外文翻譯--機(jī)械加工表面質(zhì)量

1 機(jī)械專業(yè)外語文獻(xiàn)翻譯 系 別 機(jī)電工程 系 專 業(yè) 機(jī)械設(shè)計(jì)制造及其自動化 班 級 學(xué)生姓名 學(xué) 號 日 期 2014.6.10 1 The Surface Quantity While Machine Processes A.the machine processes the surface quantity to use the influence of the function to the machine (A)The surface quantity to bear to whet the sexual influence 1. Rough degree of surface to bear to whet the sexual influence The rough degree of surface is very big to the influence that the spare parts surface wear away.Say a value of surface generally more small, it wears away sex more good.But rough degree of surface the value is too small, lubricant not easy storage, contact of the noodles easy occurrence the member glues to connect, wearing away to increase on the contrary.Therefore, the rough degree that contact face have a the best value, it is worth to have something to do with the work circumstance of the spare parts, working to carry the lotus enlargement, wore away the quantity aggrandizement in the early years, rough degree of surface the best value also enlargement. 2. The surface is cold to make to harden to bear to whet the sexual influence Process the surface cold to make to harden to make rub the vice- surface layer the metals of show minute details the degree of hardness exaltation, past can make bear to whet the sex exaltation generally.But is also not cold to make to harden the degree more high, bear to whet sex more high, this is because excessively cold make to harden and will cause the excesssive loose of the metals organization loose, even appear the crack and surface layer metals peeling off, make bear to whet sex to descend. (B)The surface influence of the quantity upon the tired strength The tired breakage that metals produce after be subjected to hand over to change to carry the lotus function usually takes place under the cold and hard layer of the spare parts surface and surfaces, therefore the surface quantity of the spare parts affects to the tired strength very greatly. 1. The surface influence of the rough degree upon the tired strength At hand over to change to carry the lotus function under, the surface part of the cave valley of the rough degree causes easily should the dint concentration, produce the tired crack.A value of surface is more big, the crackle of the surface is more deep, the crackle bottom radius is more small, the anti- tired breakage bottom ability is more bad. 2. Remaining dint, cold make to harden to the influence of the tired strength Remaining dint is very big to the spare parts influence of the tired strength.The surface layer remaining pull should the dint will make tired crack extend, accelerating the tired breakage；But the surface layer remaining should the dint can keep tired crack from expand, defer tired breakage of creation. 1 2Surface the cold and hard general companion contain remaining of should the creation of the dint, can keep the crack creation from combine the arrestment already has the crack to expand, to raise the tired strength beneficial. (C) the surface quantity to bear the eclipse influence The spare parts bears the eclipse to be decided by the rough degree of surface to a large extent.A value of surface is more big, accumulating the causticity material in the then cave valley more many.The anti- eclipse is more bad. Remaining of the surface layer pull should the dint will produce should the dint decay to open the rift , lower the spare parts to bear to whet sex, but Residual stress press should the dint then can preventfrom should dint decay open the rift . (D)The surface quantity to match with the influence of the quantity A size for be worth of surface will affect the match quantity of the match surface.Match with for the cleft, a value conference make wear away the enlargement, the cleft enlarge, the match property that break the request.For lead the over match, assemble process in a the convex peak of part of surfaces is push even, actual lead the amount of over let up, lowering the match the conjunction strength of the a. B. the influence surface factor of the rough degree (A)Slice to pare to process to affect the surface factor of the rough degree 1. The knife has several shapes to reply to reflect 2. The property of a material of work 3. Slice to pare the dosage (B)Whet to pare to process to affect the surface factor of the rough degree The influence whets to pare the rough main factor of surface to have: The degree of hardness, emery wheel of a degree, emery wheel of the emery wheel fix whole, whet to pare the speed and whet to pare the path to enter to whet number of times, the work a circumference for quantity and light to enter to the speed and stalks to enter to the quantity and cool off the lubrication liquid. C. affect the factor of process the surface layer physics machine function In slice pare process, the work piece because of being subjected to slice to pare the dint and slice the function of pare the heat, make the physics machine the function creation of the surface layer metals change, the variety of the most is variety and Residual stress s that the variety, gold that the surface layer metals shows minute details the degree of hardness organizes mutually should the creation of the dint.Because whetting to pare to process the mold produce transforms and slices to pare the hot ratio knife blade to slice to pare serious, as a result whet to pare to process to process behind the surface layer variety of above-mentioned three physicses machine function and would be very big. (A)The surface layer is cold to make the hardening 1. Cold make to harden The machine processes the process in because of slicing to pare the output mold of the dint function to transform, make the Crystal grain space distort, mutation, a creation shears to slice to slip to move, grain of Crystal grain drive make longer to turn with fiber, even broken up, these would make the surface layer metals of degree of hardnesses and strength raise, this kind of phenomenon be called cold make the 1 3hardening.