铸造翻译终稿

Chapter 2 Casting Processes of Metals

第二章：金属的铸造工艺

A casting may be defined as a \to solidify in a mold \the shape of the object being determined by the shape of the mold cavity. Casting is basically melting a solid material, heating to a special temperature, and pouring the molten material into a cavity or mold, which is in proper shape. Casting has been known by human being since the 4th century B.C.

铸造可以被定义为：“通过使熔融的金属液在铸型中凝固而得到金属物体”，物体的形状由型腔的形状决定。基本上来说，铸造就是将固态材料熔化、加热到一个特定的温度，然后将熔融的材料浇注到有确定形状的型腔或铸型中。早在公元前4世纪，铸造就被人类所了解。 2. 1 Casting Procedure 2．1铸造过程

In all casting processes six basic factors are involved. These are as follows: 所有的铸造工艺都包括六个基本因素。介绍如下：

1. A mold cavity, having the desired shape and size and with due allowance for shrinkage of the

solidifying metal, must be produced. Any complexity of shape desired in the finished casting must exist in the cavity. Consequently, the mold material must such as to reproduce the desired detail and also have a refractory character so that it will not be significantly affected by the molten metal that it contains. Either a new mold must be prepared for each casting, or it must be made from a material that can withstand being used for repeated castings, the latter being called permanent molds.

1．必须制作出一个具有所要求形状、大小和由于金属凝固过程收缩而造成的应有公差的型腔。在精密铸造中，所有需求形状的复杂部分都要存在于型腔中，通常，铸型材料必须是为了复制出所需要的零件，同时要有一定的耐火特性以确保它不会被所包容的熔融金属严重影响，每一次铸造都要准备一个新的铸型，或者必须使用一种能够经受重复铸造的模型材料，后者被称为金属模。

2. A suitable means must be available for melting the metal that is to be cast, providing not only adequate temperature, but also satisfactory quality and quantity at low cost.

2．与之相匹配的熔化铸造金属方法必须是有效的，其不仅要提供精确的温度，而且要在低成本的基础上提供令人满意的质量和数量。

3. The molten metal must be introduced into the mold in such a manner that all air or gases in

the mold, prior to pouring or generated by the action of the hot metal upon the mold, will escape, and the mold will be completely filled. A quality casting must be dense and free from defects such as air holes.

3．熔融的金属被引入型腔中时，必须采用这样一种方法：使在浇注或在热的金属液与型腔

发生作用之前，铸型中所有空气和气体将会逸出，并使型腔能够充满。 4. Provision must be made so that the mold will not cause too much restraint to the shrinkage

that accompanies cooling after the metal has solidified. Otherwise, the casting will crack while its strength is low. In addition, the design of the casting must be such that solidification and solidification shrinkage can occur without producing cracks and internal porosity or voids. 4．必须提供补缩以确保型腔不会产生太大由于金属凝固后随冷却收缩引起的应力。否则，

当强度太低时，铸件就会开裂且强度很低。另外，铸件设计必须确保在凝固和凝固收缩过程中不会产生裂纹、缩松和缩孔。

5．It must be possible to remove the casting from the mold so a permanent mold must be made in two or more sections.

5．必须使铸件能够从型中取出，这就要求金属模必须分为两个或两个以上的部分。

6．After removal from the mold, finishing operations may need to be performed to remove

extraneous material that is attached to the casting as the result of the method of introducing the metal into the cavity, or is picked up from the mold through contact with the metal.

6．将铸件从型腔中移出后，可能需要一些清理操作，以除去由于金属引入型腔或金属与模型接触而附属于铸件的多余部分。

2. 2 Casting Terms 2．2 铸造术语

In the following sections, the details of sand casting process which represents the basic process of casting would be seen. Because going into the details of the process, defining a number of casting vocabulary words would be appropriate. Reference may please be made to Fig. 2.1

在下面的部分，将会介绍代表着最基本铸造工艺的砂型铸造工艺细节，由于要进行工艺细节的探讨，定义一些铸造用词汇是十分必要的，参考如图2.1 Flask: A moulding flask is one which holds the sand mould intact. Depending upon the position of the flask in the mould structure it is referred to by various names such as drag-lower moulding flask, cope-upper moulding flask and cheek-intermediate moulding flask used in three-piece moulding. It is made up of wood for temporary applications and more generally of metal for long-term use.

砂箱：一个造型用砂箱就是保持砂型完整无缺，依据砂箱在铸型结构中位置，其被冠以多个名字，比如在三箱造型中使用的下型砂箱、上型砂箱和中型砂箱。短期使用由木头构成；长期使用通常用金属制作。

Pattern: Pattern is a replica of the final object to be made with some modifications. The mould cavity is made with the help of the pattern.

模样：模样是经过一些修改的最终产品的复制品，型腔是在模样的帮助下制作出来的。

Parting Line: This is the dividing line between the two moulding flasks that makes up the sand mould. In split pattern it is also the dividing line between the two halves of the pattern.

分型线：它是组成砂型两砂箱之间的分离线，在劈模中，它也是模样两半型之间

的分型线。

Bottom board: This is a board normally made of wood which is used at the start of the mould making. The pattern is first kept on the bottom board, sand is sprinkled on it and then ramming is done in the drag. 底板: 它通常是一个用木头制作、用于造型开始时的平板，首先把模样放在底板上，然后将砂洒在模样上，然后在下箱中捣实。

Facing sand: The small amount of carbonaceous material sprinkled on the inner surface of the moulding cavity to give a better surface finish to the castings. 面砂：少量洒在型腔内表面以得到更好的铸件表面光洁度的含碳材料。

Fig. 2.1 Cross section of a sand mould

Moulding sand: It is the freshly prepared refractory material used for making the mould cavity. It is a mixture of silica, clay and moisture in appropriate proportions to get the desired results and it surrounds the pattern while making the mould.

