JP2007167910A - Metal strip passing method in continuous process line, and metal strip manufacturing method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress occurrence of troubles such as area reduction and breakage in a vicinity of a weld of a tail end of a preceding metal strip and a fore-end of a succeeding metal strip. <P>SOLUTION: A cut out 6 is formed in a width end of a metal strip in a vicinity of a weld 2 of a tail end 1A of a preceding metal strip and a fore-end 1B of a succeeding metal strip so as to reduce the difference in the tension distribution caused by the difference in flatness between the preceding metal strip and the succeeding metal strip. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a continuous process line for a metal strip, such as a steel strip production line, in which a metal strip is passed through a continuous process line in which a tail end of a preceding metal strip and a tip of a subsequent metal strip are welded. With regard to the plate method, in particular, when the steel strip after cold rolling is passed through the continuous annealing line, troubles such as fracture and drawing around the welded portion of the tail end of the preceding metal strip and the tip of the subsequent metal strip The present invention relates to a method for treating a periphery of a welded portion in order to suppress the occurrence of the welding.

  In recent years, the size of metal strip products desired by customers has been gradually increasing as the ratio of thin products with a thickness of 2 mm or less and wide products with a width of 1200 mm or more is wide. In the product, as shown in FIG. 8, it tends to be in the shape of a metal band product such as (a) ear extension, (b) belly extension, and the like. In FIG. 8, 1 indicates a metal band.

As an index indicating the degree of shape defect of the metal strip, in the case of ear stretch or belly stretch, an index called steepness is used. As shown in FIG. 9, when the metal band 1 shown in FIGS. 8A and 8B is seen from the side, the steepness λ is defined as L, the wave period in the plate thickness direction due to ear extension or belly extension, If the wave height is d,
λ = d ÷ L × 100 (%) (1)
These are distinguished by attaching a sign “+” in the case of the ear extension and a sign “−” in the case of the abdominal extension.

  In the manufacture of metal products, in order to pass a metal strip through a certain production line, the rear end of the preceding metal strip and the front end of the subsequent metal strip are often welded and continuously processed. When the metal strip is processed in the manufacturing process immediately before the manufacturing process to be processed in the manufacturing line, the rear end portion and the leading end portion of the trailing metal strip are connected to the leading end portion and the rear end portion of the metal band. Due to the characteristics of the manufacturing principle in the immediately preceding manufacturing process, such as when no tension is applied, there are many cases where a shape defect has occurred, and as shown in FIG. When the end portion and the leading end portion of the subsequent metal band 1B having a flat shape are welded while the shape is poor and passed through a continuous processing line such as a continuous annealing line (CAL) 200 shown in FIG. When these metal strips 1 are continuously passed through the production line, the welds will break. There are, also increased when the strip passing troubles aperture and breakage due to meandering outside weld occurs, operation rate is high risk of decrease. The same is true even if the defective shape portion is reversed at the rear end portion of the preceding metal strip 1A and the front end portion of the subsequent metal strip 1B.

  In FIG. 11, 210 is a coil rewinding device, 220 is a welding machine, 230 is an annealing furnace, 240 is a cooling zone, 250 is a water cooling facility, and 260 is a coil winding device.

  Therefore, conventionally, shape correction devices such as a leveler (see FIG. 12), a temper rolling mill (skin pass mill) (see FIG. 13), or the like are installed or manufactured in the entry and exit sections of each production line. Apart from the line, there was a method of correcting the shape defect part by installing a line dedicated to shape correction.

  Examples of these include, for example, a tension leveler that corrects the shape of the metal band under high tension described in Non-Patent Document 1, and a metal band that can be corrected even at low tension described in Patent Document 1. Examples include temper rolling mills.

  Further, the present applicant has proposed an uneven metal plate clamping roll, a method for correcting the shape of a metal plate, a method for welding a metal plate using the roll, and a continuous processing line described in Patent Document 2.

