JPH1133611A - Block mill, control method for tension between its rolling stands, and method for rolling wire rod, wire or bar steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the block mill compact, to facilitate its maintenance and repair, and to roll the wire rod and the bar steel with desired dimensional precision and in a desired shape by providing a fluid shaft coupling type or viscous multiple disc clutch type tension controller on the drive shaft of a rolling stand. SOLUTION: Between the drive part M of the block mill and the drive transmission shafts 5 of rolling stands 3, torque converters 61 or viscous couplings 62 allowing to slide, are mounted. The drive transmission shafts 5 of the rolling stands 3 and the drive part M can be separated, and tension generated among the rolling stands 3 by the dispersion of the shape and the dimensions of a material R to be rolled and the dispersion of temperatures, can be absorbed. When the rotational speed of the drive transmission shafts 5 of the rolling stands 3 becomes slower than that of the drive shafts 4, even when the rotational speed of the rotating shafts 4 is in an optimum pass schedule, it can cope with the fluctuation of the tension by the torque converters 61 and viscous coupling 62. It is important that the rotational speed of the drive shafts 4 is higher tan the rotational speed of the optimum pass schedule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block mill, a method of controlling tension between rolling stands thereof, and a method of rolling a wire, a wire or a bar (hereinafter, also referred to as a "wire or a bar"). More specifically, in a so-called “common drive” type block mill in which each rolling stand serves as a common drive system, a block mill capable of automatically controlling the tension between rolling stands, a method for controlling the tension between rolling stands, and the above-described wire rod And a method for stably rolling steel bars and bars to desired dimensional accuracy and shape.

[0002]

2. Description of the Related Art In recent years, a "common drive" type block mill in which about ten rolling stands as shown in FIG.

[0003] The tension between the rolling stands in the block mill is the rotational speed of the rolls in each stand (hereinafter, simply referred to as the rotational speed of the stand; hereinafter, "rotation of the rolls in the stand" is referred to as "rotation of the stand"). The tension between stands greatly affects the dimensional accuracy and shape of the product. For this reason, rolling is performed in a rolling pass schedule such that the tension between the stands becomes a constant value or no tension.

[0004] However, even if the rolling pass schedule is adjusted, the material to be rolled has variations in shape and dimensions, and furthermore, the temperature of each part of the material to be rolled has variations. It is inevitable that the balance of “mass flow” will be lost and the tension will fluctuate. In other words, in a "common drive" type block mill,
Since the rotation speed of each stand cannot be controlled, a tensile force or a compressive force is applied to the material to be rolled between the stands, and a desired shape or dimensional accuracy may not be obtained.

As a technique for solving the above-mentioned problem in the "common drive" type block mill, for example, Japanese Patent Application Laid-Open No. 62-89514 discloses a technique of driving a roll in each rolling stand of a block mill connected by a common drive. By adding an acceleration / deceleration function for speed adjustment and a tension measuring device to the shaft (hereinafter simply referred to as the drive shaft of the rolling stand), and adjusting the speed of the stand to eliminate tension, products with excellent dimensional accuracy and shape can be obtained. A resulting "tension control device in a block mill" has been proposed.

In Japanese Patent Publication No. 3-35008, a tension measuring device is attached to each rolling stand, and the result of the tension measurement is fed back and fed forward to control the rotation speed to an optimum rotation speed at which no tension is generated, thereby achieving stable rotation. There has been proposed a technique capable of obtaining the specified dimensions.

Further, Japanese Patent Application Laid-Open No. 4-322809 and the like disclose a method in which the shape after rolling is read by a measuring instrument (profile meter), fed back and fed forward, and the rolling reduction of the rolling mill is adjusted to increase the dimension. A technique for performing high-precision rolling is disclosed.

However, in the case of the technology proposed in each of the above publications, it is necessary to use a large amount of control devices such as a control computer and various sensors, and the scale of the system becomes large. Problems arise. Furthermore, the environment in which such control computers and control sensors are mounted is extremely harsh for precision electronic components in which heat and water vapor are generated and, in some cases, dust is generated.

