From what I've helped friends build, you can use a stand alone grill, but generally you get better results either with expanded metal in a frame over a stone/brick firebox, or using steel/stainless round stock welded into a frame over the same firebo...
A Rockwell test will tell but if you try to file it and you can't or try grinding it and you get bright blue sparks off the parent metal its a good chance you have Titanium.
Titanium is stronger. Platinum can be used to make jewelry, so it can be formed and pounded into shapes. Titanium is much harder to machine and form into objects. .