Jewelry Making: Annealing & Cold Rolling Gold
Gold Fabrication, Annealing & Cold Rolling
After the metal ingot has been removed from the mold and allowed to cool it needs to be "annealed." Annealing is a metalworking process of applying force and heat of between 200º C to 500º C to a metal, in order to compact its molecular structure, and strengthen it.
Working, or "annealing" a metal makes it both harder and stronger. However, there is a point at which the metal can be overworked, which will eventually cause it to easily fracture.
Once the metal is in an annealed condition, it can be cold-rolled to form a thin sheet. With each pass through the rolling mill, Michael will reduce the gap between the metal rolls, creating a thinner sheet with each pass. The first pass (called the "rough pass") is tested with an initial "dead pass" in which little or no reduction/force will take place.
After the metal ingot has been rolled several times it is pounded, or "work hardened," to further compress its crystalline structure. Then the metal is passed through the rolling mill again, but this time it is passed through in the reverse direction. Each time it is passed through the mill, the metal's crystalline structure is elongated in the rolling direction - called the "grain flow."
The final pass of the ingot through the rolling mill is known as the "finishing pass," and therefore you will use slightly less compression/reduction than before.
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Page 2: Annealing & Cold Rolling Gold
Page 3: Stone Setting
Page 4: Final Finishing & Assembly
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