JPH05277511A - Inclined rolling mill - Google Patents

Abstract

PURPOSE:To provide an inclined rolling mill with which piercing rolling can be executed by infinitely bringing the gap between a roll for piercing and a disk roll near to zero. CONSTITUTION:This figure is the sectional drawing of the disk roll and hatched parts show annular grooves. The side face of this disk roll is circular, edge diameters are 1200mm and 1240mm and thickness between the side faces is 55mm. The annular grooves are formed on the side face of this small diameter of 1200 mm. The grooves having the width of 100mm are formed towards the center from the edge parts on the circumferetial part of this side face. The bottoms of these grooves are formed into circular arcs of the max. depth of 6mm. Using the disk roll, a carbon steel billet having the diameter of 70mm is piercing rolled into the outside diameter of 72mm and wall thickness of 2mm by the inclination of the disk roll. In such a inclined rolling mill, the position where the gap exceeds 2mm is the place at the distance of 140mm from the gorge part of the roll for piercing in the traveling direction of the rolling mill, so piercing rolling can be executed without generating peeling phenomenon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piercing and rolling mill for producing a seamless pipe from a solid billet, and more particularly to a disc roll as a guide plate for the piercing pipe.

[0002]

2. Description of the Related Art FIG. 2 is a schematic elevational view of a conventional inclined piercing and rolling mill as viewed from the exit side of a piercing tube. The cone-shaped inclined rolls 1R and 1L having the emergence angle α are arranged symmetrically with respect to the path center such that their own axes form the intersecting angle γ, and further, each forms the inclined angle β. A plug (not shown) for piercing the billet 6 is arranged between the inclined rolls 1R and 1L with the pass center as the central axis, with the tip end thereof around the gorge portion of the inclined rolls 1R and 1L.

The perforating rolls 1R and 1L are connected to drive sources (not shown) by drive shafts 2R and 2L, respectively, and are in twisted positions with respect to each other. By this, the punching rolls 1R, 1L,
When the billet 6 is rotated about its own axis in the directions of the arrows in the figure, the billet 6 is bitten by the roll for perforation and perforated while rotating clockwise around the path center as viewed from the exit side direction. The billet 6 thus pierced is rocked up and down because it is pressed by the piercing roll from both sides. In order to suppress this shaking, a pair of disc rolls 10U and 10D are arranged above and below the perforating rolls 1R and 1L. These disc rolls 10U and 10D are discs whose outer peripheral surface is formed into a concave surface, follow the rotation in the perforation direction, suppress the swing of the billet 6, and perform perforation smoothly. Billet 6 is
The piercing rolls 1R and 1L are perforated by the plugs while being pressed from both sides by the gorge portion, thereby forming a perforated pipe.

However, since the perforating rolls 1R and 1L have the flank angle α and the intersecting angle γ with respect to the path center as described above, the disc rolls 10U and 10D are formed.
There are gaps G1 and G2 between the perforation rolls 1R and 1L, respectively. The piercing rolls 1R and 1L rotate, and the billet 6 moves in a threaded manner around the path center. At that time, the metal of the perforated pipe which is in contact with the surface of the disc roll 10 has a gap G.
1, G2 is pushed out in the same direction as the billet 6 rotation direction,
It may be caught in the gaps G1 and G2 and cause a peeling phenomenon.

As a countermeasure for this, the present inventors have proposed the following method (Japanese Patent Application No. 3-359775).
FIG. 3 is an elevation view of a conventional horizontal type inclined piercing and rolling apparatus as seen from the exit side of the piercing tube. The perforating roll 1R is on the right side and the perforating roll 1L is on the left side in the exit direction of the billet 6.
They are arranged with their own axes twisted with respect to each other. In the disk rolls 10U and 10D having different left and right edge diameters, 10U is arranged above the billet 6 and 10D is arranged below the billet 6. The disc roll 10U is located above the billet 6 with the small diameter edge on the perforating roll 1R side, and the disc roll 10D is below the billet 6 with the small diameter edge on the perforating roll 1L side. The small-diameter edge is located upstream of the threading and the large-diameter edge is located downstream of the threading. Then, the disc roll axis is made horizontal with the disc roll center as an axis, and skews are given such that the exit side is tilted in the direction opposite to the rotation direction of the billet 6. Further, the edge of the disc roll 10U with a small diameter is centered on a vertical line passing through the point closest to the perforation roll 1R, that is, the diameter of the face on the small diameter side of the disc roll, κ on the perforation roll 1R side. Just tilt. Disc roll in the same way
Tilt 10D to the roll 1L side for punching by κ.

