JPS62187507A - Stretch reducing mill - Google Patents

Abstract

PURPOSE:To improve the dimensional accuracy of a product to be formed and to permit the easy manufacture of stands by inclining the transverse center of forming rolls at a specific angle with the perpendicular running through the sectional center of the pipe to be formed. CONSTITUTION:The 1st, 5th, 9th, 13th, and 17th stands are so disposed that the position 1 of the stand 2 is a peak side, the position 2 a right side, the position 3 a base and the position 4 a left side. The transverse center of the forming roll 1a in this case exists in the position inclined by 15 deg. in a counterclockwise direction around the perpendicular l running through the sectional center of a seamless pipe. The 2nd, 6th, 10th, 14th and 18th stands are so disposed that the front and rear of the stand 2 in the state of (a) are turned over and that the top and bottom are reversed. The 3rd, 7th, 11th, 15th, and 19th stands are so disposed that the front and rear of the stand 2 in the state of (a) are turned over and are inclined 90 deg. in the counterclockwise direction. The 4th, 8th, 12th, 16th, and 20th stands are so disposed that the stand 2 in the state of (a) is inclined 90 deg. in the counterclockwise direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a stretch reducing mill in which one type of stand can be used for all of a plurality of stands.

[Prior Art] In a seamless steel pipe production facility, the material that has been pierced by an upstream piercer and rolled by a mandrel mill is sequentially stretched and shaped by a stretch reducing mill with multiple stands, for example, to form a material into a predetermined shape. Molded into products with outer and inner diameters.

[Problems to be Solved by the Invention] In the conventional stretch reducing mill, as shown in FIGS. The molded product is arranged in a different manner so that the molded product is approximately perfectly circular, but the cross-sectional shape of the inner and outer diameters of the actually obtained product is approximately hexagonal, which is a problem in terms of product quality. Undesirable.

Therefore, in order to improve the cross-sectional shape of the product, it is conceivable to arrange the forming roll a at a different angle of 30 degrees for each stand. It is undesirable to do so because the stand is difficult to manufacture and equipment costs and operation and maintenance costs are high.

In view of the above-mentioned viewpoints, the present invention has been made to change the angles of the forming rolls of the front and rear stands in the tube circumferential direction by 30 degrees, and to use only one type of stand.

[Means for Solving the Problems] The present invention provides a stretch reducing mill equipped with a plurality of stands in which three sets of forming rolls for forming a seamless pipe are arranged at intervals of approximately 120 degrees in the circumferential direction of the pipe. , seats are provided at the four corners of the stand for installing the stand on a frame disposed below the stand, and one of the forming rolls of the 4n+1st stand from the most upstream side with respect to the tube feeding direction is provided. The center of the forming roll in the width direction is tilted approximately 15 degrees in the tube circumferential direction with respect to the perpendicular passing through the cross-sectional center of the tube to be formed, and the 4n+2nd stand from the most upstream side with respect to the tube feeding direction is the 4n+1st stand. The front and back of the stand are turned over and the top and bottom are reversed, and the 4n,103rd stand from the most upstream side in the tube feeding direction is the same as the 4n,103rd stand, whose front and back are turned over, and the 4n,01st stand is turned over before the front and back are turned over. Tilt 90 degrees to the side where the forming roll is arranged, which is tilted approximately 15 degrees with respect to the perpendicular line, and 4n+ from the most upstream side with respect to the tube feeding direction.
For the fourth stand, the 4n,101st stand is tilted 90 degrees toward the forming roll side, which is tilted approximately 15 degrees with respect to the perpendicular line of the 4n,011th stand (however, n in the above formula includes zero). positive integer) configuration.

``Function'' The forming rolls of adjacent stands are arranged at different angles of 30 degrees in the circumferential direction of the tube, and since there is only one type of stand, the dimensional accuracy of the molded product is improved, and the stand The production becomes easier.

[Example] Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

Figures 1 (a) to (d) show an embodiment of the present invention.
゜1b, Ic are forming rolls arranged at a pitch of 120 degrees, 2 is a stand with a substantially square outer shape on which forming rolls Ia, 1b, 1c are set, 3a, 3b,
3C and 3d are seats provided at the four corners of the stand 2 so that no matter which side of the stand 2 is placed on the base, there are seats 4a, 4b, 4c, 4d, 4e, 4.
f and 4g are frames for mounting the housing exchange beam fixed to the periphery of the stand 2; 5a, 5b, and 5C are forming rolls Ia and lb;

Coupling, field, (
2), 111 is the position of the outer edge of the stand 2, and when l, (2), mouth, and ■ are written upside down, the front and back of the stand 2 are turned over. Moreover, the seamless steel pipe is designed to be fed, for example, from this side to the opposite side with respect to the paper surface of FIG. Total of 20 stands 2 mentioned above
Stands, forming rolls 1a, l of adjacent stands
b. When arranging the ICs at different angles by 30 degrees, place the 1st stand, 5th stand, 9th stand, 13th stand, and 17th stand in place of stand 2 as shown in Figure 1 (a). Position l becomes the top, and position (2
) is on the right side, position l is on the bottom side, and position group is on the left side.

