JP6064673B2 - Apparatus and method for producing a differential thickness steel sheet having a thickness difference in the sheet width direction by a partial rolling method - Google Patents

Description

  The present invention relates to a manufacturing apparatus and a manufacturing method capable of efficiently manufacturing a differential thickness steel plate in a direction having a thickness difference in the plate width direction.

  In recent years, weight reduction has been promoted in order to improve the fuel efficiency of automobiles. Specific methods for weight reduction include changing the steel grade of the member to a thinner and higher strength, changing to a lighter specific aluminum alloy or magnesium alloy, and the thickness distribution of the member. There is a method of reducing the thickness to the limit where acceptable performance can be secured.

  Among the above-described methods, a steel plate provided with a member thickness distribution is generally called a differential thickness steel plate. For example, the difference thickness steel plate is made of a material having a length of about 1000 mm to 2000 mm and a width of about 300 mm to 600 mm. Contrary to the two-level difference type), conversely in the longitudinal direction up to 300 mm from both ends, the plate thickness is 1.8 mm, and the central part is a convex type with a plate thickness of 2.0 mm (thickness difference two-level target type). Depending on the application, there are various types, such as those in which the taper changes into a taper shape, objects with a multi-level thickness difference, and asymmetric types.

  As a manufacturing method of such a difference thickness steel plate having a thickness difference in the longitudinal direction, it is manufactured by operating a roll gap (operating a reduction position) during rolling using a rolling mill (for example, Patent Document 1). .

  Moreover, as a manufacturing method of the differential thickness steel plate having a plate thickness difference in the plate width direction, a method of manufacturing with a hot tandem rolling mill is disclosed in, for example, Patent Document 2, but in this way the plate thickness in the plate width direction is disclosed. Since camber occurs when the difference distribution exists asymmetrically, batch rolling cannot be rolled from the coil tip, and the coil roll is wound on the take-up reel before being manufactured by tilting the work roll. Constraints such as continuous rolling and tilting from the coil joint are produced. The former has a large yield drop because there is a distance of several tens of meters from the final stand to the take-up roll, and the latter requires equipment for joining and continuing hot coils upstream, increasing equipment costs. Invite.

JP-A-3-281010 JP-A-4-84607

The method of manufacturing a differential thickness steel plate using a rolling mill as described above is referred to herein as a differential thickness steel plate manufacturing method by a rolling method.
In the production method of differential thickness steel sheets by rolling method, the length of the different part of the thickness part is generally short in the thickness distribution of the differential thickness steel sheets, so the roll gap is controlled by measuring the thickness of the rolling mill exit side. It is difficult to produce a desired differential thickness steel plate because there is an effect that a dead time is generated due to the distance from the roll bite outlet to the plate thickness measuring device. Also, the inlet side plate thickness and the inlet side speed and the outlet side speed are detected, the plate thickness on the outlet side of the rolling mill is estimated using a constant mass flow rule, the roll gap is controlled based on the value, and the desired difference thickness steel plate However, there are problems such as the accuracy of tracking, the influence of widening, and the increase in equipment cost due to the installation of the plate thickness and plate speed detectors.

  Therefore, an experiment is performed in advance to determine the relationship between the roll gap (rolling position) and the plate thickness, the rotation speed of the work roll is determined with high accuracy, the rolling length is estimated, and the desired rolling length is determined based on the estimated rolling length. A method of controlling the roll gap so as to obtain a plate thickness (referred to as a preset rolling method) is common.

  Instead of the preset rolling method described above, experiments are performed in advance to determine the deformation characteristics of the mill, the rolling load during rolling is measured, and the thickness of the roll bite outlet is estimated from the deformation characteristics of the mill and the measured rolling load. There is also a method (referred to as an absolute rolling method) for controlling the roll gap so as to obtain a desired plate thickness based on the estimated rolling length described above.

In these preset rolling methods and absolute value rolling methods, the material is a cold-rolled annealing material, a hot-rolled pickling material, or a hot-rolled material, and is rolled at room temperature. In order to increase the productivity of the rolling method (to increase the production speed), a highly responsive roll gap control is required, and thus a highly responsive hydraulic reduction device is essential. Since the hydraulic reduction device is expensive, the equipment cost becomes high, resulting in an increase in manufacturing cost. Since these manufacturing methods are rolled with a slit material having a plate width of about 300 mm to 600 mm, they are suitable for the production of a small quantity and a variety of products, and the production cost aspect (of the production speed) Surface).
For this reason, there existed a request to manufacture the above-mentioned large quantity and small variety of differential thickness steel sheets at low cost.

