A water cooled box to be installed in the side wall of a metal making furnace to hold and protect implements such as a burner, a lance, or a material (i.e., carbon or lime) injection device. The box preferably comprises a copper outer shell and a steel inner shell liner welded together, whereby a chamber is formed through which cooling water passes. The box further comprises an inlet and outlet for the water flow and a plurality of conduit passages between the copper and steel shells for mounting the aforementioned implements. The copper shell has bars or slots for slag retention and the steel shell has means for mounting the box into the furnace wall. The copper shell is formed into a curved U-shape for preventing cracking due to thermal mechanical stress and to raise the natural frequency of the panel to resist vibration which can also cause cracking.

A water cooled box to be installed in the side wall of a metal making furnace to hold and protect implements such as a burner, a lance, or a material (i.e., carbon or lime) injection device. The box preferably comprises a copper outer shell and a steel inner shell liner welded together, whereby a chamber is formed through which cooling water passes. The box further comprises an inlet and outlet for the water flow and a plurality of conduit passages between the copper and steel shells for mounting the aforementioned implements. The copper shell has bars or slots for slag retention and the steel shell has means for mounting the box into the furnace wall. The copper shell is formed into a curved U-shape for preventing cracking due to thermal mechanical stress and to raise the natural frequency of the panel to resist vibration which can also cause cracking.

A water cooled box to be installed in the side wall of a metal making furnace to hold and protect implements such as a burner, a lance, or a material (i.e., carbon or lime) injection device. The box preferably comprises a copper outer shell and a steel inner shell liner welded together, whereby a chamber is formed through which cooling water passes. The box further comprises an inlet and outlet for the water flow and a plurality of conduit passages between the copper and steel shells for mounting the aforementioned implements. The copper shell has bars or slots for slag retention and the steel shell has means for mounting the box into the furnace wall. The copper shell is formed into a curved U-shape for preventing cracking due to thermal mechanical stress and to raise the natural frequency of the panel to resist vibration which can also cause cracking.

A heat treatment furnace disclosed herein may include: a heat treatment unit configured to heat-treat an object; a cooling unit configured to cool the object heat-treated by the heat treatment unit; and a conveyor configured to convey the object in the heat treatment unit and the cooling unit. The cooling unit may include a housing, wherein the housing is disposed below a conveyance path on which the object is conveyed by the conveyor and configured to cool the object being conveyed by the conveyor by liquid flowing inside the housing. The housing may include an upper plate facing the object being conveyed by the conveyor. The upper plate may be tilted so that gas stays at a predetermined portion of the housing while the liquid is flowing in the housing.