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<p>[QUOTE=&quot;JPeace$, post: 2337011, member: 42727&quot;]Not exactly.&nbsp; Without going into too much detail, the work rolls are the only 2 of the 20 in the mill box that touch the material.&nbsp; The finish on the material is directly related to the &quot;polish&quot; on the rolls.&nbsp; The other 18 rolls all play a role in shaping the material, but they do not touch the metal.&nbsp; Any small imperfection on the work rolls will be imparted on the material.&nbsp; So the mill operator is responsible for monitoring the material (along with some automated visual monitoring) and reacting to imperfections.&nbsp; If he sees a problem, he stops the mill and pulls the rolls.&nbsp; Generally, we can reduce most material 70-80% before it work hardens.&nbsp; At that point, the &quot;excess&quot; material migrates to the edges.&nbsp; What we see is edge ripple and potentially small cracking.&nbsp; To further work the material, we need to slit the edges off and then anneal the material.&nbsp; If you try to work material with any edge cracks, you risk &quot;breaking&quot; the material in the next reduction. </p><p><br /></p><p>Now, when you &quot;pull&quot; material, which in laymens terms is what is happening, you start to orient the grains in the material.&nbsp; The naturally orient in the rolling direction.&nbsp; Part of the annealing process tries to change the isotropy of the grains. </p><p><br /></p><p>Anyway, when I see stress marks like in your photograph, I believe them to be planchet &quot;errors&quot;.&nbsp; The planchets likely were not annealed properly, therefore, the material was a little brittle and the grain orientation was not minimized.&nbsp; The issue became magnified during the minting process.[/QUOTE]</p><p><br /></p>

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