型砂：用于制作型腔的新备难熔材料，它是硅石、粘土和水分为得到所需结果的适当比例的混合物。在造型过程中包围在模样的四周。

Backing sand: It is what constitutes most of the refractory material found in the mould. This is made up of used and burnt sand.

背砂：它组成了铸型中所能找到的耐火材料的绝大部分，由使用过和烧过的砂组成。

Core: It is used for making hollow cavities in castings. 芯：用于制作在铸件中的空腔。

Pouring basin: A small funnel shaped cavity at the top of the mould into which the molten metal is poured.

浇口杯：一个在铸型上端熔融金属注入的小漏斗型空腔。

Sprue: The passage through which the molten metal from the pouring basin reaches the mould cavity. In many cases it controls the flow of metal into the mould. 直浇道：熔融金属从浇口杯到达型腔的一个通道，在很多的情况下，它控制着进入型腔中的金属流。

Runner: The passageways in the parting plane through which molten metal flow is regulated before they reach the mould cavity.

横浇道：使液态金属流在到达型腔前得到调整的分型面上的通道。 Gate: The actual entry point through which molten metal enters mould cavity. 内浇口：液态金属进入型腔的实际入口点。

Chaplet: Chaplets are used to support cores inside the mould cavity to take care of its own weight and overcome the metallostatic force. 芯撑：芯撑用于支撑在型腔中的芯子，以支撑芯子本身重量和消除金属静力学应力。

chill: Chill are metallic object which are placed in the mould to increase the cooling rate of casting to provide uniform or desired cooling rate.

冷铁：冷铁是放于铸型中增加铸件冷却速度，以提供同一冷速或所需冷却速度的金属物体。

Riser: It is reservoir of molten metal provided in the casting so that hot metal can flow back into the mould cavity when there is a reduction in volume of metal due to solidification.

冒口：它是在铸造中提供液态金属的储备，目的是使热的金属在凝固过程中出现体收缩情况下能回流到型腔中。

2. 3 Sand Casting 2．3 砂型铸造：

Casting is used to make metal products of almost any desired shape by the pouring of molten metal into a reshaped hollow mold. As the metal freezes, the mold is removed. This technique was learned thousands of years ago when it was discovered that damp sand could be packed by hand into almost any shape.

铸造通过将熔融金属液浇入成型空腔以生产几乎任何所需形状的金属制品。当金属凝固后，铸型被移走，这项技术在几千年前当人们发现湿砂能够用手制作成任何形状时就已经被掌握。

Generally speaking, clean, fine sand is placed in a wooden or steel box and packed around a preformed wooden pattern or actual object. When the pattern is removed, its imprint remains in the sand. Molten metal is then poured into the hollow mold. Castings made from sand molds have a rough surface. They must be cleaned, trimmed and, at times, machined. Sand molds must be repacked after each casting to obtain additional parts. Therefore, the casting of many pieces using sand molds requires much time and labor.

总体上说，干净的细砂放于一个木制盒或钢盒子里，在一个预成型的木模或实物周围压紧，当模型移走后，它的轮廓留在砂上，然后液态金属浇入空腔中，砂型铸件表面很粗糙，他们必须清理、修型，有时还需要进行机加工，砂型在每次铸造后必须重新制作以得到其他的零件，所以，许多零件的砂型铸造需要大量的人力和时间。

2. 4 Permanent Mould Casting 2．4 金属型铸造

The mould material is selected on the consideration of the pouring temperature, size of the casting and frequency of the casting cycle. They determine the total heat to be borne by the die. Fine grained grey cast iron is the most generally used die material. Alloy cast iron, C20 steel and alloy steel (H11 and H14) are also used for very large volumes and large parts. Graphite mould may be used for small volume production

from aluminum and magnesium. The die life is less for higher melting temperature alloys such as copper or grey cast iron.

铸型材料是在考虑浇注温度、铸件尺寸和铸件循环使用频率方面的基础上进行选择的，它们决定了金属模所能承受的所有热量，有细密纹理的灰铁是最经常使用的模具材料，合金铸铁、C20钢和合金钢也被用于大体积和大件产品中，石墨型可用于小体积的铝件和镁件生产，对于高熔点合金，比如铜和灰铁，模具的寿命会减少。

For making any hollow portions, cores are also used in permanent mould casting. The cores can be made out of metal, or sand. When sand cores are used, the process is called semi-permanent moulding. The metallic core cannot be complex with under-cuts and the like. Also, the metallic core is to be withdrawn immediately after solidification, otherwise, its extraction becomes difficult because of shrinkage. For complicated shapes, collapsible metal cores (multiple-piece cores) are sometimes used in permanent moulds. Their use is not extensive because of the fact that it is difficult to securely position the core as a single piece as also due to the dimensional variations that are likely to occur. Hence, with collapsible cores, the designer has to provide coarse tolerance on these dimensions.

在金属型铸造中，生产所有带空腔型件也要使用芯子，芯子可用金属和砂制作。使用砂芯是的工艺称作半金属造型，金属芯在侧凹之类上不能太过复杂，另外，金属芯在凝固后要尽快取出，否则取出将会因为收缩变得困难。对于复杂形状，金属模中有时要使用分瓣金属芯（组合芯）。它们没有被广泛使用是因为难以有效的将芯子作为单独的一部分放置，还有就是经常出现尺寸的变化。因此，用组合芯，设计者必须在这些尺寸上提供大概的公差。

第五章：金属工艺的基本设计

Chapter 5 Basic Design of Metal Processes 第五章：金属工艺的基本设计

5.3.1 Patternmaking 5.3.1模样制作

The pattern is a physical model of the casting used to make the mold. 模样是用于制作铸型的铸件物理模型

The mold is made by packing some readily formed aggregate material, such as molding sand, around the pattern. When the pattern is withdrawn, its imprint provides the mold cavity, which is ultimately filled with metal to become the casting.

