制造技术专业英语翻译

1、-7.1 NA TURE OF PLASTIC DEFORMATION Plastic deformation is the deformation which is permanent and beyond the elastic rang of the material of ten , metals are worked by pfastic deformation because of the beneficial effect that is imparted to the mechanical properties by it. The necessary deformation

2、in a metal can be achieved by application of large amount of mechanical force only or by heating the metal and then applying a small force.7.1 塑性变形本质塑性变形是超过弹性变形范围之后的一种永久变形。通常，金属采用塑性变形加工是因为可以通过其获得良好的机械性能。金属所需要的变形可以只通过施加大量的机械力或者通过加热金属并且施加少量的应力来获得。The deformation of metals, which is caused by the displ

3、acement of the atoms is achieved by one or both of the processes called slip and twinning. The details of the microscopic deformation methods can be found in the textbooks of metallurgy. On the macroscopic scale, when plastic , deformation occurs the metal appears to flow in the solid state along sp

4、ecific directions, which are depedent on the type of processing and the direction of applied force. The crystals or grains of the metal are elongated in the direction of metal flow. This flow of metal can be seen under microscope after polishing and suitable etching of the mental surface . These vis

5、ible lines are called fibre flow lines, some representative specimens of which are presented in fig金属的变形是由原子排列引起的，这种排列是由被称作滑移和孪生过程中的一种或者两者共同作用造成的。微观的变形方式可以从冶金学课本中找到。在微观范围内，当塑性变形产生的时候，在固体内部金属的流动倾向于特定的方向，这个方向取决于加工类型和应力方向。在金属流动方向上金属晶体或者晶粒将会延长。通过显微镜观察抛光和蚀刻后的表面，可以看到这种金属的流动方式。这些可见的线条叫做纤维流线。Since the grain

6、s are elongated in the direction of flow, whey would be able to offer more resistance to stresses acting across them . As a result, the mechanically worked metals called wrought products would be able to achieve better mechanical strength in specific orientation ,that of the flow direction .since it

7、 is possible sible to control these flow lines in any specific direction by careful manipulation of the applied forces as shown in Fig. 7.1, it is possible to achieve optimum mechanical properties. The metal, of course, would be weak along the flow lines.因为晶粒在流动方向上被拉长了，这样他们就更能够抵抗作用于其上的应力。因此，在被称为锻造产品

8、的机械加工零件的金属流动方向上会获得优良的强度。这是因为，只要小心谨慎地控制应力，就能让纤维流线朝着任何一个方向流动并且获得最佳的机械性能。 当然，金属在沿着纤维线的方向也会变得疲软。The wastage of material in metal-working processes is either negligible or very small, and the production rate is in general very high .these two factors give rise to the economy in production材料的浪费在金属加工过程中是很少

9、的，甚至可以忽略不计，并且其生产率一般来说是非常高的。这两个因素使其在生产上更为经济。7.1.1 Hot Working and Cold WorkingThe metal-working processes are traditionally divided into hot -working and cold-working processes. Thedivision is on the basis of the amount of heating applied to the metal before applying the mechanical force.7.1.1 冷加工和热加

10、工传统的金属加工工艺分为热加工和冷加工。这种区分是基于机械应力施加前金属的受热程度 。Those processes , working above the recrystallization temperature, are termed hot-working processes whereas those below are termed cold-working processes在这些加工工艺中， 加热温度在再结晶温度以上的叫做热加工，在再结晶温度以下的叫做冷加工。Under the action of heat and force when the atoms reach a ce

11、rtain higher energy level, the new crystals start forming which is termed as recrystallization . Recrystallization destroys the old grain structure deformed by mechanical working and entirely new crystals, which are strain-free are formed, the grains, in fact ,start nucleating at the points of sever

12、est deformation. Recrystallzation temperature as defined by the AmericanSociety of Metals is“ the approximate minimumtemperature at which complete recrystallization of acoldworked metal occurs within a specified time”在加热和应力的作用下，当原子达到某一更高能量的等级的时候，新的晶粒就开始形成的过程叫做再结晶。再结晶破坏了由机械作用构成的原有晶体结构，并且产生了无应变的新的晶体。事