In recent years, although electronic devices have made great progress compared to the past, regular maintenance is required for normal operation of precision electronic devices in the harsh environment described above. That would require enormous costs.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a compact and easy to maintain and maintain "common drive" type block mill capable of stably rolling a wire or a steel bar to a desired dimensional accuracy and shape, and a block mill thereof. An object of the present invention is to provide a tension control method between rolling stands. It is a further object of the present invention to provide a rolling method capable of stably rolling a wire or a steel bar into a desired dimensional accuracy and shape.

[0011]

The gist of the present invention is to provide a block mill shown in (1) below, a tension control method between rolling stands of a block mill shown in (2), and a wire rod shown in (3).
Rolling method of wire or bar.

(1) The tension between the rolling stands can be automatically controlled, wherein the drive shaft of the rolling stand of the block mill has a fluid shaft coupling type tension control device or a viscous multi-plate clutch type tension control device. Block mill.

(2) A block mill characterized by providing a tension control device of a fluid shaft coupling type or a tension control device of a viscous multi-plate clutch type on a drive shaft of a rolling stand of a block mill to equalize mass flow between stands. Control method of tension between rolling stands.

(3) A method for rolling a wire, a wire or a steel bar, wherein the method is performed by using the block mill according to the above (1).

The "drive shaft of the rolling stand" refers to the drive shaft of the roll in the rolling stand as described above. "Mass flow between stands" refers to the amount (volume) of the material to be rolled present in a unit time between two adjacent rolling stands, where V is the rolling speed at the upstream rolling stand, and A is the rolling speed of the rolling stand. The cross-sectional area of the material to be rolled after being rolled by the stand is represented by “V × A”. The term "wire" refers to a metal material that has been hot-rolled into a rod shape, and is a steel material cut to a predetermined length or a steel material wound in a coil shape. The term “wire” refers to a wire that is mainly cold-worked, such as drawn, and wound into a coil. The “bar steel” refers to a steel material cut into a predetermined length from steel rolled into a bar shape.

The block mill according to the present invention is a two-way roll,
Any type of mill, such as a three-way roll or a four-way roll, may be used.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have studied a technique for stably rolling a wire or a steel bar into a desired dimensional accuracy and shape. As a result, first, the following items were found.

If the rotation speed of each stand of the block mill is controlled individually, rolling can be performed with a constant tension or no tension. However, if the drive system of each rolling stand of the block mill is separated separately, tension control can be easily performed, but the mill becomes extremely large.

Therefore, in a "common drive" type block mill, a compact mechanism capable of individually controlling the rotation speed of each rolling stand, that is, a compact mechanism capable of independently controlling the tension between the rolling stands, and which is easy to maintain and operate. The technology that can be maintained was further studied, and the following findings were obtained.

If a difference in rotation speed between the above-mentioned rolling stands is absorbed by using a mechanism capable of mechanically allowing slip on the drive shaft of a rolling stand of a "common drive" type block mill, the tension between the stands is always zero. The tension is constant. In this case, maintenance and maintenance are also easy.

In order to make the mechanism capable of allowing mechanical slippage compact, a fluid shaft coupling (hereinafter referred to as a torque converter) or a viscous multi-plate clutch (hereinafter referred to as a torque converter) is required.
Viscous coupling) may be used.

The present invention has been completed based on the above findings.

Hereinafter, the present invention will be described with reference to the drawings.

FIG. 5 is a schematic view of a conventional general block mill. As shown in this figure, a conventional general block mill transmits power to a plurality of rolling stands 3 from a single drive motor 1 via a distribution gear box 2 composed of a plurality of gears. It is a "drive" type mill. However, in this method, stable rolling can be performed only under a fixed condition, that is, under a condition in which tension between stands does not occur.

On the other hand, as shown in FIG. 1, the block mill of the present invention is a "common drive" type mill as in the prior art, but the drive unit M (drive motor 1, distribution gearbox 2) of the block mill. A torque converter 61 or a viscous coupling 62 that allows slippage is mounted between the drive shaft 4) and the drive transmission shaft 5 of the rolling stand 3. Therefore, even in the case of a “common drive” type mill, the drive transmission shaft 5 of the rolling stand and the drive section M can be separated, and the shape and dimensions of the material to be rolled R vary, and further, the material to be rolled R It is possible to absorb the tension generated between the rolling stands 3 due to the temperature variation in each part of the above. For this reason, the conventional "common drive"
Unlike a die mill, stable rolling can be performed without being affected by tension fluctuation. FIG. 1A is a schematic view of a block mill according to the present invention, and FIG. 1B is an explanatory view showing up to the third stand in FIG.

