JPH078364B2 - Width reduction press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a width reduction press in which buckling does not occur even if the width reduction amount per operation is increased.

[Prior Art] It has been researched to perform a width reduction of a material such as a slab by a press capable of achieving a large width reduction amount. Thus, when width reduction is performed by pressing, buckling occurs in the material when the width is about 1200 mm or more and the thickness is about 250 to 300 mm and the width reduction amount per time is 300 to 350 mm or more. . In order to prevent this buckling, it is possible to provide a pressing roll that presses the material surface.

[Problems to be Solved by the Invention] However, in the above-described press, buckling cannot be completely prevented unless the rolls are arranged at proper positions, and if presser rolls are provided on both sides, the number of rolls increases. However, there are problems such as high equipment costs and operation and maintenance costs.

The present invention has been made in view of the above circumstances and has an object to effectively suppress buckling with a small number of pressing rolls.

[Means for Solving the Problems] The present invention relates to a mold for performing width reduction pressing of a material, a diameter for pressing both sides of a material width direction substantially central portion of the material is approximately 600 mm or more, and a body length is approximately
It is configured with a presser roll of 00 mm or less.

[Operation] When the material is pressed from both sides in the width direction central portion by the pressing roll and the width reduction is performed by the mold, the material does not buckle even if the width reduction amount per time is large.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing the outline of a width reduction press of the present invention. In the figure, 1 is a housing, and 2a and 2b are paired left and right for width-reducing a material 4 such as a slab by mutually operating by reduction cylinders 3a and 3b. The molds 5 and 6 are a pair of upper and lower pressing rolls for pressing the substantially central portion in the width direction of the material 4 from the upper and lower surfaces and preventing the buckling of the material 4. The pressing rolls 5 and 6 have a diameter D of about 600 mm or more and a body length L of about 500 mm or less.

Next, the reason why the diameters D and the body lengths L of the press rolls 5 and 6 are set to the above values will be described based on the data obtained by the hot steel model experiment.

The relationship between the diameter D of the presser roll and the maximum contact pressure P _{0 of} Hertz is shown in the graph as shown in Fig. 2. The material is lost by the presser force of the presser roll and a dent occurs. The critical stress P ₀ ≈ PeKg The diameter D of the presser roll at / mm ² is about 600 mm, and if the diameter is more than that, no dent occurs in the material.
The shaded area A in FIG. 2 indicates the range of the pressure Pe at which no dent occurs.

The dent occurrence limit stress P ₀ is expressed by the following equation.

Where ν ₁ ; Poisson's ratio of material ν ₂ ; Poisson's ratio of roll E ₁ ; Young's modulus of material E ₂ ; Young's modulus of roll r ₀ ; Roll radius q; Load per unit width of material Kg / mm Presser roll Original slab width W ₀ without 900mm, 1200mm, 160
For 0mm material, width reduction ΔW ₁ = 100mm, ΔW ₂ = 20
When 0 mm, ΔW ₃ = 300 mm, and ΔW ₄ = 400 mm were applied and width reduction was performed, and whether or not buckling occurred in the material at that time, the graph as shown in FIG. 3 was obtained. In FIG. 3, ○ indicates no buckling, Δ indicates half buckling, and × indicates buckling. From this graph, when the slab width W ₀ is 900 mm, buckling does not occur even if the width reduction amount is about ΔW ₄ = 400 mm, and when the slab width W ₀ is 1200 mm, the width reduction amount is ΔW ₃ = 300 mm. If the width of the slab W ₀ is 1600 mm, a half buckling will occur if the width reduction is about ΔW ₂ = 200 mm. Therefore, the range in which half buckling or buckling occurs is the shaded area x above the line obtained by connecting Δ in FIG. 3, and this shaded area x is the presser roll required range. If the slab width W ₀ is about 1050 mm, the width reduction amount is ΔW ₄ = 400 m from the shaded area x.
If it exceeds m, it is considered that half buckling or buckling occurs.

Next, the relationship between the original slab width W ₀ and the dogbone foot length A when the above width reduction was performed without the presser roll is shown below for each width reduction amount ΔW ₂ , ΔW ₃ , ΔW ₄ (specific values are shown in Fig. 3 The same as in the above case), the graph of FIG. 4 is obtained. Further, when the position where the half buckling occurs for each of the width reduction amounts ΔW ₂ , ΔW ₃ , and ΔW ₄ is moved to the graph of FIG. 4 corresponding to the original slug width W ₀ , the position is indicated by ●. Therefore, the shaded area X above the line obtained by connecting the black circles is the presser roll required range.

The dogbone edge length A in the graph of FIG. 4 indicates the length of the portion where the dogbone is generated as shown in FIG.

By the way, in order to prevent the buckling of the material, it is desirable that the body length L of the presser roll is as long as possible. However, if the end of the presser roll is in the dogbone generating portion after the width reduction, the material is pressed by the width reduction. The roll will scratch it. Therefore, it is necessary that the body length L of the press roll is not applied to the dogbone portion of the material after the width reduction, and the body length L of the press roll for this is L = W ₀ −ΔW _n −2A.

For example, if the original slab width W ₀ = 1200 mm, the width reduction that causes half-buckling is ΔW ₃ = 300 mm and the dogbone rib length A = 150 mm, so the body length of the presser roll is L = (120
0-300) -2 x 200 = 500 mm, and in other cases it is about 500 mm. Therefore, if the body length of the press roll is 500 mm or less, the press roll does not scratch the dogbone generation part of the material.

Pressing the widthwise central part of the material 4 from the front and back sides with the pressing rolls 5 and 6 having a diameter D of about 600 mm or more and a body length L of about 500 mm or less,
When the width reduction is performed by the width reduction press, the material 4 does not buckle even if the width reduction amount per operation is as large as 300 to 350 mm.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[Effect of the Invention] According to the width reduction press of the present invention, it is possible to effectively prevent the buckling of the material with the pair of pressing rolls, and the equipment cost and the operation and maintenance cost are low because the pressing rolls are the minimum required number. Become. Various excellent effects can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view of one embodiment of the present invention, FIG. 2 is a graph showing the relationship between the diameter of the press roll and the maximum contact pressure of Hertz, and FIG. 3 is the width corresponding to the original slab width and width reduction amount. Fig. 4 is a graph showing the relationship with the rolling force, Fig. 4 is a graph showing the relationship between the original slab width and the dogbone foot length corresponding to the width reduction amount, and Fig. 5 is the dogbone foot length caused by the width rolling. FIG. In the figure, 2a and 2b are molds, 3a and 3b are reduction cylinders, 4 is material, 5,
6 indicates a presser roll.

Continuation of the front page (56) Reference JP-A-55-16719 (JP, A) JP-A-62-118933 (JP, A) JP-A-63-230202 (JP, A) JP-A-63-212001 (JP , A)

Claims (1)

[Claims] 1. A die for performing a width reduction pressing of a material, and a pair of upper and lower presser rolls having a diameter of about 600 mm or more and a body length of about 500 mm or less, which presses both sides of the material in the width direction at the center. Width reduction press.