| 摘要 |
The exterior layer of the accessory is the precious matal, for example gold or silver, and it's interior layor is the alloy layor having lower melting point than the precious metal and easier welding than the metal, for example lead, tin or bismuth. The temperature of the melting point is less than 500≦̸C and the pre-heating temperature is 500-600≦̸C.
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