"Straightening-How to straighten plates, pipes, bars and wires-" (Japan Society for Technology of Plasticity: 1992: Corona Co., Ltd.) Japanese Patent Laid-Open No. 55-14172 Japanese Patent Laid-Open No. 2005-131687

  As mentioned above, the importance of shape correction is increasing along with the thinning and widening of metal band products, but it is enormous to invest in correcting the shape of metal bands by installing a dedicated line for shape correction. In addition, the number of manufacturing processes increases, which is disadvantageous for shortening the product delivery time.

  Therefore, as shown in FIG. 12, for example, a tension leveler 100 as described in Non-Patent Document 1 is installed in the middle of a production line capable of continuous processing, and the shape of the metal band is corrected inline. In order to secure the necessary high tension, the entry and exit bridle rolls 100 and 130 must be installed together with the leveling unit 120, which requires a large installation space. I need it. In FIG. 12, 121 is an extension unit, 122 is a C warp correction unit, and 123 is an L return correction unit.

  On the other hand, a temper rolling mill 150 as described in Patent Document 1 is installed in the middle of a production line that can be continuously processed as shown in FIG. 13, and dull roll 152 (in the case of bright roll 154). When the shape correction of the metal strip 1 is performed in-line using the other, the shape detector 20 is installed on the entrance side of the temper rolling mill 150, etc., according to the shape of the metal strip before correction. It becomes necessary to perform complicated control such as adjusting the correction load. In addition, there may be a problem that a space for installing a large housing 151 that can withstand a correction load is still necessary.

  Further, in the invention of Patent Document 2, uneven transfer is locally increased in a part of the width direction of the metal band, or a minute amount is caused by the flow in the width direction of the metal band, without causing troubles such as drawing and breakage. Very rare problems such as the occurrence of thin streaky patterns extending in the longitudinal direction due to the occurrence of folds and overlaps occurred. If the uneven transfer increases or a streak pattern is generated, it not only causes a problem in the product quality of the metal strip, but also causes problems such as inducing drawing and breakage starting from the streak pattern in the next process.

  Thus, the conventional equipment for correcting the shape of a metal strip requires a large machine space or an additional facility thereof, and therefore requires a large installation space. In addition, since the equipment itself becomes large, the installation cost of the equipment increases. In particular, when installing a conventional metal strip shape correction facility in an entry or exit section of an existing production line, the installation may not be possible due to installation space problems. In addition, there may be a problem in product quality of the metal strip.

  The present invention has been made to solve the above-mentioned conventional problems, and does not require extensive equipment, adjustment of the correction load according to the shape of the metal band before correction, etc. A method for passing metal strips in a continuous process line that can prevent the occurrence of troubles such as breakage and the like, and enables stable plate passing around the welded part with simple equipment. The purpose is to provide.

  In order to achieve this object, a first aspect of the present invention is a plate passing method in a continuous process line in which a tail end portion of a preceding metal strip and a tip end portion of a following metal strip are welded and passed. The width end of the metal band so that the difference in tension distribution caused by the difference in flatness between the preceding metal band and the subsequent metal band is reduced around the weld at the tail end and the tip of the subsequent metal band. This is a method for passing a metal strip in a continuous process line, characterized in that a notch is provided.

  The second aspect of the invention relates to a plate passing method in a continuous process line in which a tail end of a preceding metal strip and a tip end of a following metal strip are welded and passed, A cut is given to the width end of the metal band around the welded portion at the tip of the metal band, and the size of the cut is 300 mm or more in the longitudinal direction and 1/40 or more of the width of the metal band in the width direction. In addition, the present invention is a method for passing a metal strip in a continuous process line, characterized in that the cut corner portion is cut so as to have a curvature radius of 20 mm or more.

  Furthermore, a third invention is a method for producing a metal strip, characterized by using the metal strip passing method of the first or second invention.

