JPS59173226A - Roll for cooling strip - Google Patents

Abstract

PURPOSE:To provide the titled roll capable of uniformly cooling a strip in the width direction thereof, constituted so as to realize low thermal expansion by connecting the outer cylinder and center member of the roll while controlling a roll crown amount through the sleeve of the center member by oil pressure. CONSTITUTION:In a strip cooling roll wherein a strip 5 is wound around the outer peripheral surface of a roll barrel part having a cooling water flowline 2 provided between its center member 3 and its outer cylinder inlaid therewith and cooling water is passed through the above mentioned cooling water flowline 2 from the inlet and outlet W1, W2 thereof to cool the strip 5, the above mentioned outer cylinder 1 and the center member 3 are connected at least at one place or more except both end parts thereof to realize low thermal expansion by holding the connection state even if the outer cylinder 1 is expanded by the heat from the strip 5. In addition, oil pressure is properly applied to the oil pressure chamber 8 formed between the arbor 6 constituting the center member 3 and the sleeve 7 inlaid therewith from an oil pressure source F to control a roll crown amount. By this method, the strip 5 is uniformly cooled in a state closely contacted with roll and product quality can be enhanced.

Description

[Detailed description of the invention] The present invention relates to strip cooling rolls.

More specifically, the present invention relates to a cooling roll that has a small thermal crown and is variable in a range larger than the amount of change in the thermal crown, thereby enabling uniform cooling in the width direction of the roll.

As a method of cooling the strip in a continuous annealing furnace or the like, a cooling method using a roll whose inside is water-cooled is sometimes used.

In this method, in order to improve cooling efficiency, the first
As shown in the figure, cooling water is often circulated spirally inside a thin outer cylinder (shell) 1 at a relatively high flow rate.

Since it is extremely difficult to create the cooling water flow path 2 as shown in FIG. 1 by making holes in a solid roll, the flow path is actually formed using an assembly structure as shown in FIG. 2. That is, the partition member 4 is provided between the outer cylinder 1 and the central member 3 to create a flow path, but as shown in FIG. As shown in Figure CB), the central member 3
There are three types of systems: one is an integrated system, and the other is a system that is a separate part 4 from the outer cylinder 1 and the central member 3 as shown in FIG. 2(C). In any case, in the past, no particular consideration was given to joining the outer cylinder 1 and the center member 3 at the partition part, and the outer cylinder ■ and the center part +A3 were firmly connected only at both ends of the roll body. Only. (The precautions are taken to prevent the precipitation from leaking outside.) For this reason,
Even if the outer cylinder and the center member are in direct contact with each other at the partition part at v, the temperature of the outer cylinder increases by 4 degrees due to the inflow of heat from the slip 1 to the slip, and when the outer cylinder thermally expands, both of them will be ^11. become.

Even if there is a gap between adjacent cooling water passages and the passages are connected, the effect on the flow of cooling water is very small because the gap is small, and there is no problem at all. However, as explained below, thermal expansion creates thermal crown problems. In the following, we will first explain the size and shape of thermal crowns produced in conventional methods, and then explain the problems caused by thermal crowns.

(1) Subordinate - rice shoes
5 Shin] Kuno, -ga type 8 Funai H + 1 + cooling of slip 1 by water cooling roll is ■
From the strip to the roll surface--! ``Heat transfer, ■l:1
-Heat conduction inside the roll outer cylinder, and (2) heat transfer from the inner surface of the roll outer cylinder to the cooling water.

Here, the following formula holds true.

One alpha tile (T2-Tw)... (1) Takokoshi,
” In the two equations, β, slip 1 - to the roll of! (; J angle (degree) αS
Heat transfer coefficient from strip to roll (kca I
/ tri h °C) λ: Thermal conductivity of the roll outer cylinder (kca I / mh
'C) δ: Wall thickness of roll outer cylinder (m) αW, heat transfer coefficient from roll outer cylinder to cooling water (kca
l/mh 'C) Ts: average temperature of the strip during cooling (°C)]゛1
: Roll surface temperature (average of all circumferences) ('C) T2 : Roll outer cylinder inner surface temperature (average of all circumferences) (°C) T-2 Average of cooling water inside the roll 6υ1 degrees (°C) (J) The formula is 1 for threading.
This is the equation for dimensional steady heat conduction.

