JPS63130235A - Bending method - Google Patents

Abstract

PURPOSE:To reduce bending force, and also, to improve a yield by providing a clevis corresponding to the bending inside diameter and the plate width, on the side face which becomes the inside diameter side of bending of a band plate which is rolled and comes out, thereafter, executing the bending. CONSTITUTION:A stock 1 rolled by the upper and the lower rolling rollers 2, 4 is fed out forward. Immediately after this rolling, bending moment is added by a bending control means 3 which can move to the right and left from the side direction. By providing a clevis part 5 for reducing a deformed volume quantity N, the bending moment quantity can be reduced. According to this method, the yield of a product can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the production of large circular shapes or flanges, etc., which are used as parts of welded structures, for example, using strips as raw materials, and in particular: The present invention relates to a bending method for bending a welded flange from a strip plate after cutting the segments, and particularly for improving the material yield rate.

[Conventional technology]

Conventionally, when bending is performed, as shown in Fig. 3, a clevis (notch) is not provided in the material 1 in advance.Therefore, as shown in Fig. 1, horizontal bending of a large cross-sectional shape is performed. In case 1, the material is continuously fed out by rolling against the compressive force E generated on the inner diameter side of the bend, so the material feeding force F due to the rolling torque of the upper and lower rolling rolls becomes excessive.

Along with this, there is a problem that the bending moment M given by the bending regulating means 3 also becomes excessive, making it impossible to bend the radius/plate width = 1 or less. Since it was manufactured by bonding, the material yield rate was poor. Furthermore, in the implementation of a specific device, there is a problem in that a rolling mill with an excessively high rolling torque and a bending regulating means 3 having a large rigidity capable of withstanding the above-mentioned torque are required.

[Problem that the invention seeks to solve]

The above conventional technology does not consider bending a strip with a large cross section until the bending radius becomes smaller than the strip width. Therefore, when bending a strip with a large cross section, an excessive bending moment is required. When bending is performed until one bending radius becomes smaller than the sheet width, there is a problem in that defects such as edge waves or cracks may occur.

The object of the present invention is to provide a bending method for processing a large cross-section strip plate with a smaller bending moment, and a bending radius/plate width=1
It is an object of the present invention to provide a bending method that performs the following bending of a strip plate without defects such as edge waves or cracks.

[Means for solving problems]

The above object is achieved by providing clevises (notches) 5 in accordance with the bending radius and the plate width at a pitch P in accordance with the bending radius on the side surface which becomes the bending inner diameter side after bending the material 1.

Hereinafter, the shape of the clevis 5 and the dimension determination of the pitch P will be described (see FIG. 1), however, the symbols used are as follows.

L: material length) W: material plate width (W) R: bending inner radius (mm) w: product plate width (m) P: clevis pitch (a) T: material plate thickness (m) A: clevis width (m) Δh: Reduction amount (m) B: Clevis height, ) +2 = Neutral shaft circumference after bending (, n)...When bending 180° half ring Q': Inner diameter side end circumference after bending Length (in): 180° When bending a half ring, the R, W, and T of the strip to be processed are determined by the product specifications. The dimensions of the clevis 5 are as follows. The following is the case of 180° half-ring bending. first.

Δh=o, IXT...■ B=W/10...■L
=(W/2+R)π+2W ・・・■ Clevis 5 is set at every 30° angle, so R=(R+w/2
)π...■.

Ω'=(R-Bπ)...■W=w+B・
... ■ The circumferential length difference C between the neutral axis and the inner diameter end after bending is the basic requirement of the present invention that C is the entire width of the clevis 5 set every 30' and the compressive force due to the covers L and C. In order to reduce the occurrence of clevises 5 in 180' bending, there are seven clevises in total, so A=C/7.
... becomes ■.

The reduction of the bending moment M by the clevis 5 will be described using Fig. 1. Since C generally occurs during horizontal bending, the compressive force E acts in the opposite direction to the material feeding force F due to rolling. . Furthermore, during processing, a bending moment M necessary for bending must be added to the material feeding force F from the direction of the angle α0 formed by the rolling rolls 2 and 4 axes and the bending regulating means 3. Therefore, the compressive force E must be When the bending force increases, F also increases because the material is fed out continuously, and the 1 bending moment M also increases.

Therefore, by setting - for the total amount of deformation due to compressive force E, that is, by reducing the amount of deformation to N-G/N = -, not only the generated compressive force is reduced, but also the clevis The stress concentration effect corresponding to the deformation of the triangular shape is combined, and bending can be performed with the addition of a smaller bending moment M. In addition, even in the presence of intermittent (every 3°) revis,
Since roll bending is performed in the plastic state of the material directly under the rolls, the bending radius can be made into a smooth shape.

