A cooling plate for a metallurgical furnace comprising a body (12) with a front face (18) and an opposite rear face (20), the body having at least one coolant channel (14) therein; the front face (18) being turned towards the furnace interior and preferably comprises alternating ribs (22) and grooves (24). The cooling plate includes wear detection means comprising: a plurality of closed pressure chambers (26, 28) distributed at different locations in said body, said pressure chambers being positioned at predetermined depths below the front face (18) of said body; and a pressure sensor (30) associated with each pressure chamber (26, 28) in order to detect a deviation from a reference pressure inside said pressure chamber when the latter becomes open due to wear out of said body.

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.