  On the other hand, the difference thickness steel plates manufactured by the rolling method have different rolling reductions in the rolling direction. In order to eliminate variations in the material, heat treatment is performed as necessary, and the surface is plated as necessary. Thereafter, press molding or hot press molding is performed to produce a member for an automobile.

  The present invention provides a manufacturing apparatus and a manufacturing method for a differential thickness steel sheet that can manufacture a variety of differential thickness steel sheets at low cost and can manufacture a differential thickness steel sheet having a thickness difference in the sheet width direction. With the goal.

  In order to achieve the above-mentioned object, the present inventors have conducted intensive research, provided a roll profile that partially reduces the width of the work roll without controlling the roll gap in the longitudinal direction, and Thus, the present inventors have found an apparatus and a rolling method that can efficiently produce a differential thickness steel sheet having a desired thickness difference in the sheet width direction by rolling.

According to the present invention based on the above findings,
(1) A small-diameter non-driven work roll having a roll profile that partially contacts the metal strip in the width direction at one or two symmetrical positions in the plate width direction in one housing, and the metal strip in the width direction A plurality of units comprising a large-diameter driving work roll having a roll profile that contacts the entire width and a backup roll for supporting these small-diameter non-driving work rolls are installed in the housing. An apparatus for producing a differential thickness steel plate having a thickness difference in the plate width direction.

(2) At least one or more differential thickness steel plate manufacturing apparatuses having a thickness difference in the sheet width direction as described in (1) are arranged in series, and a coiled metal strip is rewound upstream of the apparatus. Production of a differential thickness steel sheet having a thickness difference in the sheet width direction, comprising a rewinding machine and a winder that winds the partially rolled metal strip in a coil shape downstream of the apparatus. apparatus.

(3) In the apparatus for producing a differential thickness steel plate having a thickness difference in the plate width direction as described in (1) or (2) above, a small diameter non-drive having a roll profile that partially contacts the metal strip in the width direction The work roll is made up of one or more sleeve work rolls having a width W1 having bearings and a roll shaft serving as a core for fixing and supporting the position of the sleeve work roll. An apparatus for manufacturing a differential thickness steel sheet having a thickness difference.

(4) The sleeve work roll of the apparatus for producing a differential thickness steel sheet having a thickness difference in the sheet width direction as described in (3) above is symmetrical from the upstream to the downstream of the rolling and from the center of the metal strip toward the end of the sheet. An apparatus for producing a differential thickness steel sheet having a thickness difference in the sheet width direction, characterized by being arranged.

(5) In the apparatus for manufacturing a differential thickness steel sheet having a thickness difference in the sheet width direction as described in (4) above, the width W1 of the sleeve is 1/10 or less of the width W0 of the metal strip, and the sleeve A taper of 15 degrees or more and 50 degrees or less is provided at both ends of the sleeve, and the amount of overlap of the sleeve of the non-tapered portion is set to be 5 mm or more, and the rolling reduction ratio that is partially rolled by the sleeve work roll is The manufacturing method of the difference thickness steel plate which has board thickness difference in the board width direction characterized by setting it as 20% or less per pass.

(6) In the method for producing a differential thickness steel sheet having a thickness difference in the sheet width direction as described in (5) above, lubricating oil for cooling and lubricating the work roll and the metal strip is provided upstream of each unit. A method for producing a differential thickness steel sheet having a thickness difference in a sheet width direction, characterized by comprising:

(7) In the method for producing a differential thickness steel sheet having a thickness difference in the sheet width direction as described in ( 5 ) or ( 6 ) above, the large-diameter driving work roll is a roll having an outer layer having a Young's modulus of 300 GPa or more. A method for producing a differential thickness steel sheet having a thickness difference in the sheet width direction,
It is.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing apparatus and manufacturing method of a difference thickness steel plate which enable efficient manufacture of the difference thickness steel plate with a plate | board thickness difference in a plate width direction can be provided, for example, for automobiles When used as a steel plate material, it is possible to provide a lightweight material with stable quality at low cost.

It is a figure which shows one example of the manufacturing apparatus of the difference thickness steel plate of this invention. It is steel plate sectional drawing which shows the rolling schedule in the manufacturing method of the difference thickness steel plate of this invention. It is a sketch which shows 1 unit in the block mill in the manufacturing apparatus of the difference thickness steel plate of this invention. It is an example of the cross section of the difference thickness steel plate of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in this specification and drawing, about the component which has the substantially the same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

FIG. 1 is a diagram showing an example of a rolling apparatus according to the present invention.
In FIG. 1, the metal strip S is wound in a coil shape and attached to the rewinding machine 1. A tension roll 2 is disposed downstream of the unwinding machine 1, detects the tension applied to the metal strip S, and controls the motor current of the unwinding machine 1 so as to reach the target tension. Two block mills 3 a and 3 b are arranged downstream of the tension roll 2.