[0006]

By disposing such a disc roll, the gap between the perforating roll and the disc roll can be narrowed to prevent the metal of the perforated pipe to be extruded from being caught in this gap. did it. As described above, the gap becomes narrower as the skew angle δ of the disc roll and the inclination angle κ of the disc roll are increased, but since the perforation roll has a barrel-like shape with a bulged central portion of the side face, the side face of the disc roll is perforated. The disk roll could not be tilted beyond the limit angle of contact with the swollen part of the roll, that is, the maximum disk roll skew angle δ _m and the maximum disk roll inclination angle κ _m . The present invention has been made in view of such circumstances, by further forming a groove portion on the side surface of the disc roll for avoiding the bulging portion of the perforation roll, further tilting the disc roll largely, the perforation roll and the disc An object of the present invention is to provide an inclined rolling mill capable of piercing and rolling with a roll gap as close to zero as possible.

[0007]

A tilt rolling mill according to the present invention is a tilt rolling mill for perforating or expanding a diameter using a pair of tilt rolls and a pair of disc rolls. It is characterized in that an annular groove is formed.

[0008]

In the inclined rolling mill of the present invention, an annular groove is formed in the peripheral edge portion of the side surface of the disk roll so that the side surface of the disk roll can avoid the bulging portion of the punching roll.
The size of the annular groove is determined by the degree of contact of the side surface of the disc roll with the perforating roll. However, the degree of contact of the side surface of the disc roll with the perforating roll varies depending on the inclination of the disc roll, that is, the disc roll skew angle δ and the disc roll inclination angle κ. Therefore, the distance of the gap G due to various inclinations of the disc roll and the degree of contact of the side face of the disc roll with the perforating roll are obtained and described in detail below.

First, the punching roll and the disc roll are set as follows. Deflection angle 4 °, gorge diameter 4
A 10 mm roll for perforation was placed with a gorge gap of 62 mm at a crossing angle δ = 30 ° and an inclination angle β = 12 °.
Place a 00mm disc roll with a disc roll edge gap of 70mm. Then, the disc roll skew angle δ is 0 °, 2 °, 4 °, 6 °, and the disc roll tilt angle κ is 0 °, 10 °, 20 °. Also, the degree of contact of the side of the disc roll with the punching roll is calculated.

FIG. 4 shows the disk roll skew angle δ = 0.
5, FIG. 5 shows the disc roll skew angle δ = 2 °, FIG. 6 shows the disc roll skew angle δ = 4 °, and FIG. 7 shows the disc roll skew angle δ = 6 °. It is explanatory drawing showing the distance of the gap G in each case of 20 degrees, and the extent to which the side of a disc roll hits the roll for perforation. FIG. 8 is an explanatory view showing a coordinate system in the arrangement of the punching roll and the disc roll. The origin point is the point of perforation by the roll gorge part for perforation, the center point direction of the roll gorge part for perforation is X, the vertical direction is Y,
The path center direction is defined as Z, the target perforation roll side is defined as the negative Y direction, and the perforation progression side is defined as the positive Z direction. The graphs shown in FIGS. 4 to 7 show the distances of the gap G between the perforating roll and the disc roll depending on the perforation advancing direction. □ is the disc roll inclination angle κ = 0 °, ● is the disc roll inclination angle κ = 10 °, × is the disc roll inclination angle κ
It shows the case of = 20 °. When the disc roll skew angle δ = 6 ° and the disc roll inclination angle κ = 20 ° shown in FIG. 7, the gap distance is a negative value. This means that the edge portion of the disc roll contacts the perforating roll, which is out of the scope of the present invention.

Among these inclinations of the disc roll, the contact of the side face of the disc roll with the perforating roll occurs only when the disc roll inclination angle κ = 20 °. 4 to 7
The shaded area indicates the contact amount of the side of the disc roll with the roll for perforation when the disc roll inclination angle κ = 20 °, where the horizontal axis is the perforation advancing direction and the vertical axis is the vertical direction. The circle indicates the deepest position of the hit, and the number inside the circle indicates the depth. Further, the position of the disk edge is shown on the same coordinate axis.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. In the setting of the punching roll and the disc roll described above, the most effective disc roll skew angle δ and disc roll inclination angle κ are δ = 4 ° and κ = 20 ° in order to prevent the peeling phenomenon by narrowing the gap. Therefore, the size of the annular groove formed in the peripheral edge portion of the side of the disc roll on the side of the perforating roll was determined from the degree of hitting of the side of the disc roll with the perforating roll at δ = 4 ° and κ = 20 °. ..

