发展趋势[J].西北工业大学学报,2001(3):73276.
    [7]朱景宏.刹车后制动鼓化学成分的控制[J].上海大学学报(自然科学版),1999(5):1842186.
    [8]周顺隆.制动摩擦材料试验方法研究[J].摩擦磨损,1980(1):25227.
    [9]张嗣伟.石油钻机绞车刹车块摩擦性能研究[J].石油矿物机械,1983(2):2326.
    [10]平修二.热应力与热疲劳[M].北京:国防工业出版社,1982.
    [11]谢兴华,华绍忠.激光加工技术在汽车工业生产中的应用全国第九届高能束热处理学术会议论文集[C],北京:电子工业出版社,1991.
    [12]何金兆,张永振,戴宝林.灰铸铁在铁道车辆制动系统的应用[J].洛阳工学院学报, 2003(22):79-80.
    [13] Jost H.P,H.Peter,Bartz.WJ. International Tribiology council [J]. Techniscbe Akademic Essligen,2000.
    [14] Fundamentals of materials sciences and engineering fifth edition[M]化学工业出版社,1998.
    [15] Surappa M K. Wear and abrasion of cast Al-alunina particle Composites [J].J Wear,1982,77:295-302.
    [16] Hiroake N, Kenjie K, Akinori N. Development of aluminum metal matrix composites brake rotor and pad [J].JSAE Review,2002,23:365-370.
    [17] Lloyd D J. Aspect of fracture in particulate reinforced metal matrix Composites [J].Acta Metal Mater,1991,39(1):59-71.
    [18]磁场焊接[M].译文集.第五机械工业部第五设计院.前言.
    [19]贾昌申.用电磁搅拌抑制LD10CS铝合金焊接热裂纹的研究[J].第八次全国焊接会议论文集.
    [20] Chan C H. Laser in metal surface modification [J]. Metallurgical Transactions a, April 1984,15:719-728
    [21] Mazumder J. Effect of laser power on heat treatment of metals [J]. Journal of Metals, 1983,35(5):18-26.
    [22] MCPHERSON R A. Review of microstructure and properties of plasma sprayed ceramic coatings [J]. Surface and Coatings Technology, 1999,39(40):173-182.
    [23]赵亚凡,陈传忠.激光熔覆金属陶瓷涂层开裂的机理及防止措施[J].激光技术,2006.
    [24] P.Forget,M.Jeandin,Journal de Physique [J],1995.
    [25]倪敏雄,周建忠.激光冲击处理的残余应力场形成机理及影响因素分析[J].应用激光,2006年4月,26卷2期.
    [26] Z. Gue. Life-time reliability based assessment of structures submitted to thermal fatigue [J].International Journal of Fatigue 2007(29):1359–1373.
    [27]郭公喜,仿生学研究概述[M].科学文化出版社, 2001(27):47-48
    [28] Johan Lansinger,Fatigue crack growth under combined thermal cycling and mechanical loading [J]. International Journal of Fatigue 2007(29):1383–1390.
    [29]江雷.从自然到仿生的超疏水纳米界面材料[J].现代科学仪器, 2003, 22(3):6-10
    [30]范细秋.基于“荷花效应”的MEMS功能表面仿生技术[J].武汉理工大学学报, 2005,27(10):47-49
    [31]徐坚.自清洁功能的高分子仿生表面研究取得新进展[M].成果与应用,2005,20(1):45-48
    [32]路晓,管自生.自清洁仿生表面的湿润性及其制备的进展[J].材料导报, 2006,20(6):63-66
    [33]伍一军.昆虫仿生[M].昆虫知识,2005,42(1):109-112
    [34] K. Koch, A. Dommisse etc. The use of plant waxes as templates for micro and nano patterning of surfaces [J]. Alta Biomaterial a, 2007, 3:905–909.
    [35] R. Bonser, E. Johnson. etc. Towards biomimetic feathers for better insulation [J]. Comp. Biochem. Phys. a, 2007,146:S129-S141.
    [36] P. Nagaraja, D. Yao. Rapid pattern transfer of biomimetic surface structures onto thermoplastic polymers [J]. Mater. Sci. &Eng. a, 2007, 27:794-797.
    [37]王淑杰.典型生物非光滑理论及其仿生应用[J].农机化研究,2005, 1:209-213.
    [38] M.H. Dickinson. Biological insight into mechanical design [J]. Proceedings of the National Academy of Science, 1999, 25 (96):14208-14209.
    [39] D.W. Bechert, M. Bruse. Fluid Mechanics of Biological Surfaces and their Technological Application [J]. Proceedings of the National Academy of Science, 2000,87:157-171.
    [40]任露泉.仿生学与仿生技术[M].内蒙古:内蒙古出版社,1996.
    [41]丛茜.几何非光滑生物体表形状的分类研究[J].农业工程学报,1998, 8(2):7-12.
