JPH0692006B2 - Piercing and rolling method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a piercing / rolling method, and more specifically, a piercing machine and a stretching / rolling machine which are widely adopted in a Mannesmann manufacturing method, which is a typical seamless tube manufacturing method. The present invention relates to a method of perforating or stretching-rolling a material to be processed while expanding the diameter of the material to be processed by a rolling mill using so-called inclined rolls.

[Conventional technology]

For example, in the process using the punching machine, a solid billet as a work material is bitten between a plurality of inclined rolls arranged around the pass line to move the billet in the axial direction of the billet. By inserting a plug into the solid billet along its axis, the solid billet is perforated while expanding its diameter to form a hollow shell. Further, in the step of using the stretch rolling machine, the hollow shell is moved in the axial direction by engaging the hollow shell between a plurality of inclined rolls arranged around the pass line and the hollow shell The hollow shell is stretch-rolled while being expanded in diameter by inserting a plug along the axis of the hollow shell.

Thus, the material to be processed such as solid billet and hollow shell is pierced and rolled while the diameter is expanded, but when the piercing and rolling is completed and the bottom of the material to be removed from the inclined roll ( The so-called “plug clogging” occurs in which the bottom part cannot be slipped out of the inclined roll, a so-called slip-out defect occurs, or a plug used for rolling remains in the bottom part. There was something to do. Although such tail failure or plug clogging is generally referred to as tail clogging, when the tail clogging occurs and the punching machine or the stretch rolling mill is in a misroll state, it takes a lot of time to normalize the state. , Productivity is significantly reduced.

Therefore, conventionally, a rollable condition that does not cause the above-mentioned tail jamming and a biting failure and an appropriate rolling condition that does not cause defects such as scratches are obtained in advance, and the roll interval and the plug are satisfied so as to satisfy both conditions. The lead and guide shoe intervals are set.

[Problems to be solved by the invention]

Therefore, the rollable conditions are roll diameter, workpiece diameter,
Since it changes depending on the size of the piercing / rolling ratio, the piercing / expansion ratio, the roll inlet face angle, the roll outlet face angle, the plug shape, etc.,
It is very difficult to obtain this with high accuracy. Therefore, the rollable condition is obtained together with the appropriate rolling condition in advance, and even when the piercing and rolling is performed while satisfying both conditions, it is not possible to sufficiently suppress the occurrence of the tail clogging, and the piercing machine or the stretching rolling machine misrolls. However, there is a problem that productivity may be significantly reduced due to the state.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a piercing and rolling method capable of preventing the productivity of a line from being reduced by sufficiently suppressing the occurrence of the tail clogging.

[Means for solving problems]

In the present invention, the work material is moved in the axial direction of the work material by engaging the work material between the plurality of inclined rolls arranged around the pass line, and In the piercing / rolling method of piercing or stretching-rolling the workpiece by expanding the diameter of the workpiece by inserting a plug along the axis, the slope of the workpiece when the bottom part of the workpiece exits the inclined roll. The crossing angle of the roll is changed in the direction in which the roll exit side is closed or the roll opening is changed in the direction in which it is closed. Here, the roll opening means the opening determined by the gorge portion of the inclined roll.

[Action]

When perforating or stretching-rolling a workpiece using such a method of the present invention, the crossing angle or roll opening of the inclined roll is changed as described above when the trailing edge of the workpiece exits the inclined roll. By the above, a propulsive force greater than the drag force of the plug is applied to the work material, and the gap between the inner surface of the work material and the outer peripheral surface of the plug is increased to suppress the occurrence of the clogging.

It is also possible to apply the propulsion force at the time of slipping out to the work material by setting the reeling angle of the plug larger than the exit surface angle of the inclined roll when setting up the inclined roll and the plug. However, in this case, it is possible to suppress the occurrence of the clogging of the tail, but on the other hand, the propulsive force acts even in the process up to the time of slipping out of the tail, and a spiral uneven thickness is generated in the work material, etc. ,
Quality issues arise. However, in the case of the method of the present invention, the propulsive force is applied to the work material by changing the crossing angle or the roll opening of the inclined roll only at the time of the trailing edge, so that the propulsive force until the trailing edge is reached. It does not work and the above-mentioned quality problem does not occur.

〔Example〕

Hereinafter, the method of the present invention will be described with reference to the drawings showing an embodiment thereof.

FIG. 1 is a plan view schematically showing an essential part of a punching machine used for carrying out the method of the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a front view seen from the inlet side thereof. Reference numerals 12 and 12 denote inclined rolls, 13 denotes a plug, and B denotes a solid billet as a material to be processed.

Each of the inclined rolls 11 and 12 is a cone-shaped roll having an outer peripheral surface composed of two different conical surfaces, and the inclined rolls 11 and 12 have a pass line P to which the solid billet B is transferred.
On both sides of the same with respect to the horizontal plane including the pass line P so as to be inclined at mutually equal inclination angles β (see FIG. 2), and the crossing angle γ with respect to the vertical plane including the pass line P. (See FIG. 1) so as to cross each other. The peripheral surfaces of the inclined rolls 11 and 12 arranged around the pass line P as described above are solid billets B.
The inlet side has an inlet face angle α ₁ while the outlet side has an outlet face angle α ₂ (see FIG. 1).
Further, both of the inclined rolls 11 and 12 can be rotated in the same direction as indicated by an arrow in the figure.

