JPH05171299A - Method and apparatus for heat-treating metal strip - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a heat treatment method and apparatus for a metal strip, which can shorten the cooling zone as a whole and increase the heat treatment efficiency. [Structure] A heat treatment method for a metal strip according to the present invention comprises:
The metal strip which is heated and gradually cooled by gas cooling is characterized by being rapidly cooled by mist cooling using an oxygen-free gas as a spray medium, and the heat treatment apparatus for metal strips according to the present invention has a cooling zone as an annealing zone. It is divided into a quenching zone, and the quenching zone is equipped with a chamber having a plurality of atomizer mechanisms at positions sandwiching the metal strip after slow cooling from both sides, and the chamber is provided with the metal strip after slow cooling. It is characterized in that compressed oxygen-free gas for cooling the mist and cooling water are supplied through the atomizer mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment method and apparatus for metal strips, and more particularly to a heat treatment method and apparatus effective for bright annealing copper and copper alloy strips.

[0002]

2. Description of the Related Art Conventionally, as a heat treatment method for a metal strip as described above, a heat treatment apparatus provided with a heating zone and a cooling zone connected to the downstream side has been used, and the metal strip is heated in the reducing zone under a reducing atmosphere. After heating, the metal strip after heating is gradually cooled by gas cooling in a reducing atmosphere in a cooling zone (for example, JP-B-60-16499). However, such a conventional method requires a long cooling zone in order to gradually cool the metal strip after heating in the cooling zone exclusively by gas cooling,
The disadvantage is that a long footprint is required for the cooling zone.

Therefore, conventionally, a heat treatment apparatus in which a cooling zone is divided into a slow cooling zone and a rapid cooling zone is used, and in the slow cooling zone, the metal strip after heating is gradually cooled by gas cooling in a reducing atmosphere, and then the rapid cooling zone. It is also practiced to immerse the gradually stripped metal strip in a water tank to quench it. However, such a conventional method has an advantage that the cooling zone as a whole can be shortened by an amount corresponding to a part of the cooling zone being a quenching zone.
Since a water film is formed on the surface of the induction roll mounted near the water tank, and the metal strip slides and meanders due to the water film, the transport speed cannot be increased, and the heat treatment efficiency is eventually increased. There is a drawback that you cannot do it.

[0004]

The problem to be solved by the present invention is that the conventional method requires a long cooling zone.
Alternatively, the heat treatment efficiency of the metal strip cannot be increased.

[0005]

SUMMARY OF THE INVENTION The present invention, however, provides a method for heat treating a metal strip which heats and cools the metal strip under a reducing atmosphere, wherein the metal strip heated and gradually cooled by gas cooling is supplied with an oxygen-free gas. A heat treatment method for a metal strip characterized by rapidly cooling by mist cooling using a spray medium, and a heat treatment apparatus for a metal strip comprising a heating zone under a reducing atmosphere and a cooling zone connected to the downstream side of the heating zone, The strip is divided into a slow cooling zone and a quenching zone, and the quenching zone is equipped with a chamber having a plurality of atomizer mechanisms at positions sandwiching the metal strip after the slow cooling, and the chamber is provided with the slow cooling zone. Compressed oxygen-free gas for cooling the metal strip afterwards through the atomizer mechanism to mist and cooling water are supplied. According to the heat treatment apparatus of the metal strip.

In the present invention, a heat treatment apparatus having a heating zone and a cooling zone connected to the downstream side of the heating zone, and the cooling zone is divided into a slow cooling zone and a quenching zone connected to the downstream side is used. To do. The heating zone is equipped with a chamber having a plurality of nozzles at positions sandwiching continuously conveyed metal strips from both sides, and is also equipped with a direct fire burner, a radiant tube, a heater and the like as a heating source. The heating zone is maintained under a reducing atmosphere, and the heating reducing atmosphere gas is injected from the chamber through the nozzle onto both sides of the metal strip to bring the metal strip to a predetermined temperature, e.g. for strips of copper and copper alloys. In this case, it is heated to about 600 to 750 ° C.

The slow cooling zone is equipped with a chamber having a plurality of nozzles at positions sandwiching a heated and continuously conveyed metal strip from both sides, and a cooler as a cooling source. The slow cooling zone is maintained in a reducing atmosphere, and the cooling reducing atmosphere gas is injected from the chamber through the nozzle onto both sides of the heated metal strip to bring the metal strip to a predetermined temperature, for example, copper and copper. In the case of an alloy strip, it is slowly cooled to about 200 ° C.

The quenching zone is equipped with a chamber having a plurality of atomizer mechanisms at positions sandwiching the gradually-cooled metal strip that is continuously conveyed from both sides, and the chamber is provided with the slowly-cooled metal strip through the atomizer mechanism. Compressed oxygen-free gas for cooling the mist and cooling water are supplied. As a result, the quenching zone is maintained in an oxygen-free atmosphere, and mist generated from the chamber through the atomizer mechanism and having a particle size of about 10 to 100 μm is sprayed onto both surfaces of the metal strip after the slow cooling. To a given temperature, for example 60 in the case of copper and copper alloy strips.
Quench to about ℃.

In the quenching zone, the oxygen-free gas supplied to the atomizer mechanism of the chamber to generate mist is an inert gas such as nitrogen gas or argon gas, or a mixed gas such as hydrogen gas or carbon monoxide gas. A reducing gas is used. In the heating zone, when a direct-burning burner is used as a heating source, the atmosphere of the heating zone is burned in a rich fuel gas in order to maintain the reducing atmosphere. It is advantageous to use it as gas. In this case, the combustion exhaust gas is cooled by a cooler, further compressed by a compressor, and then supplied to the atomizer mechanism of the chamber in the quenching zone.

