JPS5881915A - Roll in furnace - Google Patents

Abstract

PURPOSE:To prevent the occurrence of pick-up and to elevate cooling effeciency by a method in which the roll with cooling part in the center is composed of an inner cylinder and an outer cylinder, and the predetermined filler is filled into the predetermined gap between the inner cylinder and the outer cylinder. CONSTITUTION:The titled roll is composed of an inner cylinder 2 having a passage 3 through which cooling medium passes in its center and an outer cylinder 1 having a gap of 2-4mm. between the inner cylinder 2 and the outer cylinder 1. The gap is filled with filler with the heat conductivity of 0.9-1kcal/m.h. deg.C. By this roll, the cooling capacity of the inner part of the cylinder 2 is fully transmitted to the outer part of the cylinder 1, and the surface temperature of the outer cylinder 1 is lowered. Consequently, the occurrence of pick-up on the roll surface is prevented and the defect on the product is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a furnace roll installed in a heating furnace, etc., and aims to prevent the pickup generation of four-wheel surface and to significantly reduce the heat loss of cooling water. It is well known that a continuous annealing furnace, etc., has multiple in-furnace holes installed in order to meander the strip in the vertical direction. In general, indirect water-cooling systems and direct water-cooling systems are known for this reactor internal roll, but each has its advantages and disadvantages.In other words, an indirect water-cooled roll consists of a cylinder and an outer cylinder, and the cooling medium is placed in the center of the roll. It has a structure in which a flow path tube is formed, and the inner cylinder and outer cylinder are hollow, creating a gas (air) layer.

The thermal conductivity of this gas layer is very small, 0.02~0.0
5 Kaa//n, h, °C, the cooling capacity inside the cylinder is not sufficiently conducted to the outside of the outer cylinder, and the roll surface temperature is approximately the same as the furnace atmosphere temperature, or at most 100 °C lower. Direct water-cooled rolls simply use the hollow part of the roll as a cooling medium flow path, which creates pickups on the roll surface and causes defects on the product surface. Heat conduction is carried out by the pipe wall thickness of the roll material. For this reason, the roll surface temperature is 150 to 200°C, which is effective in preventing the generation of pickup, but the heat loss of the cooling water is 1'&X1.
G'-20 configured and p
- In a furnace rail having a cooling medium passage tube in the center of the rail, if the distance between the inner cylinder and the outer cylinder is 1 kg m to 4 cm, the hollow part has a thermal conductivity of 0.9 to 1. OKea
Filling with a filler of t/m, h, and °C.

The purpose is to prevent the generation of pick-up on the surface of the cylindrical roll and to reduce heat loss from the inside of the furnace.

Hereinafter, a specific example of the present invention will be explained. First, Fig. 1 shows a cross-sectional view of the roll body of the present WAK.
o), the roll is composed of an outer cylinder (1) and a cylinder (2), and the central part of the inner cylinder (2) is used as a cooling medium (usually water) passage (3), and the outer cylinder (1) and inner cylinder (2)
The filler (4) has a thermal conductivity of o, e to Lo.
Kca4/a, h, C granular, lumpy refractory # or metal material is used, and specific examples include Ka castable, p, etc. In addition, in the present invention, the outer cylinder (1) and the inner cylinder (2) O distance (to is limited to 3-4 mK.

To explain this based on Fig. 5, as mentioned above, the filler (
The most popular and easily available materials for 4) are refractories such as castable and P, and their thermal conductivity is o, e.
~1. OKca&/m, h, C.

On the other hand, it is preferable to maintain the roll surface temperature between 400°C and WOO°C, that is, above 600°C, pick-up occurs, and below 400°C, heat loss due to heat loss is large. Roll surface temperature (to)! 4
In order to maintain the temperature between 00°C and 600°C, the distance between the outer cylinder (1) and the cylinder (2) (4) must be t-2~4 as shown in Figure 5.
mK is limited to %/A.Next, in order to confirm the effective column tube of the present invention, Figure 8 shows the amount of heat lost when using the in-furnace roll tube according to the present invention. A comparison was made with a conventional indirect roll (Figure 3) and a direct water-cooled roll (Figure 4). In addition, in the roll of the present invention, the distance between the outer cylinder and the inner cylinder is (4) tB■, and the thermal conductivity of the filler is 1.
．． OKcaj/n, h, tl: use refractories, t
fc#! Figure 4 O*ta water-cooled roll is (A) ¥cBwr,
The hollow part was filled with gas xf having a thermal conductivity of 0.02 Kcat/m, h2, and C (1200°C in both cases).

As is clear from the above experimental examples, in the conventional indirect water-cooled roll, the roll surface temperature becomes as high as 1050'cK and pickup occurs, and in the 1 m water-cooled roll, the loss of heat from the cooling water is large and uneconomical. On the other hand, with the present invention V4, the surface temperature t of the P-ru is kept at the optimum temperature of 400C to sooC (500C in the original intention), so no pickup is generated and the heat loss of the cooling water is reduced by 5x. lG' ~ lOX h
O' Ke*t/Hr, you can save a lot of money and save energy.

Suitable as the inside of a 4IK direct-fired furnace.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a roll in a furnace according to the present invention, and FIGS. 2, 3, and 4 are optical graphs showing the temperature at each part in the roll thickness direction. 111411 is a conventional indirect roll, 111411 is a conventional direct water-cooled roll, and Figure S is a graph showing the optimal distance between the outer cylinder and the inner cylinder.In the figure, (1) is the outer cylinder, (2) is the cylinder, (3) indicates the cooling medium passage, and (4) indicates the filler material. Patent applicant Nippon Kokan Co., Ltd. Inventor Tadao Hiroshi Hakama wearer Yukihiro Hiro
Figure 1 2 3 4 5 6 7 8 9 10 External Portrait Inner Cylinder f) Penalty (mm) 0 20 40 60 80 No.\-sn-y
4th surface thickness (mm) 0 20 40
60 80 bar roll thickness (mm) Figure 4

Claims (1)

[Claims] The furnace roll Kl is composed of an inner cylinder and an outer cylinder, and has a cooling medium flow path in the center of the roll! The distance between the inner cylinder and the outer cylinder is 2 to 4 cm, and the hollow part has a thermal conductivity of 0.9 to 1. OKCAJ/RQ, H, C filler is filled with t4I mold.