铸型是通过将一些易变形的聚合体材料紧实得到的，像型砂，包围在模样周围。当模样取出后，它的轮廓提供了最终浇满液态金属形成铸件的型腔。 If the casting is to be hollow, as in the case of pipe fittings, additional patterns, referred to as cores, are used to form these cavities. As has been defined earlier, a pattern is a replica of object to be made by the casting process, with some modification. The main modifications are:

如果铸件是中空的，比如在管件装配的条件下，其他模样像芯子将用于形成这些空腔。就像前面所定义的，模样是铸造所生产的实物经过某些改变后的复制品，主要的改变有：

(a) the addition of pattern allowances, (b) the provision of core prints,

(c) the elimination of fine details which cannot be obtained by casting and hence are to be obtained by further process. (a)增加模样的余量； (b)提供芯头；

(c)对于精密铸件，不能通过铸造得到的部分，要通过进一步的工艺来完成。

5.3.1.2 Core prints 5.3.1.2 芯撑

For all those casting where coring is required, provision should be made to support the core inside the mould cavity. One of the methods that is universally followed is to provide core prints where possible. In Fig 5.22 is shown an example of the provision of core prints. The size of the core prints to be provided is to be

estimated based on the specific casting.

Fig.5.22 Typical job, its pattern and the mould cavity

对所有需要芯子的铸件，应该采取措施来支撑型腔中的芯子，其中的一个普遍使用的方法是在可能的地方使用芯撑，在图5.22展示了一个芯撑使用的例子，所提供的芯撑的尺寸将在精确的铸件的基础上进行估算。 5.3.2Moulding Materials 5.3.2 造型材料

A large variety of materials are used in foundries for manufacturing moulds and cores. They are:

Moulding sand,

System sand (backing sand), Rebounded sand, Facing sand, Parting sand, Core sand.

在铸造中，许多种材料被用于生产铸型及芯子。它们包括：

型砂 背砂

加粘土回用砂 面砂 分型砂

5.3.2.1 The properties of moulding sand 5.3.2.1 型砂性能

The choice of moulding materials is based on their processing properties. The properties that are generally required in moulding materials are:

造型材料的选择是基于它们的工艺性能，通常造型材料要求的性能包括： Refractoriness: it is the ability of the moulding material to withstand the high temperatures of the molten metal so that it dose not cause fusion.

耐火度：造型材料承受熔融液态金属的高温而不会熔解的能力。 Green strength: The moulding sand that contains moisture is termed as green sand. The green sand should have enough strength so that the constructed retains its shape.

湿强度：包含湿气的型砂通常术称为湿型砂，湿型砂应该有足够的强度以保持所构造的形状。

Dry strength: When the moisture in the moulding sand is completely expelled, it is called dry sand. When molten metal is poured into a mould, the sand around the mould cavity is quickly converted into dry sand as the moisture in the sand immediately evaporates due to the heat in the molten metal. At this stage, it should retain the mould cavity and at the same time withstand the metallostatic forces.

干强度：当型砂中的湿气都被排出的时候，其被称为干砂。当熔融金属浇入型中，型腔周围的型砂由于液态金属中的散热，湿气快速蒸发而迅速转变成干砂，此时，它应该保持型腔同时承受金属静力学的作用力。

Hot strength: After all the moisture is eliminated, the sand would reach a high temperature when the metal in the mould is still in the liquid state. The strength of the sand that is required to hold the shape of the mould cavity then is called hot strength.

热强度：所有的湿气消除以后，当铸型中的金属仍处于液态时砂子就会达到一个高温。砂子要求保持型腔形状的强度就被称作热强度。

Permeability: During the solidification of a casting, large mounts of gases are to be expelled from the mould. The gases are those which have been absorbed by the metal in the furnace, air absorbed from the atmosphere and steam and other gases that are generated by the moulding and core sands. If the gases are not allowed to escape from the mould, they would be trapped inside the casting and cause defects. The moulding

sand should be sufficiently porous so that the gases are allowed to escape from the mould. This gas evolution capability of the moulding sand is termed as permeability.

渗透性：在铸件的凝固过程中，大量的气体将从铸型中排出，气体包括炉中金属吸收的、从大气和水蒸气中吸收的和其他由于浇注及型芯砂产生的。它们会在铸件中聚集并形成缺陷。型砂应该充分地多孔以使气体能够从铸型中逃逸。型砂的气体逸出能力被称为渗透性。

Beside those specific properties, the moulding sand should also have collapsibility so that during the construction of the solidified casting, it dose not provide any resistance which may result in cracks in the casting, they should be reusable and should have good thermal conductivity so that heat from the casting is quickly transferred.

除了这些明确的性能，型砂应该还有溃散性以确保在铸件凝固的过程中，不会有任何在铸件中可能导致裂纹的阻力。它们应该有重复使用性及好的热传导特性，以使铸件中的热量能够快速的转移出来。 5.3.3 Coremaking 5.3.3 制芯

Cores are forms, usually made of sand, which are placed into a mold cavity to form the interior surfaces of castings. Thus the void space between the core and mold-cavity surface is what eventually becomes the casting.

芯子使用砂子制作，放于型腔中以形成铸件内表面的一种实物形态，芯子和型腔表面的空间最终形成铸件。

Cores are the materials used for making cavities and hollow projections which cannot normally be produced by the pattern alone.

Any complicated contour or cavity can be made by means of cores so that really intricate shapes can be easily obtained. These are generally made of sand and are even used in permanent moulds. In general, cores are surrounded on all sides by the molten metal and are therefore subjected to much more severe thermal and mechanical conditions and as a result, the core sand should be of higher strength than the

moulding sand.

芯子是用于制作单个模样不能生产出的空腔和中空的突起部份的材料。

所有复杂的外型或型腔都能用芯子来实现，这才使得复杂形状容易得到。它们通常使用砂子制作，即使在金属型中也会使用。通常，芯子周围被金属液所填充，所以它要承受更加剧烈的传热学和力学条件。所以，芯砂应该比型砂有更高的强度

5.3.3.3 Core prints 5.3.3.3 芯撑

The core prints are provided so that the cores are securely and correctly positioned in the mould cavity. The design of core prints is such as to take care of the weight of the core before pouring and the upward metallostatic pressure of the molten metal after pouring. The core prints should also ensure that the core is not shifted during the entry of the metal is poured into the mould cavity.

