JPS60227910A - Method for sizing outside diameter - Google Patents

Abstract

PURPOSE:To raise the complete roundness of a pipe end part of a pipe material and the size accuracy of the outside diameter, and to improve the yield of a formed part by setting a roll gap to a different value with respect to both end parts and the center part of the pipe material, in the last stand of plural rolling stands. CONSTITUTION:When a steel pipe 11 is bitten successively into plural stands 12x, y and z of a sizer 12 and its outside diameter size is sized, photosensors 15a, b for detecting the passing of the tip of the steel pipe 11 moving in the direction as indicated with an arrow and also detecting its moving speed, and a photosensor 15c for detecting the passing of the rear end are installed at a prescribed position between the rolling stands 12x, 12y. In this way, the tip and the rear end of the steel pipe which have been detected are rolled by controlling motors 14y, z through controlling circuits 21y, z by an operation control device 20, and adjusting the roll gaps of caliber rolls 13y, z so that one and the other are larger and smaller than the roll gap to the center part of the steel pipe 11.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an outer diameter shaping method for finishing the outer diameter dimension of a tube material using an outer diameter shaping machine such as a sizer or reducer, and in particular, relates to an outer diameter shaping method for finishing the outer diameter dimension of a tube material. This paper proposes an outer diameter shaping method that can improve the roundness and outer diameter dimensional accuracy of parts.

[Prior art]

Seamless steel pipes, welded steel pipes, etc. are polished and polished by a reeler after pipe production.
After the shape has been corrected, it is fed to a sizer, reducer, etc., which consists of multiple rolling stands each equipped with a pair of caliber rolls arranged so that their opposing directions are alternately 90° different, and the outer diameter is finished. That is, the outer diameter is shaped and sent to the finishing process.

By the way, in the conventional sizing process, each rolling stand 2χ of the sipe 2 is used as shown in FIG.

2y, 2z (the final 3 stands are shown in the drawing), kalihal rolls 3x, 3y, 3z roll gaps (
(distance between groove bottoms of a pair of Kariha rolls) on each rolling stand 2x
.

A predetermined value is set for each 2y and 2z according to the standard dimensions of the steel pipe 1, and the steel pipes 1 that are sequentially fed to these are gradually adjusted to the required outer diameter at several stands (for example, 5 to 6 stands) on the upstream side. The final 2nd stand 2y+ 221 was used to create a perfect circle with high precision.

Therefore, in the finishing process at the final stand 2z), the roll gap of the final stand 2z does not match the outer diameter of the product in the direction in which the rolls are installed, and the outer diameter of the product in the direction perpendicular to the direction in which the rolls are installed does not match. The outer diameter also does not match the roll gap of the final second stand 2y.This is because when one outer diameter is reduced during the deformation process of the tube, the outer diameter in the direction perpendicular to it expands, ie, a so-called flattening phenomenon occurs.

Such flattening is caused by shaping force acting on the central part of the steel pipe 1, which is constantly rolled with both ends supported by adjacent rolling stands, due to the tension applied from both rolling stands. 2z, it can be solved by setting these roll gals to a value that can eliminate the flatness of the central part of the steel pipe 1. However, during rolling, the tip and rear ends of the steel pipe 1 become cantilevered at a portion corresponding to the distance between the rolling stands 2y and 2z, so the above-mentioned shaping force does not act and the flattening is eliminated. Not done. Therefore, when using such a conventional method, the roundness and outer diameter dimensional accuracy of the tip and rear ends of the steel pipe 1 deteriorates compared to the center part, so it is necessary to cut them off, which reduces the yield in the regular forming process. This had become a bottleneck in efforts to improve.

Now, as a method different from the conventional method of fixing the roll gap of the final two stands 2y, 2z to a set value, there is a method disclosed in Japanese Patent Laid-Open No. 57-44411.

In this method, the roll gap of the final two stands and the corresponding outer diameter of the exit steel pipe are measured during rolling, and based on the measurement results, a calculation device is used to estimate the influence coefficient of the roll gap on the exit steel pipe outer diameter. Based on the influence coefficient, the roll gap of the final two stands is controlled to obtain a desired outer diameter dimension when rolling the next steel pipe. If this method is used, it is possible to improve the roundness of the central part of the steel pipe and the accuracy of the outer diameter dimension, but as with the conventional method mentioned above, both pipes are rolled with the same glue and lugyasop over the entire length. ,
The flattening of the tip and rear ends could not be resolved.

