Kipmank,
This info was posted a while back in one of the forums here, see if you can use this info to determine your material.
"If you have a grinder you can use it to differentiate between steel and cast iron, or just about any other type of metal, by observing the sparks. Cast iron will have a very short spark stream - steel will have a noticeably longer stream.
Check out this site for some diagrams of spark streams - hit the "next" link at the top of page. http://www.tpub.com/steelworker1/5.htm
Do this in dim light so that you can easily see the difference in the carrier lines, forks, sprigs, etc. It will help if you have some material that you know is steel or cast iron to compare the sparks with." - flasherburner1
HTH,
John Wright