Both the torque converter 61 and the viscous coupling 62 can only absorb the rotational speed difference between the drive shaft 4 and the drive transmission shaft 5 of the rolling stand by mechanical slip. In other words, when the rotation speed of the drive transmission shaft 5 of the rolling stand is lower than the rotation speed of the drive shaft 4, the rotation speed of the drive shaft 4 is at the optimal pass schedule (pass schedule in which there is no tension). Even if there is, the torque converter 61 and the viscous coupling 62 can cope with the tension fluctuation. However, even if the rotational speed of the drive shaft 4 is the optimal pass schedule, the torque converter 61 and the viscous coupling 62
Therefore, the drive transmission shaft 5 of the rolling stand cannot be rotated faster than the drive shaft 4 to improve the tension imbalance.
Therefore, it is important that the rotation speed of the drive shaft 4 of the rolling stand of the block mill be higher than the rotation speed of the above-mentioned optimal pass schedule.

In the case of the torque converter 61, the rotation speed of the drive shaft 4 is equal to the rotation speed (n) of the optimal path schedule.
It is possible to control the rotation speed of the drive transmission shaft 5 of the rolling stand even when it is increased to about 1.9 times. However, from the viewpoint of practical efficiency, the rotation speed of the drive shaft 4 is 1.
It is preferable to set it to about 4n. Above all, the rotational speed of the drive shaft 4 having a high control effect in the torque converter 61 is about 1.05n to 1.3n.

On the other hand, in the case of the viscous coupling 62,
Even when the rotation speed of the drive shaft 4 increases to about 2n, the rotation speed of the drive transmission shaft 5 of the rolling stand can be controlled. However, from a practical efficiency point of view, the rotational speed of the drive shaft 4 is 1.
It is preferable to set it to about 4n. Above all, the rotational speed of the drive shaft 4 having a high control effect in the viscous coupling 62 is about 1.05 n to 1.3 n.

The slip ratio in the case of the torque converter may be adjusted by, for example, the shape of the stator or the viscosity of the sealed fluid. Further, the adjustment of the slip ratio in the case of the viscous coupling may be performed by, for example, the number of plates, the viscosity of the sealed fluid, or the sealed amount of the fluid. Here, the slip rate is
(Rotation speed of drive transmission shaft 5 of rolling stand) / (Rotation speed of drive shaft 4), that is, (Rotation speed of rolling stand 3) / (Rotation speed of drive shaft 4).

The above-mentioned torque converter and viscous coupling need not be special, and a normal torque converter (FIG. 2 (a)) and a normal viscous coupling (FIG. 2 (b)) shown in FIG. Is fine.

FIG. 3 is a view showing a state where the material to be rolled R is rolled by a "common drive" type block mill. When the balance of “mass flow” is lost as in rolling using a conventional “common drive” type block mill,
Failure occurs in the rolling shape. That is, (a) the material to be rolled R
When the cross-sectional area of the material R to be rolled between the stand 31 and the stand 32 becomes larger than the optimum state due to the temperature and the size variation, that is, the cross-sectional area A ₁₁ during the actual rolling becomes the optimum cross-sectional area A ₁ (V ₀ When the cross-sectional area A ₁ ) is larger than A ₀ = V ₁ A ₁ , the “mass flow” between the stands increases because the rotation speed V ₁ of the stands 31 is constant, and the material R to be rolled after the stands 31 increases. The shape tends to bite out. Conversely, (b) the actual cross-sectional area A ₁₁ in the rolling is smaller than the optimum cross-sectional area A _1, between a stand "mass flow"
Becomes smaller, the shape of the material R to be rolled after the stand 31 tends to be unfilled. Conventional type "common drive"
When rolling is performed using a die block mill, the above-described phenomenon occurs, and therefore, a product with stable dimensional accuracy cannot be obtained. In the above, V ₀ is the rolling speed before entering the stand 31 and A ₀ is the stand 31
V ₁ is the rolling speed after rolling on the stand 31, and A ₁ is the cross sectional area of the rolling material R after rolling on the stand 31.

