JP3497339B2 - Heating method for ultra-thin metal strip - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for heating an ultrathin metal strip.

[0002]

2. Description of the Related Art As a heating method for an ultra-thin metal strip, the surface temperature of the laminate roll and the surface temperature of the metal strip after lamination (after coating with the resin film) are used when the resin film is pressure-bonded to the pre-heated metal strip with a laminate roll. Japanese Patent Application Laid-Open No. 5-57860 discloses that when the heating of the metal strip is uneven, the temperature control mechanism on the entrance side of the laminating roll is instructed to uniformly heat the metal strip.

[0003]

As described above, in controlling the temperature of the metal strip, the temperature of the metal strip before lamination is uniformly heated based on the surface temperature of the laminating roll or the temperature of the resin-coated metal strip after lamination. A resin coating having an inhomogeneous crystallinity is generated, which causes problems such as deterioration of corrosion resistance and adhesion of the resin film. The method of the present invention has been made in order to advantageously solve such a problem, in the preheating of the metal strip, by uniformly heating by heating the low temperature portion by the heating roll in the preheating zone, the temperature nonuniformity of the metal strip. It is an object of the present invention to provide a method for heating an ultrathin metal strip that reduces the yield of products due to the above.

[0004]

The method of the present invention is characterized in that a metal strip is introduced into a preheating zone, heated by bringing it into contact with a heating roll, and a low temperature zone of the metal strip immediately after heating is heated in the preheating zone. The method for heating an ultrathin metal strip is characterized by uniform heating.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The heating of an ultrathin metal strip (thickness 0.13 to 0.38 mm) in a preheating zone (preheating device) is generally performed by using a plurality of electric wires in the width direction of the heating roll 1 as shown in FIG. The heating roll 1 for heating the surface of the roll 1 through the uniform heating plates 3 and 3a provided with the induction heating bodies 2, 2a and 2b is disposed in contact with the front and back surfaces of the metal strip and is passed through the metal strip to continuously form the metal strip. It is to heat. In heating the metal strip by the heating roll 1 as described above, as compared with the electric induction heating members 2, 2a, 2b,
The temperature of the surface of the heating roll 1 in the space 4 becomes low. Therefore, the heating roll 1 of the metal band to be heated, the electric induction heating elements 2, 2
In the a and 2b interval portion 4 abutting portions, a lower temperature portion than the target heating temperature is continuously generated in the metal strip rolling direction (longitudinal direction), which causes quality deterioration.

However, in the preheating zone as described above, the low temperature zone of the metal zone is heated to the target temperature in the preheating zone immediately after the heating of the metal strip by the heating roll to uniformly heat (equalize the temperature). As a heating mode, it is preferable to heat with a flameless non-contact heating body (source) so that an oxide film or the like is not formed on the surface of the metal strip. As a heating method for such a low temperature zone of the metal strip, for example, an electric panel (plate-shaped) heater is movably arranged in the metal strip width direction, and the metal strip temperature after heating by the heating roll between the heating roll and the electric panel heater is performed. Is measured, moved to a low temperature part, heated and uniformly heated. The heating temperature of the ultra-thin metal band heated in this way varies slightly depending on the resin film to be coated, but at 150 to 330 ° C., the low temperature part becomes 0.1 to 2.0 ° C. low. It is possible to reliably raise the temperature of the low temperature portion and uniformly heat the low temperature portion. By using, for example, a stainless steel plate as the electric panel heater, the heat reflection function is exhibited to improve the heat efficiency, and precise temperature control can be performed.

As a method for heating the ultrathin metal strip according to the method of the present invention, in addition to the metal strip for resin coating as described above, for example, metal strip heating such as metal-based coating (zinc-based, chromium-based, tin-based) is used. Can be applied to the method.

Next, an example of the method of the present invention will be described with reference to the drawings. In FIG. 1, heating rolls 1 and 1a in which a metal band 5 is internally provided with an electric induction heating body in a preheating region 6 (preheating device)
Heating by. Then, the temperature of the metal strip 5 is measured with a temperature measuring device 7 (radiation thermometer or the like), and the low temperature heating portion of the metal strip 5 is placed in the preheating zone 6 immediately below the heating rolls 1 and 1a. After heating the metal strip 5 uniformly by heating it with 8a, it is guided between the laminating rolls 9 and 9a, and at the same time, the resin films 10 and 10a are laminated with the laminating roll 9,
The metal strip 5 between 9a is introduced into the front and back surfaces of the metal strip 5 for thermocompression bonding, and then immersed in water in the cooling device 11 to be cooled to obtain a resin-coated metal strip. It is preferable to dispose the heating rolls 1b and 1c immediately below the electric panel heaters 8 and 8a in the preheating region 6 because uniform heating can be achieved.