[How the invention was completed]

Therefore, the inventors of the present invention have proposed that when a steel pipe is rolled using the roll gear of the final two stands with a roll gap that can eliminate the flatness of the central part of the steel pipe, the flatness that occurs at the tip and rear ends of the steel pipe can be reduced. We have taken various measures to reduce the flatness of the leading and trailing ends when the roll gap of the final two stands is made larger or smaller than that of the center rolling. I found out that this is possible.

Although this is clear from the graph shown later, the reason why such a phenomenon occurs is unknown. What can be inferred is that the final two stands apply the shaping force due to the rolling itself and the shaping force due to the tension between them when rolling the central part of the pipe, so the final stand was designed to be appropriate for this central part of the pipe. In the roll gap, flattening occurs due to the fact that the shaping force does not act on the first part, and on the other hand, the latter part does not act, and therefore,
Ahead.

For the rear end, it is necessary to set a roll gap in the final stand that allows the tube to be shaped into a perfect circle only by the shaping force of the former.

The roll gap when rolling the tip and rear end of the tube in the final two stands may both be made larger than when rolling the central portion of the tube, or one may be made larger and the other smaller. The conditions are determined by the pipe type, pipe size, rolling speed, etc.

〔the purpose〕

The present invention was made based on this knowledge, and the roll gap of the final two stands is set at the tip of the pipe material.

By setting different values when rolling the rear end and center part, the outer diameter standard shape can improve the roundness and outer diameter dimensional accuracy at the tip and rear end of the pipe material, and improve the yield of finished products. The purpose is to provide a method.

[Structure of the invention]

The outer diameter shaping method according to the present invention is a method of sequentially fitting a tube material into a plurality of rolling stands and shaping its outer diameter, in which the roll gears of the last two stands of the rolling stands are fixed to the outer diameter of the tube material. It is characterized in that different values are set during rolling at both ends and at the center.

〔Example〕

The present invention will be described in detail below based on drawings showing embodiments thereof.

FIG. 1 is a schematic side view showing the implementation state when the method of the present invention is applied to the sizing process of seamless pipes, and FIG. 2 is a schematic side view showing the control procedure of the method of the present invention.

The seamless steel pipe 11 is polished using a reeler (not shown).

After the shape has been modified, a plurality of rolling stands 12x and 12y (the final three stands are shown in the drawing) are formed.

It is sent to Sipe 12 consisting of 12z. Calibar rolls 13z and 13x (the front side is shown in the drawing) of the final rolling stand 12z and the third and final rolling stand 12χ are installed horizontally opposite each other, and motors 14z and 14x
It is designed to move towards and away from each other by rotating forward and backward.

This structure is the same for the final second rolling stand 12y in which the Caliba rolls 13y are disposed vertically opposite each other.

A steel pipe 1 is installed at a predetermined position between the rolling stands 12y and 12z.
Photosensors 15a and 15b detect the passage of the tip of 1.
are arranged with the photosensors 15a on the downstream side in the direction of movement of the steel pipe 11, separated from each other by a suitable length, and input their respective tip detection signals to the arithmetic and control unit 20.

Further, a rear end detection signal is inputted to the calculation control bag W20 from a photosensor 15c disposed near the exit side of the rolling stand 12x in order to detect the passage of the rear wheel of the steel pipe 11.

As shown in FIG. 2 (al), when the tip of the steel pipe 11 reaches the exit side of the rolling stand 12x and the photosensors 15a and 15b detect its passage, both photosensors 15a and 15b detect the passing of the steel pipe 11. The moving speed of the steel pipe 11 is calculated based on the time difference between the points in time.Then, the steel pipe 11 is moved to the rolling stand '12, which is preset at this calculated moving speed.
After the time required to move the distance between the rolling stand 12y and the biting position of y, the roll gap of the rolling stand 12y is changed to 01.
2, a predetermined signal is issued to the motor drive control circuit 21y to drive the motor 14y. Here, G12 is the roll gap G set during rolling of the central part of the steel pipe 11.
This is a setting value slightly larger than ll. In order to set the roll gap of rolling stand 2z to 022, a predetermined signal is issued to motor drive control circuit 212 to drive motor 14z.

Here, 022 is a set value slightly smaller than the roll gear G21 set when rolling the central portion of the steel pipe 11.

Then, as shown in FIG. 2(b), when the time required for the tip of the steel pipe 11 to reach a predetermined position on the exit side of the rolling stand 12z has elapsed, the arithmetic and control device 20 moves the rolling stand 12y,
A predetermined signal is issued to the motor drive control circuits 21y and 21z to change the roll gap of 12z to GIL G21.

