JPS59133931A - Rolling method of pipe - Google Patents

Abstract

PURPOSE:To enable considerable reduction in the sectional area of a pipe by pressure with a relatively small-sized installation by oscillating at least one of plural ring rolls installed between roll calibers in the direction intersecting with a mandrel shaft. CONSTITUTION:Plural ring rolls 3-5 are superposedly disposed between a caliber C1 formed by rolls 1, 1' and a roll caliber C2 formed by rolls 2, 2'. A pipe 7 inserted therein with a mandrel 6 advances into the caliber arrays C1, D1, D2, D3, C2. Said ring 4 is oscillated in the direction intersecting with a mandrel shaft 8 and the wall thickness of the pipe is reduced by pressure. The outside diameter or both of the outside diameter and the wall thickness are press reduced by the calibers C1, C2.

Description

[Detailed Description of the Invention] Conventionally, seamless pipes have been manufactured by plastic working methods such as rolling, extrusion, drawing, or forging, but each processing method alone has reached its technical limit, and a dramatic improvement is needed. Technological improvements are becoming increasingly difficult.

The object of the present invention is to significantly reduce the cross-sectional area of a seamless pipe using small-capacity equipment.

The core technology of the present invention is to arrange one or more link rolls between the roll grooves with their grooves overlapping each other, to insert a tube into which a mandrel is inserted into the groove row, and to close the ring roll. At least one of the tubes is vibrated in a direction perpendicular to the mandrel axis to reduce the wall thickness of the tube, and in the case of a roll hole type, the outer diameter or the outer diameter and wall thickness are reduced.

To explain the present invention in detail, FIG.
and one or more ring rolls 3, 4. , 5 are arranged so that the holes DI, D2, and D3 are partially overlapped as shown in FIG.

D. 1, D2, D3, C2, enter the tube 7 into which the mandrel 6 is inserted, and at least -
4, for example, in a direction intersecting the mandrel axis 8 to reduce the wall thickness of the tube '7, and roll hole shapes C1, C
In No. 2, the outer diameter or both the outer diameter and the wall thickness are reduced. Second
The figure is the I-I Vfi plane of FIG. 1, and shows an example of the vibration mechanism of the vibrating ring roll 1.

That is, the tube 7 loaded with the mandrel 6 is passed through the ring roll hole mold D2, and the gear '9 whose outer surface 12 is supported by the housing is driven once in the direction of the arrow 10. The inner surface 13 moved eccentrically, and the center of the song roll lj and ring roll hole type D2 supported on the circular surface of the gear is a radius centered on the center K of the outer circle of the housing 7 ring 11 and the gear 9. Perform a circular motion of LK. At this time, if the diameter of the ring roll hole D2 is selected close to the pipe diameter at that position, the wall thickness of the tube changes between the mandrel 6 and the ring roll hole D20, as shown in FIGS. 1 and 2. built,
The mandrel is bent and its center moves from K to M, which is separated from K. By appropriately selecting the rigidity of the mandrel and the sizes of ring roll hole shapes D1 and D2 around ring roll hole shape D20, song roll hole shape D1' can be obtained. The wall thickness of the tube is also reduced at points j, E and D2. When the ring roll is moved eccentrically in this way, due to the difference between the inner circumference of the ring roll hole and the outer circumference of the tube at that position, frictional force in the rotational direction acts at the contact point between the two, which causes twisting of the tube. becomes. In order to prevent this, it is desirable to support the ring roll so that it can rotate freely, and for example, the sliding surface shown in FIG. 2 and 13 should be designed to reduce frictional resistance. In addition, when rotating and exciting adjacent ring rolls, it is desirable that the angular velocities of the gears be made equal and the phases be slightly different by 0 degree.

In the present invention, as shown in FIG.
, C2 can be provided to apply a forward force to the tube 7 at the same time as rolling it. In addition, by making the circumferential speed of the rolls on the exit side sufficiently higher than the circumferential speed of the rolls on the input side between the roll holes C1 and C2 on both sides of the link roll hole type, a tensile force is applied to the pipe, and the ring roll hole type The wall thickness of the pipe can be reduced more effectively.

To illustrate an embodiment of the present invention, when the equipment is arranged as shown in Fig. 1 and the conditions shown in Table 1 are carried out, from a raw pipe with an outer diameter of 80 mm and a wall thickness of 25 mm, at the equipment outlet the outer diameter is 4r)) mm and the wall thickness is 5Tom
A tube with an elongation rate (-cross-sectional area ratio) of 785 was obtained, which is sufficiently thick compared to the maximum elongation rate of 4 of a conventional stand mandrel mill.

Table 1 The method of the present invention is not limited to the rolling of circular tubes, and the mandrel may be rectangular and rotated around the axis of the ring roll mandrel or the mill center line in a state perpendicular to the axis. (It may be a so-called grinding motion, and circular motion can be applied to the processing of all materials.

11.--Uzongu

Claims (1)

[Scope of Claims] 1. One or more song rolls are arranged in a row between substantially circular roll hole molds so as to overlap each other, and a circular tube into which a cylindrical mandrel is inserted is inserted into the row of hole molds, At least one of the ring rolls is vibrated in a direction perpendicular to the mandrel axis to increase the thickness of the tube. A rolling method for reducing tubes. 2. The method for rolling a tube according to claim 1, characterized in that one or more of the loaf single hole type rolls are driven. 3. The rolling method for pipe according to claim 1, wherein the rolling method is carried out while applying a tensile force to the lightning between the roll grooves on both sides of the link roll groove.