13、实上，新的晶粒是在严重变形的时候开始形核的。再结晶温度是由美国金属学会这样定义的 “在一定的时间段内， 冷加工金属完成再结晶时的最小温度 ”。The recrystallization temperature generally varies between one-third to half the melting point of most of the metals. Typical values of recrystallisation temperatures are given in table 7.1,the recrystallization temperature also

14、depends on the amount of cold work a material has already received. the higher the cold work the lower would the recrystallization temperature as shown in Fig 7.2大多数的金属再结晶温度一般在金属熔点的三分之一到二分之一内。表 7.1 给出了具有代表性的再结晶温度值。再结晶温度取决于材料已经改变的冷加工量。冷加工量越高，再结晶温度越低，如图 7.2 所示。In hot working, the process may be carrie

15、d above the recrystallization temperature with or without actual heating.For example,for lead and tin,the recrystallization temperature is below the room temperature and hence working of these metals at room temperature is always hot working.Similarly for steels,the recrystallization temperature is

16、of the order of 1000 ,and therefore working below that temperature is still cold working only.在热加工中，在加热或者不加热的实际条件下再结晶可能在再结晶温度以上发生。例如，铅和锡，它们的再结晶温度都在室温以下，所以室温下的加工都属于热加工。同样，钢也是一样的，钢的再结晶温度达到 1000 摄氏度， 因此，在这温度以下的加工都是冷加工。In hot working.,the temperature at which the working is completed is important since

17、any extra heat left after working will aid in the grain growth,thus giving poor mechanical properties.The effect of temperature of completion of hot working is shown schematically in Fig.7.3.A simple heating is shown in A,where the grains start growing after the metal size would be larger than-when

18、started in A.After heating,when the metal is worked,because of recrystallization,the grain size is reduced.This is made of possible because the working of metal gives rise to a large number of nucleation sites for the new crystals to form.But if the hot working is completed much above the recrystall

19、ization temperature as in.C,the grain size starts increasing and finally may end up as a coarse grain size.This increase in size of the grains occurs by a process of coalescence of adjoining grains and is a function of time and temperature.This is not generally desirable.If the hot working is comple

20、ted just above the recrystallization temperature as in D then the resultant grain size would be fine.The same is schematically shown for hot rolling operation in Fig.7.4.在热加工中，加工完成后的温度是很重要的，因为加工完成后任何余热都能让晶粒长大，这样会得到很差的机械性能。热加工最后温度的影响如图表7.3 。如 A 中的一个简单加热过程，当温度超过再结晶温度后，晶粒就开始长大。当在没有热加工的条件下冷却时，如 B ，晶粒最后的

21、尺寸将会比 A 开始的时候大。加热之后，由于再结晶作用，当金属加工的时，晶粒尺寸就会减小。金属的加工将会增加在大量的形核点形成新核的可能性。但是，热加工的最后温度比再结晶温度高太多的话，如C,晶粒的尺寸就开始增大并且最后会得到粗大的晶粒尺寸。晶粒的尺寸的增大是通过合并相邻晶粒的过程发生的，这是时间和温度相互作用的结果。一般情况下，这都不是我们想要的。如果热加工的最终温度在再结晶温度以上，如 D ，这样得到的细小的晶粒尺寸。HOT Working Advantages1. As the material is above the recrystallization temperature,any

22、 amount of workingcan be imparted since there is no strain-hardening taking place.2. At a high temperature,the material would have higher amount of ductility andtherefore there is no limit on the amount of hot working that can be done on a material.Even brittle material can be hot worked.3. Since th

23、e shear stress gets reduced at higher temperatures,hot working requiresmuch less force to achieve the necessary deformation.热加工益处1. 当材料温度在再结晶温度以上时，加工量的多少都是可以的，因为这时候没有加工硬化的产生。2. 在较高温度下，材料将会有较高的韧性，因此材料的热变形量没有限制。即使脆性材料也可以进行热加工。3. 因为在较高温度下剪切应力将会减小， 热加工中少量的应力就能获得所需的变形。4. 热加工中，晶粒的继续改良是有可能的，如果温度和加工率得到适当的控制

24、，将会获得优良的晶粒尺寸和良好的机械性能。Disadvantages1.Some metals cannot be hot worked because of their brittleness at high temperatures.2.Higher temperatures of metal give rise to scaling of the surface and as a result,the surface finish obtained is poor.Also,there is a possibility of the decarburization of skin in

