JP4556744B2 - Manufacturing method of unequal side unequal thickness angle steel - Google Patents

Description

  The present invention relates to a method for producing an unequal side unequal thick angle steel having excellent surface properties.

  Unequal side unequal thickness angle steel has an asymmetrical shape with long and short sides that differ greatly in length and thickness, and is often welded inside the hull and used as a stiffener in shipbuilding. .

  Due to its shape, the unequal side unequal thickness angle steel is difficult to produce by continuous rolling, and the produced parallel flange channel steel is coldly divided into two in the rolling direction, or by hole roll rolling. Manufactured.

  FIG. 3 is a diagram for explaining the steps of the perforated roll rolling method. The steel slab heated to a predetermined temperature in the heating furnace is subjected to rough rolling (BD) and intermediate rolling (R1, R2) and then finish rolling. Rolled into final product shape.

In rough rolling (BD), a steel slab having a rectangular cross section is made into a rough steel slab having a short side and a long side, and multiple passes of reciprocating rolling are performed by intermediate rolling (R1, R2). It is a flat shape in which only a part of the long side of the rectangle is convex, and it is made into a product shape all at once by finish rolling with an upper roll and a lower roll having product shapes.
Therefore, by bending in finish rolling, a phenomenon called “biting” occurs in which a part near the toe part of the long side is scraped off by a hole mold, and then that part is crimped to the surface of the long side. .

  FIG. 4 is a diagram for explaining a state in which “biting” occurs in finish rolling. The unequal side unequal thick angle steel 300 is partly short between the upper perforated roll 100 and the lower perforated roll 200. The side 320 forms a convex part, and the long side 310 is bitten horizontally.

  The unequal side unequal thick angle steel 300 is rolled into a final product shape by the long side part 110 and the short side part 120 of the upper perforated roll 100 and the long side part 210 and the short side part 220 of the lower perforated roll 200. .

  At the time of rolling, the corner portion 110a of the upper perforated roll 100 is in acute contact with the tip of the long side 310, so that a part of the long side 310 is scraped off, and the scraped portion is removed by subsequent rolling. Crimped to the surface of the long side 310.

  FIG. 5 schematically shows a state in which the surface scrapes C are generated by continuously pressing the portion cut off on the surface of the long side 310.

In order to prevent this, it is effective to enlarge the R portion at the tip of the long side 110a of the upper perforated roll 100.
Patent Document 1 relates to an unequal side unequal thick angle steel, its manufacturing method and manufacturing apparatus, using two universal rolling mills as an intermediate rolling mill, and the first Ubersal rolling mill with the short side of the rough steel slab as the vertical direction After rolling, it is described that the biting portions formed at the corner portions of the short side and the long side are extinguished by rolling using the other versal rolling mill.
In addition, since the short side of the coarse steel slab is conveyed in the vertical direction, only the short side can be reliably cooled to a desired temperature by using a cooling device that injects cooling water in the horizontal direction. When transported to the product, the temperature of the long side and the short side of the product can be made uniform, and the occurrence of left and right bends can be prevented.
JP 2003-205301 A

  However, as shown in FIG. 4, when the R portion at the tip is enlarged, rolling at that portion becomes insufficient, and a new phenomenon occurs in which the material protrudes from the joining portion of the upper and lower rolls.

  FIG. 6 is a diagram for explaining the pinch phenomenon. The tip of the long side 310 is rolled by the long side 210 of the lower hole roll and the tip 110a of the long side of the upper hole roll. When the part is large, the ear part 210a is generated. In addition, since the pressing with the upper roll is weakened, the lower end of the long side 310 is rounded without being angular, and the shape is deteriorated.

  The method described in Patent Document 1 uses a universal rolling mill for intermediate rolling in the configuration of the rolling line, and it is necessary to form the hole shape so that the short side is substantially in the vertical direction. It is difficult to apply to.

  Therefore, the present invention provides a method for producing an unequal side unequal thick angle steel with excellent surface properties that reliably prevents surface defects due to bite breakage by partially changing the shape of the perforated roll used for finish rolling. The purpose is to do.

The object of the present invention is achieved by the following means.
1 Unequal side unequal thickness that is finished and rolled using an upper roll provided with a taper portion so that the plate thickness near the tip portion of the long side increases toward the tip portion at the tip portion of the portion that rolls the long side It is a manufacturing method of angle steel, Comprising: The said taper part is made into the length which becomes 4 to 6% of each product long side width from the flat part of a long side to the most advanced part, The long side side of an upper roll The manufacturing method of the unequal side unequal thickness angle steel characterized in that the taper part is separated by 1.2 to 4% of the long side plate thickness of each product from the regular hole type dimension part.

  2 At the tip of the portion that rolls the long side, a curved portion that connects from the tip to the flat portion of the long side with a predetermined curvature so that the plate thickness near the tip of the long side increases toward the tip. It is a manufacturing method of unequal side unequal thick angle steel that is finish-rolled using an upper roll provided, wherein the curved part extends from the flat part of the long side to the most advanced part, and the section is divided into each product long side width. 4 to 6% of the length, and at the most distal portion on the long side of the perforated roll, the radius is 100 to the outside of the normal perforated dimension portion and 1.2 to 4% of the long side plate thickness of each product. A method for producing unequal side unequal thick angle steel, characterized by a curved portion of ˜350 mm.