Since the outer cylinder wall thickness is very small compared to the roll radius and plate width, the heat flow is close to one-dimensional, and a good approximation can be made using equation 4). (1) In Equation 2, the slip wraps around the entire circumference ((l) The fact that the slip is not wrapped around the entire circumference is corrected by a coefficient of β/360, or the roll rotation speed is large and each point on the roll surface is If heating and non-heating are repeated a large number of times within a certain period of time, the temperature inside the outer cylinder will be nearly uniform in the circumferential direction, and the approximation by this coefficient will also be good. Since the heat transfer between the atmospheric gas and the atmospheric gas is very small, in equation ([), if jl((viewing.) 1 and T2 can be found as equations. Therefore, β, αS, λ of equation (1),
Find T1 and T2 by substituting practical values for a continuous annealing furnace for one plate into δ, αW, 'S, and Go4.

I'll see it.

β is 180°.

αS is (2000kcal/% from the actual results since π)
Since we know that the temperature is around b℃, it is 2000kca.
Let it be l/mh'C.

λ is approximately 40 kcal/mb°C for steel and 300 kcal/mb°C for copper, and in both cases, the material must be inspected and inspected.

δ is 10-0.01 m.

α is about 10,000 kcal when calculated using the tube turbulent heat transfer equation (II), assuming a flow rate of about 3 m/sec.
/n(h'C, so use the value.

Nu = 0.023 Re'''Pr'
(El) Nu: Nusselt number, Re: Reynolds number,
Pr nib run number Ts is 550'C, Tw is 50°C.

By substituting the above values]'+:'ij and T2, if the outer cylinder is made of steel, T+ = 180'c,'r, .
-87° (:, and the outer cylinder is i), T+ =
109°C31, -94°C.

Next, the radius of one call is set to 500II11, and the amount of round crowns per half i is determined.

The linear expansion coefficient of steel is 1.1xlO/'C - The linear expansion coefficient of copper is 1.7xlO=/'C, so this (direction) is
Assuming thermal expansion occurs due to the difference between the average temperature of the Jb seal (<=-H□) and the cooling water temperature, the amount of thermal crown per radius is 0461 for steel and 044W for copper-ζ.
It becomes llN. With this calculation method (simplified method and 11.J), the shape of the thermal crown is unknown, and the size is also positive 6'.
We will use the finite element method to accurately determine the shape and size of a normal crown.

The conditions for thermal expansion calculation using the finite element method are as follows.

・Roll body length - 1600 mu ・Plate width ~ 6001 and 12 (lo++ m ・Position inside the plate (temperature distribution at the node -1゛changes linearly from 1 to T2) : Temperature distribution inside the outer cylinder J - Given the condition that the temperature distribution suddenly changes in the plate Mill so that it is more than 50'C (-cooling water average temperature) uniform from the outer surface to the inner surface, the outer cylinder is made of steel. The δI calculation was performed for the case of , and the calculation result was a smooth thermal crown shape as shown in Fig. 3. The following is clear from Fig. 3.

1. The size of the thermal crown almost matches the value obtained by the simple method. Therefore, if you only need to find the size of the thermal crown, a simple method is sufficient.

2. The shape of the thermal crown varies greatly depending on the plate width. If the width of the board is wide, the area near the center will be cra/l-, but if the width of the board is narrow, there will be no flat part.

(2) As mentioned above, in the conventional method, a thermal crown occurs, and it is impossible to cancel it in all cases by using a concave initial crown. With Zunawara Ye/Al Crown, only one type of thermal crown with the size and shape of P can come up, or the size of the thermal crown depends on the plate temperature and winding angle = The method of changing the shape is to change the roll a) (generally by changing the angle), and as shown in Figure 3, the shape changes greatly depending on the width of the plate.In various conditions, the roll can be made almost flat. I can't do anything. For example, if a convex crown is formed on the edge 1-knop, both ends of the s1-i knob (=J
When the roller comes in contact with the roll, the cooling by the amount of g++ will be delayed. (Since metal strips have a large Y/G ratio, poor adhesion is very likely to occur even when the crown size is quite small.) For this reason, uniform cooling in the width direction of the plate is impossible. For this reason, the quality of the abrasive grain is not uniform in the width direction, and C12 is likely to occur.

In order to investigate the occurrence of shape defects, the following experiment was conducted. Water cooling with the same dimensions as the subtraction example described in jtI [:2
We conducted 7θ cooling experiments with various plate thicknesses by additionally installing a roll (+A" IF is steel) in the primary cooling furnace (subordinate, J34J Kasso, y: 71-Cooling). 9 horns: LL's L1-L (Yes.As a result of the experiment, if the board thickness becomes smaller, the shape becomes larger, or the shape becomes larger.)! r': 0.4
FC smaller than mm is completely unviable as a product, and Denso 3-L-
<A significant shape defect occurred that could not be corrected using a cooing tool. Furthermore, if the shape was defective, the meandering or large strips would start to come into contact with the wall, making it impossible to continue the experiment. In this way, when the material becomes thin, it becomes impossible to operate using the conventional method. However, in the conventional strip cooling l, l, it is not possible to avoid the influence of thermal crown, uniform cooling cannot be obtained, and furthermore, the shape of the strip lip is defective. There are many cases.

