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<p>[QUOTE=&quot;Lehigh96, post: 1000117, member: 15309&quot;]I can only help a little as I have not worked in the metallurgical field for many years.&nbsp; The need to anneal silver prior to the coining process is actually caused by earlier processes within the coining process.&nbsp; In order to make the planchets, the silver must be rolled in order to get the sheet of metal to the desired thickness before the planchets can be punched.&nbsp; This rolling process is a form of cold working which has the effect of increasing hardness while simultaneously decreasing ductility.&nbsp; The annealing stage allows for the softening of the metal by raising the temperature of the metal to the point that it recrystallizes.&nbsp; Once this is done and the metal is air cooled, it will be sufficiently ductile for the coin process.</p><p><br /></p><p>Now here is where my absence from the metallurgical field hurts me.&nbsp; Most of my experience with annealing was applicable to engineering metals such as steel and aluminum.&nbsp; I have very little experience with precious metals such as silver.&nbsp; However, I do know that controlling the annealing process is important with all metals and the greater measure of control with regards to time and temperature will yield better results.&nbsp; In that regard, I must assume that the gas furnaces were capable of producing a much more consistent product.</p><p><br /></p><p>Having said all that, I am not sure if the annealing process has anything at all to do with the corrosion of the metal.&nbsp; Martensitic steel will corrode just as easily as ferritic steel, or even pearlitic steel.&nbsp; Given that knowledge, I don&#039;t know what effect (if any) the annealing process would have on the corrosion process of silver.&nbsp; The crystalline lattice structure of silver is FCC (Face Centered Cubic).&nbsp;&nbsp; Annealing affects the mechanical properties of the metal (ductility &amp; hardness) by changing grain size and orientation but the crystal structure remains unchanged.&nbsp; The effect of grain size on the corrosion of silver is beyond the scope of my metallurgical background.[/QUOTE]</p><p><br /></p>

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