外文翻譯--鑄造和鑄造過程

1、<p>　　Casting and its processes </p><p>　　Introduction</p><p>　　Manufacturing process can be classified into two general groups known as primary and secondary processes. The primary process

2、es, namely, casting, forging, cold heading, cold extruding, brake forming, and so on, are those that convert raw material into shapes. These forming methods include both hot and cold working processes and, in general, wi

3、ll still require further finishing operations in order to obtain an end product.</p><p>　　The secondary processes are those that bring the part to the dimensions and surface finish specified. One may also in

4、clude in the secondary processes such operations as heat treating and surface treatments for corrosion resistance, hardness, and appearance. Secondary processes are planning , turning ,milling, drilling , boring , reamin

5、g , broaching , grinding , honing ,lapping , polishing , and special methods of metal removal such as electrochemical machining. Operations like screw cutting, tap</p><p>　　A complete discussion of these pro

6、cedures is beyond the scope of this text. Therefore, we will confine ourselves to succinct descriptions of the most prominent techniques.</p><p>　　1.2 Castings</p><p>　　Castings are identified b

7、y the type of mold or the force required toy fill the mold. Molds are either permanent or expendable. The pattern of sand, shell, and plaster molds, however, can be used repeatedly for making new molds. As the metal cool

8、s, it takes the shape of the cavity. The basic casting methods are described below.</p><p>　　Sand castings.</p><p>　　1. The green sand process is one in which most, bonded sands packed around a

9、wood or metal pattern. The pattern is then removed and molten metal is poured into the cavity .When the metal solidifies, the mold is broken and the casting is removed . Almost any metal can be used, with virtually no li

10、mit as to the size or shape of the part . The method permits casting complex components at a low tooling cost and is the most direct route from pattern to casting .</p><p>　　Some machining is always necessar

11、y with the green sand process, and large castings have rough surface finish .Close tolerances are difficult to achieve, and long, thin projections should not be cast. It is possible , however , to design for bosses, unde

12、rcuts and inserts .The minimum core hole diameter advisable are aluminum,3| 16—1|4 in. ;and the minimum section thicknesses advisable are aluminum ,3|16 in .;cooper , 3|32 in .; iron ,3|32 in .; magnesium,5|332 in ;and s

13、teel , 1|4—1|2 in .</p><p>　　2. The dry sand process is similar to the green sand process except that core boxes are used in place of patterns .This method is usually limited to smaller parts than method 1.

14、The sand is bonded with a setting binder, and the core is then oven baked at 300—400 to remove the moisture.</p><p>　　3.The carben dioxide sand process is one in which the sand molds are bonded whit sodium s

15、ilicate solutions and set by forcing carbon dioxide gas through the sand .This type of mold is strong and permits the production of better dimensionally controlled castings than either method 1 or 2 .</p><p>

16、;　　4 .The core—sand mold process is one where the molds are put together completely from oven baked cores set with organic binders such as oil or dextrines.</p><p>　　Shell Mold Casting . This is a process wh

17、ere the molds are made by coating the sand with a thermosetting plastic .The mold is then supported on the outsaid by sand or shot, and molten metal is poured .When the metal has solidified , the mold is broken away from

18、 the finished casting.</p><p>　　Shell molding produces casting with smooth surfaces, uniform grain structure ,high dimensional accuracy , rapid production rate and minimal amount of finishing operations . Th

19、e minimum section thickniss castable is 1|16—1|4 in .but section differences where the maximum –minimum ratio is greater than 5 to 1 should be avoided. Bosses, undercuts and inserts are easily cast and the minimum cored

20、hole diameter is 1|8—1|4 in .The method is relatively costly is limited to few metals.</p><p>　　Full-Mold Casting . A process in which a green sand or cold-setting resin bonded is packed around a foamed plas

21、tic pattern (for example ,polystyrene ).The plastic pattern is vaporized with the pouring of the molten metal into the mold .An improved casting surface can be obtained by putting a refractory type of coating on the patt

22、ern surface before sand packing .The pattern can be one piece or several pieces , depending upon the complexity of the part to be cast .</p><p>　　The plastic patterns are handled easily . They do not require

23、 any draft ,and produce no flash on the casting . For small quantity production this method can be expensive, depending upon the size and complexity of the casting .The minimum recommended section thickness is 0 .1 in .,

24、and the maximum section thickness is unlimited .Bosses, undercuts , and inserts present no problem in this type of casting . The minimum cored hole diameter is 1|4 in.</p><p>　　Permanent Mold Castings .These

25、 are formed by a mold that can be used repeatedly . Some applications have reported as many as 25 000 castings being made from the same mold .Usually , the mold requires some redressing after about 3000 uses . The molds