The present invention is aimed at solving the above-mentioned drawbacks of the prior art.More specifically, it is an object of the present invention to solve the above-mentioned drawbacks of the prior art.
The present invention provides a cooling roll which has a structure in which the roll crown can be varied within a range larger than +ffi, and which enables uniform cooling of the strip in the width direction.

According to the present invention, in the strip cooling roll in which the roll outer cylinder is composed of a central member and a core outer cylinder, and a cooling medium flow path is formed between the body and the core outer cylinder, By joining the outer cylinder and the cough center part so that the joint remains in a joined state even if the temperature outside ↑3j rises due to the fit from the strip at at least one or more places (1 mo 1 place). Achieving low heat III expansion, the central member is composed of an arm and a sleeve fitted to the arm, and a gap is formed between the arm and the sleeve,
The gap is configured to communicate with a pressurized fluid and control the amount of roll crown through the joint by changing the pressure.
A lip cooling roll is provided.

That is, the first feature of the present invention is that the outer cylinder of the roll and the center member are firmly joined at one or more places other than both ends of the roll body. The thermal crown caused by heating becomes significantly smaller. The reason for this will be explained below.

The temperature of the outer cylinder is higher near the center of the roll ((J) than near the end of the roll, and the sleeve (cylindrical) of the center member has a uniform temperature distribution that is almost the same as the temperature of the cooling water. This is because most of the heat from the strip flows into the cooling water tube and only a small amount is transmitted to the cylinder, and the inner tube is also in contact with the cooling water with a large heat transfer connection similar to the outer tube.
The reason why the i7 is not transmitted to the inner cylinder/L7 is because the mechanical resistance of the joint is large and the heat flows laterally while passing through the partition and is transmitted to the cooling water. As described above, since the temperature distribution is uniform, the inner cylinder does not attempt to form a thermal crown, but only the outer cylinder attempts to form a thermal crown. Now line up with the inner cylinder and set the wall thickness of the outer cylinder to A
If the rigidity is made small by 'j<, then even if thermal expansion is attempted at the outside t61 or near the center of the roll, it will be stopped by the cylinder, and in the end almost no thermal crown will be formed.

If the strip before cooling is completely flat and the temperature distribution in the width direction is also completely uniform, uniform cooling can be achieved using a furanotrol with extremely small thermal expansion and almost no crown. L7 but the actual slip before cooling is medium elongation, shape defects such as ear waves, lly, 4 strength? There is an unevenness of A71 degrees, and in this case, uniform cooling is not possible unless a roll crown of appropriate size is used.

Therefore, in this case, the center member of the roll itself creates a pressure fluid passage (Q). It has a roll structure that makes the car i3J different.For this reason, by changing the fluid pressure, the strip has a convex crown, a convex crown for strips with medium elongation and width center, and a convex crown for strips with high temperature near J. By using recesses in the strips, uniform cooling is achieved.

The present invention will be described by way of examples with reference to the drawings in 1. and 1.

FIG. 4G is a schematic cross-sectional view of a cooling roll according to an embodiment of the present invention.

As shown in the diagram, I:J-ru in FIG. A cooling water flow path 2 is provided. The outer cylinder 1 and the center part (A3 will be described later) are properly shrink-fitted. The cooling water flow path 2 is arranged in a helical manner, and the cooling water flow path 2 is connected from the cooling water sea (4" shown in the figure) at Wl. Cooling water is introduced and circulated near the outer circumference of the roll to Ll-
After cooling the outer surface of the tube, it is discharged at W2.

The center part +23 consists of an arm 6 and a sleeve 7 fitted to the core arm 6, and a hydraulic chamber 8 or liquid rich is provided between the two, and a suitable hydraulic power source (not shown) is installed at 1:''. There is a quick connection to

Below, the joining method, dimensions, etc. of each member of the rotor in this embodiment will be explained item by item.

(1) -Outside, fLζ'1 [Structure Δ5] Fire joining methods include brazing, adhesive bonding, welding, Pol I-
Two methods are considered: a method that maintains the bonded state even if a force is applied to pull the joint apart, such as a method that uses shrink fitting. The latter method using baked pops is easier to implement, but that's all for now.

It is necessary to use the shrink fit allowance as explained here.

