JPH0315541Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The invention allows a heating medium to circulate inside the device,
The present invention relates to improvements in a threading roll that heats a strip.

[Conventional technology and issues to be solved]

In continuous strip annealing equipment, threading rolls with a heating medium flowing through them are used.For example, the heating medium is used in the heating furnace's threading roll, and the cooling material is used in the quenching furnace's threading roll. The heating medium for each strip is made to flow, and the strip is heated and cooled. However, in heat transfer rolls used for heating, it is normal that both edge parts of the strip are less likely to be heated than the center part in the width direction due to heat dissipation, etc., and this causes variations in temperature distribution in the width direction of the strip. However, it is difficult to obtain uniform material in the width direction.

[Means for solving the problem] The present invention was devised in view of the above-mentioned difficulties, and its purpose is to provide a threading roll that can uniformly heat a strip in its width direction. Therefore, the roll surface roughness is changed so that the roll surface roughness is rougher on the width center side than on the width end side in the width direction of the strip to be passed.

[Effect]

By configuring the roll surface roughness in this way, the thickness of the gas (for example, atmospheric gas) between the roll surface and the strip becomes larger at the center of the width than at both ends in the width direction of the strip. As a result, the thermal conductivity of the central portion, which is easily heated, is reduced, and the strip is heated uniformly in the width direction.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described based on the drawings.

Figures 1A to 1C show embodiments of the present invention, in which the roll surface roughness increases toward the center in the width direction of the roll. Among these, in case A, only the surface part a with a predetermined width at the center is particularly roughened, and in case B, the roughness is applied from the center to both ends, and the roughness is applied to the surface parts b ₁ , b ₂ , b ₂ and b ₃ , b and ₃ , and the roughness of C is changed continuously from the center to both ends.

The roll surface roughness as described above can be selected as appropriate depending on the required heat transfer coefficient.
Generally, a fine roll surface of 15R ₂ μ or less and a rough roll surface of 40R ₂ μ or more are used. For example, if we take the roll shown in Figure 1 A as an example, The roughness of the other parts is about 40 to 50R ₂ μ, and the roughness of other parts is about 10 to 15R ₂ μ.

The present invention adjusts the thickness of the gas interposed between the roll surface and the strip by adjusting the roll surface roughness, but the selection of the roll roughness, that is, the gas thickness, is based on the following formula. It is adjusted accordingly.

Uo=1/〓〓+〓〓+〓〓+〓〓 However, U ₀ : Overall heat transfer coefficient of the roll h _f : Heat transfer coefficient of the heat medium flowing inside the roll λ _r : Thermal conductivity of the roll shell λ _g : Thermal conductivity of gas between the roll surface and the strip λ _s : Thermal conductivity of the strip d _r : Roll shell thickness d _g : Thickness of gas between the roll surface and the strip d _s : Thickness of the strip The idea is to determine the overall heat transfer coefficient U ₀ of the roll in the width direction in order to make it uniform based on the heating situation in the width direction of the strip that is heated by passing through the roll. This determines the gas thickness d _g between the roll surface and the strip, and thus the roll surface roughness.

Figure 2 shows an example of the relationship between the roll surface roughness and the overall heat transfer coefficient U ₀ of the roll.
The figure shows the case where U ₀ =100 when the roll surface roughness R ₂ =40μ.

In addition, the range in which the roll surface roughness is changed in the roll width direction is appropriately selected depending on the width of the strip and its heating condition, but for example, taking the strip in Figure 1A as an example, it is 500 to 800 mm at both ends. It is possible to make the center part have a large roughness, leaving a certain degree of roughness.

Note that the manner in which the roll surface roughness is changed is the first one.
It goes without saying that the invention is not limited to what is shown in the figure.

In the threading roll configured as above, a heating medium flows inside it (inside the roll shell),
The belt-like object (for example, a strip) that is passed through is heated, but during this heating, the thickness of the gas interposed between the roll surface and the belt-like object is greater in areas where the roll surface roughness is greater than in other areas. Become,
As a result, the overall heat transfer coefficient U ₀ in that portion decreases, resulting in poor thermal conductivity. Therefore,
In general, in a heating roll whose ends tend to be difficult to heat, the thermal conductivity of the central part, which is easily heated, is reduced, thereby ensuring uniformity of heating with both ends.

The threading roll of the present invention can be used for strips, as well as belt-shaped objects such as non-ferrous materials, plastics, and paper.

[Effect of idea]

According to the threading roll of the present invention described above, the roll surface roughness is changed in the width direction of the strip to be threaded so that the width center side is rougher than the width end side, so that the center part is rougher than the width end side. reduce the thermal conductivity of the
It has the advantage of being able to uniformly heat the strip in the width direction. For example, when applied to a steel strip, it not only makes the material uniform in the width direction of the strip, but also improves its shape and threadability. It is possible to obtain effects such as restraining.

[Brief explanation of the drawing]

FIGS. 1A to 1C are explanatory diagrams showing an embodiment of the present invention. FIG. 2 shows an example of the relationship between roll surface roughness and its overall heat transfer coefficient.

Claims (1)

[Scope of utility model registration request] In a threading roll that heats the contacting strip by circulating a heating medium inside it, the roll surface roughness is rougher on the width center side than on the width end side in the width direction of the strip being threaded. A threading roll for heat transfer of a band-shaped body, characterized by being changed as follows.