JPS6154482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing scratches on a supply reel of a temper rolling mill.

In the manufacturing process of cold strips, in order to improve the mechanical properties of the annealed strips and to correct the surface condition and shape, a light skin pass rolling with an elongation rate of about 0.3 to 3.0% is performed. The skin pass rolling strip is coiled and unwound from a supply reel. At that time, if the coil is not in a proper baked-in state, the strip surfaces will rub against each other during unwinding, causing scratches and lowering the product yield. This trend is particularly striking.

Conventionally, as a means of preventing scratches that occur in the skin pass rolling process, the winding tension of the coil is increased in the pre-annealing process, the coil is seized during annealing, and the seizing force is used to prevent slips and scratches. This was done to prevent scratches from occurring. However, if the winding tension is increased in this way, the coil will seize more than necessary, causing a decrease in the yield of finished products. If an attempt is made to prevent scratches, reel marks will occur, resulting in a decrease in yield. Therefore, the adjustment technique that relies on the winding tension (unwinding reel expansion pressure) has its limitations.

An object of the present invention is to eliminate such drawbacks in the conventional supply reel portion, and to obtain a means for preventing or minimizing the occurrence of scratches and reel marks, thereby improving product yield. It is in.

Originally, scratches would not occur if the coil was wound properly, so scratches can be prevented by increasing the core expansion pressure on the supply reel and increasing the surface pressure on the inner circumference of the coil. It becomes a trend. On the other hand, reel marks are less likely to occur when the outer diameter of the coil is large, but as unwinding progresses and the outer diameter of the coil decreases, the thickness of the coil that is subject to the mandrel's expansion pressure decreases, causing the reel mark to・Marks will appear.

Therefore, in the present invention, in consideration of the above two types of flaw occurrence tendency, when the outer diameter of the coil is in the scratch occurrence area, the expansion pressure of the mandrel serving as the winding core tends to increase. In addition, when the outer diameter of the coil decreases and goes out of the range where scratches occur and reaches the outer diameter range where reel marks are likely to occur, the mandrel expansion pressure is automatically returned to normal. It has characteristics.

Although the method of the present invention targets large coils with a coil outer diameter of 2200 mm or more that are prone to scratches, the configuration of the device itself can be applied to coils with a normal outer diameter other than large coils. The configuration will be specifically explained with reference to FIG.

The coil C on the supply reel 1 is supported by an expanding and contracting mandrel 11 that is driven to expand and contract by a fluid pressure cylinder 12, and the strip S that is sequentially unwound is sent to a skin-pass rolling mill T and subjected to skin-pass rolling. , a normal rolling process in which the material is wound onto a take-up reel R is being performed. In this state, a pulse generator 2 is connected to the rolling roll to detect the rolling speed of the strip S and input this to the control device 3. Furthermore, a signal representing the number of rotations from the motor 13 that rotationally drives the mandrel 11 is input to the control device 3 . In the control device 3, the actual outer diameter of the coil C is calculated from the above-mentioned rolling speed and the rotation speed of the motor 13.

In addition to the above-mentioned detection signal, the control device 3 also has set values such as cut-off coil outer diameter d ₀ and strip plate thickness.
t ₀ , initial setting pressure P ₁ , final setting pressure P ₂ , coil outer diameter d ₁ at the start of pressure fluctuation, etc. are input.

The control device 3 sends an expansion/contraction pressure fluctuation command to a switching circuit 4 and a pressure regulating circuit 5 connected to a fluid pressure supply source 6 that drives a fluid cylinder 12 as an expansion/contraction drive mechanism. Drive motor 13 for mandrel 11
The load fluctuation signal may be sent to the control device 3 to check the change in the outer diameter of the coil C.

In the method of the present invention, the plate thickness is 0.8 to 1.2 mm and the outer diameter is
The target is a large coil of 2200 mm or more, and when the coil C having an initial coil diameter d ₀ is installed on the supply reel 1 and skin pass rolling is performed, as shown in Figure 2, at the start of the work. is mandrel 11
The expansion _/ contraction _pressure of Pressure regulating circuit 5 of cylinder 12
command to switch the expansion/contraction pressure of the mandrel 11 to the final set pressure _P2 , which is the normal pressure.

In the present invention, the final set pressure _P2 is, for example, 60
Apply normal pressure value of Kg/ ^cm2 , but default pressure
P ₁ is set in the range of 70 to 90 Kg/cm ² , for example, 80 Kg/cm ² to increase the surface pressure on the inner surface of the coil. Further, the command to switch from the initial setting pressure P ₁ to the final setting pressure P ₂ is issued when the coil diameter d ₁ reaches 2200 mm.

In the method of the present invention, the pressure circuit configuration of the fluid cylinder 12 is set as shown in FIG.
Specifically, a relief valve 51, a manual switching valve 52, and a pressure reducing valve 53 are provided as a set. In this case, for example, if the upper limit pressure of the relief valve 51 is set to 60 kg/cm ² and the upper limit pressure of the pressure reducing valve 53 is set to 80 kg/cm ² , then when the manual switching valve 52 is opened, the upper limit pressure of the pressure reducing valve 53 is 60 kg/cm 2 .
A pressure circuit of Kg/cm ² is formed, and conversely, when it is closed, a pressure circuit of 80Kg/cm ² is formed. Therefore, in the case of a normal coil that is not intended for large coils, a normal pressure circuit of 60 kg/cm ² may be set from the beginning of rolling.

When the plate thickness is 0.8 mm or more and the coil outer diameter is 2200 mm or more, the reason why the mandrel pressure is set to a high pressure is because of the knowledge that a lot of tightening occurs during coil unwinding, which causes many scratches. In addition, when the plate thickness is less than 0.8 mm and the coil outer diameter is 2200 mm or less, the mandrel pressure is set to a low pressure because scratches are less likely to occur, and if the mandrel expansion pressure is high, mandrel marks may occur and quality may deteriorate. This is because it will happen.

By carrying out the present invention, the number of scratches in large coils is reduced to half that of the conventional method, and since there is no fear of reel marks, it is possible to significantly improve the yield in the temper rolling process.

[Brief explanation of the drawing]

FIG. 1 is a block explanatory diagram showing the configuration of means for implementing the method of the present invention. FIG. 2 is a graph showing the relationship between change in coil diameter and mandrel expansion/contraction pressure in the method of the present invention. FIG. 3 is a pressure circuit diagram of the fluid cylinder. 1: Supply reel, 11: Expansion mandrel, 1
2: Fluid cylinder, 13: Motor, 2: Pulse
generator, 3: control device, 4: switching circuit,
5: Pressure regulating circuit, 51: Relief valve, 52: Manual switching valve, 53: Pressure reducing valve, 6: Fluid pressure supply source, C: Coil, S: Strip, T: Temper rolling mill, R: Take-up reel.

Claims (1)

[Claims] 1 The supply pressure of the mandrel pressure circuit on the supply reel must be set so that it can be switched between two different pressure values, and a coil with a plate thickness of 0.8 mm or more and a coil outer diameter of 2200 mm or more must be set on the supply reel. When installed, the initial pressure of the mandrel is set to a predetermined high pressure, the variation of the coil winding diameter on the supply reel is captured by the line speed of the strip, and when the coil diameter reaches a predetermined value. Switching the mandrel expansion pressure on the supply reel to the normal low pressure, and the plate thickness being 0.8mm.
A method for preventing scratches on a supply reel of a skin pass rolling mill, characterized in that when a coil with a coil outer diameter of 2200 mm or less is installed on the supply reel, the pressure is set to the normal low pressure described above.