JPS62156018A - Method preventing seam twist of resistance welded tube - Google Patents

Abstract

PURPOSE:To correct seam twist of resistance welded tubes and to prevent the twist by moving a forming stand being ahead of a fin pass roll in the orthogonal direction to the manufacturing line based on a detected twist value of a welded part against the advancing direction of the manufacturing line. CONSTITUTION:A seam twist is measured by a seam detector A set in the outlet side of a sizer or of a post annealer and a fin pass stand 5 is moved by a necessary distance based on a detected signal from the detector A. The moving method is such that the stand 5 is put on a rail 6, the position of a stopper 9 having a screw type sliding mechanism is changed by a motor 8, the stand 5 is moved with the stand 5 abutted on the stopper 9 using a hydraulic cylinder 7 so as to always hold a pressure in the right side in the figure. 'B' in the figure shows an arithmetic unit for a fin pass moving amount. In this method, keeping of high welding strength by reduction of insufficiently annealed seal parts, keeping of a good product shape after changing to weld beads, a yield, and improved productivity are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for preventing seam twisting of an electric resistance welded pipe.

(Prior Art) A seam guide device is generally used to prevent seam twisting of an electric resistance welded pipe. However, this device is not installed in a pipe manufacturing line that manufactures electrical resistance welded pipes with a relatively large outer diameter. The reason for this is that the load applied to the equipment becomes large in the pipe-making line, making the equipment itself large, which is undesirable because the value of equipment investment is low.

Therefore, the following problems regarding seam twist remain in the pipe-making line.

(,) If the seam portion exceeds the follow-up limit of the seam annealer installed in the pipe-making line due to twisting, the thermal annealing quality of the seam portion will be significantly degraded.

(b) In the above-mentioned seam annealer, especially in a device having a horizontal movement type tracking mechanism, even if the tracking limit is not exceeded, if the seam is twisted to some extent, the temperature gradient in the thickness direction of the seam portion increases, and the thermal annealing temperature condition This results in parts that are not satisfactory and reduces the quality of thermal annealing.

(C) When cutting the inner weld bead, if the seam part exceeds the cutting range, a cut part and an uncut part will appear,
- Damages the shape quality of mother Eve.

(Problems to be Solved by the Invention) An object of the present invention is to provide a method for preventing seam twisting that can solve the various problems caused by seam twisting described above.

(Means for Solving the Problems) The present invention has solved the above object, and its gist is that when manufacturing an ERW pipe by ERW welding,
A twist detection device detects the phenomenon in which the welded part twists in the direction of the pipe-making line, and based on the detected value, the forming stand in front of the fin pass roll is moved in a direction perpendicular to the direction of the pipe-making line and replaced. This is a method for preventing seam fencing of an ERW pipe, which is characterized by correcting the following.

The present invention will be explained in more detail with reference to the embodiments shown in FIGS. 1 to 3.

Figure 1 shows a pipe cut out in a twisted state, where 1 is the deviation of the butt point in the pipe-making direction, and 2 is the pipe cut out in a twisted state.
This is the center line of 9ig. As described above, since seam twist is caused by the deviation 1 of the abutting points, this must be corrected before pipe production.

Describing the method of correcting torsion using FIG. 2, 3 is the center line of the forming roll group, 4 is one of the fin pass stands, and the arrow indicates the tube forming direction. The fin/shelf stand 4 is moved by a necessary amount perpendicular to the pipe-forming direction and offset with respect to the center line 3 of the fog roll to correct the twist.

Next, a method for correcting torsion will be described in detail with reference to FIG.

Remove seam defects from the side exit side or with a boss annealer.
Measurement is performed by a seam detection device A installed on the exit side, and the fin pass stand 5 is moved by the required amount based on the detection signal. How to move is example Ehafinno J? The stand 5 is placed on the rail 6, and the position of the stopper 9, which has a screw-type sliding mechanism, is moved by the motor 8, and the pressure is always maintained in the right direction in the drawing, and the hydraulic cylinder 7 is applied to the stopper surface. Do it by method.

B in the figure is a calculation device for calculating the amount of fin path movement.

FIG. 4 is a diagram showing the relationship between the amount of movement of the fin stand and the amount of change in twist of the pipe at that time.

Based on this relationship, the required amount of movement of the fin pass stand is calculated from the measured value of the amount of seam twist.

The forming stand used in the present invention can be moved by placing the forming stand on a rail and moving it using a hydraulic cylinder, placing the forming stand on a rail and moving it using a screw, or using various methods of moving the forming stand on the lock part of the forming stand.・! Various methods can be considered, such as a method of changing the position by using -, but the method is not particularly important.

(Effect of the invention) By preventing the seam twisting of the electric resistance welded pipe of the present invention, the seam part
This leads to maintaining the quality of the welding strength by reducing J-ring defects, maintaining the quality of the product shape after weld pea cutting, and improving yield and productivity, and the effects are extremely large.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a pipe cut out with a twisted seam, Fig. 2 is an explanatory diagram showing a group of fin pass forming stands and a squeeze stand, and Fig. 3 is an explanatory diagram showing the seam twist prevention method of the present invention. FIG. 4 is a diagram showing the relationship between the amount of movement of the fin 2 stand and the change in the amount of twist of the fin 2 stand on the side exit side. 1: Misalignment of butt point in pipe forming direction, 2: Center line of pipe, 3: Center line of forming roll group, 4: Fin pass stand, 5: Fin pass stand, 6: Rail, 7: Hydraulic cylinder, 8 :Motor, 9:Stotsuno♀-0," Jf Low 1 Koji Niibu j,. -111---J Figure 1 Figure 3 Cyst-l Par 2nd Centroid

Claims (1)

[Claims] When manufacturing ERW pipes by ERW welding, a twist detection device detects the phenomenon in which the welded part is twisted with respect to the direction of movement of the pipe production line, and the detected value is used to manufacture the forming stand before the fin pass roll. A method for preventing seam twisting of an ERW pipe, characterized by moving in a direction perpendicular to the direction of the pipe line to correct twisting.