Abstract: Apparatus for and process of heat treating open coils of strip metal, such as strip steel, by passing hot gases or atmospheres through spaces between spaced convolutions of the coil, in which a shielding structure is provided at the upper end of the coil where the coil edge portions are exposed to radiant heat from the furnace and where they may tend to move and distort from gas velocity or localized thermal expansion. The shielding structure protects these portions of the coil from excessive heat and restricts harmful movement thereof, thus improving the quality of the heat treated product. The disclosed shielding structure comprises spaced upwardly extending walls the height of which is sufficient to, and the spacing of which is such as to, prevent direct impingement of radiant heat on the upper end of the coil while permitting adequate flow of gas through the shielding structure for treating purposes.