If used on a patio, will the 12 ft. Corrugated Galvanized Steel 29-Gauge Roof Panels cause the heat to raise?

They will cause the patio temperature to raise.

They will cause the patio temperature to raise. Not because they are metal, you will have the same experience with plastic, or fiberglass sheets. The issue of higher temperature exists because heat rises, and with a solid top on your patio, you will have shade, but the heat will have no means to escape, therefore trapping itself on your patio and raising the temperature.