JPS6216708B2 - - Google Patents

Description

Detailed Description of the Invention Generally, coated steel plates such as rolled steel plates and plated steel plates are coated after being subjected to a prescribed pretreatment, and coated steel plates that are further baked are not heat-treated in advance. However, during the baking process, the material is held at high temperatures for a certain period of time, which causes the yield point to recover and age hardens.

In order to eliminate this drawback, skin pass processing or leveler processing is performed after the baking process.

The present invention relates to a method for manufacturing the above-mentioned baking-painted steel sheet, and it is possible to easily maintain the condition of the painted coating surface even if the width, thickness, material, etc. of the painted original sheet (hereinafter referred to as original sheet conditions) are different. This manufacturing method aims to achieve a uniform finish.

As a result of various studies to achieve the above object, the present invention has developed a method of skin pass processing performed after baking treatment, that is, a surface shape of the skin pass roll that improves the smoothness, gloss, and matte finish (dull finish) of the coating film surface. The focus is on the fact that it greatly affects the uniformity of the state. In other words, as shown in Fig. 1, the axis of the skin pass roll 1 is deflected by the temper rolling load when the steel plate 2 is passed through, but if this original plate condition changes, the deflection state of the skin pass rolls will change. If not corrected properly, pressure will not be applied uniformly across the width of the paint film surface, which may affect the smoothness of the paint film surface, the uniformity of the gloss or matte finish (dull finish), or the adhesion of the paint film to the original surface. The uniformity of gender deteriorates.

The present invention solves the above-mentioned problems, and has a variable crown structure in which a steel plate is baked and painted, and then hydraulic pressure is generated inside the roll to change the surface shape of the roll body in the axial direction. This is a method for manufacturing a baked-coated steel sheet having a uniform coating surface, which is characterized by skin-passing using a skin-passing device equipped with rolls.

Next, embodiments of the present invention will be described based on the drawings. In the manufacturing process, as shown in FIG. 2, a steel plate 10 that has been pretreated and then coated with a paint such as polyester resin, acrylic resin, or fluororesin is placed in a baking furnace 11.
The plate is baked to a temperature of 180°C to 250°C, and then cooled to near room temperature in the cooling section 12. This coating thickness is 10
~30μ.

Next, the material is passed through bridle rolls 13, 13 and subjected to surface conditioning and tempering in a skin pass device 15 of the present invention comprising skin pass rolls 14, 14'. At this time, the elongation rate of the steel plate should be in the range of 0.1 to 3%.

Next, it is passed through bridle rolls 16, 16, and the shape is corrected and tempered with a tension leveler 17.
Winding is performed through the bridle rolls 18, 18. Tension is applied to the steel plate 10 by a roll above the bridle rolls 18, 18. Also, in the tension leveler, the elongation rate of the steel plate should be in the range of 0.1 to 2.5%.

The skin pass roll 14' below the skin pass device of the present invention is a variable crown roll that generates hydraulic pressure to change the surface shape of the roll body in the axial direction, and is similar to the roll shown in FIGS. 3 to 6. The shaft 2 is attached to the cylindrical shell 20 which is the body of the
1 is inserted concentrically, the shaft 2 is connected to both ends of the shell 20 via bearings 22, 22.
1 is rotatably supported, and a cylindrical intermediate chamber is formed between opposing peripheral surfaces of both 20 and 21. Then, this intermediate chamber is divided into approximately two equal parts vertically in the circumferential direction, and the upper intermediate chamber portion is provided with a sealing mechanism 2 in which both ends in the circumferential direction and both ends in the axial direction are provided on the shaft 21.
3 and 24 are also formed in a pressurized chamber 25 which is shielded and sealed. The shaft 21 is connected to an oil feeding mechanism (not shown), and has a press-fit passage 26 communicating with the pressurizing chamber 25 and an oil drain passage 2 communicating with the oil drain chamber 27.
8 is formed.

As shown in FIGS. 4 and 5, the sealing mechanism 23 has one end of each sealing body 29, 29 extending in the axial direction supported by a step 21a formed on the shaft 21, and the other end supported by a plate spring. 30 is disposed in pressure contact with the inner peripheral surface of the shell 20,
Each seal body 29, 29 is
is pressed against the inner peripheral surface of the shell to form a seal.

As shown in FIGS. 3 and 6, the sealing mechanism 24 includes a groove 31 formed in the end surface of the shaft 21.
A seal body 3 extends circumferentially along the pressurizing chamber 25.
2 is slidably inserted and supported in the axial direction, and the seal body 3
2 is brought into pressure contact with the seal receiving surface 34 via a spring 33, and the seal body 32 is configured to be pressed against the seal receiving surface 34 through the communication hole 35 by the hydraulic pressure in the pressurizing chamber 25.