25、steels due to the high temperature.3.Because of the thermal expansion of metals,the dimensional accuracy in hot working is hart to achieve since it is difficult to control the temperature of workpieces.4.Handling and maintaining of hot metal is difficult and troublesome.弊处1. 由于在较高温度下材料脆性的原因， 一些金属不能进

26、行热加工。2. 高温下，金属表面比例将会增大，这样将会导致最后得到的表面质量很差。而且，由于高温会使钢表面有脱碳的可能性。3. 由于金属内热扩散的原因，控制工件的温度是很困难的，所以在热加工中很难获得精确的尺寸。4. 操作和维持加热金属是很困难和麻烦的。Cold working advantages1. Cold working increases the strength and hardness of the material due to strain hardening which would be beneficial in some situation.Table 7.3 give

27、s some comparative values for t he properties obtained after hot working and cold working.Further,there is no possibility of decarburization of the surface.2. Since the working is due in the cold tate,no oxide would form on the surface and conseque ntly,good surface finish obtained.3. Better dimensi

28、onal accuracy is achieved.4 It is far easier to handle cold parts and also is economical for smaller size.冷加工益处1. 由于加工硬化的原因，冷加工将会增加材料的强度和硬度，这在某些方面是有利的。图表 7.3 给出了热加工和冷加工后获得的性能的一些比较值。而且，冷加工不会有表面脱碳的可能性。2. 因为加工是在冷态下完成的，所以表面不会产生氧化物，最后会得到良好的表面质量。3. 能获得良好的尺寸精确性。较小尺寸的冷态零件更容易控制，而且也很经济Disadvantages1.Since the

29、 material has higher yield strength at lower temperatures,the amount of deformation that can be given to is limited by the capability of the presses or hammers used.2.Since the material gets strain hardened,the maximum amount of deformation that can be given is limited.Any further deformation can be

30、 given after annealing.3.Some materials which are brittle cannot be cold worked.弊处1. 因为低温下材料拥有较高的屈服强度， 所以变形量将会受到压力机和锤头能力的限制。2. 因为加工硬化的原因，最大变形量也会受到限制，任何后续的变形都需经过退火。 一些脆性材料不能进行冷加工。7.2.1 PrincipleRolling is a process where the metal is compressed between two rotating rolls for reducing its cross-sectio

31、nal area.This is one of most widely used of all the metal working processes,because of its higher productivity and low cost.Rolling would be able to produce components having constant cross section throughout its length.many-shapes such as I,T,L and channel sections are possible asroll-separating fo

32、rce.This in turn,can be achieved byshown in fig.7.6,but not very complex shapes.It is alsoreduction.The smaller rolls would not have enoughpossible to produce special sections such as railwayregidity to support a large roll-separatingwagon wheels by rolling individual pieces.force.Hence,backup rolls

33、 are attached to the small rolls to7.2 辊轧provide the necessary rigidity.Though higher friction辊轧是在两根旋转辊之间对金属施加压力使其横截面积减少的between rolls and the metal is required for increasing the一种工艺。由于较高的生产率和较低的花费使其广泛应用于各reducition achieved, it also increases the roll separating种金属加工工艺。辊轧可以生产在沿长度方向上拥有恒定截零force.件。如

34、图 7.6 是中的 I 、T、 L 和槽型等许多形状，但是不能生辊上的压力从进入部分到中点逐渐增大，其中中点的最大，然产复杂的形状。它也可以通过辊轧单独的零件来制造特定截面后到出口部分一直变小。分离两个辊的卷分离力可以通过辊的的零件，如铁路货车车轮。平均压力和总的接触面积的乘积得到。通过加少最大压力可以Rolling is normally a hot-working process unless减小接触长度上的平均压力，这也有可能减小卷分离力。反过specifically mentioned as cold rolling.The metal is taken来说，也可以通过减小辊的直径来获

35、得， 因为，减少相同的量，into rolls by friction and subsequently compressed to较小的辊比较大的辊拥有减小的接触长度。较小的辊用于减少obtain the finial shape.The thickness of the metal that can量较大和卷分离力较大的冷轧的情况下。但是小辊没有足够的be drawn into rolls depend on the roughness of the roll刚度来支撑较大的卷分离力，因此，支撑辊被附加在小辊上已surface.Rougher rolls would be able to