[0032] In contrast, when the sectional area A ₁₁ in the actual rolling by temperature and dimensional variation of the rolled material R in the same manner in the block mill of the present invention is greater than the optimum cross-sectional area A _1, "mass flow" The torque converter or the viscous coupling is slipped to maintain a constant, and an adjustment is made to reduce the speed V ₁ so as to keep the “mass flow” constant. Conversely, when the cross-sectional area A ₁₁ during actual rolling becomes smaller than the optimum cross-sectional area A ₁ , the speed is increased to “mass flow”
Is adjusted to be constant. As a result, the tension between the stands becomes 0 or a constant value, and the shape of the rolled material R after the stand 31 is stabilized.

FIG. 1 shows a case where the torque converter 61 or the viscous coupling 62 is provided on the drive shafts of all rolling stands after the first stand of the block mill. 62 may be provided on at least two stands on the most downstream side.

Hereinafter, the present invention will be described in further detail by taking, as an example, a case where the first rolling stand of the block mill is a fixed type as in the past and a torque converter is provided on a drive shaft after the second rolling stand.

Rolling stands are arranged along the pass line of the block mill.
Consider a case where the motor is connected to a drive motor by a distribution gear box. The distribution gearbox and the first rolling stand are directly connected by a drive shaft, but the distribution gearbox and each of the rolling stands after the second rolling stand have a drive shaft and a drive transmission shaft of the stand connected by a torque converter. It has a structure, that is, a structure in which a torque converter is provided on a drive shaft of a rolling stand.

The driving force of the driving motor is transmitted to the distribution gear box and distributed to each rolling stand. At this time, the first
Since the rolling stand is a fixed type in which the distribution gear box and the stand are connected directly by a drive shaft as in the related art, the rotation speed (rotation speed) serving as a reference for rolling by the driving force described above.
Rotates the rolling stand. After the second rolling stand, the driving force is transmitted to the drive transmission shaft of each rolling stand via a torque converter, whereby the rolling stand rotates.

The material to be rolled in the first stand is rolled here and then enters the next stand, the second stand.
Then go to the next stand. At this time, if the mass flow between the first stand and the second stand is not equal to the mass flow between the second stand and the third stand, a force acts between the rolling stands, so that the torque converter connected to the second stand slips. The rotation speed (rotation speed) of the second stand is automatically adjusted so that the mass flow between the first stand and the second stand and the mass flow between the second stand and the third stand become equal. A similar effect is obtained when the mass flow between the second and third stands and the mass flow between the third and fourth stands are not equal.
Happening in a torque converter connected to the stand, the mass flow is automatically adjusted to a constant.

In the above, the distribution gear box is connected to the second
The rotation speed of the drive shaft after the stand is
The structure is such that the rotation speed of the drive shaft of the stand is about 1.05 to 1.4 times, that is, the drive shafts of the second and subsequent stands are 5 times smaller than the drive shaft of the first stand which is an ordinary common drive. If the gear ratio is such that it can be rotated about 40% faster, even if a mass flow condition in which the rolling speed is increased occurs, the tension applied between the stands by the action of the torque converter connected to each stand is reduced to zero or zero. It can be rolled in a constant state. Therefore, rolling with high dimensional accuracy can be stably performed.

As shown in FIG. 4, a profile meter is attached to the downstream side of the block mill according to the present invention to measure the shape of the material to be rolled R, and the measurement result is blocked by a dimensional control device and a draft adjusting device. 2 on the most downstream side of the mill
By feeding back to the stand, higher dimensional accuracy rolling is possible. This is because, according to the present invention, the rolling can be basically performed with the stand-to-stand tension being almost zero, so that after setting the diameter in the final stand (the most downstream stand), the stand before the one that determines the free surface is set. This is because a desired wire diameter can be easily obtained by changing the shape of the wire.

Hereinafter, the present invention will be described in more detail with reference to examples.