As described above, the result obtained by measuring the entire width of the metal strip 5 heated by the heating rolls 1 and 1a by the temperature measuring device 7 is shown in FIG. Necessary for calculating the amount of temperature rise from the temperature difference and moving the electric panel heaters 8 and 8a to the low temperature part of the metal strip through the position controller 14 via the controller 13 and at the same time raising the temperature to the energization adjuster 15. The electric panel heaters 8 and 8a are energized by instructing a proper energization amount. By such heating, the metal strip 5 is uniformly heated in the preheating zone 6, and when laminating the resin films 10 and 10a, the resin strips 10 and 10a can be always laminated to the uniformly heated metal strip 5. The crystallinity (biaxial orientation) of the coating resin can be made uniform over the entire width of the metal strip 5, and the quality stability such as adhesion and corrosion resistance can be improved.

[0010]

EXAMPLES Next, examples of the method of the present invention will be given. 1) Metal strip (steel strip): thickness 0.18 mm, width 1048 m
m. 2) Heating roll: diameter 600 mm, surface temperature 235 ° C. 3) Electric panel heater: length 50 mm, heating temperature 30
0 ° C, distance 40mm from metal strip. 4) Resin film: PET (polyethylene terephthalate), thickness 25 μm, preheating temperature 160 ° C. 5) Laminating roll: Surface temperature 90 ° C, diameter 520m
m. 6) Distance between laminating roll and cooling water: 3.2 m. In this manner, the resin film was laminated on the metal strip while heating the low temperature portion of the metal strip by the electric panel heater to uniformly heat the metal strip. As shown in Examples 1 and 2 in Table 1 below, the width direction was measured. The crystallinity could be adjusted to be extremely uniform. In addition, the yield did not decrease due to the poor crystallinity of the coating resin layer due to the occurrence of the low temperature portion of the metal strip.

[0011]

[Table 1]

Note 1: Resin crystallinity is the biaxial orientation of the resin layer of the resin-coated metal strip after thermocompression bonding of the resin film to the metal strip and cooling. The end is the resin coated metal band width direction end (both ends)
30 mm, the middle part is 1 / of the total width in the width direction of the resin-coated metal
4, 3/4 vicinity, the central part is the central part excluding both ends and the middle part. The values of the resin crystallinity of the middle portion and the central portion are relative values when the end portion is 1, and show the deviation of the resin crystallinity in the width direction.

[0013]

According to the method of the present invention, the crystallinity (biaxial orientation) of the resin layer of the resin-coated metal strip (plate) can be made uniform, and the quality can be improved. Further, since the metal strip is uniformly heated in the preheating region, excellent effects such as high thermal efficiency and precise temperature control can be obtained.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the method of the present invention.

FIG. 2 is a front view showing an embodiment of the method of the present invention.

FIG. 3 is a cross section of a heating roll.

Front page continuation (72) Inventor Koichi Nishizawa 5-3 Tokai-cho, Tokai-shi, Aichi Pref.Nippon Steel Works, Ltd. (72) Masaaki Mori 5-3 Tokai-cho, Tokai-shi, Aichi Shin Nippon Steel Nagoya Steel Co., Ltd. (56) Reference JP-A-7-97634 (JP, A) JP-A-5-57860 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C21D 9/56 C21D 1/34

Claims (3)

(57) [Claims] 1. An ultrathin metal strip characterized in that a metal strip is introduced into a preheating zone, brought into contact with a heating roll for heating, and a low temperature zone of the metal strip immediately after heating is heated in the preheating zone for uniform heating. Heating method. 2. The method for heating an ultrathin metal strip according to claim 1, wherein the low temperature zone of the metal strip is heated by an electric panel heater in a preheating zone. 3. The method for heating an ultrathin metal strip according to claim 1, wherein the resin coating metal strip is uniformly heated.