Re: cast iron

Just my 2 cents worth.
A few years ago we were modifying vintage motorcycles into vintage
racing motorcycles - worth more money <g>
All the old frame lugs were made from mallable iron and pinned and
brazed on. Made enquiries at local foundries and found mallable iron
was no longer cast. We were advised to use SG Iron [ Spheridol
Graphite <sp> ] as it was a nearer to mallable. After being cast
these were sent for heat treatment which was about 24 hours at
something like 1200 degrees and a slow cool down. Once we got them
back we could split them with a hacksaw, heat them up and spread them
open so they fitted over the tubes. Once closed up they were then
brazed up. I noticed on working these fittings that they performed
more like steel than cast iron. No way even heating a cast iron lug
up you could expand it to go over a 1 1/2" tube without cracking.