26、are machined of metal (for example ,gray iron ) for casting nonferrous metals and cast itons . Machined graphite molds are used to cast steel.</p><p>　　This method produces castings that have a good surface

27、finish as well as a good grain structure ,low porosity ,and high dimensional accuracy .The initial mold cost is relatively expensive, but castings weighing as little as several ounces to castings are limited to relativel

28、y simple shapes and forms. The maximum recommended section thickness is about 2.0 in .The minimum thickness , however ,dependsuoon the material being cast as follows :3|16 in .for iton ,3|32—1|8 in .for aluminum, 5|32 in

29、 .for</p><p>　　Die Casting . A process used extensively in the quantity production of intricately shaped zinc, alumimum, lead and magnesium alloys .The method is limited in use with tin and copper alloys.&l

30、t;/p><p>　　Castings are formed by forcing molten metal under pressures of 1500-25 000 psi into an accurately machined steel die .The steel die ,which is water cooled ,is held together by a hydraulic press until

31、 the metal casting(s) solidifies., To ease the ejection of the cast parts, a lubricant is sprayed on the die forming surface and the ejection pins. For small die cast components .,multiple cavity dies are used .</p>

32、;<p>　　The surface finish of the resulting castings is quite smooth and has excellent dimensional accuracy .Although the cost of production is relatively cheap ,the initial die cost is high .Diecasting is limited

33、to nonferrous metals and by the size of the part that can be cast .The maximum wall section thickness is usually restricted to 3|16 in . but certainly to no greater than 0.50 in.</p><p>　　Plaster Mold Cast

34、ing . These are made by pouring a nonferrous alloy (for example , aluminum ,copper ,or zinc alloy ) into a plaster mold ,which is then broken to remove the solidified casting . The castings produced by this process are s

35、mooth, have high dimensional accuracy, low porosity, and can be made in many intricate shapes. The method, however, has disadvantages in that is limited to nonferrous metals, small castings and also requires a relatively

36、 long time to make the molds. The minimum</p><p>　　The show process, developed within the last decade, is a cost promising method .It employs the use of plaster molds .This procedure produces castings with f

37、ine detail and excellent dimensional accuracy and surface finish.</p><p>　　Ceramic Mold Casting . This process uses a mold made of a ceramic powder ,binder ,and gelling agent. The mold can also be made of a

38、ceramic facing reinforced with a sand backing .The method is restricted to casting intricate parts requiring fine detail ,close tolerances ,and smooth finishes .The minimum wall thickness recommended is 0.025-0.050 in. T

39、here is, however, no limit to the maximum wall thickness.</p><p>　　Investment Casting. These are made when parts are desired that are intricate in shape ,have excellent surface finish , and require a high de

40、gree of dimensional accuracy .In addition ,this method of casting permits the use of a variety of metal alloys and does not have In addition ,this method of casting permits the use of a variety of metal alloys and does n

41、ot have any metal flashing to be removed from the finishes casting.</p><p>　　The technique of investment casting requires careful workmanship and expensive patterns and moths. The minimum castable wall thick

42、ness is about 0.025-0.050 in .and the maximum thickness should not exceed 3 in .</p><p>　　Centrifugal Casting . This is a method of casting a shape by pouting the molten metal into a rotating fladk containin

43、g the mold .The molds are made of sand ,metal ,or graphite (depending on the metal cast ) and are rotated about their axial centers either in a horizontal or vertical position .</p><p>　　Relatively large dia

44、meter and bulky components are made are pipe ,gun barrels, hollow shafts ,machinery drive rolls, long sleeves , tubing , and so on .Where the diameter to length ratio is rather large ,the rotational axis can be verticall

45、y mounted molds ,the method is called semmicentrifugal casting ,and it is used to make parts such as wheels, turbosupercharger diaphragms , disks ,flywheels ,and so on .Figure 1-5-2 shows a schematic section of a semicen

46、trifugal casting of a cored flywheel .</p><p>　　Generally, the method of centrifugal casting is expensive and is also limited in the shapes which can be cast .However ,the castings made by this mehod are ver

47、y sound and have good dimensional accuracy .It should also be noted that this method is the only way to obtain a large cylindrical part.</p><p>　　Continuous Casting. This is a method whereby a molten metal i

48、s continuously gravity fed from a ladle into an ingot mold of a desired shape which is open at both ends. As the metal “falls”</p><p>　　through the mold , it takes its shape ,and is rapidly cooled by a water

49、 spray .It is then cut to specific lengths.</p><p>　　The continuous casting process has the advantage of being low in cost and having a high rate of production .In addition, this method permits casting mater

