The caliber of the roll tube mill

 

(57) Abstract:

The use of the invention relates to the caliber of the grooved roll tube mill, mostly round shape for reducing rolling mill with a three-roll mill, in particular for rolling thin-walled tubes with the relationship of wall thickness to diameter of more than 0.25. The inventive circuit caliber of each roll is in the area of the bottom of the gauge widening in diameter, which can be deformed area of the material, laminated in the ledge roll appropriate, previous in the direction of rolling, caliber. The invention can improve the contour of the caliber that prevents or makes it more flat unwanted sharpening on a contact surface between the rolled product and roller. 2 C.p. f-crystals, 2 Il.

The invention relates to the caliber of the grooved roll, mostly round shape for reducing rolling mill with a three-roll mill, in particular for rolling thin-walled pipes with the ratio of wall thickness to diameter of more than 0.25.

In the pressure reducing pipe rolling mill according to the prior art for walled pipes usually are not round, and EA. Long axis lies along the line of recoil rolls and is longer than the short axis of the previous caliber. Due to this, try to avoid output of rolled material in the rolling gap and printing rolling gap. Such forms caliber limited, however, by rolling technology, if rolled pipe with respect to the thicknesses higher than 0.1. That's when the so-called polygonization, i.e. the deviation of the inner contour of the pipe from the desired round shape. In the extreme case, this polygonization can lead to approximately hexagonal cross-section, which greatly limits the application of the pipe.

If you want to laminate thin-walled pipe, it can hardly be done using the well-known oval calibration, in this case, you must use the calibration, which is close to a round shape. Using these calibrations, polygonization suppressed stronger; the relationship to that described in the journal "Archiv fuer das Eisenhuettenwesen", year 41, No. 11, November 1970, pages 1047 - 1053. The result, according to this prior art are invited to apply for pipe lines with a thin range of pipes, special calibration is atki, that is mainly round the calibration. This is possible because the thin-walled pipes are much less prone to the formation of the imprint of the rolling gap on the outer surface than the thin-walled tube. The choice of caliber holes should be carried out in such a way that the difference between the longest and shortest length of the contact surfaces is minimal, so the contact surface of the roller/tube of rectangular form.

When applying the ideas according to the above publication, it was found that in the ranks of calibers with a small hole gauge between the pipe and the roller is not achieved uniform contact. Using conventional processing techniques calibers get the contact surface with 3 vertices, namely in the bottom of the gauge and the protrusions caliber. This is shown on page 1052, Fig. 11 the specified publication. Peaks at the contact surface between the roller and the rolled product produce pipes with a very thin wall with the ratio of wall thickness to diameter of more than 0.25 and again to the roundness of the pipe, and obviously affect the quality. Additionally, increased friction, which leads to more severe wear of the rolls.

For solving the problem, according to the invention, it is proposed that the contour of each roll had in the area of the bottom of the gauge widening in diameter, which can be deformed area of material laminated to the tops of the roll corresponding to the previous in the direction of rolling, caliber.

Targeted expansion of the diameter of the caliber in the area of the bottom of the gauge it is possible to reduce the contact length in the bottom of the gauge in such a way that results in an even contact surface. Thanks to this pipe in the area of the bottom of the gauge is no longer subjected to excessive stresses, as is clearly visible in the prior art tops flattened.

Particularly favorable, if the extension in diameter from the diameter of the gauge is approximately 0,5-1% of the diameter of the caliber and occurs on both sides of the middle of the bottom of the gauge ring angle equal to approximately 10 - 15o. When these dimensions are obtained good results in the pipe, i.e. the contact surface between the rolls is m invention provides for expanding the diameter in the area of the protrusion gauge, in addition to expanding the diameter in the bottom of the gauge. This extension diameter can be achieved, for example, an increase of 3-5 mm radius transition at the edge of the swath. It was found that with these radii, which in the prior art are less than 3 mm, also achieved a significant improvement deformation ratios in the caliber and contact of taper can be significantly reduced and in the marginal zone of the caliber roll.

In Fig. 1 shows a front view in partial section of a caliber roll, according to the invention, the incoming pipe; Fig. 2 - the projection on the horizontal contact area between the pipe and the caliber of the roller according to the invention.

In Fig.1 position 1 indicated one of the three roll calibers, forming the entire caliber, according to the invention, rotating around the axis 2. Rolled pipe is shown schematically position 3. Mainly, round caliber 4 roll 1 is in the area of the bottom of the caliber of the extension 5 in diameter, that is, the recess in the bottom of the gauge. Other extensions under the digit 6 in diameter is provided in the area of top caliber, namely in the form of increased diameter at the edge of the roll caliber. In Fig.1 for a better understanding of the dashed line 7 shows the typical shape of the caliber. This normal form In the drawing shows the contact top 8 in the area of the bottom 9 of the caliber 1 roll and in the area of the protrusion 10 gauge on both edges of the roll 2. These peaks 8 and 10 are formed on the inlet side of the roll 1 and result in the described internal roundness of the finished pipe 3.

If we consider the contact surface of the pipe on the roll according to the invention, carried out by the solid line in Fig. 2, we can see that the vertices 8 and 10 are greatly reduced, due to what turns out almost rectangular contact surface with a contact length of 10. These changes to the contact surface caused by the extensions 5 and 6 of a diameter in the bottom of the gauge and in the area of the top caliber.

1. The caliber of the roll, mostly round shape for reducing rolling mill with a three-roll mill, in particular for rolling thin-walled pipes with the ratio of wall thickness to diameter of more than 0.25, characterized in that the caliber of each roll (1) has a contour in the area of the bottom of the caliber of the expansion (5) in diameter, which can be deformed area of the material, laminated in the vertices of the corresponding roll, previous in the direction of rolling, caliber.

2. Caliber under item 1, characterized in that the extension (5) the diameter is, if we assume the diameter of the caliber, about 0.5 - 1.0 of the diameter of the caliber and is located on both sides from the center of the bottom of the gauge with angle environment is about the diameter of the bottom (9) has the expansion (6) in diameter in the area of the top caliber.

 

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