    [42]王国林.蜣螂体表几何非光滑结构单元分布的分形特性[J].农业机械学报, 1997, 12:5-9.
    [43]贾贤.土壤动物体表及仿生复合涂层的润湿性[J].材料研究学报,1996, 10(5):556-560.
    [44] Q. Cong,L.Q. Ren. Taxonomic research on geometric non-smooth surface shapes [J]. Trans. Chinese Soc. Agr. Eng., 1992,8(2):7-12.
    [45] L.Q. Ren, S.Q. Deng etc. Design principles of the non-smooth surface bionic plow mold board [J]. Bionics Eng., 2004,1(1):9-19.
    [46] L.Q. Ren, Z.W. Han etc. Effect of non-smooth characteristics on bionic bulldozer blades in resistance reduction against soil [J]. Terramechanics, 2003,39:221-230.
    [47] L.Q. Ren, Q. Cong etc. Reducing adhesion of soil against loading shovel using bionic electro-osmosis method [J]. Terramechanics, 2001,38:211-219.
    [48] L.Q. Ren, J. Tong etc. Reducing sliding resistance of soil against bulldozing plates by unsmoothed bionics surfaces [J]. Terramechanics, 1995,32:303-309.
    [49]魏铁华.仿生工程[J].水利电力机械, 2001.
    [50] Ren Luquan, Li Jianqiao, Chen Bingcong. Unsmooth surface on reducing resistance by bionics [J].Chinese Science Bulletin, 1995, 40(13):1077-1088.
    [51] Nicoletto G, Tucci A, Esposito L. Comparative dry wear behavior of hard coatings [J]. Wear, 1993,162-164.
    [52]任露泉.激光处理非光滑凹坑表面耐磨实验的均匀设计研究[J].材料科学与工程, 2002,20(2):93-95.
    [53]任露泉.仿生非光滑耐磨复合层的研究[J].农业工程学报,2001, 17(3):7-9.
    [54]王再宙.激光处理非光滑凸包表面的耐磨性试验[J].吉林大学学报(工学版),2002,32(2):45-48.
    [55]任露泉.生物非光滑耐磨表面仿生应用研究展望.农业机械学报, 2005, 36(7):144-147.
    [56]齐彦昌.轧辊表面激光雕刻仿生非光滑形态耐磨性研究[J].应用激光, 2006,26(1):1-4.
    [57]王云鹏.柔性仿生技术的研究与应用[J].公路交通科技,2006, 13(4):45-49
    [58]丛茜.土壤粘附机理的化学吸附分析[J].农业工程学报,1996, 12(2):40-44.
    [59]阎备战.交变电流在仿生非光滑表面电渗中作用原理的试验研究[J].农业工程学报,1997,3(6):27-31.
    [60] G.M. Bond, R.H. Richman etc. Mimicry of natural material designs and processes [J]. Mater. Eng. Perform,1995,4(3):334-345.
    [61]陈国华.天然材料微观结构与过程仿生研究进展[J].化学通报,1998, 1:6-10.
    [62]张学骜.贝壳珍珠层生物矿化及其对仿生材料的启示[J].无机材料学报, 2006,21(2):257-266。
    [63]王国林,生物体表几何耦合结构单元分布的分形特性[J],农业机械学报,1997,12(5):5-9.
    [64] Kuhn-spearing L T,Kessler H,Chateau E,et al. Fracture mechanisms of the thrombus gig as conch shell: implications for the design of brittle laminates [J]. Mater. Scil.1996,31:65-83.
    [65] Curry. Fatigue fracture of mother-of-peal and its significance for predatory techniques [J].Nature,2001,204-541.
    [66]李恒德,冯庆铃,崔福斋.贝壳珍珠层及仿生制备研究[J].清华大学学报:自然科学版,2001,41(4):41-47.
    [67] Mai K,Zhang W,Tan B,et al. J Exp Mar Biol,2003.
    [68]袁根福.激光加工技术的应用与发展现状[J].安徽建筑工业学院学报(自然科学版),2004,12(1):30-34
    [69]刘斌,徐金瑞,林建明等,激光应用于玻碳电极表面的预处理[J],华侨大学学报(自然科学版),1996,17(4):362-364.
    [70]王秀彦,安国平,李栋,梁小兵,模具及模具材料激光相变硬化的初步探索与实验[J],锻压机械,2002,2(7):57-61.
    [71] SAMROUT H, ABDI R E. Fatigue behavior of 28CrMoV5 steel under thermomechanical loading [J]. International Journal of Fatigue, 1998, 8(20): 555-563.
    [72] TONG X, ZHOU H, CHEN L, et al. Effects of C content on the thermal fatigue resistance of cast iron with biomimetic non-smooth surface [J]. International Journal of Fatigue, 2008, 30: 1125-1133.

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