FIG. 1 is a sectional view of a disk roll according to this embodiment. The shaded area indicates the annular groove. The sides of this disc roll are circular with an edge diameter of 12
00mm and 1240mm, the thickness between the sides is 55mm. An annular groove is formed on this small diameter side surface of 1200 mm in diameter. A groove with a width of 100 mm is formed from the edge to the center on the circumference of this side surface. This groove bottom is formed in an arc shape with a maximum depth of 6 mm. When the disc roll skew angle δ = 4 ° and the disc roll inclination angle κ = 20 °, the hitting position and the hitting amount are approximately 75 mm in the vertical direction from the disc edge as shown in FIG. Therefore, the actual surface of the disk roll is approximately 80 mm in the vertical direction from the disk edge. Moreover, the maximum depth of the hit amount is 5 mm. From this,
It can be seen that the above-described annular groove of the present embodiment is formed at a position where the punching roll hits and has a size larger than the hitting amount.

A carbon steel billet having a diameter of 70 mm was pierced and rolled to an outer diameter of 72 mm and a wall thickness of 2 mm by using the above-described disc roll with the inclination of the disc roll described above. In such an inclined rolling mill, the position where the gap exceeds 2 mm is 140 mm from the piercing roll gorge portion in the rolling mill advancing direction, and piercing and rolling can be performed without causing a peeling phenomenon. On the other hand, the conventional slant rolling mill was used, the disc roll skew angle δ = 4 °, the disc roll slant angle κ
When the same rolling piercing was carried out with the setting of = 10 °, the position where the gap exceeded 2 mm was 75 mm from the roll gorge part for piercing in the rolling mill advancing direction, and the peeling phenomenon occurred at the position of 80 mm. .. Therefore, in this embodiment, the gap can be further narrowed as compared with the prior art, and the perforated tube can be rolled and perforated without being caught in the gap. Further, the present invention has an outer diameter ratio before and after perforation
It is also effective when expanding pipes such as 1.3, 1.5 and 2.0.

In the present embodiment, the piercing and rolling machine for piercing the billet is described as an example, but the present invention can be applied to a stretching and rolling machine for expanding the diameter of a hollow round bar.
Further, in the present embodiment, the cone type inclined roll is described as an example, but any roll having a bulged portion on the side surface such as a barrel type can be used.

[0016]

As described above, in the inclined rolling mill of the present invention, the gap between the piercing roll and the disc roll can be made as close to zero as possible, so that the tube material is prevented from being caught and the effective roll length is increased. Since it can be set, stable piercing and rolling can be performed, and the present invention has excellent effects.

[Brief description of drawings]

FIG. 1 is a sectional view of a disc roll of the present invention.

FIG. 2 is a schematic elevation view of a conventional inclined piercing and rolling mill viewed from the exit side of a piercing tube.

FIG. 3 is an elevation view of a conventional inclined piercing and rolling apparatus as seen from the exit side of a piercing tube.

FIG. 4 shows the distance of the gap G and the degree of contact of the side of the disc roll with the punching roll when the disc roll skew angle δ = 0 ° and the disc roll inclination angle κ = 0 °, 10 °, 20 °. FIG.

FIG. 5 shows the distance of the gap G and the degree of contact of the side of the disc roll with the punching roll when the disc roll skew angle δ = 2 ° and the disc roll inclination angle κ = 0 °, 10 °, 20 °. FIG.

FIG. 6 shows the distance of the gap G and the degree of contact of the side of the disc roll with the perforating roll when the disc roll skew angle δ = 4 ° and the disc roll inclination angle κ = 0 °, 10 °, 20 °. FIG.

FIG. 7 shows the distance of the gap G and the degree of contact of the side of the disc roll with the punching roll when the disc roll skew angle δ = 6 ° and the disc roll inclination angle κ = 0 °, 10 °, 20 °, respectively. FIG.

FIG. 8 is an explanatory diagram showing a coordinate system in the arrangement of a punching roll and a disc roll.

[Explanation of symbols]

1R, 1L Perforation roll 6 Billet 9 Perforation tube 10U, 10D Disc roll β Perforation roll inclination angle γ Perforation roll crossing angle α Perforation roll exit angle δ Disc roll skew angle κ Disc roll inclination angle G1, G2 For perforation Roll and disc roll exit gap

Claims (1)

[Claims] 1. An inclined rolling mill for perforating or expanding a diameter using a pair of inclined rolls and a pair of disc rolls, wherein an annular groove is formed in a peripheral edge portion of a side surface of the disc rolls. Rolling mill.