Next, as shown in FIG. 2 (C1), when the rear wheel of the steel pipe 11 reaches the exit side of the rolling stand 12x and is detected by the photo sensor 15c, the roll gap of the rolling stand 12y is changed to G.
GI3, which is slightly larger than ll, and rolling stand 12
In order to set the roll gap G23 slightly smaller than the roll gap G21 of z, predetermined signals are issued to the motor drive control circuits 21y+21z, respectively. Through such control, the tip and rear end portions of the steel pipe 11 are rolled at the rolling stand 12y with a larger roll gap than the center portion, and the rolling stand 12
z with a roll gap smaller than that at the center, it is possible to improve the roundness and outer diameter dimensional accuracy at the leading and trailing ends, as explained in the section on the history of the completion of the invention.

In addition, in such control, the roll gap is set to G12.
G13<Gll, G22. G23>G21, that is, the roll gap of the rolling stand 12y is made smaller during rolling of the front and rear ends than that during rolling of the central part, and the roll gear of the rolling stand 122 is made larger than that during rolling of the central part. Good too.

(Effects) Next, the effects of the present invention will be explained based on examples.
The figure shows a case where the outside diameter of a steel pipe is determined by the method of the present invention [
Fig. 3(a)] is a graph comparing the variation in the outer diameter dimension over the entire length of the steel pipe with the conventional method (Fig. 3(b)), and the vertical axis is The outer diameter of the steel pipe is shown, and the horizontal axis shows the distance from the tip of the steel pipe.In the graph, ○ indicates the outer diameter of the final stand of the steel pipe in the direction in which the rolls are installed, and × indicates the diameter perpendicular to the direction in which the rolls are installed. FIG. 4 also shows the outer diameter of the method of the present invention [FIG. 4(a)
] and the conventional method [No. 4]
This is a graph that compares the variation in the outer diameter between the rear end and the center of the steel pipe when the outer diameter is determined using the method shown in Fig. Indicates the distance from the rear end of the steel pipe.

In the graph, ○ indicates the outer diameter of the final stand of the steel pipe in the direction in which the rolls are installed, × indicates the outer diameter in the direction perpendicular to the direction in which the rolls are installed, Δ indicates the maximum outer diameter of the steel pipe, and the mouth Indicates the minimum outer diameter.

However, the number of stands is 8, and the roll gap when rolling the tip and rear end of the steel pipe on the second final stand is 1 dragon larger than that when rolling the center part, and the roll gap at the tip and rear end of the final stand is The roll gap during end rolling was 1fi smaller than that during center rolling.

As is clear from FIG. 3, in the case of the present invention, the tip of the steel pipe,
The accuracy of the outer diameter dimension at the rear end has been significantly improved compared to the conventional method, and as is clear from Figure 4, the outer diameter dimension and steel pipe in the direction in which the rear end rolls are opposed and in the direction perpendicular to this are significantly improved. The maximum outer diameter dimension and the minimum outer diameter dimension are substantially the same, respectively, and the oblateness is small, that is, the roundness is significantly improved.

As described in detail above, the outer diameter shaping method according to the present invention has a final
Since the roll gap of the stand is set to different values when rolling the tip, 1&end, and center of the tube, the roundness and outer diameter dimensional accuracy at the tip and rear end of the tube are greatly improved. The present invention has excellent effects, such as improved production and improved yield of finished products.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing the implementation state of the present invention, FIG. 2 is a schematic side view showing the control procedure, FIG. 3.4 is a graph for explaining the present invention in detail, and FIG. FIG. 2 is a schematic side view showing a state in which a conventional method is implemented. 11...Steel pipe 12...Sipe 12x, 12y
, 12z...Rolling stand 13x, L3y, 13
z-Calihalol 15a, 15b, 15c...
・Photosensor 20...Arithmetic and control device patent Applicant: Sumitomo Metal Industries Co., Ltd. Agent Patent attorney: Noboru Kono 1 Figure 2: 0 distance (m) Figure 3: xoo +660 1200 8C1) 400 0 bond bank. 19. l distance memory hunting) V: fk Mizuri-ra road-backed bird W (animal trap) Calculation 4 Figure

Claims (1)

[Claims] 1. In a method of sequentially fitting a tube material into a plurality of rolling stands and determining its outer diameter, the roll gap of the last two stands is determined by setting the roll gap between both ends and the center of the tube material. An outer diameter shaping method characterized by setting different values during rolling.