芯撑是为了使芯子在型腔中完整正确的放置。设计芯撑是为了支撑浇注前芯子的重量和浇注后熔融金属的静压力，芯撑应当确保芯子在液态金属浇入到型腔时不会被冲走。

5.3.4 Elements of Gating systems 5.3.4 浇注系统的组成

As defined earlier, gating system refer to all those elements which are connected with the flow of molten metal from the ladle to mould cavity. The various elements that are connected with a gating system are (Fig. 5.26):

就像前面所定义的，浇注系统涉及到所有与液态金属流从浇包到型腔过程相关联的结构组成，这些与浇铸系统相关联的结构包括： ? Pouring basin ? Sprue

? Sprue base well

? Runner

? Runner extension ? Riser ? Chill

Fig. 5.26 Typical gating system

浇口杯； 直浇道； 直浇道窝； 横浇道； 横浇道延伸； 冒口； 冷铁；

In this section the functions and the design of the various elements of a gating system will be discussed. Any gating system designed should aim at providing a defect free casting. This can be achieved by making provision for certain requirements while designing the gating system. These are as follows:

在这一部分，将会讨论许多浇注系统元素的设计和作用。所有浇注系统设计的目标是为了得到无缺陷铸件，在设计浇注系统时，可以通过针对特定的要求做出安排来实现。

1. the mould should be completely filled in the smallest time possible without

having to raise metal temperature nor use higher metal heads. 2. the metal should flow smoothly into the mould without any turbulence. A

turbulent metal flow tends to form dross in the mould 3. unwanted material such as slag, dross and other mould material should not be allowed enter the mould cavity

4. the metal entry into the mould cavity should be properly controlled in such a

way that aspiration of the atmospheric air is prevented 5. a proper thermal gradient should be maintained so that the casting is cooled without any shrinkage cavities or distortions 6. metal flow should be maintained in such a way that no gating or mould

erosion take place. 7. the gating system should ensure that enough molten metal reaches the mould

cavity

8. the gating system design should be economical and easy to implement and

remove after casting solidification

9. ultimately, the casting yield should be maximized

1.铸型应该在尽可能短的时间里完全充满，而不必要通过提高金属温度或使用高的金属静压头。

2.金属应该没有任何紊流的平稳流入铸型中，紊动的金属流容易在铸型中形成渣滓。

3.不期望的材料，比如熔渣、渣滓和其他模型材料不应允许进入型腔内。 4.对进入型腔中的金属液应该用一种阻止大气气体吸入的方法进行适当的控制。

5.应该保持一个适当的温度梯度以使铸件在冷却中不会出现任何的缩孔或变形。

6.金属应当保持一种不会出现浇注腐蚀或铸型腐蚀的流动方式。 7.浇铸系统应当确保足够的熔融金属到达型腔中。

8.浇注系统的设计应当经济和易于实施及在铸件凝固后移走。 9.最终，铸件应该实现大批量生产。

To have all these requirements together is a tall order, still a mould designer should strive to achieve as many of the above objectives as possible. Before going into the mechanics of gating design, let us describe some of the functions and types of various gating system elements

满足以上的需要是一个很高的要求，一个铸型设计人员应当努力去达到以上尽可能多的

目标。在进行浇注系统结构设计之前，让我们先讲述一下多种浇注系统组成的作用及分类。 5.3.3.1

Pouring basin

5.3.4.1 浇口杯

The molten metal is not directly poured into the mould cavity because it may cause mould erosion. Molten metal is poured into a pouring basin which acts as a reservoir from which it moves smoothly in to sprue. The pouring basin is also able to stop the slag from entering the mould cavity by means of a skimmer or skim core as shown in Fig.5.27. It hold back the slag sand dirt which floats on the top and only allow the clean metal underneath it into the sprue. The pouring basin may be cut into the cope portion directly or a separate dry sand pouring basin may be prepared and used as shown in Fig.5.27. the molten metal in the pouring basin should be full during the pouring operation, otherwise a funnel is likely to form through which atmospheric air and slag may enter the mould cavity.

(a) Green sand (b) Dry sand Fig. 5.27 Pouring basin

由于可能造成铸型的腐蚀，熔融的金属液并没有直接浇入到型腔中。熔融金属倒入一个有贮存作用的浇口杯并平稳的进入到直浇道中，浇口杯还有通过图5.27所示的撇渣器或撇渣芯阻挡渣子进入型腔的能力。它保留了漂浮在上层的砂污渣子，只允许其下方的洁净金属进入直浇道。浇口杯可以直接从端盖部分分开，

或者可以准备一个如图5.27所示单独的干砂浇口杯使用。在浇注操作中，熔融的金属液应该充满浇口杯，否则易于形成一个漏斗，大气气体和渣滓会通过它进入到型腔中去。

One of the walls of the pouring basin is made inclined at about 45°to the horizontal. The molten metal is poured on this face such that metal momentum is absorbed and vortex formation is avoided. In some special cases the pouring basin may consist of partitions to allow for the trapping of the slag and maintaining constant metal height in the basin.

浇口杯的其中一个壁做成了与水平呈45度的倾斜。液态金属倾倒在这个平面上以消除

金属动量和避免形成涡流。在一些特别的情况下，浇口杯可构成允许截渣和保持杯中恒定的金属高度的部分。 5.3.3.2

Sprue

5.3.4.2 直浇道

Sprue is the channel through which the molten metal is brought into the parting plane where it enters the runners and gate to ultimately reach the mould cavity. The molten metal when moving from the top of the cope to the parting plane grains in velocity and as a consequence requires a smaller area of cross section for the same amount of metal to flow at the top. If the sprue were to be straight cylindrical as shown in Fig. 5.28(a), then the metal flow not be full at the bottom, but some low pressure area would be created around the metal in the sprue. Since the sand mould is permeable, atmospheric air would be breathed into this low pressure area which would then be carried to the mould cavity. To eliminate this problem of air aspiration the sprue is tapered to gradually reduce the cross section as it moves away from the top of the cope as shown in Fig.5.28(b).

