JP2012232335A - Method of manufacturing ring having irregular cross-sectional shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a 3-roll type ring rolling method of such a product having unsymmetrical and irregular cross-sectional shape wherein no disturbance of product attitude occurs during rolling, no cavity flaw occurs on the annular surface and the service life of a roll is not reduced when manufacturing a product having complex and irregular unsymmetrical cross-sectional shape.SOLUTION: In the ring rolling method, two main rolls 1a and 1b are inclined right and left, the tip ends of the two main rolls 1a and 1b are brought into contact with each other like V shape, and a loop material 4 is engaged with a hole 3a formed of a recessed groove with a complex and unsymmetrical cross-sectional shape that is formed on the tip end. The outer circumferential surface 6b of a mandrel 6 is brought into contact with the inner surface 4a of the loop material 4, and it is put into the hole 3a and is pressed thereto, thereby working a rolling force on the entire surface of the loop material 4. At the same time, the respective numbers of rotation of the two main rolls 1a and 1b inclined right and left are made to be variable by a motor, and a difference between a roll circumferential velocity and a circumferential velocity of the annular product, namely a relative velocity is set to 700 mm/sec or less.

Description

  The present invention is an irregular cross-sectional shape by a three-roll type ring rolling device composed of two main rolls inclined in a V-shape on the left and right sides, which is suitable for manufacturing an annular shaped member having an irregular cross-sectional shape having an asymmetric cross section. The present invention relates to a method for manufacturing a ring.

  A general ring rolling device called a two-roll type ring rolling device or a horizontal ring rolling device is effective for manufacturing a product having a rectangular cross section. However, it is considered that it is difficult to manufacture a ring-shaped material having a deformed cross section, particularly an asymmetric cross section, by this ring rolling apparatus, or that a high rolling control technique is required.

  As a machine suitable for the production of annular profiles or annular asymmetric cross-section profiles, two rolls that press the outside of the annular object are tilted to create a hole shape between the adjacent side and the roll or mandrel, and the mandrel is advanced and retracted. Thus, a ring rolling device has been proposed in which a rolling force is simultaneously applied to the entire surface of the annular profile member to produce an annular product (see, for example, Patent Document 1). However, the reason and grounds that this ring rolling device is suitable for manufacturing an annular profile or an annular asymmetric cross-section profile are not clarified. Therefore, the control method for improving the formability of the annular asymmetric cross-section having a complicated cross section as described above has been unknown.

  Moreover, in order to obtain a deformed cross-section ring, a method has been proposed in which a spinning roller is partially pressed sequentially and rolled into a deformed cross-section ring (see, for example, Patent Document 2). Further, in order to eliminate the peripheral speed difference, there has been proposed a deformed ring rolling apparatus in which a synchronous plate is provided as an additional disk to a rotating disk provided on the side of the mandrel (see, for example, Patent Document 3). ). However, these apparatuses are not related to a three-roll type ring rolling apparatus.

Japanese Patent Publication No. 34-7408 Japanese Patent Laid-Open No. 4-361833 JP 2001-121233 A

  The problems enumerated when manufacturing a product (hereinafter referred to as “product”) which is a ring-shaped cross section shaped material having an irregular cross section, particularly an asymmetric cross section, by a ring rolling device are as follows. Since the outer diameter dimension of each part of the surface perpendicular to the axis of the product is different for each part, the peripheral speed of the part of the main roll contacting the part is also different. For this reason, a difference in peripheral speed, that is, a relative speed is generated between the peripheral speeds of the main roll and the product. The greater the difference in relative speed at the outer diameter portion of the product, the more slippage occurs between the main roll and the product at that portion during rolling by ring rolling. The greater the slip, that is, the greater the difference in relative speed, the more disturbed the posture of the product during rolling, and the surface properties of the product deteriorated due to slip, resulting in mushy wrinkles on the surface of the annular part. In addition, adverse effects such as a reduction in roll life are brought about.

  On the other hand, a ring rolling device in which the tip ends of two main rolls of a three-roll type are in contact with each other in a V shape is a conventionally used mechanism. This three-roll type ring rolling device is said to be advantageous in the production of products. However, in the manufacture of products using a three-roll type ring rolling device, the reduction mechanism is not technically clear, and therefore a method for further improving moldability has not been known.