[0010]

According to the present invention, the cooling zone is divided into the slow cooling zone and the quenching zone, the heated metal strip is gradually cooled by gas cooling in the slow cooling zone, and the metal strip after the slow cooling is further quenched. Since the material is rapidly cooled by mist cooling, the cooling zone can be shortened to about 1/2 as a whole as compared with the conventional method in which the metal strip after heating is gradually cooled in the cooling zone exclusively by gas cooling. Also according to the invention,
The metal strip after gradual cooling is rapidly cooled by mist cooling in the quenching zone, and at this time, by controlling the spray amount and temperature of the mist in relation to the temperature of the metal strip, the metal strip can be so-called dry type rapid cooling. Therefore, the metal strip does not meander by sliding on the surface of the induction roll, and therefore, as compared with the conventional method in which the metal strip after slow cooling is rapidly cooled by immersing it in a water tank in a quenching zone,
The transport speed of the metal strip can be increased, and the heat treatment efficiency can be increased accordingly.

[0011]

1 is a longitudinal longitudinal sectional view schematically showing an embodiment of the present invention, and FIG. 2 is a laterally enlarged partial longitudinal sectional view schematically showing the same embodiment. The heat treatment apparatus 11 has a heating zone 12
And a cooling zone 13 connected to the downstream side thereof,
The cooling zone 13 is divided into a slow cooling zone 14 and a quenching zone 15 connected to the downstream side thereof. The heating zone 12 is equipped with chambers 21 and 22 having a plurality of nozzles (not shown) at positions sandwiching the continuously conveyed metal strip A from above and below, and a plurality of open flame burners 31 as a heating source. .. The open flame burner 31 is burned in a rich fuel gas, and therefore the heating zone 12 is maintained in a reducing atmosphere by the combustion exhaust gas. The heat-reducing combustion exhaust gas is jetted from the chambers 21 and 22 to the upper and lower surfaces of the metal strip A through nozzles (not shown) to heat the metal strip A to a predetermined temperature.

The slow cooling zone 14 is equipped with chambers 23, 24 having a plurality of nozzles (not shown) at positions sandwiching the heated and continuously conveyed metal strip A from above and below,
Also, a cooler (not shown) is equipped as a cooling source.
Reducing gas is supplied to the slow cooling zone 14, and thus the slow cooling zone 14 is maintained in a reducing atmosphere. The metal strip A is gradually cooled to a predetermined temperature by injecting the cooling reducing atmosphere gas from the chambers 23 and 24 to the upper and lower surfaces of the heated metal strip A through a nozzle (not shown).

The quenching zone 15 is equipped with chambers 25 and 26 having a plurality of atomizer mechanisms 41 and 42 at positions sandwiching the continuously conveyed gradually cooled metal strip A from above and below, and the atomizer mechanisms 41 and 42 are provided with the chambers 25 and 26. Is generated in the heating zone 12, is cooled by the cooler 51, and is supplied with the reducing combustion exhaust gas compressed by the compressor 52 and the cooling water. As a result, the quenching zone 15 is maintained in a reducing atmosphere, and the quenching zone 15 moves from the chambers 25 and 26 to the atomizer mechanisms 41 and 4.
Metal strip A after slow cooling of mist generated via 2
The metal strip A is rapidly cooled to a predetermined temperature by spraying the upper and lower surfaces of the metal strip A.

Although the illustrated embodiment is a horizontal heat treatment apparatus, the present invention is not limited to this embodiment, and the present invention can be similarly applied to a vertical heat treatment apparatus.

[0015]

As is apparent from the above, the present invention described above has an effect that the cooling zone can be shortened as a whole and the heat treatment efficiency can be increased in the heat treatment of the metal strip.

[Brief description of drawings]

FIG. 1 is a longitudinal cross-sectional view schematically showing an embodiment of the present invention.

FIG. 2 is a partially enlarged vertical sectional view in a lateral direction schematically showing the same embodiment as FIG.

[Explanation of symbols]

11 ... Heat treatment apparatus, 12 ... Heating zone, 13 ...
Cooling zone, 14 ... Slow cooling zone, 15 ... Quenching zone, 21 ...
26: chamber, 31: open flame burner, 41, 4
2 ... Atomizer mechanism, 51 ... Cooler, 52 ...
・ Compressor, A ... Metal strip

Claims (4)

[Claims] 1. A method of heat treating a metal strip for heating and cooling the metal strip under a reducing atmosphere, wherein the metal strip heated and gradually cooled by gas cooling is rapidly cooled by mist cooling using an oxygen-free gas as a spray medium. A method for heat treating a metal strip, comprising: 2. The heat treatment method for a metal strip according to claim 1, wherein the oxygen-free gas is obtained by cooling combustion exhaust gas generated when the metal strip is heated by an open flame burner. 3. A heat treatment apparatus for a metal strip, comprising a heating zone under a reducing atmosphere and a cooling zone connected to the downstream side of the heating zone, wherein the cooling zone is divided into a slow cooling zone and a rapid cooling zone. The strip is equipped with a chamber having a plurality of atomizer mechanisms at positions sandwiching the metal strip after slow cooling from both sides, and for mist cooling the metal strip after slow cooling in the chamber through the atomizer mechanism. A heat treatment apparatus for a metal strip, characterized in that compressed oxygen-free gas and cooling water are supplied. 4. The heat treatment apparatus for metal strips according to claim 3, wherein the oxygen-free gas is obtained by cooling the combustion exhaust gas of the direct-burning burner in the heating zone.