JPH0357282Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an inclined rolling mill for seamless pipes, and particularly to an inclined rolling mill such as an elongator or a reeler using a roller shoe.

<Conventional technology> The manufacturing process for seamless pipes basically consists of a drilling process in which holes are made in the material, a stretching process in which the perforated rolled blank tube is stretched with reduced thickness, and a hollow blank tube that has been stretched and rolled. It consists of three steps: a finish rolling step in which the material is reduced to a predetermined outer diameter.

FIG. 4 to FIG. 6 are explanatory diagrams showing the elongation rolling process in the manufacturing process of the seamless pipe. 1
A and 1B are rolling rolls, rolling rolls 1A,
1B are arranged such that their rotation axes are inclined at an inclination angle θ in opposite directions with respect to the rolling pass line through which the hollow rolled blank tube 2 passes, and are rotatable in the same direction. A pair of roller shoes 3 are provided on both sides of the rolling area sandwiched between these rolling rolls 1A and 1B.
A and 3B are arranged to suppress the rolled raw pipe 2 that bulges out during thinning drawing and rolling. Further, a plug 4 is arranged at the center of the rolling area.

In the above-mentioned inclined rolling mill, when the rolling stock pipe 2 enters the rolling region from the direction of arrow F and comes into contact with the rolling rolls 1A and 1B, the rolling stock pipe 2 is moved at a distance between the rolls due to the effect of the inclination angle θ. The tube is rotated forward toward the gorge portion where it is the smallest, and the tube is contracted and then stretched between the rolling rolls 1A, 1B and the plug 4 while being thinned and expanded.

In addition, when roller shoes 3A and 3B are used as shoes for suppressing the bulging of the raw tube 2 as in the above-mentioned inclined rolling mill, on the surface of the raw tube 2,
There is no surface scratching due to sliding contact as is the case when using a fixed shoe (see FIG. 10).

However, this roller show 3A, 3B
is an idle roller shoe, which rotates but is not forced to drive. Therefore, in this case, if the raw pipe 2 escapes into the gap between the rolling rolls 1A, 1B and the roller shoes 3A, 3B, the roller shoes 3A, 3B will not be able to pull out the raw pipe 2, and rolling will stop. (See Figure 7).

As a method for solving such problems, for example, Japanese Patent Application Laid-Open No. 60-68104 discloses an inclined rolling mill in which a drive roller shoe that is forcibly driven is arranged at an angle on the side of the rolling area formed by the rolling rolls. Proposed. According to this inclined rolling mill, the drive roller show imparts rotation to the rolling stock tube, and as a result, the rolling stock tube is pulled toward the adjacent rolling roll while being guided by the drive roller show, making it compact. This structure enables smooth rolling.

Regarding the rotational force exerted by this drive roller shoe on the rolled raw tube, the largest force is applied to the rolled raw tube when the roller shoe and the rolled raw tube are in contact with each other in a state of fixed friction while rotating synchronously.

However, it is impossible to completely match the change in the longitudinal direction of the roller shoe diameter with the change in the average outer diameter of the rolled blank tube due to equipment considerations and the need to use different roller shoe sizes. therefore,
The contact surfaces of the roller shoe and the rolled blank tube do not contact each other in a fixed friction state over the entire length, but have regions of fixed friction and sliding friction, respectively.
FIG. 11 shows an example of this situation.
Naturally, in region A, which is a fixed friction region in FIG. 11, a larger rotational force is applied to the rolled blank pipe by the drive roller shoe than in region B, which is a sliding friction region. Furthermore, in the sliding friction region (region B), a rotational force in the opposite direction to the rotational force applied in region A may be applied (region C in FIG. 11). Therefore, the 11th
As shown in the figure, it is desirable that the drive roller shoe and the material to be rolled come into contact with each other in a fixed frictional state in the region where the plastic buckling of the rolled stock pipe is greatest. However, depending on the surface condition of the roller shoe, the desired state may not always be achieved, and there may be cases where the region of the rolled blank pipe with the largest plastic buckling contacts the roller shoe in a sliding friction state. In such a case, the rotational force of the drive roller shoe does not work effectively to prevent plastic buckling of the rolled blank tube.