In water-cooled rolls assembled by shrink fitting, as the temperature of the outer cylinder rises due to heat from the strip, the shrink fit pressure becomes weaker, and when the average temperature of the outer cylinder exceeds a certain value, the joint will separate. do. Therefore, a large thermal crown will be formed when the temperature reaches - or below. In order to prevent this situation, calculate the maximum value of the temperature rise of the outer cylinder under the water-cooled roll usage conditions using the formula 8 above, and then calculate the It is necessary to use a shrinkage allowance.

(2) Kyushu and T (to the sleeve) Inner cylinder (Nuribuno) If the wall is too thin or rigid and lacks rigidity, the outer cylinder will be pulled by the expansion and the inner cylinder will also expand. As a result, a large thermal crown occurs.The stiffness under such deformation is approximately proportional to the product δE of the shell wall thickness δ and Young's modulus E. Let δ1 be the wall thickness of the outer cylinder, and El be the outer cylinder. +A of cylinder
Young's modulus of the material, δ2 is the wall thickness of the inner cylinder, L12 is the Young's modulus of the material of the inner cylinder J, Δr0 is the amount of thermal crown when the inner cylinder and the outer cylinder are joined and ``ζ'' is 1, and Δ1-7 is the Assuming the amount of thermal crown when the inner cylinder and outer cylinder are joined, the following equation holds approximately.

Therefore, when δ2E2-δ, E+, the thermal crown decreases by . In order to fully achieve the effect 'A' of the present invention, at least 62E2, δ, and E+ must be satisfied. In short, δ2 The larger E2 is, the better from the point of view of lowering thermal expansion. However, if δ2E2 is too large, the crown variable amount due to hydraulic pressure will become smaller, so it is necessary to select an appropriate value. On the other hand, the smaller the value of δ+E+ is, the better for both the thermal crown and hydraulic crown control.

(3) In order to minimize the temperature rise in the inner tube of the pile, it is desirable to increase the thermal resistance of the joint by the following method.

(, I) By decreasing 12 and increasing n3 in Fig. 5, the thermal resistance of the partition 4 to the heat flow in the radial direction increases, and the heat that has flowed into the partition 4 flows laterally and is cooled. The proportion absorbed by water increases,
The amount of heat flowing into the inner cylinder (sleeve) 7 is reduced. In addition,! If you increase , /ρ2, the proportion of heat flowing into the cooling water will increase even if the thermal resistance of the joint is the same, and the proportion of heat flowing into the partition 4 will decrease, so β, /p2 will be increased. That may also be effective.

(l) The material of the partition A4 is made of a material with low thermal conductivity. Alternatively, a layer of material with low Takha conductivity is interposed at the joint.

((,) In the case of shrink fit or hole-type bonding, the surface roughness of the contact surface should be checked.

(4) It's been a long time since I-3'y-1! For strip cooling, it is possible to uniformly cool the slip I/slip with a uniform temperature distribution in the width direction with a considerable amount of heat.
- Changes in the thermal crown due to differences in slip temperature and wrap angle (which are extremely small in the roll of the present invention, as described above) are controlled by hydraulic pressure (4). At the very least, it is necessary to be able to cancel the roll and make the roll flat at all times.In this case, one call is made of a concave Ininoal Crown with the opposite sign and the same as the largest thermal crown that is generated. The bulge caused by the maximum t113 pressure is the same as the concave ininoal crown.

Therefore, in terms of profit, L7-le becomes flat at maximum oil pressure, and under conditions where the maximum thermal crown occurs, t11+
1] - L in cello - le becomes cla, 1.

(I-' before cooling) In order to eliminate poor shape of the knob and uneven temperature in the width direction, increase the amount of crown variable by hydraulic pressure and the initial amount of concave crown.
It is necessary to be able to change the shape from concave to convex even under maximum thermal crown conditions.

It goes without saying that the range of crown variation from the gate to the convexity by hydraulic pressure is preferably as large as possible, but it cannot be made too large from the viewpoint of material strength.

(The more the hydraulic pressure is applied, the more the tension in the circumferential direction increases.) Therefore, without the low thermal expansion mechanism of the present invention, the range of crown variation due to hydraulic pressure will be the same as the range of crown variation due to thermal crown. It would be difficult to make it larger. That is, concave under any conditions ~
It becomes difficult to allow convexity. This point will be explained by comparing the present invention with the prior art.

Calculations explained using the size and shape of the thermal crown produced by the conventional method mentioned above (in E-11, the thermal crown (per radius) in the case of a roll of 1/2 inch and 500 mm is -
In the case of 0.46 mm copper, the opening is -110 and /14, and the strain in the circumferential direction is 0.46 0.44 500 500, respectively. Therefore, if the amount of crown variation due to hydraulic pressure is made to match the amount of crown variation due to thermal crown,
The circumferential stress at maximum oil pressure is of the fourth order.