(a)Straight sprue (b) Tapered

Fig. 5.28 Sprue

直浇道是液态金属被引入分型面的一个通道，通过分型面，液态金属进入横浇道和浇口并最终进入到型腔中。液态金属从顶端到分型面获得了一个速度，结果，当等量的金属在顶端流动时，要求一个更小的横截面即可。如果直浇道做成如图5.28（a）所示的直圆柱形，金属流在底部将不会充满，而会在直浇道中围绕金属液形成低压区。由于砂型具有渗透性，大气气体将会被吸入这个低压区，并随后进入到型腔中。为消除气体吸入的问题，直浇道做成锥形的以逐渐减少如图5.28（b）中金属从顶端往下流动的横截面积。

5.3.3.3 Sprue base well 5.3.4.3 直浇道窝

This is a reservoir for metal at the bottom of the sprue to reduce the momentum of the molten metal. The molten metal as it moves down the sprue grains in velocity, some of which is lost in the sprue base well by which the mould erosion is reduced. This molten metal changes direction and flows into the runners in a more uniform way.

这是一个为了减少熔融金属动量而设计的在直浇道底部的金属液储存器，在金属从直浇道中下降时获得速度，其中的一些在直浇道窝中失去了，从而减少了铸型的腐蚀。熔融的液态金属改变了方向并以一种更均匀的方式流进了横浇道。

5.3.4.4 Runner 5.3.4.4 横浇道

It is generally located in the horizontal plane (parting plane) which connects the sprue to its ingates, thus letting the metal enter the mould cavity. The runners are normally made trapezoidal in cross section. It is a general practice for ferrous metals to cut the runners in the cope and the ingates in the drag. The main reason for this is to trap the slag and dross which are lighter and thus trapped in the upper portion of the runners. For effective trapping of the slag, runners should flow full. When the amount of molten metal coming from the down sprue is more than the amount flowing through the ingates, the runner would always be full and thus slag trapping would take place. But when the metal flowing through the ingates is more than that flowing through the runners, then the runner would be filled only partially and the slag would then enter the mould cavity.

它通常位于连接直浇道到内浇口的水平分型面上，从而使金属进入到型腔中。直浇道横截面形状通常做成梯形。对于黑色金属，通常实际生产中在上箱开辟横浇道、在下箱开辟内浇口。主要的原因是为了阻挡较轻的位于直浇道上部的渣滓，为了有效的挡渣，横浇道应该充满，当从直浇道进入的熔融金属液量多于流经内浇口的量时，横浇道就会被充满从而实现了挡渣。但是当流经内浇口的金属多于流经横浇道的时，横浇道只有部分被填充，渣滓将会进入到型腔中去。

5.3.4.5 Runner extension 5.3.4.5 横浇口延伸端

The runner is extended a little further after it encounters the ingate. This extension is provided to trap the slag in the molten metal. The metal initially comes along with the slag floating at the top of the ladle and this flows straight, going beyond the ingate and trapped in the runner extension.

当横浇道和内浇口相交时它会有一点延伸，这个延伸是为了阻挡熔融金属液中的渣滓。最初金属和漂浮在浇包上方的渣滓向前直流，流过内浇口并在横浇口延伸端被阻挡渣滓。

5.3.4.6 Riser

5.3.4.6 冒口

Most of the foundry alloys shrink during solidification. Table 10.1 shows the various volumetric shrinkages for typical material. As a result of this volumetric shrinkage during solidification, voids are likely to form in the castings unless additional molten metal is fed into these places which are termed as hot spots since they remain hot till the end. Hence a reservoir of molten metal is to be maintained from which the metal can flow readily into the casting when the need arises. These reservoirs are called risers.

多数的铸造合金在凝固过程中收缩。表格10.1说明了典型材料的各种体积收缩量。由于这种在凝固过程中的体积收缩量，铸件就趋于形成缩孔，除非额外的液态金属进入到由于直到最后都是保持热而被术称为热节的区域内。因此一个熔融金属的储存器必须准备，通过它金属在需要时能够平稳的流入到铸件中。

As shown in Table 5.6, different materials have different shrinkages and hence the riser requirements vary for the materials. In grey cast iron, because of graphitization during solidification, there may be an increase in volume sometimes. This if course, depends on the degree of graphitization in grey cast iron which is controlled by the silicon content.

如表5.6的说明，不同的材料有不同的收缩，因此冒口的要求因材料不同而不同。在灰铸铁中，由于凝固过程中的石墨化，有时会出现体积膨胀。这种情况的出现，取决于灰铸铁中由含硅量所控制的石墨化程度。

In order to make them effective, the riser should be designed keeping the following in mind.

1. the metal in the riser should solidify in the end.

2. the riser volume should be sufficient for compensating the shrinkage in

the casting.

为了使其有效，冒口应该遵循如下规则进行设计. 1、冒口中的金属应该最后凝固。 2、冒口体积应当足够进行铸件的补缩。

Table 5.6 volumetric liquid shrinkages Material Medium carbon steel High carbon steel

Nickel Monel Aluminum

Aluminum alloy (11-13% Si)

Aluminum bronze

Copper 70-30 brass Bearing bronze Grey cast iron White cast iron Magnesium Zinc

5.3.4.7 Chill 5.3.4.7 冷铁

In a casting, metallic chills are used in order to provide progressive solidification or to avoid the shrinkage cavities. Chills are essentially, large heat sinks. Whenever , it is not possible to provide a riser for a part of the casting which is heavy, a chill is placed close to it as shown in Fig. 5.29, so that more heat is quickly absorbed by the chill from the larger mass making the cooling rate equal to that of the thin sections. Thus, this dose not permit the formation of a shrinkage cavity. But use of a chill means essentially providing higher cooling rate which is also likely to form a hard spot at the contract area with the chill and may therefore cause a problem if that area needs further processing way of machining.