The heated solid billet B is transported along the pass line P between the inclined rolls 11 and 12, and the solid billet B is on the roll entrance side of the inclined rolls 11 and 12. When it is bitten in, it is transported in the axial direction while being rotated around the axis by the inclined rolls 11 and 12, so-called screwing movement is performed. Furthermore, the solid billet B
The plug along the axis of the
13 is inserted, and the solid billet B is expanded and perforated by the plug 13 to obtain a hollow shell H. In addition, 1 shown in FIG.
Reference numerals 4 and 15 are guide shoes for slidingly contacting the upper and lower parts of the hollow shell H in order to suppress the expansion of the outer diameter of the hollow shell H.

The tilt rolls 11 and 12 are supported by roll shafts 11a and 12a, but the roll shafts 11a and 12a have a structure capable of tilting horizontally with the roll entrance side as a tilt center. Then, at the time of slipping out, the roll shafts 11a and 12a are tilted in the direction in which they approach each other as indicated by the blank arrow on the roll exit side, and the crossing angle γ of the inclined rolls 11 and 12 changes in the direction in which the roll exit side closes. It is designed to let you. In addition,
When the roll shafts 11a and 12a cannot be tilted, the roll opening may be changed in the closing direction instead of changing the crossing angle γ.

When the solid billet B is punched using such a punching machine, when the bottom of the solid billet B slips out of the inclined rolls 11 and 12, the cross angle γ of the inclined roll is changed to the direction in which the roll exit side closes. Or the roll opening is changed in the closing direction. By doing this, when the tail slips out, the pressing force on the delivery side by the opposing inclined rolls 11 and 12 increases, the amount of wall thickness processing for the solid billet increases, and the amount of wall thickness reduction or wall thickness processing increases. can do. Along with this, the wall thickness becomes thinner and the work piece extends in the rolling direction, but the inner circumference of the work piece also becomes larger, and the gap between the plug maximum diameter part and the work piece inner surface becomes larger. , The contact area between the plug and the work material becomes smaller, the drag force of the plug (the force that impedes the progress of the work material) becomes smaller, and the propulsive force applied to the work material increases accordingly, and plug clogging can be prevented. Of.

In addition, the increase in the amount of wall thickness processing increases the gap between the plug and the inner surface of the material to be rolled, and the inclined rolling makes it easier for the plug to separate from the material to be rolled, thus suppressing the occurrence of clogging.

Since the crossing angle γ or the roll opening is changed only when the trailing edge is removed, the propulsive force is not applied in the process up to the trailing edge removal so that uneven thickness can be prevented.

Next, the specific effect of carrying out the method of the present invention will be described.

4 and 5 both show the occurrence of clogging of the tail when punching a solid billet under various conditions of the expansion ratio and the piercing / rolling ratio. The expansion ratio and the piercing / rolling ratio on the vertical axis are variously changed. The conditions in which clogging occurs are shown by black circles, and the conditions in which clogging does not occur are shown by white circles. FIG. 4 shows the case of the conventional method and FIG. 5 shows the case of the method of the present invention (the change amount of the roll crossing angle: 0.1 ° to
1.2 °) are shown respectively, and the conditions other than both conditions are as shown in Table 1.

From these results, in the case of the method of the present invention, the conditions under which tail clogging does not occur are greatly expanded as compared with the case of the conventional method, and the excellent effect of the method of the present invention can be confirmed.

In the above-described embodiment, the two inclined rolls 11 and 12 are arranged on the left and right sides. However, even if there are three or more inclined rolls, the arrangement positions are other than left and right (for example, upper and lower). However, the method of the present invention can be applied. Further, the method of the present invention can be applied even if the roll shape is other than the above-mentioned cone type (for example, barrel type). Further, the method of the present invention can be applied not only to the above-described punching machine, but also specifically to a stretching and rolling machine for stretching and rolling while expanding the diameter of the hollow shell. In the two-roll type using two inclined rolls, the method of the present invention can be applied regardless of whether the guide shoes 14, 15 are plate type, disc type, or roller type.

〔effect〕

When piercing or stretching rolling is performed using the method of the present invention as described above in detail, the crossing angle of the inclined roll at the time of trailing out is changed to the direction in which the roll exit side is closed, or the roll opening is changed to be closed. Thus, a propulsive force can be applied to the material to be processed, and the propulsive force can suppress the occurrence of clogging of the material to be processed. As a result, the punching machine and the drawing rolling machine are less likely to be in a misrolled state due to clogging of the tail, and it is possible to prevent the productivity from being significantly reduced.

[Brief description of drawings]

FIG. 1 is a plan view schematically showing a main part of a punching machine used for carrying out the method of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a front view seen from the inlet side, and FIG. FIG. 5 is a graph showing the occurrence of tail clogging when the method is used, and FIG. 5 is a graph showing the status of tail clogging occurring when the method of the present invention is used. 11,12 …… Inclined roll, 13 …… Plug 14,15 …… Guide shoe, P …… Pass line B …… Solid billet, H …… Hollow shell

Claims (2)

[Claims] 1. A work material is moved in the axial direction of the work material by engaging a work material between a plurality of inclined rolls arranged around a pass line, and the work material is provided with its shaft. By inserting the plug along the core wire,
In a piercing / rolling method of piercing or drawing-rolling while expanding the diameter of the material to be processed, when the bottom portion of the material to be processed comes out of the inclined roll, changing a crossing angle of the inclined roll to a direction in which the roll-out side is closed. A piercing and rolling method characterized by: 2. A work piece is moved in the axial direction of the work piece by engaging the work piece between a plurality of inclined rolls arranged around a pass line, and the work piece is provided with the shaft. By inserting the plug along the core wire,
In a piercing / rolling method of piercing or stretching-rolling the work material while expanding the diameter of the work material, the roll opening degree of the tilt roll is changed to a closing direction when the bottom portion of the work material exits the tilt roll. Perforating and rolling method.