In this case, the widthwise center of the forming roll 1a is a perpendicular line passing through the cross-sectional center of the seamless steel pipe! 15 counterclockwise based on
It is in a tilted position.

In addition, the 2nd stand, 6th stand, 10th stand, 14th stand, and 18th stand are arranged by turning over the front and back of the stand 2 in the state of FIG. (See Figure <0)). In this case, the widthwise center of the forming roll 1C is 4 in the counterclockwise direction with respect to the perpendicular 1.
The molding rolls of the 1st and 2nd stands, the 5th and 6th stands, the 9th and 10th stands, the 13th and 14th stands, the 17th and 18th stands are tilted at 5 degrees. The angle in the circumferential direction of the tube is 3
It has been changed by 0 degrees.

Furthermore, the third stand, the seventh stand, the eleventh stand,
The 15th stand and the 19th stand are arranged by turning over the front and back of the stand 2 shown in FIG. 1(A) and tilting it 90 degrees counterclockwise (see FIG. 1(C)).

In this case, the center in the width direction of the forming roll 1a is inclined 75 degrees counterclockwise with respect to the perpendicular 1, and the second stand, the third stand, the sixth stand, the seventh stand, and the tenth
The angles of the forming rolls of the stand and the 11th stand, the 14th stand and the 15th stand, and the 18th stand and the 19th stand differ by 30 degrees.

Furthermore, the 4th stand, the 8th stand, the 12th stand, the 16th stand, and the 20th stand are the 1st stand.
Place the stand 2 in this state so that it is tilted 90 degrees counterclockwise (see figure 1). In this case, forming roll 1
The widthwise center of a is a perpendicular line! 10 counterclockwise based on
The forming rolls of the 3rd and 4th stands, the 7th and 8th stands, the 11th and 12th stands, the 15th and 16th stands, the 19th and 20th stands are tilted at 505 degrees. The circumferential angle has been changed by 30 degrees.

Furthermore, as shown in Figure 1), the widthwise center of the forming roll 1b is a perpendicular line! It is tilted 15 degrees clockwise based on
The angles of the forming rolls in the 6th stand and the 17th stand in the tube circumferential direction are changed by 30 degrees.

As mentioned above, the angle of the forming rolls in the circumferential direction of the pipe in all adjacent stands is changed by 30 degrees, so the formed seamless steel pipe becomes even closer to a perfect circle in both the outside and inside diameters. . Further, since only one type of stand 2 is required, the stand is easy to manufacture.

In the embodiments of the present invention, the case where the number of stands is 20 has been described, but the number is not limited to 20, and it can be applied not only to steel pipes but also to various types of pipes. Of course, changes may be made.

[Effects of the Invention] According to the stretch reducing mill of the present invention, the dimensional accuracy of seamless pipes can be improved and product quality can be improved, and since only one type of stand is required, the stand It is easier to manufacture, and equipment costs and operation and maintenance costs are lower.

[Brief explanation of drawings]

Figures 1 (a) to (d) are explanatory diagrams of the arrangement of forming rolls and stands in the stretch reducing mill of the present invention, and Figures 2 (a) and (0) are illustrations of the arrangement of the forming rolls and stands in the stretch reducing mill of the present invention. It is an explanatory view of the arrangement state of forming rolls. In the figure, 1a, ib, 1c are forming rolls, 2 is a stand, 3a, 3b, 3c, 3d are seats, 4a, 4b
, 4C, 4d, 4e, 4f, and 4G indicate frames.

Claims (1)

[Claims] 1) In a stretch reducing mill equipped with multiple sets of stands in which three sets of forming rolls for forming seamless pipes are arranged at intervals of approximately 120 degrees in the circumferential direction of the pipe, stands are installed at the four corners of the stands. One of the forming rolls of the 4n+1st stand from the most upstream side with respect to the pipe feeding direction is provided.
The center of the forming roll in the width direction is tilted approximately 15 degrees in the tube circumferential direction with respect to the perpendicular passing through the cross-sectional center of the tube to be formed, and the 4n+2nd stand from the most upstream side with respect to the tube feeding direction is the 4n+1st stand. Flip the front and back of the stand and turn it upside down, and the 4n + 3rd stand from the most upstream side with respect to the tube feeding direction is turned over the front and back of the 4n + 1st stand, and with respect to the perpendicular line of the 4n + 1st stand before turning the front and back. 9 to the side where the forming roll is placed, tilted approximately 15 degrees.
The 4n+4th stand from the most upstream side with respect to the tube feed direction was tilted 90 degrees toward the forming roll side, which was tilted approximately 15 degrees with respect to the perpendicular line of the 4n+1st stand. However, in the above formula, n is a positive integer including zero).