JPS5841123B2 - rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides a roll having a variable roll crown amount structure (hereinafter referred to as a crown roll for convenience of explanation) on either the upper or lower backup roll or intermediate roll of a multi-high rolling mill.
The present invention relates to an improvement of a multi-high rolling mill that has a plate crown and shape control function using the crown roll.

This invention will be explained using a quadruple rolling mill as an example.

As shown in Figure 1, a normal four-layer rolling mill has a pair of upper and lower work rolls W' with the same diameter and a pair of upper and lower back-up rolls with the same diameter to control the shape of the material and the plate crown. is performed by combining the roll crowning method and roll bending method.

Conventionally, in this type of four-layer rolling mill, a method has been adopted in which the crown roll is used as a backup roll in order to further improve the ability to compensate for roll deflection due to rolling load when rolling various materials and material dimensions.

As shown in Fig. 2, the crown roll has a cylindrical gap between the arm μ1 and the sleeve 2, and a pressure medium is supplied to this gap to make the amount of crown variable. By applying this to the backup roll of a four-layer rolling mill, we first change the amount of crown on the backup roll, and the effect of the change in the amount of crown is applied to the work roll, thereby changing the deflection curve of the entire axis of the work roll. We have adopted a method that allows

A column plate crown with a large amount of change in deflection of the work roll axis has a high shape control function.

However, the work roll diameter of a four-layer rolling mill is usually 530 mm.
Since it has a large diameter of mmφ to 580 mmφ and therefore has a considerably large bending rigidity, the influence on the plate thickness distribution of the backup roll crown is small to % or more, which has the disadvantage that the control ability may be insufficient.

This invention has been improved in order to solve these drawbacks, and is a four-fold roller that can further increase the crown effect of the backup roll (crown roll) by simple means and further increase the influence on the plate thickness distribution. This paper proposes a type rolling mill.

This invention is characterized in that one of the backup rolls of a conventional four-layer rolling mill is configured with a crown roll, and the diameter of the work roll on this backup roll side is smaller than the diameter of the other work roll. FIG. 3 shows an example of this.

That is, in a four-layer rolling mill that has a pair of work rolls and a pair of backup rolls, for example, the crown roll shown in FIG. 2 is applied to the upper backup roll, and the work roll in contact with this backup roll It is composed of a work roll W-2 having a smaller roll diameter than roll W-1.

3 indicates the material.

By reducing the diameter of the work roll in contact with the backup roll using a crown roll in this way, the bending rigidity of the work roll becomes smaller. The impact will be greater.

Therefore, the plate crown control effect is greater than that of a conventional four-layer rolling mill that uses work rolls of the same diameter on the upper and lower sides.

Note that the bending rigidity of a roll is proportional to the fourth power of the roll diameter, so if the work roll diameter is reduced by 10%, the bending rigidity of the work roll will decrease to about 66%.

Therefore, apply the crown roll to the backup roll,
If the diameter of the work roll in contact with the roll is made smaller, the plate crown control effect of the backup roll becomes greater.

The axial deflection of the work rolls of a quadruple rolling mill is determined by the rolling load distribution received from the material and the contact pressure distribution between the work roll backup rolls.

In other words, when the backup roll swells, the work roll tries to follow the swell, so the contact pressure distribution between the work roll and the backup roll changes, and as a result, the work roll axis deflection changes, but at this time, the bending rigidity of the work roll changes. The smaller the amount, the greater the amount of change in work roll axis deflection due to the bulge of the backup roll.

However, the work roll diameter cannot be made infinitely small.

As the work roll diameter becomes smaller, the contact area between the work roll and the back-edge roll becomes smaller for the same load, which increases the contact pressure and makes respauling more likely to occur. This is because the roll unit consumption decreases accordingly, and the smaller the diameter, the smaller the angle of entry, making it difficult to roll thick materials.

For this reason, the diameter of the work roll W-2 in contact with the backup roll to which the crown roll is applied is usually 1500 m.
For a backup roll of πφ, it is desirable to set the diameter to about 400 mmφ.

