| 配方類型： |
METALS AND THEIR TREATMENT |
| 配方說明： |
Mold Wash |
| 配方組成： |
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| 配制方法： |
For casting of copper alloys in permanent iron molds a mold wash is often required to prevent the alloys from sticking to the molds. The copper alloys are particularly liable to stick to the steel if they contain tin and, to a lesser extent, zinc. For such casting the mold must be hot in order to avoid too rapid chilling of the metal as it is cast. Thus the mold wash must be stable at 500 to 800F.
In some cases, an iron oxide coating obtained by heating the mold to redness will suffice, but often this is not sufficient.
A coating of carbon applied each time before casting is often effective.
A good coating can be obtained from acetylene smoke by waving a flame of burning acetylene over the surface of the mold that will be in contact with the freezing metal. Another carbon coating that may be used is 1 part of "Aquadag" diluted with 2 parts of water. This may be brushed or sprayed on while the mold is sufficiently hot to volatilize all of the water.
Various alloys may require other substan |
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