<Problems to be solved by the invention> By the way, even in the above-mentioned drive roller show, the rotational force of the roller show is limited due to limitations in the installation space and the capacity of the drive device, so it is difficult to When rolling ultra-thin tubes with a particularly small thickness (t)/outside diameter (D) of the tube, the tube is prone to plastic buckling and flaring, especially at the tip and rear ends of the tube ( (See FIG. 8) There is a problem in that a stateska phenomenon occurs.

Therefore, as one means to prevent this stuckness phenomenon, for example, in Japanese Patent Application Laid-Open No. 61-67512, a guide member 6 is inserted between the rolling rolls 1A, 1B and the roller shoes 3A, 3B (see FIG. 9). ) is proposed.

However, when this guide member is used, although the frequency of occurrence is small, the same problems as in the fixed shoe, namely,
Guide members are a type of consumable item that wears out, so they are expensive, and if they are used beyond a certain level of wear, surface flaws will occur more frequently on the rolled raw pipe. It is necessary to perform maintenance using a grinder or the like, which causes problems such as a decrease in production.

The present invention was developed to solve the above-mentioned problems, and even when rolling raw tubes with a small t/D, it is possible to prevent stays caused by flaring at the leading and trailing ends and to reduce wear on the guide members. The purpose of the present invention is to provide an inclined rolling mill capable of

<Means for Solving the Problems> The present invention provides an inclined rolling mill for seamless pipes mainly consisting of a pair of rolling rolls disposed at an angle, a pair of roller shoes, and a rolling plug. A seamless pipe inclined rolling machine, characterized in that a concave shape and/or a convex shape is processed between a position corresponding to the gorge part of the rolling roll in the direction and a position corresponding to the terminal end of the rolling plug. It is.

<Function> The present inventors conducted a detailed investigation on the wear status of the guide member in the Elongator. Figure 12 shows a 1% Cr low-alloy steel seamless tube (inlet side raw tube wall thickness 1〓8mmt x outer diameter 200mmφ, outlet side raw tube This figure shows the change in the wear condition when rolling a material (wall thickness: 5 mmt x outer diameter: 223 mmφ). As is clear from the group of curves A to D shown by solid lines in this figure, the wear points of the guide member are quite limited, especially between the rolling roll gorge (point F) and the end of the rolling plug (point G). It can be seen that the wear is significant, and the amount of wear becomes deeper as the number of rolled sheets increases. After investigating various causes of this wear, we discovered that because the tensile force of the drive roller shoe itself is small, the flare that occurs at the end of the raw pipe increases, accelerating wear.We completed this invention. reached.

That is, in the present invention, by processing the longitudinal surface of the drive roller shoe into a concave shape and/or a convex shape, it is possible to increase the force that pulls the raw tube of the roller shoe in the rotational direction.
It is possible to reduce the occurrence of flare and to reduce wear on the guide member due to contact with the flare.
The area where the concave and/or convex shapes are formed is preferably provided in a range from the rolling roll gorge to the end of the rolling plug, corresponding to the area where the guide member is most severely worn.

Furthermore, by increasing the force that pulls the raw tube of the roller show in the rotational direction, it is possible to further reduce t/D, which requires a guide member.

<Examples> Examples of the present invention will be described below based on the drawings.

FIG. 1 is a partially cutaway side view of an example of an inclined rolling mill used in carrying out the present invention.

This inclined rolling mill (elongator) 8 has an entrance side angle and an exit side angle, and a rolling roll 9 arranged at an inclination at a constant advance angle, and an entrance side angle and an exit side angle, and a rolling roll 9 having an entrance side angle and an exit side angle. The roller shoe 10 has a body length L and is disposed adjacent to the roller shoe 10 at a constant angle of inclination in a drivable state, and a drive motor 11 that applies a driving force to the roller shoe 10.
12 is a fixed pedestal, 13 is a movable pedestal, and 14 is a support pedestal. The roller show 10 is supported by a support stand 14, and the support stand 14 is connected to the movable frame 1 by bolts 15.
It can be fixed to this movable frame 13 by a wedge 16 fixed to 3. The movable pedestal 25 is
The lock cylinder 18 is placed on a tapered stand 17 movably provided on the fixed stand 12.
It is fixed to the fixed pedestal 12 by the screw spacing adjustment motor 19, and is movable in the shoe spacing adjustment direction by movement of the tapered base 17 as the screw shaft 20 is rotated by the shoe spacing adjustment motor 19. Further, the drive motor 11 is fixed to a fixed frame 12 and engages with the roller shoe 10 via a universal joint 21, so that the roller shoe 10 can be forcibly driven. In addition, 2
2 is a plug, 23 is a trough, 24 is a rolled raw pipe, 2
5 is a canon, 26 is a pusher, and 27 is a guide member.