  In the upstream block mill 3a, a metal strip is partially contacted in the width direction at one or two symmetrical positions in the plate width direction in one housing within the main frame 10a and the main frame. Supports a small-diameter non-driving work roll 5 having a roll profile, a large-diameter driving work roll 6 having a roll profile that contacts the metal strip over the entire width in the width direction, and the small-diameter non-driving work roll 5 Six units 4 (4a to 4f) comprising backup rolls 7 and 8 are stored. A reduction device 9 for applying a rolling force to each unit is provided above the upper backup roll chock of each unit. In FIG. 1, the subscript a is added to the work rolls 5 and 6 to the reduction device 9 for the unit 4a on the most upstream side in the upstream block mill 3a. A plurality of similar units are also arranged in the downstream block mill 3b.

  A small-diameter non-driven work having a roll profile that partially contacts the metal strip in the width direction at one or two symmetrical positions in the plate width direction from upstream to downstream of each unit in the block mill of 3a and 3b. The roll 5, the drive work roll 6, and the backup rolls 7 and 8 are arranged as shown in FIG. FIG. 3 shows the arrangement relationship of roll groups in the unit 4f.

  Although not shown, a spindle is connected to the drive work roll 6 of the block mill and is driven by a single motor via a gear. Moreover, the peripheral speed of the work roll is designed to increase by several percent as it goes downstream. Further, although not shown, rolling lubricating oil (mineral oil-based rolling lubricating oil 100%) is supplied on the entry side of each unit.

  A tension roll 11 and a winder 12 are disposed downstream of the block mill, and the rolled metal strip S is wound in a coil shape. The tension applied to the metal strip is detected by the tension roll 11, and the motor current of the winder is controlled so as to reach the target tension.

A search experiment was conducted using the apparatus shown in FIG.
The metal strip S is a material having a tensile strength of 600 MPa, called 60 kg high tensile strength, and is a hot-rolling / pickling material having a plate thickness of 3 mm and a plate width of 1900 mm. This material is finished into a differential thickness steel plate having a plate thickness difference in the plate width direction shown in FIG.
The small diameter work roll has a roll diameter of 50 mm and a width of 120 mm. However, 10 mm from both ends is tapered at an angle of 45 degrees. This small-diameter, non-driven work roll 5 is a sleeve work roll 51 having a bearing, and this sleeve work roll is set on a roll shaft 52 as a core that fixes and supports the position of the sleeve work roll. (See FIG. 3).
The backup rolls 7 and 8 that support the work roll have a diameter of 100 mm, and the lower drive work roll 6 has a diameter of 200 mm and a trunk length of 2200 mm.

  In the present invention, most of the material of the reduced portion needs to move in the plate width direction. For this reason, only one of the above units is attached with one sleeve roll, and only the sleeve length of the sleeve roll is changed to perform partial rolling. As a result, the reduction ratio is about 20% when it is 1/10 or less of the material width. Until then, it was found that most of the material in the reduced portion moves in the sheet width direction, but if it is larger than that, most of the material in the reduced portion moves in the rolling direction to cause buckling. For this reason, the trunk length of the sleeve roll is set to 1/10 or less of the material width.

Further, when the rolling reduction per pass is increased, the shear stress at the boundary between the rolled portion and the non-rolled portion is increased, and the material is cracked (separated). Therefore, the rolling amount per pass is set to 20% or less.
The above-mentioned critical rolling reduction depends on the taper angle, but considering the ease of material movement in the width direction and the non-separability, it is preferable to provide tapered portions of 15 to 50 degrees at both ends of the sleeve. I found something favorable. Further, it has been found that the overlap amount of the sleeve of the non-tapered portion is preferably 5 mm or more from the viewpoint of quality (sheet thickness accuracy).

  Furthermore, it has been found that by making the material of the lower drive work roll 6 super hard with a Young's modulus of 300 GPa or more, the contact length is shortened and the rolling load is reduced, so that the size of the block mill can be made compact.

  In addition, in order to acquire this effect, it is not necessary to make the whole driving | working work roll superhard, and even if it makes only an outer layer super hard, it is equivalent, and the cost reduction of a work roll can be aimed at.

