Accidentally finding high-grade tool steel

I was at the local scrap yard the other day looking for some project scrap. In the “mild steel” section, I found a few plates of fairly nice looking stuff that were about the dimensions I was looking for, roughly 1/8th" thick x 12" wide x 3-4 feet long. I paid my .30 cents per Lb and went on home. (Picture 1)

I managed to cut it with a cut-off wheel on my 4-1/2" angle grinder, but noticed it was a lot slower/harder going than normal. I later noticed that I had also burned through a full cut-off wheel cutting through about 16 inches of linear cut.

The real fun started when I tried to drill a few holes in my piece. 1 hour, 3 burned up titanium-coated drill bits, and 2 burned up diamond-coated Dremel bits later I had only managed to make 4 very small dents (about the size of golf-ball divots) in my piece. (Picture 2)

I finally found a brand name printed on a piece, as well as a 6 digit number. The number didn’t bring up anything helpful on Google, with or without the brand name. The brand name, Uddeholm, brought up a Swedish company that solely deals in high-grade knife and tool steels. That would explain why I had such a hard time working with it!

This find is somewhat of a mixed blessing. The obvious positive being that I have several square feet of plate tool steel that I got at a fraction of it’s value/normal cost. That said, I now have an arm load of steel that I can’t work with using my tools and don’t have any appropriate sheets for what I bought this stuff for in the first place.