Here, since a compressive force is applied to the inner diameter side of the bend, even if there is a stress concentration effect at the tip of the clevis, cracks or the like will not occur from the tip of the clevis.

In this way, bending can be performed by applying a smaller bending moment M.

The material 1 with the clevis 5 set according to this calculation formula is rolled by ordinary upper and lower rolling rolls 2°4 with their respective axes parallel to each other, and after the same rolling direction, the material 1 is bent from the side. By adding moment M, it is possible to achieve a large cross section with a smaller bending moment, and bending radius/plate width =
It is also possible to bend products in the form of strips of 1 or less.

[Effect]

The upper and lower rolling rolls 2 and 4 are set parallel, that is, the angle formed by each axis is 0, the upper rolling roll 2 rotates under a constant rolling blade P, and the material 1 is rolled by about 10% of the plate thickness. and sent forward. Immediately after this rolling, the bending moment M is
is added.

At this time, when the clevis part 5 is reached, which reduces the deformed volume N due to the compressive force E generated on the inner diameter side of the bend, the compressive force E is reduced by the amount of deformation, and accordingly, the bending moment M is also reduced. Reduced. By providing the clevis portions 5 at 30° intervals around the entire circumference of the material 1, the bending moment M is reduced as a whole, and in the same bending shape, the bending process is performed with a smaller bending moment, and one clevis is provided. Therefore, bending with a bending radius/plate width of 1 or less can be achieved with a large cross section.

〔Example〕

An embodiment of the present invention will be described below.

Bending inner radius R=590nm, ill! Product plate width W = 600
According to the calculations described above, when processing a large cross-section 180° half-ring bent product with a specification of material plate thickness T = 150 rrn, the reduction amount Δh = 15 mm, the clevis height B = 60 mm,
Material board width W=660. Material length L = 4209 m, clevis pitch P = 278 m, and clevis width A = 1611 m were calculated. A clevis was set on the material by gas cutting, and then the gap between the upper and lower rolls 2 and 4 was set to 135 rm.

After that, one material is heated in a heating furnace, and the upper and lower rolling rolls 2
4, a bending moment was applied by the bending regulating means 3, which had been set in advance at a geometrically determined position, and the bending process was performed.

As a result of actually measuring the dimensions of the obtained 180° half-ring bent product, the plate thickness after bending was 135 m (outer diameter end).

137m (inner diameter end) 9 plates after bending @ (plate thickness center) = 60
5mm... After bending, the clevis part was placed on a turntable and removed by gas cutting, so the plate width and inner radius of bending after one bend are as follows:
Measured after this. A bending inner radius of 59,511 ml was obtained.

Furthermore, as shown in Fig. 3, the same shape is bent, that is, the material plate thickness T = 150 m, the plate width W = '; l Q
Qm.

For rolling bending with a reduction amount Δh=6 mm, the bending moment required for bending with a bending radius R=1000 mm to 2000 nm was able to be reduced to about 415. For example, in the comparison of bending radius R=1500m.

Without clevis, the required bending moment M is 9 tons-
m, on the other hand, if a clevis is provided, 6.5 ton" m
It became clear that the material could be processed with a bending moment of about 415.

Conventionally, it has been manufactured by cutting into segments by gas cutting or the like and then joining them by welding or the like. It becomes possible to bend products with bending radius/plate width = 1 or less from a straight strip material, and the material yield rate of segment products with bending radius/plate width = 1 or less is improved. In addition, in this example, 40%
Improved material yield rate. Since the bending moment applied by the bending regulating means can be processed in just a few minutes, the bending regulating means in the specific equipment used has a simple structure with low rigidity.
A simpler structure can be achieved.

〔Effect of the invention〕

According to the present invention, by applying a bending moment from the side direction by a bending regulating means immediately after normal rolling of a material in which a clevis (notch) is provided on the side surface that becomes the inner diameter side after bending, A strip plate with a large cross section can be bent from the rolled portion with a smaller bending moment.

[Brief explanation of the drawing]

FIG. 1 is a plan view (a) of a material according to an embodiment of the present invention, a plan view (b) during bending, and a cross-sectional side view (C), and FIG. 2 is an enlarged plan view during bending according to the present invention. Fig. 3 is a diagram showing the relationship between bending radius and bending moment in one embodiment of the present invention, and Fig. 4 is a cross-sectional view (a) and a plan view (b) of the prior art.
, (c). 1...Material, 2...Top rolling roll, 3...Bending regulation means, pot 2 section $j Kasumi

Claims (1)

[Scope of Claims] 1. Rolling in which a bending moment is applied to the strip rolled by upper and lower rolling rolls from the side direction of the bending outer diameter of the strip immediately after rolling, using a bending regulating means. A bending method, characterized in that a clevis is provided on the side surface of the strip plate on the inner diameter side of the bending plate, in accordance with the inner diameter of the strip and the width of the plate.