So far, the details of science of sand casting processes have been discussed. But sand casting is not suitable nor economical in many applications where the special casting process would be more appropriate. In the following pages the details of some of the commonly used special casting methods would be described.
三、PERMANENT MOULD CASTING
In all the processes that have been covered so far, a mould need to


到目前為止，已經(jīng)有詳細(xì)的科學(xué)資料對(duì)砂型鑄造方法進(jìn)行了描述。但是在許多應(yīng)用中，砂型鑄造既不適合也不經(jīng)濟(jì)，而特殊鑄造方法則更適合些。下面的文章中就描述了幾種常用的特殊鑄造方法。
三、永久模具鑄造
到目前為止，在整個(gè)生產(chǎn)過(guò)程中這種鑄造造方法都被隱藏，每個(gè)鑄件需要準(zhǔn)備一個(gè)模具。對(duì)于大規(guī)模生產(chǎn),為每個(gè)鑄件生產(chǎn)一個(gè)模具是困難又昂貴的。
根據(jù)溫度的傳遞、鑄件的尺寸大小、鑄造的頻率來(lái)選擇模具的材料。它們決定了模具所腀@惺艿淖畬笱沽Γㄈ榷齲?。带结晶的灰铸铁视H畛Ｓ玫哪＞卟牧?。狠狕桚铁、C20鋼和合金鋼（Ｈ11和Ｈ14）也用于大體積的零件中。石墨模具可以用來(lái)做小體積的鋁或鎂