  Therefore, the problem to be solved by the present invention is that the peripheral speed of the left and right main rolls can be changed in accordance with the peripheral speed of the outer diameter of the annular deformed cross-section material whose section of the workpiece is a deformed product. Yes, this work can be done by changing the peripheral speed of the main roll according to the peripheral speed of the outer diameter of the annular deformed cross-section material, which is the work material, using a three-roll type ring rolling device that can manufacture products. The object is to provide a method for producing a near net shaped product by improving the formability of an annular profile section of a product. That is, in the manufacture of products having a complicated cross section by a ring rolling device, particularly products having an asymmetrical annular profile, the ring shape is deteriorated due to the deterioration of the surface properties of the rolled product without disturbing the posture of the product during rolling by ring rolling. It is an object of the present invention to provide a method for producing a product having an asymmetrically deformed cross section by a three-roll type ring rolling device which does not cause creaking on the surface and does not reduce the roll life.

  The means of the present invention for solving the above-mentioned problems is, in the means of claim 1, a method for producing a product having an asymmetric cross section by a ring rolling device. In this method, two main rolls are tilted to the left and right so that the leading end of the main roll comes into contact with the V-shape, and the asymmetric cross-section of the concave groove formed at the tip that makes contact with the V-shape. An annular material, which is a workpiece, is fitted into the hole mold, and the outer peripheral surface of the mandrel is brought into contact with the inner peripheral surface of the annular material, and the outer peripheral surface is fitted into the hole mold. Ring rolling by pressing the outer peripheral surface of this mandrel that abuts against the hole mold, applying a rolling force to the entire surface of the annular material, and varying the number of rotations of the main roll inclined to the left and right within a certain range with a motor A method for manufacturing a product having an asymmetric cross section.

  According to a second aspect of the present invention, the method of ring rolling by rotating the rotation speed of each of the main rolls tilted to the left and right within a certain range with a motor is the roll diameter and rotation at the locations where the left and right main rolls respectively contact the annular material. The number of rolls is controlled so that the peripheral speed of the roll at this location is within a certain range, and the main roll inclined to the left and right and the peripheral speed of the roll at the location where the annular material that is the work material abuts and the work material. 2. The asymmetric cross section of the means of claim 1 comprising ring rolling the annular material such that the difference in peripheral speed of the annular material (hereinafter referred to as “relative speed”) is 700 mm / sec or less. It is a method of manufacturing a product having the same.

  By adopting the above means, in the means of claim 1, the rolling force is applied to the entire surface of the annular material, and the rotational speed of the main roll inclined to the left and right is made variable by a motor within a certain range. By controlling the rotation speeds of the left and right main rolls that are in contact with the same part of the asymmetrical annular material, which is a processed material, to a ratio within a certain range, it is possible to suppress the occurrence of deviation between different parts. Yes, especially in the manufacture of products with asymmetric cross-section, the irregular shape of the annular material that is the workpiece during rolling and the deterioration of the surface properties of the annular material, that is, the left and right main rolls and the annular variant that is the workpiece It is possible to suppress mushy wrinkles generated on the surface of the annular deformed cross-section material due to the slip speed due to the deviation from the surface of the cross-section material, while each main roll roll Such a reduction in the life can be suppressed, the present invention provides excellent effects.

The typical sectional view showing the basic shape of the 3 roll type hot rolling device by a right and left main roll and a mandrel. FIG. 4 is a schematic cross-sectional view showing arrows of the left and right main roll diameters, the rotation directions of the left and right main rolls, the roll diameters at the positions of the workpiece, and the rotation directions of the workpiece. Typical sectional drawing which shows the length and angle of each location of a product with an arrow, respectively. (A) of a taper inner ring | wheel is an external appearance, (b) is a figure which shows a cross section. Schematic diagram of mussels that occur on the tapered inner ring when the sliding speed is high. (A) The cross-sectional shape before a process of a cyclic | annular deformed raw material, and the schematic diagram of the cross-sectional shape after a (b) process.