Shrinkage,(%) 2.50 to 3.50

4.00 6.10 6.30 6.60 3.50 4.10 4.92 4.50 7.30 1.90 to negative 4.00 to 5.75

4.20 6.50

Fig. 5.29 Chill

在铸件中，经常使用冷铁以达到逐层凝固或者避免收缩孔洞。冷铁本质上讲，是大的吸热源。无论何时，为厚重铸件的一部分提供一个冷铁是不可能的，冷铁与其紧密接触，如图5.29所示，从而冷铁从厚大质量部分中快速的吸收了更多热量，使得冷却速度和薄壁部分的相当。从而，阻止了缩孔的形成。但是使用冷铁意味着更高的冷却速度，它也会在和冷铁交叉区趋于形成麻点，如果这个区域需要进一步的机械加工，就会导致问题的出现。 5.3.5 Melting Practice 5.3.5 熔炼操作

The preparation of molten metal for casting is referred to simply as melting. Melting is usually done in a specifically designated area of the foundry, and the molten metal is transferred to the pouring area where the molds are filled. After moulding, melting is the major factor which controls the quality of the casting. There are a number of methods available for melting foundry alloys such as pit furnace, open hearth furnace, rotary furnace, cupola furnace, etc. The choice of the furnace depends on the cupola in its various forms is extensively used basically because of its lower initial cost and lower melting cost.

铸造中熔融金属液的准备阶段通常被称为熔炼，熔炼通常在一个专门设计的车间区域内完成，然后熔融金属转移到铸型充满的浇注区域内。造型结束后，熔炼就成为控制铸件质量的主要因素。有很多有效的方法熔炼铸造合金比如：坑式炉、 开式炉、 旋转炉、冲天炉等，炉子的选择取决于多种形式冲天炉的广泛应用，主要是因为低的原始成本和低的熔炼成本。

5.3.6 cleaning 5.3.6 清理

Cleaning refers to all operations necessary to the removal of sand, scale, and excess metal from the casting. The casting is separated from the mold and transported to the cleaning department. Burned-on sand and scale are removed to be improved the surface appearance of the casting. Excess metal, in the form of fins, wires, parting line fins, and gates, is removed. Castings may be upgraded by welding or other procedures. Inspection of the casting for defects and general quality is performed

清理涉及到所有为清除砂子、 鳞屑状物和铸件多余的上金属，铸件从铸型中分离出来然后输送到清理工位，清理烧结的砂子和鳞屑状物以改善铸件的表面形貌。多余的金属，以飞翅、线状物、分型线飞翅和浇口的形式清理掉。铸件可以通过焊接或其他步骤进一步成型，再进行铸件的缺陷和质量检测。 5.3.7 Other processes 5.3.7 其他工艺

Before shipment, further processing such as heat-treatment, surface treatment, additional inspection, or machining may be performed as required by the customer's specifications.

在运输之前，进一步的工艺比如热处理、 表面处理、附加检测，或机加工也要根据消费者的需要进行操作。

Chapter 6 Advanced Technologies of Metals 第六章：金属的先进技术 6.2 Casting Processes 6.2 铸造工艺方法 6.2.1 Shell Moulding 6.2.1 壳模法

It is a process in which, the sand mixed with a thermosetting resin allowed to come into contact with a heated metallic pattern plate, so that a thin and strong shell of mould is formed around the pattern. Then the shell is removed from the pattern and the cope and drag are removed together and kept in a flask with the necessary back up material and molten metal is poured into the mould.

在这种造型工艺中，将砂子和热固性树脂混合并将其与加热的金属模型表面紧密接触，，从而围绕着模型形成了一个薄且坚固的铸型壳层。然后将壳层与模型分离，并将上下型同时移出放入到有必需的填背材料的砂箱中，随即将熔融的金属浇入到铸型中。

Generally, dry and fine sand (90 to 140 GFN) which is completely free of the clay is used for preparing the shell moulding sand. The grain size to be chosen depends on the surface finish desired on the casting. Too fine a grain size requires large amount of resin which makes the mould expensive.

通常，完全没有粘土成分的干的细砂（90-140目）用于做壳型造型砂，颗粒尺寸的选择取决于铸件所要求的表面光洁度，太细的颗粒尺寸需要大量的树脂进而使造型成本提高。

the synthetic resins used in shell moulding are essentially thermosetting resins, which get hardened irreversibly by heat. The resins most widely used, are the phenol formaldehyde resins. Combined with sand, they have very high strength and resistance to heat. The phenolic resins used in shell moulding usually are of the two-stage type, that is, the resin has excess phenol and acts like a thermoplastic material. During coating with the sand the resin is combined with a catalyst such as hexa-methylene-tetramine (hexa) in a proportion of about 14 to 16% so as to develop the thermosetting characteristics. 壳型造型中使用的人造树脂实质上就是热固性树脂，热量导致它不可逆硬化，应用最广泛的树脂是酚醛树脂。与砂子相结合时，它们有很高的强度和耐热性。壳型造型中使用的酚醛树脂通常属于两级类型式，即树脂有过量的酚醛时会在使用中体现热塑材料的性质，在对砂进行覆膜的过程中，树脂中会加入一种催化剂比如以14%-16%的比例加入六甲撑四胺以产生热固性。

Additives may sometimes be added into the sand mixture to improve the surface

finish and avoid thermal cracking during pouring. Some of the additives used are coal dust, pulverised slag, manganese dioxide, calcium carbonate, ammonium borofluoride and magnesium silicofluoride. Some lubricants such as calcium stearate and zinc stearate may also be added to the resin sand mixture to improve the flowability of the sand and permit easy release of the shell from the pattern.