36、achieve greeter提供所需的刚度。 虽然辊和金属间较大摩擦力可以增大减少量，reduction than smoother rolls.But the roll surface gets但是这也会增加卷分离力。embedded into the rolled metal thus producing rough7.2.2 Rolling Stand Arrangementsurface.The arrangement of rolls in a rolling mill, also called除非特别提出将其作为冷加工，不然辊轧一般都属于热加工。rolling stand,var

37、ies depending on the application.The辊轧通过摩擦力和之后的压力将金属放入旋转辊中来获得最终various possible configurations are presented in的形状。金属最终拉伸的厚度取决于辊的表面粗糙度。粗糙的Fogs.7.7and 7.8.The names of the rolling stand旋转辊比光滑的辊更能得到较少的横截面，但是旋转辊表面会arrangements are generally given by the number of rolls嵌employed.The first one in Fig.7.7

38、a,the 2-high nonThe reduction that could be achieved with a given set ofreversing rolling stand arrangement,is the most commonroll is designed as the“ angle of bite” and is shown inFig.7.5.This depends on the type of rolling and theon arrangement.In this ,the rolls always move in only onedirection .

39、The arrangement shown in Fig.7.7b is a 2-highconditions of the rolls an shown in Table 7.4.The volumereversing rolling stand,where the direction of roll rotationof the metal that enters the rolling stand should be thecan be reversed.This type of stand is particularly useful insame as that leaving it

40、 except in initial passes when therereducing the handling of the hot metal in between themight be some loss due to filling of voids and cavities inrolling passes.When all the metal has reached the rightthe ingots. Since the area of the cross section getsside of the Fig7.7,the direction of the rolls

41、is reversed anddecreased,the metal leaving the rolls would be at a higherthe metal is allowed to enter into the next pass.Thesevelocity than when it entered.Initially,when the metalstands are more expensive compared to the non reversibleenters the rolls,the surface speed of rolls is higher thantype

42、because of the reversible drive needed.that of the incoming metal,whereas,the metal velocity at7.2.2 轧钢架布置如图 7.7the exit is higher than of the surface speed of辊轧机轧辊的布置也叫轧钢机架因应用的不同而不同。rolls.Between the entrance and exit,the velocity of the和 7.8 是几种可能的布图 7.7metal is continuously changing,whereas the r

43、oll velocity置。轧钢机架布局是通过所应用的轧辊的数量来命名的。remains constant.Somewhere in the contact length,the（ a）的第一个图是二辊不可逆轧钢机架的布置，这是最常见的velocities of the metal and rolls are same,which is布置。在这种布置中，轧辊只会朝着一个方向运动。图designated as neutral plane in Fig.7.5.7.7（b）是轧辊只能旋转可以倒转的二辊不可逆轧钢机布置。横截面的减少可以通过一套设计有轧入角的旋转辊获得，如图这种机架主要用于减少加热

44、金属通过辊轧机时的操作。当所有7.5。这取决于辊轧类型和辊轧条件，如表7.4。金属进入辊轧金属到达图 7.7 的右边时，轧辊的旋转方向就会倒转过来，金属就有可以通过下一个通道。因为需要反转驱动，所以这种钢机和离开辊轧机的体积应该保持不变，除了最初通过辊轧机填充铸锭中的空位和型腔时会使体积减少。由于横截面积的减少，架比不倒转的钢架更贵。金属离开辊轧机的速度会比进入时的高。金属开始进入辊轧机The 3-high rolling stand arrangement shown in Fig.7.7 is的时表面速度比将要进入的金属高，然而，在出口处的金属速used for rolling of tw

45、o continous passes in a rolling度比旋转辊的速度高。在出口与入口之间，金属的速度持续变sequence without reversing the drives.After all the metal化的，但是旋转辊的速度却保持恒定。在接触长度上，金属和has passed through the bottom roll set,the end of the旋转辊的速度保持一致， 这个地方被设计为中性平面， 如图 7.5。metal is entered into the other set of the rolls for the nextThe pressur

46、e on rolls gradually builds up form the entrypass.For this purpose,a table-tilting arrangement isto the neutral point where it is highest and then decreaserequired to bring the metal to the level with the rolls.till it reaches the exit.The roll-separating force which三辊轧机的布置如图 7.7（c）。这种布置用于在轧制次序中不需se