  According to the present invention, stable plate passing around the welded portion of the metal strip is possible without requiring a large shape correction facility, and the tail end of the preceding metal strip and the tip of the subsequent metal strip are Occurrence of troubles such as drawing and breaking around the welded portion can be suppressed.

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

(First embodiment of the present invention)
Fracture and squeezing around the welded portion of the metal band occur due to a difference in the tension distribution in the width direction due to the difference in the shape of the preceding metal band and the subsequent metal band. This principle will be described in more detail with reference to FIG.

  In FIG. 2, 1A is a preceding metal band, 1B is a following metal band, and 2 is a welded portion between the preceding metal band and the following metal band. 3A shows the vicinity of the welded portion of the preceding metal strip, 3B shows the periphery of the welded portion of the subsequent metal strip, and the tension distribution at 3A is 4A and the tension distribution at 3B is 4B. FIG. 2 is an example in which the leading metal band 1A has an ear-extending shape and the trailing metal band 1B has an abdominal-extending shape. The longitudinal tension distribution in the ear-extending shape is a distribution in which the tension at the central portion of the width is large, such as 4A. Thus, the abdominal stretch shape has a distribution in which the tension at the width end is large as in 4B.

  When a tension distribution acts in the longitudinal direction of the metal strip, elastic elongation occurs in the longitudinal direction and elastic shrinkage also occurs in the width direction, which is a perpendicular direction. The relationship of the elastic contraction in the width direction to the elastic extension in the longitudinal direction is called a Poisson's ratio, and is about 0.3 in the case of a metal material. Accordingly, in the preceding metal band, a large tension acts in the longitudinal direction at the center of the width at the periphery 3A of the welded portion, and at the same time, a stress that tends to shrink in the width direction is generated. In the trailing metal strip, in the periphery 3B of the welded portion, the longitudinal tension at the center of the width is small, so that no stress is generated to shrink in the width direction. Therefore, in the welded part 2, the metal band is folded and overlapped at the center of the width of the succeeding metal band in such a manner that it is dragged by the shrinkage in the width direction of the preceding metal band. It causes trouble.

  Here, an example has been described in which the preceding metal band has an ear extension shape and the following metal band has an abdominal extension shape. However, the present invention is not limited to this example, and the preceding metal band and the following metal band having different shapes are welded and passed. In some cases, a similar problem occurs.

  Therefore, in the present invention, as shown in FIG. 1, a notch 6 is given to the width end portion at the welded portion periphery 3A, 3B at the tail end portion of the preceding metal strip 1A and the tip portion of the succeeding metal strip 1B. is there. Here, FIG. 1 shows an example in which the leading metal band 1A has an ear-extending shape and the trailing metal band 1B has an abdominal-extension shape, as in FIG. 2, but the tension distribution is almost uniform. . With such a tension distribution, stress that shrinks one of the metal bands at the center of the width as described with reference to FIG. 2 does not act, and it is possible to suppress occurrence of troubles such as drawing and breakage. .

  If the size of the cut is less than 300 mm in the longitudinal direction, it is not possible to completely prevent troubles in passage of the plate such as drawing or breaking as described in the following examples. preferable. The upper limit is not particularly limited, but is preferably set to 1000 mm or less from the reality of the specifications of a shearing machine or the like appearing in the next embodiment.

  If the size of the cut is less than 1/40 of the width of the metal strip in the width direction, it will not be possible to completely prevent the occurrence of troubles such as drawing and breakage as shown in the examples below. , 1/40 or more is preferable. On the other hand, if the size of the cut is too large in the width direction, the metal band is broken by the tension, and therefore it is preferable to set it to 1/4 or less.

  If the radius of curvature of the cut is less than 20 mm, it is not possible to completely prevent the trouble of passing the plate such as drawing or breaking as described in the following examples. The upper limit is not particularly limited, but is preferably 500 mm or less from the reality of specifications of a shearing machine or the like appearing in the next embodiment.