( or be called to enhance)The result that the surface layer metals enhance, will enlarge the resistance that metals transform, let up the mold of the metals, the physical property of the metals also will take place the variety. 2. Affect cold main factor that make to harden Slice to pare a radius of the blade bluntness to enlarge, to the squeeze of the surface layer metals function to build up, the mold transforms to turn worse, causing the cold and hard to build up.After knife have the knife faces to wear away the aggrandizement, empress the knife face with is process surface of friction turn worse, the mold transform the aggrandizement, causing the cold and hard to build up. Slice to pare the speed aggrandizement, the knife has to shorten with function time of the work piece, making mold transform expand the depth to let up, the cold and hard layer depth let up.After slicing to pare the speed aggrandizement, slice to pare the heat on a surface of work layer of function time also shorten the joy, will make the cold and hard degree increment.Enter to enlarge for quantity, slice to pare the dint to also enlarge, surface layer the mold of the metals transforms to turn worse, the cold and hard function strengthen. The mold of a material of work is more big, the cold and hard phenomenon is more serious. (B)The surface layer remaining should dint 1. Produce remaining of should the reason of the dint a. Slice to pare have the mold to transform the occurrence in process the surface metals layer, make the metal ratio of surface permit the enlargement.Because the mold transform only creation in the surface layer metals, but the ratio of the surface layer metals permits the aggrandizement, the physical volume inflation, the mile layer that want to be subjected to connect with each other with it inevitably metals of arrestment, so produced in the surface metals layer Remaining dint, but produce the remaining to pull in in the layer metals should dint. b. Slice to pare to process medium, slice and pare the area and there will be to slice to pare the hot creation in great quantities. c. The different gold organizes the density of have the dissimilarity mutually, also having the different ratio to permit.If the surface layer metals produced the variety that gold mutually organize, the variety that the surface layer metals compares to permit want to be subjected to by all means with its the bar of the base body metals for connect with each other, as a result there is Remaining dint creation. 2. The end work preface of main work surface of spare parts processes the choice of method The end work preface of main work surface of spare parts processes the method to choose to the pass importance, because the end work preface is should work remaining of surface leave should the dint will affect the usage function of the machine parts directly. Choose the main end work preface of surface of work of spare parts processes the method, must consider the concrete work condition and possible breakage forms of the surface of main work of that spare partses. At hand over to change to carry the lotus function under, superficially partial tiny 1 4view crack of machine parts, meeting because of pull should the function of the dint make living at first the crack extension, causing spare parts split finally.The spare parts resists from the exaltation tired breakage of angle consider, the end work preface of that surface shoulds choose and can produce the remaining to press in that surface should the dint process the method. 1 5機(jī)械加工表面質(zhì)量 A、機(jī)械加工表面質(zhì)量對機(jī)器使用性能的影響 （ A）表面質(zhì)量對耐磨性的影響 1. 表面粗糙度對 耐磨性的影響 表面粗糙度對零件表面磨損的影響很大。一般說表面粗糙度值愈小，其磨損性愈好。但表面粗糙度值太小，潤滑油不易儲存，接觸面之間容易發(fā)生分子粘接，磨損反而增加。因此，接觸面的粗糙度有一個最佳值，其值與零件的工作情況有關(guān)，工作載荷加大時，初期磨損量增大，表面粗糙度最佳值也加大。 2. 表面冷作硬化對耐磨性的影響 加工表面的冷作硬化使摩擦副表面層金屬的顯微硬度提高，故一般可使耐磨性提高。但也不是冷作硬化程度愈高，耐磨性就愈高，這是因?yàn)檫^分的冷作硬化將引起金屬組織過度疏松，甚至出現(xiàn)裂紋和表層金屬的剝落 ，使耐磨性下降。 （ B）表面質(zhì)量對疲勞強(qiáng)度的影響 金屬受交變載荷作用后產(chǎn)生的疲勞破壞往往發(fā)生在零件表面和表面冷硬層下面，因此零件的表面質(zhì)量對疲勞強(qiáng)度影響很大。 1. 表面粗糙度對疲勞強(qiáng)度的影響 在交變載荷作用下，表面粗糙度的凹谷部位容易引起應(yīng)力集中，產(chǎn)生疲勞裂紋。表面粗糙度值愈大，表面的紋痕愈深，紋底半徑愈小，抗疲勞破壞底能力就愈差。 2. 殘余應(yīng)力、冷作硬化對疲勞強(qiáng)度的影響 余應(yīng)力對零件疲勞強(qiáng)度的影響很大。表面層殘余拉應(yīng)力將使疲勞裂紋擴(kuò)大，加速疲勞破壞；而表面層殘余應(yīng)力能夠阻止疲勞裂紋的擴(kuò)展， 延緩疲勞破壞的產(chǎn)生。 表面冷硬一般伴有殘余應(yīng)力的產(chǎn)生，可以防止裂紋產(chǎn)生并阻止已有裂紋的擴(kuò)展，對提高疲勞強(qiáng)度有利。 （ C)表面質(zhì)量對耐蝕性的影響 零件的耐蝕性在很大程度上取決于表面粗糙度。表面粗糙度值愈大，則凹谷中聚積腐蝕性物質(zhì)就愈多?？刮g性就愈差。 表面層的殘余拉應(yīng)力會產(chǎn)生應(yīng)力腐蝕開裂，降低零件的耐磨性，而殘余壓應(yīng)力則能防止應(yīng)力腐蝕開裂。 （ D）表面質(zhì)量對配合質(zhì)量的影響 表面粗糙度值的大小將影響配合表面的配合質(zhì)量。對于間隙配合，粗糙度值大會使磨損加大，間隙增大，破壞了要求的配合性質(zhì)。對于過盈配合 ，裝配過程中一部分表面凸峰被擠平，實(shí)際過盈量減小，降低了配合件間的連接強(qiáng)度。 B、影響表面粗糙度的因素 （ A）切削加工影響表面