Embodiments of the present invention will be described below with reference to the drawings. First, prior to this description, a known basic shape of a three-roll type ring rolling device will be described with reference to FIG. The two main rolls 1 composed of the right main roll 1a and the left main roll 1b are inclined to the right and left by 20 degrees from the horizontal to the left and right respectively to obtain a right main roll main axis angle θ ₁ and a left main roll main axis angle θ ₂ . The inclined front end 2a of the right main roll 1a and the front end 2b of the left main roll 1b are brought into contact with each other to form a V shape. In this case, the left and right main rolls 1 have the same diameter and the same rotational speed. In this way, the V-shaped tip 2 composed of the two right main rolls 1a and the left main roll 1b in contact with the V-shape is formed. A rectangular hole mold 3 a made up of concave grooves 3 having a uniform shape on the left and right is formed at the distal end portion 2. Next, an annular material 4 as a workpiece is fitted into a rectangular hole 3a formed in contact with the V shape of the tip 2 of the right main roll 1a and the left main roll 1b. Further, the mandrel 6 is disposed on the inner peripheral surface 4 a of the fitted annular material 4, the outer peripheral surface 6 b of the mandrel 6 is brought into contact with the inner peripheral surface 4 a of the annular material 4, and the outer peripheral surface 6 b of the mandrel 6 is Is fitted into a rectangular hole mold 3a made of a concave groove 3. The shape of the rectangular hole 3a is bilaterally symmetrical and uniform. Accordingly, the cross-sectional shape of the annular material 4 as the workpiece is also symmetrically formed evenly. Further, the outer peripheral surface 4b of the annular material 4 which is a workpiece located on the opposite side to the left and right main rolls 1 is supported by the backup roll 7 from behind and formed into a three-roll type ring rolling device. ing.

  Next, a three-roll type ring rolling device that forms the product 6 having an asymmetric cross section according to the present invention will be described with reference to FIG. The shape of the right main roll 1a of the left and right main rolls 1a and the tip 2 of the left main roll 1b of the three-roll type ring rolling device is different from the three-roll type ring rolling device of FIG. 1 described above. doing. That is, as shown in FIG. 2, the right and left main rolls 1a and left main rolls 1b are formed with concave grooves 3 having a cross-sectional shape that is asymmetrical on the left and right. When the annular material 4 having a deformed cross section, which is a workpiece, is fitted into the groove 3 having an asymmetric sectional shape, the inner peripheral surface 4a of the annular material 4 of the left and right asymmetric hole mold 3a at the tip 2 of the main roll 1 is obtained. The mandrel 6 is disposed in contact with the outer peripheral surface 6b. Further, since the left and right main rolls 1 are the same as those in FIG. 1 and are omitted in FIG. 2, the mandrel 6 is an annular material that is a workpiece that is symmetrically positioned on the opposite side of the hole mold 3a. 4 is supported by a backup roll 7 from behind to form a ring rolling device.

  By the way, in the three-roll type ring rolling device for forming the product 6 having an asymmetric cross section according to the present invention, the roll diameter and roll width of the right main roll 1a and the roll diameter and roll width of the right main roll 1b are the same. If it exists, since the manufacturing cost of these two main rolls 1 itself becomes low, it is preferable. However, since the product 6 having an asymmetric cross section is formed, the tip portion 2 abutted in a V shape is formed from a hole mold 3a which is a concave groove 3 having an asymmetric shape on the left and right sides. The left and right shapes are not necessarily the same. For example, in the case where the tapered inner ring 9 of the roller bearing 8 having the shape shown in FIG. 4A is manufactured, as shown in FIG. 2, the shape of the hole mold 3a is not necessarily the same symmetrical shape. Therefore, when viewed in the cross-section of FIG. 2, at the points where the shape of the asymmetric hole mold 3a is mutated, as indicated by the respective arrows, at the respective mutating points of the right main roll 1a and the left main roll 1b. The roll radius and the roll width of each part of the right main roll 1a and the left main roll 1b are not the same.