Next, embodiments of the invention will be described.

A four-layer rolling mill with the roll configuration shown in Fig. 3 has a back-up roll diameter of 1422 m1φ for both the upper and lower work rolls, and the upper work roll has a diameter increase shown in Fig. 4 (a is a pressure of 100 kg).
/cT1. , b is a pressure of 300 kg/cr/l, C is a pressure of 500 kg/cut), and the lower work roll diameter is changed to 570mmφ, the upper side is changed to 57011Lmφ, 510mmφ, 450mmφ, and the plate A steel plate with a width of 12307 na and a thickness of 1 mm is made into a plate with a thickness of 0.
It was rolled for 8 hours.

Is the entry tension 6kg/cI at that time? L, exit tension is 8k
g/cr? It was L.

FIG. 5 shows the crown roll pressure O and plate thickness distribution of 400 kg/i when the work roll diameters on the crown roll side are 570mmφ, 510mmφ, and 450mmφ.

In the same figure, from the top, the work roll diameter is 5701ft7nφ.
, 510 mmφ, and 450 mmφ are shown, .

Furthermore, FIG. 6 shows the relationship between the work roll diameter and the amount of change in plate crown.

As is clear from the results shown in FIGS. 5 and 6, the amount of work roll deflection due to the bulge of the crown roll is larger when the work roll has a smaller diameter, and the plate crown control effect is greater.

Moreover, FIG. 7 shows the plate crown control effect when a crown roll and a roll bender are combined.

In the figure, o081. o indicates the effect of the crown roll, .--. indicates the effect of the roll bender, and x-.--x indicates the effect of the crown roll + roll bender.

From Fig. 7, the crown roll and roll bender have almost the same effect, and when they are combined, the effect is almost doubled, and it is also possible to combine two types of control patterns, allowing for complex work roll axis deflection. It was found that

In the description of this invention, description of multi-high rolling mills other than the four-layer rolling mill has been omitted, but as shown in Fig. 8, one of the upper and lower backup rolls or intermediate rolls other than the work rolls of the multi-high rolling mill It consists of a roll ■ that has a structure that changes the amount of roll crown by supplying pressure medium to the cylindrical gap between the arm and the sleeve, and the diameter of the two rolls on the variable side of this roll crown is set to be larger than the diameter of the other work rolls. The above-mentioned 4.
The same effect as a heavy rolling mill can be obtained.

As mentioned above, this invention uses a crown roll as one of the upper and lower backup rolls or as an intermediate roll, and the diameter of the work roll on the crown roll side is made small, thereby achieving a four-layer type with a large plate crown control effect. A rolling mill and a multi-stage rolling mill are obtained, which can be extremely effective in rolling various materials and sizes.

[Brief Description of the Drawings] Fig. 1 is an explanatory diagram showing a conventional four-layer rolling mill, Fig. 2 is a longitudinal sectional view showing a roll having a variable crown amount structure, and Fig. 3 is an explanatory diagram showing a conventional four-layer rolling mill.
The figure is an explanatory diagram showing one embodiment of the present invention, FIG. 4 is a chart showing the amount of increase in the diameter of the crown roll in the embodiment of the invention, FIG. 5 is a chart showing the plate thickness distribution in the same embodiment, and FIG. 6 and 7 are charts showing the plate crown control effect in the same embodiment as above, and FIG. 8 is an explanatory diagram showing an embodiment of the present invention in a multi-stage rolling mill. In the figure, 1...Arμ, 2...Sleeve, 3...Material, B, ■-B...Backup roll, Wl, W-2 ...Work roll.

Claims (1)

[Claims] 1. Either the upper or lower backup roll or the intermediate roll of the multi-high rolling mill is a roll having a crown amount variable structure that provides a cylindrical gap between the arm and the sleeve and supplies pressure medium to the gap. A rolling mill characterized in that the diameter of the work roll on the variable crown amount roll side is smaller than the diameter of the other work roll.