铸造翻译终稿(7)

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。

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