47、parates the two rolls apart can be obtained by要反转驱动的两个连续通道的轧制。当所有的金属都通过轧制multiplying the average roll pressure with the total机的尾部的时候， 金属的末端进入另一个轧制机的通道。为此，contact area.The average roll pressure can be decreased需要一个倾斜板布置将金属带到辊轧机的水平位置。by reducing the maximum pressure,which is a function ofA 4-high roll

48、ing stand shown in Fig.7.7 is essentially athe contact length,it is possible to decrease the2-high rolling mill,but with small-sized rolls.The other-tuo rolls are the backup rolls for providing the necessary rigidity to the small rolls.A better backup can be provided to the small rolls with a cluste

49、r arrangement of rolls as shown in Fig.7.7.For the rolling arrangements requiring large reduction,a number of free rotating wheels instead of a single small roll,are fixed to a large backup roll in the planetary rolling mill arrangement shown in Fig.7.8.四辊轧机钢架布置如图 7.7（d），它的本质其实是一个拥有小轧辊的二辊轧机。其他两个轧辊是为

50、小轧辊提供所需刚度的支撑轧辊。如图 7.7（e）是能够为带有一串轧辊的小轧辊机提供支撑的布置。对于需要大量缩减量的轧制机布置来说，大量的自由旋转轮代替了单独的小轧辊，这些旋转轮被安在行星轧制机中的大支撑轧辊上，如图 7.8 。Since the final shape required cannot be obtained in a single pass,the rolling mills are generally arranged with rolls which have more than one pass machined into them so that the materia

51、l coming out of one pass is then to be fed back to the other pass by reversing the roll direction or by arranging the rolling mills in tandem.It is general practice to maintain tension in the strip between the stands in the interest of keeping it flat and also to control the thickness closely.This a

52、lso helps in reducing the roll-separating force.因为在单通道中不能获得所需的最终形状，轧制机上安排有制造出不止一个通道的辊轮，这样从一个通道出来的材料就能通过反转辊的方向和联合的辊轧机将其返回到另一个通道。通常通保证钢架上带的拉力来保持它的平直，并且紧密地控制它的厚度。这样也有助于减小卷分离力。The steel coming out of a blast furnace or a remelting shop is in the form of an ingot which has a cross section of the order of

53、 600*600 mm.These ingots are further processed in rolling mills tl produce the inter mediate shapes such as blooms,slabs and billets.Blooms are generally square cross sections varying from 150*150mm to 400*400mm.Slabs are rectangular cross sections with widths varying from 500to 1800mmand thicknesse

54、s varying from 50 to300 mm.Billets are rectangular cross sections with sizes varying from 40*40 mm to 150*150 mm.从鼓风炉或者熔炼车间出来的钢都是横截面是600600mm 的铸锭。这些铸锭之后会被辊轧机制成像初轧方坯、板坯和坯锭。初轧方坯的横截面通常是在150150mm 到 400400mm 之间。板坯矩形横截面的宽度是在500 到 1800mm 之间，厚度从50到 300mm 之间不等。The ingot obtained by casting would normally hav

55、e defects such as shrinkage cavities,blow holhes and slag inclusions.When the ingot is rolled,the shrinkage cavity(called pipe) is towards the end ,which is then cropped after a few initial passes to reduce the defects in the defects in the finished product.通过铸造获得的初轧方坯一般带有缩孔、气眼、夹渣等缺陷。当初轧方坯被轧制的时候，缩孔会

56、移到末端，为了在最终的产品中减少这些缺陷，在最后通过的时候会将其末端剪掉The blooming and slabbing mills which produce blooms and slabs from the ingots are generally the reversible2-high rolling stands.The metal is turned 90 degrees in the initial passes to enable the material to be uniformly compressed from all sides,so that any of the internal voids such as blow holes are eliminated and the slag inclusions are segregated.能够将初轧方坯制成板坯和坯锭的轧制机通常是二辊轧钢机架。为了使材料各个方向能均匀受压，金属在通过轧制机前被弯成 90 度，因此，像气眼这样的空隙就能被排除夹渣也会被分离。The rolls are generally manufactured of chilled cast iron ,carbon steel and alloy steels