As shown in FIG. 2, the roller shoe 10 is processed to have an uneven shape in the range from the rolling roll gorge (point F) to the rolling plug terminal end (point G) with respect to the body length L of the roller shoe. The height of the uneven portion is about 1 to 5 mm, and the pitch is about 2 to 5 mm.

The wear condition of the guide member 27 when rolling 2000 1% Cr low-alloy steel seamless pipes using the roller shoe 10 having the uneven shape is shown by the dotted line in Fig. 12 above, and it is almost average. It can be seen that there is no local wear.

It should be noted that the shape of the processing performed on the surface of the roller show is not limited to the uneven shape of this embodiment, but the same effect can be achieved even if the surface is only concave or only convex as shown in FIG. Not even.

Although the above-mentioned embodiments are those in which the guide member 27 is used, the present invention has the possibility of preventing stickiness to a considerable degree even without using the guide member 27.

In other words, FIG. 13 shows the situation in which stumps occur due to tip and trailing end flare when a rolled raw pipe is rolled using a drive roller show without the guide member 27, and when uneven processing is applied to the surface of the roller show (characteristics). The graph shows a comparison between curve M) and the case where no coating is applied (characteristic curve N). As is clear from Fig. 13, by applying unevenness to the roller shoe surface, the area where stakes occur due to tip/rear end flare is reduced from the conventional B area and C area to only the C area, where t/D is smaller. I understand that. This shows that the area that can be rolled is expanded without using the guide member 27. However, in rolling the rolled blank pipe when t/D is in the C region, the guide member 2
I have no choice but to rely on 7.

<Effects of the invention> As explained above, according to the invention, since the surface of the roller shoe is processed to have a concave shape and/or a convex shape, it is possible to suppress the flare that occurs at the end of the rolled blank pipe. Since the wear of the guide member can be reduced, the life of the guide member can be improved, and the outer surface flaws of the rolled raw pipe can be reduced.
In addition, it becomes possible to prevent the occurrence of stains, contributing to improved productivity.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of an embodiment of the present invention, FIG. 2 is an enlarged perspective view of a roller shoe according to the present invention, and FIG. 3 is a surface view of the roller shoe according to the present invention. Diagram 4 showing another example of the processing to be performed
The figure is a plan view showing the rolling state by a general inclined rolling mill, FIG. 5 is a side view of FIG. 4, and FIG. 6 is a
FIG. 7 is a front view showing the main parts of a conventional inclined rolling mill equipped with a roller shoe. FIG. 7 is a front view showing the flare of the raw pipe that occurs in the conventional inclined rolling mill. FIG. 8 is a front view showing the tube end of the rolled raw pipe. FIG. 9 is a front view showing the main parts of an inclined rolling mill equipped with a guide member, and FIG. 10 shows the main parts of a conventional inclined rolling mill equipped with a fixed shoe. Front view shown, 1st
Figure 1 is a diagram illustrating the rolling action of the drive roller shoe and the rolling element, Figure 12 is a diagram showing the wear status of the guide member, and Figure 13 is the rolling element when the guide member is not used. FIG. 3 is a diagram showing the t/D of a tube and the rate of occurrence of stains. 8... Incline rolling mill (Elongator), 9... Roll roll, 10... Roller shoe, 11... Drive motor, 22... Plug, 24... Rolling tube, 2
7...Guiding member.

Claims (1)

[Scope of utility model registration request] In a seamless pipe inclined rolling mill mainly consisting of a pair of rolling rolls arranged at an angle, a pair of roller shoes, and a rolling plug, 1. An inclined rolling mill for seamless pipes, characterized in that a concave shape and/or a convex shape is formed between positions corresponding to the terminal ends of a rolling plug.