The original boards to be painted come in various widths, thicknesses, and materials. Regarding board width, 711mm, 760mm914
mm, 1000mm, 1100mm, 1230mm, etc., and depending on the width, the deflection in the axial direction of the skin pass roll surface shown in Figure 1 differs. Regarding plate thickness, various thicknesses are coated between 0.16 mm and 3.0 mm, but since the skin pass load differs depending on the plate thickness, if the plate thickness changes, the axial deflection of the skin pass roll surface will decrease. Change. The plate material is SAE1008 to SAE1050, and is cold-rolled or galvanized and painted. However, the skin pass load differs depending on the plate material, and the axial deflection of the skin pass roll surface differs depending on the plate material. .

The axial deflection of the skin pass roll surface, that is, the deformation of the axial surface shape of the roll body, is solved by using the hydraulic skin pass roll 14', and uniform rolling force is applied to the painted steel plate. . That is, as shown in FIG. 7, hydraulic pressure is generated in the hydraulic chamber 25 of the hydraulic skin pass roll 14', and the surface shape of the roll body surface 140 in the axial direction is bent from a state shown by a solid line to a state shown by a dotted line. do. As a result, the painted steel plate is rolled down uniformly in the width direction.

In addition, only the roll on the skin pass device or the top,
The lower roll may also be the hydraulic skin pass roll.

Next, the effects of the present invention will be listed.

(1) By using the skin pass roll according to the present invention, the coated steel plate is rolled down uniformly in the width direction, and force is applied uniformly to the coating film surface, improving the gloss and smoothness of the coating film surface. A uniform and beautiful coated steel plate can be obtained.

(2) Also, since the skin pass effect is made even, it is possible to eliminate the occurrence of stretching, warping, etc. of the painted steel plate caused by improper skin passes.
Furthermore, workability is improved, and when tension leveler processing is performed after skin pass, the appearance of leveler breaks (wrinkles caused by leveler processing) can be suppressed and a smooth coated steel plate can be obtained.

(3) Even if the original sheet conditions change, it can be handled by simply adjusting the oil pressure in the hydraulic chamber 25, so there is no need to prepare several rolls depending on the original sheet conditions, and it is possible to prevent the rolls from bending. This eliminates the need for a mechanism such as a backup roll, which reduces equipment costs and running costs.

Moreover, more appropriate and immediate adjustments can be made.

(4) Depending on the paint, matte paints may be difficult to work with and may cause uneven gloss. In this case, by using the upper roll 14 of the hydraulic skin pass as a dull roll, a uniform matte finish (matte means 30% or less at 60° specular reflectance) in the width direction, regardless of the original plate conditions. can do.

In addition, the hydraulic skin pass roll 14' is the 8th to 1st roll.
A similar effect is produced even with rolls having different structures as shown in FIG.

Figure 8 shows the inner surface of the shell 200 and the shaft 210.
This is a roll in which the gap between the outer circumferential surfaces of the roll has a circumferential hydraulic chamber 250.

FIG. 9 shows a roll in which the roll is hollow and the entire hollow portion is used as a hydraulic chamber 250'.

FIG. 10 shows a roll in which a hydraulic chamber 250'' is provided in a shaft 210 and a piston-shaped pressing member 40 is pressed against the inner surface of a shell 200.

[Brief explanation of the drawing]

FIG. 1 is a front view for explaining the state of the skin pass roll during sheet passing. 2 to 10 show an embodiment of the present invention, in which FIG. 2 is a partial side view of a coating line, FIG. 3 is a longitudinal sectional front view of a variable crown roll, and FIG. 5 is an enlarged sectional view of the seal portion in FIG. 4, FIG. 6 is an enlarged sectional view of the end seal portion in FIG. 3, and FIG. 7 is a front view for explaining the adjustment state. It is. 8th
Figures 1 to 10 are longitudinal sectional side views of variable crown rolls of other embodiments. Explanation of symbols, 10... Steel plate, 14', 140'... Crown variable roll, 15... Skin pass device, 2
0,200...roll body (shell), 25,25
0,250',250''...Hydraulic chamber.

Claims (1)

[Claims] 1 A uniform coating characterized in that a steel plate is baked and coated, and then skin-passed using a skin-pass device equipped with a variable roll roll that generates hydraulic pressure inside the roll to change the surface shape of the roll body in the axial direction. A method for producing a baked painted steel plate having a coating surface.