U-Shaped Radiant Tube for Industrial Furnaces FH® Alloy manufactures U-shaped radiant tubes for industrial furnaces, heat treatment furnaces, and indirect heating systems. The U-shaped configuration provides a large radiant heating surface within a compact furnace space and is widely used where the combustion process needs to be separated from the furnace atmosphere. Our U-shaped radiant tubes can be customized according to customer drawings, furnace dimensions, operating