That is, as shown in FIG. 2, the main shaft angle of the rotation main shaft 15 of the right main roll 1a is θ ₁ , and the main shaft angle of the rotation main shaft 16 of the left main roll 1b is θ ₂ . Further, Rr ₁ indicated by the arrow of the right main roll 1a is the roll radius of the arrow, and the arrow Rr ₂ of the right main roll 1a is the roll radius of the arrow. Rl ₁ indicated by the arrow of the left main roll 1b is the roll radius of the arrow, and Rl ₂ indicated by the arrow of the left main roll 1b is the roll radius of the arrow, and is indicated by the arrow of the left main roll 1b. Rl ₃ is the roll radius of the arrow, and Rl ₄ indicated by the arrow of the left main roll 1b is the roll radius of the arrow. The dimensions of the product (Product) 6 shown in FIG. 6B are shown in FIG. 3. The large outer diameter is P ₁ , the small outer diameter is P ₂ , the groove outer diameter is P ₃ , the width is P ₄ , The width of the outer diameter portion is P ₅ and the width of the small outer diameter portion is P ₆ . Furthermore, the angle that forms the slope between the groove outer diameter from the small outer diameter right end portion is P ₇ , the length of the slope between the groove outer diameter and the large outer diameter left end portion is P ₈ , and the groove outer diameter from the small outer diameter right end portion is the length P ₉ between the width P ₁₀ between the grooves outer diameter and the large outer径左end, small outer diameter mutation point and Mizogai span length of P _11, the difference between the large outer diameter and Mizogai diameter P ₁₂ , the length of the slope between the right end of the small outer diameter and the groove outer diameter is P ₁₃ , the angle of the slope between the left end of the large outer diameter portion and the groove outer diameter with respect to the large outer diameter is P ₁₄ , and The angular velocity of the product 6 is ωp, and as shown in FIG. 2, the angular velocity of the right main roll 1a is ωr, and the angular velocity of the left main roll 1b is ωl.

At this time, in FIG. 2, the coincidence point between the outermost peripheral portion of the roll radius Rr ₁ of the right main roll 1a and the outermost peripheral portion of the roll radius Rl ₁ of the left main roll 1b is defined as A point. This and the peripheral speed Vr ₁ of the annular profile industrial castings are products 5 at the point A, the peripheral velocity Vl ₁ peripheral speed Vr ₁ and the left main roll 1b of right main roll 1a is assumed to be coincident, respectively, each The roll radius and roll peripheral speed are obtained by the following equations.

Roll radius Rr ₁ = Rr ₂ + P ₅ × sin θ ₁
Rl ₃ = Rl ₂ + P ₆ × sin θ ₂ + P ₉ × sin (θ ₂ −P ₇ )
Rl ₁ = Rl ₃ −P ₁₄ × sin (90 ° −θ ₂ −P ₁₄ )
Rl ₄ = Rl ₂ + P ₆ × sin θ ₂
Roll peripheral speed Vr ₁ = Rr ₁ × ωr
Vr ₂ = Rr ₂ × ωr
Vl ₁ = Rl ₁ × ωl
Vl ₂ = Rl ₂ × ωl
Vl ₃ = Rl ₃ × ωl
Vl ₄ = Rl ₄ × ωl
On the other hand, from the assumption A, the peripheral speed of each product 5 is determined.
By the way, since the peripheral speed of the arrow r ₁ of the right roll at point A is Vr ₁ and the large outer diameter of the product 5 is P ₁ , the angular velocity ωp of the workpiece to be the product 5 is ωp = Vr ₁ ÷ P _1.
It is obtained by
Therefore, the peripheral speed Vp ₂ of the small outer diameter P ₂ of the product 5 is
Ｖ Vp ₂ = ωp × P ₂
It is obtained by Also,
The peripheral speed Vp ₃ of the groove outer diameter P ₃ of the product 5 is
Ｖ Vp ₃ = ωp × P ₃
It is obtained by
From the above, the Rr ₁ site, Rr ₂ site, Rl ₁ site, Rl ₂ site, Rl ₃ site, Rl ₄ site shown in the following Table 1 and the roll of each site are shown. Peripheral speed, product peripheral speed, and difference (relative speed). The aim of the invention according to claim 2 of the present invention is to set the relative speed difference in Table 1 to be 700 mm / sec or less.

The number of rotations of the main rotation shaft of each of the right main roll 1a and the left main roll 1b, right roll arrow r ₂ , left roll arrow l ₂ , right roll arrow r ₁ , left roll arrow l ₁ , relative speed difference (mm / sec) Table 2 shows the relative speed difference in each case, the stability of the posture when machining the workpiece, the evaluation of the surface properties of the workpiece, the roll life, and their overall evaluation. It was.

  In each evaluation in Table 2, ◎ is excellent, ○ is good, △ is not good but is acceptable, x is inferior outside the acceptable range, xx is out of acceptable range The moldability is very poor. When these evaluations in Table 2 are compared with the values of the relative speed difference, No. 7 has a relative speed difference of 684.9 mm / sec. The relative speed difference of No. 8 is 709.5.9 mm / sec. 7 and no. Between 8, there is a relative speed difference mutation point to obtain a product 5 that can withstand use. In the overall evaluation, when looking at the relative speed differences indicated by 、, ○, △, in the present invention, 700 mm / sec or less is the most important requirement for forming the product 5 that is the annular deformed cross-section shape material. It can be understood from this comprehensive evaluation.