砂混合物中有时会加入附加物以改善表面光洁度和浇注过程中的热裂。附加物中一些是煤粉、粉状渣滓、二氧化锰、碳酸钙、胺基氟硼酸盐和镁基氟硅酸盐。一些润滑剂比如硬脂酸钙和硬脂酸锆也可以加入到树脂砂中来改善型砂流动性和壳型与模型容易脱离。

The first step in preparing the shell mould is the preparation of sand mixture in such a way that each of the sand grain is thoroughly coated with resin. To achieve this, first the sand, hexa and additives which are all dry, are mixed inside a Mueller for a period 1 min. Then the liquid is added and mixing is continued for another 3min. To this cold or warm air is introduced into the Mueller and the mixing is continued till all the liquid is removed from the mixture and coating of the grains is achieved to the desired degree.

准备壳型的第一步是以一种将砂粒完全覆盖树脂的砂混合物的准备，为了达到这个要求，首先是将干的砂子、六甲撑四胺和附加物在缪勒中混合一分钟。然后加入到液体中并继续混合三分钟，向缪勒中导入冷的或者热的空气，继续混砂知道液体从混合物中析出，沙粒覆盖到所需要的程度。

The metallic pattern plate is heated to a temperature of 200 to 350 oC depending on the type of the pattern. It is very essential that the pattern plate is uniformly heated so that the temperature variation across the whole pattern is within 25 to 40 oC depending on the size of the pattern. A silicone release agent is sprayed on the pattern and the metal plate. The heated pattern is securely fixed to a dump box, as shown in Fig. 6.7 (a), wherein the coated sand in an amount larger than required to form the shell of necessary thickness is already filled in.

Fig. 6.7 Shell moulding procedure

取决于模型的类别金属型板被加热到200-350度不等。型板能够均匀加热以使整个模型温度变化在25-40度范围内。在模型和金属板涂一层聚硅酮脱模剂，加热的铸型不可见的固定在翻斗中，如图6.7（a）中所示，腹膜砂以一种大于所需形成壳型厚度的量填入到其中。

然后旋转翻斗，如图6.7（b）所示以使覆膜砂落到加热板上。模型的热量熔化相邻树脂，从而使得型砂混合物黏附在模型上。

When a desired thickness of shell is achieved, the dump box is rotated backwards by 180 so that the excess sand falls back into the box, leaving the formed shell intact with the pattern as in Fig. 6.7 (d). The average shell thickness achieved depends on the temperature of the pattern and the time the coated sand remains in contact with the heated pattern. The actual shell thicknesses required depends on the pouring metal temperature and the casting complexity. This may normally be achieved by trial and error method.

Fig.6.8 Shell mould ready for pouring

当得到一个所需厚度的壳型时，翻斗旋转180度以使多余的砂子回落到斗中，留下如图6.7（d）中所示的与模型紧密接触的壳型，平均的壳型厚度取决于模型的温度和腹膜砂与型板的接触时间，实际所需的壳型厚度取决于浇注金属的温度和铸件复杂程度。通常这可以通过试验和错误分析方法达到.

Since the shells are thin, they may require some outside support so that they can withstand the pressure of the molten metal. A metallic enclosure to closely fit the exterior of the shell is ideal, but is too expensive and therefore impractical. Alternatively, a cast iron shot is generally preferred as it occupies any contour without unduly applying any pressure on the shell. With such a backup material, it is possible to reduce the shell thickness to an economical level.

由于壳型很薄，它们需要一些外部的支持以承受熔融金属液的压力，在壳型的外部固定一个金属外壳十分的理想，但是由于太昂贵而不合实际。相比之下，通常使用一种铸铁金属丸，其占去了所有的轮廓，除去了壳型上不应有的压力。

6.2.2 Die Casting 6.2.2 压力铸造

Die casting involves the preparation of components by injecting molten metal at high pressures into a metallic die. Die casting is closely related to permanent mould casting, in that both the processes use reusable metallic dies. In die casting, as the metal is forced in under pressure compared to permanent moulding, it is also called

'pressure die casting'. Because of the high pressure involved in die casting, any narrow sections, complex shapes and fine surface details can be easily produced.

压力铸造涉及到将熔融金属在高压下射入到金属铸型中制备部件。压力铸造与金属型铸造密切相关，与金属造型相比由于金属在压力下注入，其也被称为压力模型铸造，由于压力铸造中涉及到高压，所以所有的窄小部分、复杂形状以及精密表面结构零件制作便容易实现。

In die casting, the die consists of two parts. One called the stationary die or cover die which is fixed to the die casting machine. The second part called the ejector die is moved out for the extraction of the casting. The casting cycle starts when the two parts of the die are apart. The lubricant is sprayed on the die cavity manually or by the auto lubrication system. The two die halves are closed and clamped. The required amount of metal is injected into the die. After the casting is solidified under pressure the die is opened and the casting is ejected.

在压力铸造中，模具由两部分组成，一部分固定在压铸机上的被称为固定模或者凹压模，第二部分称为凸压模，当其移动时，铸件才能取出。当模具的两部分分开时铸件循环开始，润滑剂通常由人工或自动润滑系统洒到型腔内。两个半模进行合模并夹紧。所需量的金属注入到模型中，铸件在压力下凝固后，模型打开，铸件随即被取出。

The die casting machines are of two types: hot chamber die casting, and cold chamber die casting. The main difference between these two types is that in hot chamber, the holding furnace for the liquid metal is integral with the die casting machine, whereas in the cold chamber machine, the metal is melted in a separate furnace and then poured into the die casting machine with a ladle for each casting cycle which is also called 'shot'.