  According to the present invention, the tip of the perforated roll prevents a part of the surface of the material to be rolled from being scraped off, resulting in an unequal side unequal thick angle steel with excellent surface properties, which is extremely useful in industry. It is.

  The present invention is used for finish rolling, and defines the dimensional shape of the upper hole-type roll, and when the taper part and the curved part are provided on the long-side tip of the hole-type roll, when in contact with the material to be rolled, The contact pressure is reduced.

  FIG. 1 is a schematic diagram for explaining a roll arrangement in finish rolling, in which 1 is an upper perforated roll, 11 is a long side portion of the upper perforated roll 1, and 11 a is a long side portion of the upper perforated roll 1. The front end portion, 12 is the short side portion of the upper perforated roll 1, 2 is the lower perforated roll, 21 is the long side portion of the lower perforated roll 2, and 22 is the short side of the lower perforated roll 2. The side part 23 is a long side part of the lower perforated roll 2, and is opposed to the front end part 11 a of the long side part of the upper perforated roll 1 and forms a corner part of the front end part of the long side of the product. Show.

  The portion a surrounded by the long-side tip portion 11a of the upper perforated roll 1 and 21 and 23 of the lower perforated roll 2 is a portion where rolling deformation is restricted.

  FIG. 2 is a diagram for explaining an upper perforated roll used in the method for manufacturing an unequal side unequal thickness chevron according to the present invention so that a portion extruded by rolling can escape to the long side end portion 11a. A taper part and a curved part are provided.

When providing a taper part, from the flat part of the long side to the most advanced part, the section l _{AB is set} to 4 to 6% of the long side width of each product, and the most advanced part on the long side of the perforated roll In this case, the taper portion has an amount h that is 1.2 to 4% outside the long-side plate thickness of each product from the regular hole-shaped dimension portion.

In the case of providing a curved portion, from the flat portion of the long side to the most advanced portion, the section l _{AB is set} to 4 to 6% of the long side width of each product, and the most advanced portion on the long side of the perforated roll , A curved portion having a radius of 100 to 350 mm is provided so as to obtain an amount h that is 1.2 to 4% outside the long-side plate thickness of each product.

When the length l _{AB of the} section to which the taper portion or the curved portion is imparted and the distance from the regular hole-shaped dimension portion to the outside in the most distal portion on the long side of the hole-shaped roll: h exceeds the upper limit of the above range, Thickness at the end of the long side of the product increases, resulting in dimensional defects, and the rolling balance at each part of the long side during molding and rolling is lost, and the unloading direction becomes unstable when unloaded from the rolling mill after rolling. . In particular, the reduction balance is greatly influenced by the length of the section to which the tapered portion or the curved portion is added.

  On the other hand, when it is less than the lower limit of the above range, the occurrence of the bite-out phenomenon cannot be prevented.

  Forming and rolling was performed using unequal side unequal thickness angle steel with various dimensions and plate thicknesses varied, and the occurrence of biting phenomenon was observed.

  Table 1 shows the observation results, the dimensional shape of the unequal side unequal thick angle steel subjected to the test, and the shape applied to the long side tip of the perforated roll. The comparative example shows a case where a dimensional shape is outside the scope of the present invention, and the conventional example uses a perforated roll that does not process the long side end portion. The number of test pieces was 250, and the occurrence rate was less than 10%.

The figure explaining the roll arrangement | positioning in finish rolling. The figure explaining this invention. The figure explaining the rolling process of an unequal side unequal thickness angle steel. The figure explaining a chewing stick. The figure which shows an example of a chewing rod. The figure explaining an ear part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper perforated roll 11 Long side part 11a of upper perforated roll Long edge part of upper perforated roll 12 Short side part of upper perforated roll 2 Lower perforated roll 21 Lower perimeter roll 21 Long side portion 22 of the perforated roll Short side portion 23 of the lower perforated roll 100 Location for forming the corner portion 100 Upper perforated roll 200 Lower perforated roll 300 Unequal side unequal thick angle steel 310 Long side 320 Short side

Claims (2)

  An unequal side unequal thickness angle steel that is finished and rolled using an upper roll provided with a tapered portion so that the plate thickness near the tip of the long side increases toward the tip at the tip of the portion that rolls the long side. The taper portion has a length that is 4 to 6% of the long side width of each product from the flat portion of the long side to the foremost portion, and the longest side on the long side of the upper roll. A method for producing an unequal side unequal thickness angle steel, characterized in that the tip part is a tapered part separated from the regular hole type dimension part by 1.2 to 4% of the long side plate thickness of each product.   At the tip of the part that rolls the long side, a curved part that connects from the tip to the flat part of the long side with a predetermined curvature is provided so that the plate thickness near the tip of the long side increases toward the tip. In this method, the curved portion extends from the flat portion of the long side to the foremost portion, and the section is divided into 4 pieces of each product long side width. A radius of 100 to 350 mm, which is a length of about 6%, and is separated from the regular hole mold dimension part by 1.2 to 4% of the long side plate thickness of each product at the longest side of the perforated roll. A method of manufacturing an unequal side unequal thick angle steel characterized in that