Cracking Metal

Orchidians, Help…

I cast a 25% silver and 75% copper billet by the Japanese -through
the water technique-. It produced a super dense billet about 1 1/2
inches in diameter and is about a 1/2 inch thick in the center and a
3/8 inch thick at the edges. The billet is supposed to be oxygen
free.

I had been rolling it trying to make sheet about 5/32 thick. It
really does not want to roll as it work hardens after less than a
quarter turn of the roller height and that takes four passes. It has
been rolled in the same direction after every annealing. It had
started to show small cracks. I filed the cracks out, annealed the
billet again and went to see a blacksmith in the area who has an air
hammer.

The billet is a little thinner now but we had to stop as it is
showing some serious cracks. I can probably repair/fill the cracks
with hard silver solder but I still have the problem of trying to
make a sheet 1 inch wide by whatever length comes out of the 3
ounces.

Are there the same problems with 4% gold in 96% copper? This billet
is also very dense.

Thanks,
Bill in Vista