50、ials that cannot be extruded. However, continuous casting is restricted to shapes of uniform cross section (that is ,in the direction of casting),The minimum wall thickness depends on the shape being cast . The minimum s

51、ize of casting is 1|2 in .and the maximum size is about 9 in .</p><p><b>　　鑄造和鑄造過程</b></p><p><b>　　1.1簡介</b></p><p>　　制造過程可分為兩個一般群體稱為初級和中級的進程。主要過程，即鑄造，鍛造，冷

52、鐓，冷擠壓，制動形成等等，使那些原料轉換成工件形狀.這些成型方法包括冷熱工作程序，以及一般還需要進一步加工工作，以獲得最終產品。 二級進程是那些把部分的尺寸和表面光潔度指明。其中可能也包括在二級處理流程，如工件的熱處理和表面處理的耐腐蝕，硬度，和表面粗糙度。其次，進程規(guī)劃，車削，銑，鉆，鏜，鉸孔，拉削，磨削，珩磨，研磨，拋光，和特殊方法去除金屬如電化學加工。行動像螺絲切割，攻絲，螺紋銑削，齒輪加工等，是次要的過程，只是一個適應的

53、過程，上述只是之一的上述進程。  一個完整的討論這些程序的范圍以外的文字。因此，我們將僅限于簡潔的描述具有代表性的技術。</p><p><b>　　1.2件</b></p><p>　　鑄件所確定類型的模具或部隊需要臺島填補模具。鑄?；蛘哂谰没蚋窬稚?，貝殼，和石膏模具，然而，可重復使用作出新的模具。金屬冷卻，它的形狀腔。基本鑄造方法介紹如下。 &l

54、t;/p><p><b>　　砂鑄件。 </b></p><p>　　1 綠色砂過程是一個潮濕，保稅裝在一個木制或金屬的模式。該模式，然后刪除和熔融金屬注入模腔。當金屬鞏固，模具破裂和鑄造被刪除。幾乎所有的金屬可用于幾乎沒有限制的大小或形狀的一部分。該法允許鑄造復雜零件加工費用低，是最直接的路線從模式鑄造。 </p><p>　　一些加工始終是必要

55、的綠色型砂進程，并有大型鑄件毛坯表面光潔度。關閉公差是難以實現(xiàn)，以及長期薄預測時應不是可能的，但是，設計的老板，削弱和插入。最起碼的核心孔徑可取的鋁， 3 | 16-1 | 4英寸;和最低節(jié)厚度最好是鋁， 3 |一六英寸;庫珀， 3 |三十二英寸;鐵， 3 | 32英寸;鎂， 5 | 332中;和鋼鐵， 1 | 4-1 |二英寸</p><p>　　2干砂過程是類似的綠色砂工藝，但核心方塊代替模腔。這種方法通常僅

56、限于一些小的部分比方法1 。沙子是保稅的設置粘結劑，其核心是然后烤箱烘焙300-400刪除水分。 </p><p>　　3二氧化碳砂過程是一個砂鑄模的保稅白衣硅酸鈉的解決方案和設置，迫使二氧化碳氣體通過沙子。這種類型的模具是強有力的，并允許生產更好地控制鑄件尺寸比方法1或2 。 </p><p>　　4核心砂型過程是在模具把完全從烤箱烤內核設置與有機粘結劑如石油或。</p>

57、<p>　　殼型鑄造。這是一個過程，模具是由涂層砂的熱固性塑料。模具然后支持對的沙子或槍殺，和熔融金屬倒入。當金屬凝固，模具是脫離成品鑄件。 </p><p>　　殼牌成型生產鑄件表面光滑，顆粒均勻的結構，尺寸精度高，快速的生產速度和最低數(shù)量的精加工工序。最低節(jié)澆注是1 | 16-1 |四英寸但部分差異的最高最低比例大于5至1月應當避免。老板，削弱和插入很容易演員，和最小芯孔直徑為1 | 8-1 | 4

58、英寸該方法是比較昂貴的是僅限于少數(shù)金屬。 </p><p>　　全金屬型鑄造。在這一進程中一個綠色沙子或冷戰(zhàn)設置樹脂包裝約泡沫塑料模式（例如，聚苯乙烯） 。塑料格局蒸發(fā)與澆注的熔融金屬的模具。一種改進鑄件表面可通過把一個難治型的涂層表面的格局面前砂包裝。格局可一件或幾件，這取決于復雜的部分。 </p><p>　　塑料的處理方式很容易。它們不需要任何決議草案，并沒有閃光的生產鑄件。對于小

