A heat treatment device includes: a heat treatment chamber which accommodates an object to be treated; a cooling gas supply unit which supplies a cooling gas into the heat treatment chamber; a cooling gas circulation unit which circulates the cooling gas in the heat treatment chamber; and a gas purge unit which gas-purges, with an inert gas, a portion in which there is a possibility of mixing of the cooling gas supplied into the heat treatment chamber and an oxygen gas, in which the cooling gas supply unit supplies a hydrogen gas into the heat treatment chamber as the cooling gas.

A heat treatment device includes: a heat treatment chamber which accommodates an object to be treated; a cooling gas supply unit which supplies a cooling gas into the heat treatment chamber; a cooling gas circulation unit which circulates the cooling gas in the heat treatment chamber; and a gas purge unit which gas-purges, with an inert gas, a portion in which there is a possibility of mixing of the cooling gas supplied into the heat treatment chamber and an oxygen gas, in which the cooling gas supply unit supplies a hydrogen gas into the heat treatment chamber as the cooling gas.

The present invention provides a nitriding treatment method for forming a compound layer of ε phase (Fe.sub.2-3N) and γ′ phase (Fe.sub.4N) iron nitride excellent in wear durability in a steel material, from which a sliding member is formed, by short treatment, with a high thermal efficiency, with a reduced amount of used nitriding gas, and with a low environmental load. The nitriding treatment method of the present invention includes heating a sliding member made of a steel material at a temperature of 600° C. to 700° C. for a time of 1 to 25 minutes under an atmosphere of nitriding gas through high frequency induction heating or resistive heating, to form a compound layer of ε phase (Fe.sub.2-3N) and γ′ phase (Fe.sub.4N) iron nitride, the compound layer having a nitrogen content of higher than 4.5%, in a surface layer portion of the sliding member.

The present description concerns a gas cooling cell, comprising: a chamber; at least one opening in the chamber, of access to a treatment space internal to the chamber; at least one door for closing the opening; and a system (4), internal to the chamber, comprising at least one wall (42) mobile between a first position where this wall forms a screen between the opening and the treatment space, and a second position where said wall clears the access to the treatment space from the opening.

The present description concerns a gas cooling cell, comprising: a chamber; at least one opening in the chamber, of access to a treatment space internal to the chamber; at least one door for closing the opening; and a system (4), internal to the chamber, comprising at least one wall (42) mobile between a first position where this wall forms a screen between the opening and the treatment space, and a second position where said wall clears the access to the treatment space from the opening.

The present invention enables quick cooling of steam-treated objects and thus reduces the manufacturing time of steam-treated products such as black coated steel sheets. The present invention provides a method for manufacturing steam-treated products, which involves a steam treatment step that introduces steam into a closed container (10) containing a treatment object (1) and brings the treatment object (1) into contact with the steam, and a treated object cooling step that cools the object (1) treated with steam in the steam treatment step, wherein said treated object cooling step introduces coolant gas into said closed container (10), brings said treated object (1) into contact with the coolant gas, and discharges the introduced coolant gas from said closed container (10).

The present invention enables quick cooling of steam-treated objects and thus reduces the manufacturing time of steam-treated products such as black coated steel sheets. The present invention provides a method for manufacturing steam-treated products, which involves a steam treatment step that introduces steam into a closed container (10) containing a treatment object (1) and brings the treatment object (1) into contact with the steam, and a treated object cooling step that cools the object (1) treated with steam in the steam treatment step, wherein said treated object cooling step introduces coolant gas into said closed container (10), brings said treated object (1) into contact with the coolant gas, and discharges the introduced coolant gas from said closed container (10).

Direct flame preheating section for continuous metal strip processing lines, comprising a connecting zone between an active zone provided with burners capable of operating in “no flame” mode and a recuperative zone for preheating the strip by exchange with combustion fumes originating from the active zone, the connecting zone having chambers capable of orienting the flow of fumes such that they flow head-on relative to the strip when exiting the active zone and entering the recuperative zone depending on the direction of flow of the fumes.

Direct flame preheating section for continuous metal strip processing lines, comprising a connecting zone between an active zone provided with burners capable of operating in “no flame” mode and a recuperative zone for preheating the strip by exchange with combustion fumes originating from the active zone, the connecting zone having chambers capable of orienting the flow of fumes such that they flow head-on relative to the strip when exiting the active zone and entering the recuperative zone depending on the direction of flow of the fumes.

The invention relates to a chamber (1) for the controlled oxidation of metal strips in a furnace for annealing a continuous production line of strips which are hot-coated, for example by galvanisation, the oxidation chamber allowing the oxidation of the metal strips by means of an oxidising gas injected on at least one of the faces of a strip (15), the oxidation chamber comprising oxidation portions (17) extending over the width and/or length thereof, each portion comprising at least one blow opening (4) and at least one suction opening (5) between which an oxidising gas circulates, each portion being controllable in a different way so as to adjust the oxidation induced on the strip over the width and length of the oxidation chamber.