  FIG. 3 shows an embodiment in which the present invention is applied to a passing plate obtained by joining a preceding metal band and a subsequent metal band in a continuous annealing line (CAL) as shown in FIG. In FIG. 3, the preceding metal band and the subsequent metal band are welded by a welding machine 220. In the present invention, a notch is applied by a notch applying device 270 around the welded portion.

  The test specimens are low-carbon cold-rolled steel sheets (strips) of several thicknesses and widths as shown in Table 1 below, and are conducted on a continuous line that seams welds the preceding steel strip and the subsequent steel strip. did. The shape of the metal strip is a steepness measured by a contact-type split load cell, and the plus of the case of the ear extension shape and the minus of the abdominal extension shape with respect to the center of the width is displayed.

  A shearing machine as shown in FIG. 4 was used as the notching device 270 for imparting a notch to the width end portion around the welded portion. In FIG. 4, 1 is a metal band, the horizontal direction of the drawing is the width direction of the metal band, and the vertical direction is the thickness direction. 11 is a punch, 12 is a die, and 13 is a stopper. The metal band 1 placed on the die 12 is pressed while being sandwiched between the stoppers 13, and the punch 11 is lowered and cut to make a cut.

  FIG. 5 shows an example of a metal band with cuts, where L is the cut length, D is the cut depth, and R is the radius of curvature of the cut corner.

  As an example of the present invention, an incision length L of 400 mm, an incision depth D of 80 mm, and a corner radius R of 100 mm were prepared.

  As a comparative example, a sample not provided with a cut was prepared.

  In the continuous annealing line, Table 1 shows the results obtained by cutting and applying the notch around the welded portion of the preceding metal band and the succeeding metal band by the notch applying device 270. Here, the squeezing and rupturing are carried out by examining the ratio of occurrence of squeezing or rupture when the plate-passing experiment is performed 10 times under each condition. When it was 10% or more, it was set as x.

  In Table 1, Experiment No. which is an example of the present invention. In 2-1 to 7, no drawing or breakage occurred. Therefore, in the present invention example, stable continuous annealing line passing is possible.

  Experiment No. which is a comparative example. In 1-1 and 2, drawing or breakage has occurred.

  From the above results, it is possible to narrow the continuous line by cutting the width end portion of the metal strip around the welded portion of the tail end portion of the preceding metal strip and the tip portion of the succeeding metal strip. It is possible to suppress the occurrence of troubles such as breakage.

  In addition, in this invention, the method of giving a notch to the board edge part around a welding part does not need to be a shearing machine (press shear type) like FIG. 4, The roll shear type which gives a notch while rotating a circular blade Needless to say, any material can be used as long as it can cut the metal strip.

(Second embodiment of the present invention)
As a result of intensive studies on the relationship between the size of the cut in the first invention and the occurrence of plate troubles such as drawing and breakage, it was found that there is a suitable range for the size of the cut.

  FIG. 6 shows the results of investigation on various conditions regarding the longitudinal length L of the cut, the depth D of the cut, and the occurrence rate of plate troubles such as breakage and drawing. The depth in the width direction of the notch has a strong relative meaning with respect to the width of the metal band, so it was arranged by the ratio (%) to the width of the metal band. Here, the squeezing and rupturing are carried out by examining the ratio of occurrence of squeezing or rupture when the plate-passing experiment is performed 10 times under each condition. When it was 10% or more, it was set as x.

  As the size of the cut becomes longer in the longitudinal direction, the occurrence rate of drawing and breakage decreases. As shown in FIG. 6, it can be seen that the occurrence rate is zero under any condition as long as it is 300 mm or more. As the depth of cut increases in the width direction, the occurrence rate of drawing and fracture decreases, and the occurrence rate is zero under any conditions as long as it is 1/40 (2.5%) or more with respect to the width of the metal strip. It turns out that it becomes.

