Infrared rays are emitted by red hot steel, or other red hot bodies for that matter. Ultraviolet rays are emitted from the arc when arc welding. Buy some cutting goggles from your welding supply, Home Depot, etc. with a #5 lens and you are well protected, both for forging and acetylene welding and brazing. If you are going to fire up an arc welder then you need protection from both IR and UV. Incidentially, most clear safety glasses offer IR and UV protection but I wouldn't want to use them to forge with.