59、批量的生產這種方法可以是昂貴的，這取決于項目的規(guī)模和復雜的鑄件。建議的最低部分厚度為0 0.1英寸，最大切片厚度是無限的。老板，削弱，并插入本沒問題這種類型的鑄造。最低芯孔直徑為1 |四英寸</p><p>　　永久模鑄件。這些都是由一個模具，可以反復使用。一些應用程序已經(jīng)報告多達25 000件是由相同的模具。通常情況下，模具需要一些糾正后，約3000用途。模具是機械加工的金屬（例如，灰口鑄鐵）鑄造有色金屬。加工

60、石墨模具用于鑄鋼。 </p><p>　　這種方法生產鑄件具有良好的表面光潔度，以及良好的晶粒結構，低孔隙度，高尺寸精度。最初的模具成本比較昂貴，但鑄件重量只有幾盎司，至鑄件限于相對簡單的形狀并建議第最大厚度約為二點〇英寸的最小厚度，，材料被拋如下： 3 |十六英寸的iton ， 3 | 32-1 | 8英寸為鋁， 5 | 32英寸的鎂，以及3 | 32 -5 | 16英寸對銅。最低澆注洞3 | 16-1 |四英

61、寸的直徑。</p><p>　　壓鑄的過程中廣泛使用的數(shù)量型生產錯綜復雜鋅，鋁，鉛，鎂合金。方法是有限的使用錫和銅合金。 </p><p>　　鑄件形成迫使熔融金屬壓力下的1500至1525年為000磅精確加工鋼模具。鋼鐵死亡，這是水冷，是一起舉辦了水壓機，直到金屬鑄件（縣）鞏固。 ，以減輕彈射的演員部分，潤滑劑是噴涂成型模具表面和彈射引腳。對于小型壓鑄部件。 ，多腔模具的使用 

62、的表面光潔度由此產生的順利，具有良好的尺寸精度。盡管生產成本的價格相對便宜，最初的模具成本就很高。壓鑄限于有色金屬和大小的部分，可演員。墻節(jié)的最大厚度通常僅限于3 | 16英寸但肯定不超過0.50英</p><p>　　石膏型鑄造 這些都是由澆注1有色合金（例如，鋁，銅或鋅合金）為石膏模具，然后打破刪除凝固鑄造。鑄件生產的這一進程的順利進行，具有尺寸精度高，低孔隙度，并可以在許多錯綜復雜的方法，不過，缺點是僅限

63、于有色金屬，小件，也需要相對較長的時間使模具。最低墻厚度0.040-0.060節(jié)的。為鑄造領域小于2平方米。在。對于較大的鑄造領域，最小壁厚增加。 </p><p>　　逸夫過程中，發(fā)達國家在過去十年中，是一個有希望的方法成本。員工使用石膏模具。此過程鑄件生產與罰款和尺寸精度和良好的表面光潔度。 </p><p>　　陶瓷型鑄造 這個過程使用的模具制成的陶瓷粉末，粘結劑，和膠凝劑。模具也

64、可以陶瓷面臨加強與沙子的支持。該方法僅限于鑄造復雜的部分需要細節(jié)，密切公差，并順利完成。最小壁厚建議是0.025-0.050 ，但，沒有限制的最大壁厚。</p><p>　　熔模鑄件 這是取得理想時，部分有復雜的形狀，具有良好的表面光潔度，并需要高度的尺寸精度。此外，這種方法鑄造允許使用各種不同的金屬合金，沒有此外，這種方法的鑄造允許使用各種不同的金屬合金，并沒有任何金屬閃光被遣送完成鑄造。 </p>

65、;<p>　　技術精鑄需要仔細的做工和昂貴的模式和飛蛾。最低澆注壁厚約0.025-0.050英寸，最大厚度不應超過3英寸</p><p>　　離心鑄造 這是一個方法鑄造形狀的熔化金屬的身份進入一個旋轉載模具。模具是沙子，金屬，或石墨（取決于金屬鑄造） ，并旋轉軸中心對他們無論是在一個水平或垂直位置。 </p><p>　　比較大的直徑和笨重的部件都被管，槍管，空心軸，機械驅

66、動器卷，長袖，油管等。凡直徑長度比例是相當大的旋轉軸可垂直安裝模具，在方法被稱為鑄造，這是用來制造部件，如車輪，隔膜，磁盤，飛輪等。圖1-5-2顯示原理部分的芯鑄造的飛輪。</p><p>　　一般來說，離心鑄造法是昂貴的，也是有限的形狀，可演員。然而，鑄件作出這一mehod都非常健全，有良好的尺寸精度。還應當指出，這種方法是唯一的出路獲得一個大圓筒的一部分。  連續(xù)鑄造 這是一個方法，即熔融金