  In the present invention, the right main roll 1a is rotated at a constant rotational speed, and the left main roll 1b is set to No. 1 in Table 2. 1-No. As shown in FIG. 8, ring rolling is performed by rotating at the same constant rotation speed, or the right main roll 1a is rotated at a constant rotation speed, and the left main roll 1b is set to No. 2 in Table 2. 9-No. When ring rolling is performed by rotating at different constant rotational speeds as in FIG. 13, in any case, the asymmetric hole mold 3 a of the tip 2 formed by the right main roll 1 a and the left main roll 1 b is used. The roll diameters at the respective locations will be different. Therefore, the rotational speeds are different between these portions. Due to the difference in rotational speed, a rotational speed shift occurs between the different locations of contact between the main roll 1 and the annular material 4 that is the workpiece. Due to the deviation of the rotational speed, the ridge 10 is formed on the outer peripheral surface 4b of the annular material 4 which is the workpiece. For example, as shown in FIG. 5, a mussel rod 10 having a depth of 1 to 2 mm is formed on the circumferential surface 9 b of the large-diameter portion 9 a of the tapered inner ring 9. Therefore, an embodiment of manufacturing a method for forming the product 5 having an asymmetrical cross section by ring rolling so as not to generate the mussels 10 as much as possible using the above-described three-roll type ring rolling device is described. This will be further described below.

  First, the diameter indicated by the arrows of the right main roll 1a and the left main roll 1b, the diameter of the deformed annular portion of the workpiece, the rotation direction of the right main roll 1a and the left main roll 1b, and the annular shape that is the workpiece The direction of rotation of the material 4 is indicated by arrows, and a three-roll type ring rolling device shown in the schematic cross-sectional view of FIG. 2 is prepared.

  When the preparation of the above-described three-roll type ring rolling device is completed, the outer peripheral surface 6b of the mandrel 6 abutting against the inner peripheral surface 4a of the annular material 4 is pressed against the hole mold 3a, followed by the hole mold 3a. A rolling force by the mandrel 6 is applied to the entire surface of the annular material 4 inside. In this case, the number of rotations of the right main roll 1a inclined to the right and the left main roll 1b inclined to the left is arbitrarily set by a motor, and the annular material 4 is formed by the right main roll 1a and the left main roll 1b. The inner wall of the hole mold 3a and the outer peripheral surface 6b of the mandrel 6 are pressed into the shape of the tapered inner ring 9 of the roller bearing 8 having a cross-sectional shape shown in FIG. Ring rolling is performed to form a shape, and the asymmetric cross section of the shape of the tapered inner ring 9 of the roller bearing 8 having the sectional shape shown in FIG. For example, the dimensions of the tapered inner ring 9 of the roller bearing 8 having a cross-sectional shape shown in FIG. 6A before pressing are as follows: the large outer diameter 11 is φ166 mm, the small outer diameter 12 is φ115.6 mm, the inner diameter 13 is φ70 mm, Although the width 14 was 50 mm, in the product 5 of the tapered inner ring 9 after processing, the overall diameter of the tapered inner ring 9 of the roller bearing 8 having the cross-sectional shape shown in FIG. The outer diameter 11 was φ200 mm, the small outer diameter 11 was φ160 mm, and the inner diameter 13 was φ130 mm. However, the width 14 of the product 5 of the tapered inner ring 9 was not changed at 50 mm.

  In the method of the present invention, the material flow due to the force applied to the deformed annular material 4 which is a workpiece at the time of rolling by the three-roll type ring rolling device promotes the material filling of the product 5 on the large outer diameter 11 side. The shape of the tapered inner ring 9 is improved, and the ridge 10 is not seen on the circumferential surface 9b of the large diameter portion 9a of the tapered inner ring 9 of the tapered bearing 8. On the other hand, there is one main roll 1, and this one main roll 1 faces the mandrel 6 to produce a product by a conventional two-roll type ring rolling device that performs ring rolling on the deformed annular material 5 that is a workpiece. 5 can be molded, but the material flow in this case has almost no effect of promoting the filling of the material of the above-mentioned three-roll type device, and improvement in moldability cannot be expected. Furthermore, the occurrence of mussel wrinkles 10 was observed on the circumferential surface 9b of the large-diameter portion 9a of the tapered inner ring 9.