Further, by adjusting the number and position of the upper work rolls, it is possible to manufacture differential thickness steel plates having various profiles.
In addition, in FIG. 1, although the example which has arrange | positioned two block mills is shown, you may arrange | position one or three or more by the dimension of the difference thickness steel plate to manufacture.

(Example)
Using the apparatus shown in FIG. 1, a differential thickness steel plate having a thickness difference in the plate width direction shown in FIG. 4 was produced. The material and the like are the same as the conditions of the above-described sample of the differential thickness steel plate, and the dimensions of the differential thickness steel plate having a thickness difference in the longitudinal direction manufactured in the present invention are also the same as the above-described conditions.

In the embodiment of the present invention, rolling is performed by controlling the reduction device so that the reduction rate of each unit is 16.6% in the upstream block mill, and the reduction rate of each unit is 20% in the downstream block mill. It rolled by controlling a reduction device so that it might become. In the present invention, it was possible to produce at a rolling speed of 100 m / min.
Although it could be created by the conventional technique, the rolling speed is limited to about 1.5 m / min in order to keep the length of the tapered portion between 50 mm because the high speed reduction speed under electric reduction is 300 μm / sec. It was done.

  According to the present invention, it is possible to manufacture a differential pressure steel sheet having a sheet thickness difference in the rolling direction without passing through the tentering rolling process or with a part thereof being produced with a small number of passes. It is possible to produce differential thickness steel plates efficiently at low cost, which has great industrial significance.

DESCRIPTION OF SYMBOLS 1 Rewinding machine 2,11 Tension roll 3a, 3b Main frame 4a-4l Unit 5a-5l (Small diameter non-drive) Work roll 51 Sleeve roll 52 Roll shaft 6, 6a (Large diameter drive) Work roll 7, 7a, 8, 8a Backup roll 9a Reduction device 10a, 10b Main frame 12 Winder

Claims (7)

In a single housing, a small-diameter non-driven work roll having a roll profile that partially contacts the metal strip in the width direction at one or two symmetrical positions in the plate width direction, and the metal strip to the full width in the width direction. A plate width direction characterized in that a plurality of units comprising a large-diameter driving work roll having a roll profile in contact with each other and a backup roll for supporting these small-diameter non-driving work rolls are installed in the housing. An apparatus for manufacturing a differential thickness steel sheet having a difference in thickness.   At least one or more differential thickness steel plate manufacturing apparatuses having a thickness difference in the sheet width direction according to claim 1, and a rewinding machine for rewinding a coiled metal strip upstream of the apparatus. An apparatus for producing a differential thickness steel sheet having a sheet thickness difference in the sheet width direction, comprising a winder that winds the partially rolled metal strip in a coil shape downstream of the apparatus.   3. The apparatus for manufacturing a differential thickness steel plate having a thickness difference in the plate width direction according to claim 1 or 2, wherein a small-diameter non-driven work roll having a roll profile that partially contacts the metal strip in the width direction is a bearing. A thickness difference having a plate thickness difference in the plate width direction, comprising one or more sleeve work rolls having a width W1 and a roll shaft serving as a core for fixing and supporting the position of the sleeve work roll Steel plate manufacturing equipment.   The sleeve work rolls in the apparatus for producing a differential thickness steel sheet having a thickness difference in the sheet width direction according to claim 3 are arranged symmetrically from upstream to downstream of the rolling and from the center of the metal strip toward the edge of the sheet. An apparatus for producing a differential thickness steel sheet having a thickness difference in the sheet width direction.   5. The apparatus for manufacturing a differential thickness steel sheet having a thickness difference in the sheet width direction according to claim 4, wherein the width W1 of the sleeve is set to 1/10 or less of the width W0 of the metal strip, and 15 at both ends of the sleeve. A taper of not less than 50 degrees and not more than 50 degrees is provided, and the amount of overlap of the sleeve in the non-tapered portion is set to 5 mm or more, and the reduction ratio partially rolled by the sleeve work roll is set per pass. The manufacturing method of the difference thickness steel plate which has board thickness difference in the board width direction characterized by setting it as 20% or less.   In the manufacturing method of the differential thickness steel plate which has a board thickness difference in the board width direction of Claim 5, supplying the lubricating oil for cooling and lubricating this work roll and a metal strip upstream of each unit. A method for producing a differential thickness steel sheet having a thickness difference in the sheet width direction. The method for producing a differential thickness steel plate having a thickness difference in the plate width direction according to claim 5 or 6, wherein the large-diameter driving work roll is a roll having an outer layer having a Young's modulus of 300 GPa or more. A method for producing a differential thickness steel sheet having a thickness difference in the width direction.

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