[0041]

【Example】

(Example 1) An S45C billet produced by melting and hot forging in a test furnace by a usual method is roughly rolled and intermediate-rolled by a usual method, and then finish-rolled to obtain a wire having a diameter of 14.0 mm. Was. In this rolling, in the final stage of the finish rolling, rolling using a conventional block mill of the `` common drive '' type, and rolling using a block mill provided with a torque converter on the drive shaft of the rolling stand according to the present invention, The dimensional accuracy was compared. The torque converter was provided on the drive shaft of the third and subsequent rolling stands of the block mill having six stands.

The dimensional accuracy was measured by measuring the diameter with a micrometer, and evaluated by the deviation in diameter (the difference between the maximum and minimum diameters in the same cross section of the wire).

When the final finish rolling was carried out using a conventional "common drive" type conventional block mill, the deviation in diameter was 0.6 mm. On the other hand, when the final finish rolling is performed using a block mill provided with a torque converter on the drive shaft of the rolling stand according to the present invention, the eccentricity difference is 0.2%.
mm and the dimensional accuracy was high.

(Example 2) A billet of SCr420 produced by melting and hot forging in a test furnace by a usual method was subjected to rough rolling and intermediate rolling by a usual method, followed by finish rolling to a diameter of 1 mm.
An 8.0 mm steel bar was obtained. In this rolling, in the final stage of finish rolling, rolling using a conventional block mill of the "common drive" type and rolling using a block mill provided with a viscous coupling on a drive shaft of a rolling stand according to the present invention are performed. , And dimensional accuracy were compared. The viscous coupling was provided on the drive shaft of the third and subsequent rolling stands of the block mill having five stands.

The dimensional accuracy was measured by measuring the diameter with a micrometer, and evaluated by the deviation in diameter (the difference between the maximum and minimum diameters in the same cross section of the steel bar).

When the final finishing rolling was performed using a conventional "common drive" type conventional block mill, the deviation in diameter was 0.4 mm. On the other hand, when the final finishing rolling was performed using a block mill provided with a viscous coupling on the drive shaft of the rolling stand according to the present invention, the deviation in diameter was 0.15 mm and the dimensional accuracy was high.

[0047]

By using the block mill of the present invention, the mass flow between the rolling stands can be kept constant even if the shape and dimensions of the material to be rolled vary and the temperature of each part of the material to be rolled varies. The wire and the bar can be stably manufactured with high dimensional accuracy. Furthermore, since it is a mechanical adjustment mechanism that keeps the mass flow between the rolling stands constant, it does not require many control devices,
Maintenance / maintenance is easy because precision electronic components operate normally even in extremely harsh environments where heat and water vapor are generated and dust is generated in some cases.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a block mill according to the present invention,
(A) is a schematic diagram of the configuration, and (b) is an explanatory diagram showing up to the third stand.

FIG. 2 is an explanatory view of a tension control device according to the present invention, wherein (a)
1 is a schematic diagram of a general torque converter, and FIG. 2B is a schematic diagram of a general viscous coupling.

FIG. 3 is a view showing a situation where a material to be rolled is rolled by a “common drive” type block mill.

FIG. 4 is a diagram illustrating an outline of a rolling control system to which the present invention is applied.

FIG. 5 is an explanatory view of a conventional general “common drive” type block mill.

[Explanation of symbols]

 M: drive unit, R: material to be rolled, 1: drive motor, 2: distribution gear box, 3, 31, 32: rolling stand, 4: drive shaft, 5: drive transmission shaft, 61: torque converter, 62: viscous Coupling

Claims (3)

[Claims] 1. The drive shaft of a rolling stand of a block mill,
A block mill capable of automatically controlling the tension between rolling stands, comprising a tension control device of a fluid shaft coupling type or a tension control device of a viscous multi-plate clutch type. 2. A block mill according to claim 1, wherein a tension control device of a fluid shaft coupling type or a tension control device of a viscous multi-plate clutch type is provided on a drive shaft of a rolling stand of the block mill to equalize mass flow between stands. Method of controlling tension between rolling stands. 3. A method for rolling a wire, a wire or a steel bar, comprising rolling using the block mill according to claim 1.