1 main roll 1a right main roll 1b left main roll 2 tip 2a right main roll tip 2b left main roll tip 3 concave groove 3a hole type 4 annular material 4a inner peripheral surface 4b outer peripheral surface 5 product (annular deformed cross section) Raw material)
6 Mandrel 6a Axis 6b Outer peripheral surface 7 Backup roll 8 Roller bearing 9 Tapered inner ring 9a Large diameter portion 9b Circumferential surface 10 Musillet 11 Large outer diameter 12 Small outer diameter 13 Inner diameter 14 Width 15 Right main roll rotating main shaft 16 Left main role of the rotary spindle theta _1: right main roll shaft angle theta _2: shaft angle ωr of the left main role: the right main roll velocity Omegaeru: left main roll velocity .omega.p: angular .omega.p product (workpiece) _2: small products Angular velocity of outer diameter ωp ₃ : Angular velocity of groove outer diameter of product Rr ₁ : Radius of arrow r ₁ of right roll Rr ₂ : Radius of arrow r ₂ of right roll Rl ₁ : Radius of arrow l ₁ of left roll Rl ₂ : radius Rl of arrow l ₂ of the left roll _3: radius Rl of arrow l ₃ of the left roll _4: radius Vr of arrow l ₄ of the left roll _1: peripheral speed Vr arrow r ₁ of the right roll _2: right low Arrow r ₂ of the peripheral velocity Vl _1: peripheral speed Vl ₂ of arrow l ₁ of the left roll: peripheral speed of arrow l ₂ of the left roll Vl _3: peripheral speed Vl ₄ of arrow l ₃ of the left roll: the left roll arrow l ₄ peripheral speed P ₁ : Large outer diameter of the product P ₂ : Small outer diameter of the product P ₃ : Groove outer diameter of the product P ₄ : Full width of the product P ₅ : Width of the large outer diameter portion of the product P ₆ : Product Width of small outer diameter part P ₇ : Angle between right outer edge of small outer diameter and slope forming a slope between the outer right edge of the product and the outer diameter of the groove P ₈ : Groove outer diameter and left edge of the outer diameter of the product Slope length between parts P ₉ : Length between right outer edge of small outer diameter of product and groove outer diameter P ₁₀ : Width between outer diameter of groove and large outer diameter of product P ₁₁ : Small outer diameter of product P ₁₂ : Length of the difference between the outer diameter of the product and the outer diameter of the groove P ₁₃ : Length of the slope between the right end of the outer diameter of the product and the outer diameter of the groove P ₁₄ : To the large outer diameter left end of the slope between the large outer diameter left end and the groove outer diameter Angle Vp _1: Product large outer diameter peripheral speed Vp _2: small outer diameter peripheral speed of the product Vp _3: Product of the groove outside diameter peripheral speed assuming A: Suppose point and the peripheral speed of the peripheral speed and the product of the main roll is the same

Claims (2)

  The two main rolls are arranged so as to be inclined to the left and right, the tip portions of the two main rolls are in contact with a V shape, and the shape of the asymmetric cross section formed on the tip portion that is in contact with the V shape is formed. An annular material, which is a work material, is fitted into a hole mold made of a concave groove, and the outer peripheral surface of the mandrel is brought into contact with the inner peripheral surface of the annular material. Pressing the outer peripheral surface of the mandrel in contact with the peripheral surface against a hole mold to apply rolling force to the entire surface of the annular material, and ring rolling with each motor rotating the number of rotations of the main roll inclined to the left and right A method for producing a ring-shaped cross-section having an asymmetric cross section.   The method of ring rolling by rotating the rotation speed of each main roll inclined left and right with a motor is to control the roll diameter and rotation speed of the left and right main rolls so that the peripheral speeds of the left and right main rolls are in a certain range. The difference between the peripheral speed of the roll at the contact point between the main roll inclined to the left and right and the annular material that is the workpiece and the peripheral speed of the annular material that is the workpiece, that is, the relative speed is 700 mm / sec or less. The method of manufacturing an annular deformed cross-sectional element having an asymmetric cross section according to claim 1, wherein the ring-shaped element is ring-rolled.

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