What is the difference between steel plate and steel sheet.I need to buy a piece that is 7ga and 6"long/6" wide to mount 2 -4"bearings on that will be on top of a oven at 525degF.What grade steel to use and plate or sheet?
The difference (between plate and sheet) is primarily related to the thickness, and is not of much importance either way. I think a sheet is usually 1/8" or thinner, but then I've heard of 1/4" plates also referred to as sheet metal. 7ga steel is 3/16". Most common stainless steels (302/304/316/317/410/420/430/440) can be used at working temperatures which are typically above 1000F.
McMaster Carr sells a 6" X 6" X 3/16" plate of stainless for $20 or thereabouts.