If you are using materials that have kg/m♂ζ,
iiJ using hydraulic pressure in conventional technology (not a low thermal expansion roll)
Even if a modified crown roll is applied, it is only possible to maintain 6 hills under the above-mentioned minimum condition (keeping the roll always flat), but depending on the material, -ζ may not be able to maintain even this. Furthermore, as shown in FIG. 3, the shape of the thermal crown varies greatly depending on the sheet width, so it is not possible to make the roll approximately flannel for all types of rolls. On the other hand, if a low thermal expansion structure is used as in the present invention, the size of the thermal crown can be reduced to more than a fraction of the conventional size.
The amount of crown variation due to hydraulic pressure can be made several times more than the amount of crown variation due to the thermal crown. Zuna is concave to wealth - convex to kuranotoh or i + J ability. Also,
Since the absolute value (G) of the thermal crown is small, differences in the shape of the thermal crown due to differences in plate width are of little concern.

If the inner cylinder wall thickness is increased in order to achieve a low thermal expansion structure, the hydraulic pressure required to obtain the same amount of expansion will increase, so it is disadvantageous to make the cylinder wall thickness extremely thick. On the other hand, the thinner the outer cylinder wall is, the smaller the deviation, the lower the thermal expansion, and the smaller the hydraulic pressure required to obtain the same amount of bulge, so a thinner one is advantageous.

Note that the sleeve 7 is inserted from the center of the roll as shown in Fig. 4.
>I: 1 part becomes tapered in the direction of force.ivi
When it is a flat surface, the shape of the roll crown due to hydraulic pressure is inclined from near the center, making it suitable for cooling narrow strips. (When the sleeve thickness is constant, the bulge shape is close to the center near the center, so it is smaller than the narrow width.) Length j1 example - Figure 0 G does not show a partial cross section. A cooling roll was manufactured. The dimensions of each part of the roll are as follows.

Roll length: 400+i+i Outer cylinder wall thickness L+: 6mm Partition member (outer cylinder and body) height゛L2: 12□□Middle 2:
R1 (shrine sleeve thickness!, 3 Niji 2 part partition part +8'
T1: 8m11 T2 in the cooling water passage ・22 Open The maximum oil pressure of the hydraulic chamber 8 is 200 kg/cffl,
The temperature of 76 added water in the cooling water passage 2 is about 50°C.

The wrapping angle of the strip and roll is 180°, the strip temperature is 800'c, and the heat transfer coefficient on the D-ru surface is 150.
Thermal crown (If
(A) was 0.12mm, and the hydraulic crown variable range (A) was 0.38I1m. That is,
The latter is about three times as large as the former, and we have shown that by adding a concave inine alklon, it is possible to form a convex shape even under such conditions.

As a result of conducting this roll-strip cooling experiment, it was possible to achieve uniform cooling by adjusting the oil pressure in both cases of entry side slip, slip slip, and 14 waves.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a conventional strip cooling roll, and FIGS.
The details of the connecting parts are shown respectively. FIG. 3 is a graphical representation of the results of calculating the thermal crown of a cooling roll according to the prior art. FIG. 4 is a schematic cross-sectional view of a strip cooling roll according to one embodiment of the present invention. FIG. 5 is a detailed view of the cold JIIJ water passage between the roll barrel and the center member. FIG. 6 shows a cross-sectional structure of a slip-slip cooling I-cooler according to an embodiment of the present invention for calculation purposes. (Reference number) 1: Outer cylinder, 2: Cooling water flow path, 3. Center member, 4: (earth cutting member, 5 varnish, 1-lip, r: Arno\, 7 sleeve, 8, hydraulic chamber. Representative Sumitomo Metal Industries, Ltd. Patent attorney Kazuhiko Arai Figure 1 Figure 2? Figure 3 Roll center l゛ Q distance Cmm) Figure 4 Figure 5 Figure 1, Figure 6

Claims (1)

[Claims] In a strip cooling roll in which the roll body consists of an outer cylinder and a central member, and a cooling medium flow path is formed between the outer cylinder and the central member, at least one location other than both ends of the body By joining the outer cylinder and the center member in such a way that even if the temperature of the outer cylinder rises due to heat from the strip at the location, the joint remains in a joined state, low thermal expansion is achieved, and the center The member is comprised of an Ar/N and a sleeve fitted onto the Arno, a gap being formed between the Arno and the slinib, the gap communicating with a source of pressure fluid to generate pressure by changing the pressure. 2. A lip cooling roll characterized in that the roll crown amount is controlled through the joint.