  In addition, when the corner portion of the cut is sharp, breakage may occur in rare cases starting from the corner portion. Therefore, it is desirable to provide a cut with a curvature in the corner portion. However, as shown in FIG. 7, when the curvature radius R of the corner portion and the occurrence rate of breakage are examined, a curvature radius of 20 mm or more is obtained. When applied, the occurrence of breakage is zero.

  From the above results, the cutting process is performed so that the size of the cut is 300 mm or more in the longitudinal direction, 1/40 or more of the width of the metal strip in the width direction, and the corner portion of the cut has a curvature of 20 mm or more. It can be seen that it is a suitable range.

  An example in which the present invention is applied to a sheet-passing plate in which a preceding metal band and a subsequent metal band are joined in a continuous annealing line (CAL) similar to that in Example 1 will be described.

  In this example, the shape of the cut was changed as shown in Table 2.

  In Table 2, Experiment No. which is an example of the present invention. In 2-1 to 7, no drawing or breakage occurred. Therefore, in the present invention example, stable continuous annealing line passing is possible.

  Experiment No. which is a comparative example. In 1-1 and 2, slight squeezing or breaking has occurred.

  From the above results, a cut is given to the width end of the metal strip around the welded portion of the tail end of the preceding metal strip and the tip of the subsequent metal strip, and the size of the cut is further increased in the longitudinal direction. 300 mm or more, width of 1/40 or more of the width of the metal strip, and cutting and giving a cut corner portion with a curvature radius of 20 mm or more, more reliably in a continuous line It is possible to suppress the occurrence of troubles such as breakage such as breakage.

The figure which shows an example of embodiment of 1st this invention Diagram explaining the cause of threading troubles such as squeezing and breaking around conventional welds The figure which shows typically the continuous annealing line (CAL) in the Example of this invention. The figure which shows the example of the shearing machine used in the Example of this invention The figure which shows the example of the incision around the welding part in this invention The figure which shows the suitable condition range of the cut length and the depth in 2nd invention The figure which shows the suitable condition range of the curvature radius of the corner part in 2nd invention. The figure which illustrates the shape of metal strip products, such as (a) ear extension and (b) belly extension A diagram illustrating the definition of steepness A diagram illustrating the appearance of welding with the tip of the trailing metal strip when the shape of the trailing end of the leading metal strip is defective The figure which shows the conventional continuous annealing line (CAL) typically The figure which illustrates technology about shape correction of the metal belt using the conventional tension leveler A diagram illustrating the technology related to shape correction of metal strips using a conventional temper rolling mill

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal band 1A ... Tail edge part of preceding metal band 1B ... End part of succeeding metal band 2 ... Welded part 3A ... Around welded part of preceding metal band 3B ... Around welded part of following metal band 4A ... At 3A Tension distribution 4B ... Tension distribution at 3B 6 ... Incision

Claims (3)

  In the passing method in the continuous process line in which the tail end of the preceding metal strip and the tip of the succeeding metal strip are welded and passed, the welded portion between the tail end of the preceding metal strip and the tip of the following metal strip In a continuous process line characterized in that a cut is given to the width end of the metal band so as to reduce the difference in tension distribution caused by the difference in flatness between the preceding metal band and the subsequent metal band. Metal strip passing method.   In the passing method in the continuous process line in which the tail end of the preceding metal strip and the tip of the succeeding metal strip are welded and passed, the welded portion between the tail end of the preceding metal strip and the tip of the following metal strip In the periphery of the metal band, a cut is given to the width end of the metal band, the size of the cut is 300 mm or more in the longitudinal direction, 1/40 or more of the width of the metal band in the width direction, and the corner of the cut is curved. A method for passing a metal strip in a continuous process line, which is applied by cutting so as to have a radius of curvature of 20 mm or more.   A method for producing a metal band, comprising using the method for passing a metal band according to claim 1 or 2.

Images