Fig. 6.9 Operation sequence of hot chamber process

压铸机有两种类型：热室压铸法和冷压铸造。两种类型之间主要的不同在于，在热室中，液态金属所用的保温炉是和压铸机一体的，然而在冷室机中，金属在单独的炉子中熔炼，然后每次浇注过程中用一个浇包将其浇入到压铸机中，这一过程又称为压射。

6.2.3 Investment Casting 6.2.3 熔模铸造

This is the process where the mould is prepared around an expendable pattern. Casting processes in which the pattern is used only once are variously referred to as \of the desired form out of wax or plastics (usually polystyrene). The first step in this process is the preparation of pattern for every casting made. To do this, molten wax which is used as the pattern material is injected under pressure of about 2.5 MPa into a metallic die which has the cavity of the casting to be made. The wax when allowed to solidify would produce the pattern. To this wax pattern, gates, runners and any other details required are appended by applying heat. 这是围绕一个可消耗的模型制作铸型的工艺过程，在这种铸造工艺中模型只使用一次，通常被冠以不同名称为“失蜡铸造”或者“精密铸造”工艺。在所有情况

下，他们包括用蜡或塑料（通常为聚苯乙烯）制作需要形状的模型。工艺的第一步是将要制作的铸件的模型准备阶段。在这一步中，用于做模型材料的熔融蜡注射入有将要制作铸件的腔形状的金属型中，当蜡凝固时生产出模型。对蜡模来讲，内浇道、直浇道和其他需要的结构通过作用热悬挂上去。

The process has been described as the lost wax, precision casting, and investment casting process. The last-dimensional name has been generally accepted to distinguish the present industrial process from artistic, medical, and jewelry applications. The basic steps of the investment casting process are as follows (Fig. 6.11): 1. Production of heat disposable patterns, usually in wax or plastic. 2. Assembly of these patterns onto a gating system.

3. Investing, or covering the pattern assembly with ceramic to produce a monolithic mold. 4. Melting out the pattern assembly to leave a precise mold cavity.

5. Firing the ceramic mold to remove the last traces of the pattern material, to fire the ceramic and develop the high temperature bond, and to preheat the mold ready for casting. 6. Casting.

7. Knock-out, cut off, and finishing.

Fig. 6.11 Old but modern investment casting with many new developments 熔模铸造的工艺的基本步骤如下：

1、热量可支配模型的制作，通常用蜡或塑料。 2、装配这些模型到一个浇注系统上。

3、熔模，或者用陶瓷覆盖装配模来生产一个整体铸型。 4、熔融装配模已得到精密的型腔。

5、烘烤陶瓷型以除去模型材料最后的痕迹，烘烤陶瓷型并使其高温结合，提前加热铸型以为铸造做准备。 6、铸造过程

7、敲落，切断和表面清理。 8、

6.2.4. Squeeze Casting 6.2.4 挤压铸造

Squeeze casting also known as liquid metal forging, is a combination of casting and forging process (Fig. 6.12). The molten metal is poured into the bottom half of the pre-heated die. As the metal starts solidifying, the upper half closes the die and applies pressure during the solidification process. The amount of pressure thus applied is significantly less than used in forging, and parts of great detail can be produced. Coring can be used with this process to form holes and recesses. The porosity is low and the mechanical properties are improved. Both ferrous and non-ferrous materials can be produced using this method.

Fig. 6.12 Schematic of squeeze casting process

挤压铸造也被称为液态金属锻压，是一个将铸造和锻压结合的工艺过程（图6.12），液态金属浇入到经过预热金属铸型的半型的底部，当金属开始凝固时，上半型合型并在凝固过程中提供压力，所提供的压力显著低于锻压中使用的压力，由此重要零件部分被生产出来，芯子在这个工艺过程中用于形成孔和凹进处。多孔性低从而使机械性能改进，铁基和非铁基材料均可使用这种方法进行生产。

6.2.5 Lost Foam Casting 6.2.5 消失模铸造

Lost foam casting allows the production of complex parts. The process produces complex parts and reduces finish machining of the part produced by lost foam casting.

消失模铸造能够生产复杂结构的产品。这种工艺生产复杂零件并且减少通过消失模生产出零件的机加工量。

The basic steps to the process include (Fig. 6.13):

1. A foam pattern and gating system are made using a foam molding press

2. The foam pattern and the gating system are glued together to form a cluster of patterns

3. The cluster is coated with a permeable refractory coating and dried under controlled conditions

4. The dried, coated cluster is invested in a foundry flask with loose, unbonded sand that is vibrated to provide tight compaction

5. The molten metal is poured on to the top of the gating system which directs the metal throughout the cluster and replaces the foam gating and patterns

6. The remaining operations such as, shake out, cut-off, grinding, heat treat, etc. are straightforward and similar to other casting processes.

Fig. 6.13 Schematic of lost foam casting process

这项工艺的基本步骤包括（图6.13）：

1、使用泡沫造型压力机制作泡沫材料模型及浇注系统 2、泡沫模型及浇注系统胶合在一起形成模型团簇。

3、所形成的团簇用可渗透的耐火材料覆盖并在控制条件下加热。

4、干的、覆盖团簇在一个含有松散、不含粘结剂砂的砂箱中熔模，砂子用来震荡以提供高的紧实度。

5、液态金属从浇注系统的上部浇入，浇注系统使液态金属通过团簇并代替泡沫内浇道和模型。

6、其余的操作比如：打箱，截断，研磨，热处理等都是简单的，与其他的铸造工艺过程类似。

Generally, all ferrous and non-ferrous materials can be successfully cast using the Lost Foam process. Because the foam pattern and gating system must be decomposed to produce a casting, metal pouring temperatures above 1000°F are usually required. Lower temperature metals can be poured, but part size is limited. In addition, very low carbon ferrous castings will require special processing.

通常，所有的铁基与非铁基材料都能用消失模工艺进行铸造，由于消失模和浇注系统在逐渐制作过程中必须分开，金属浇注温度通常要求在1000F以上，低温的液态金属也能进行浇注，但是零件尺寸受到限制，另外，低碳的铁基铸件需要特殊的工艺。

本文来源：https://www.bwwdw.com/article/om87.html