DE102006053773B4 - Process for rolling a long product in a rolling mill - Google Patents

Abstract

Method for rolling long goods (1) in a rolling mill (2), wherein a plurality of rollers (3, 4, 5) arranged over the circumference of the rolling stock (3, 4, 5) contact and transform the rolling stock (1) over an axial extent (z), characterized in that over at least a part of the axial extent (z ₀ ) over which the rollers (3, 4, 5) transform the rolling stock (1), between two successive rolling in the rolling direction (a, b) the ratio (V ) of the radius (r ₁ ) of the rolling stock (1) to the radius (r ₃ ) of the roller (3, 4, 5) is kept constant.

Description

The The invention relates to a method for rolling a long product in one Rolling mill, with several over The circumference of the rolling stock arranged rollers over an axial extent Contact and reshape the rolling stock.

The rolling of long goods is well known in the art. It is for example on the DE 30 30 052 C2 and on the DE 101 26 411 B4 pointed. There the planetary oblique rolling of a tube blank is described.

The at the planet inclined rolls typical torsion of the rolling stock is caused in the area of the forming zone, where the "bevel gear" between roller and Rolled as it is in the smoothing zone still works, no longer exists. The planetary slanting process as a convergent forming process thus has a torsion-free Lead-in area; the divergent skew rolling, z. B. the Assel process, is torsion-free in the outlet.

About the Entire rolling caused by rolling results however, in both methods a torsion in the rolling stock, d. H. either the billet as well as the tube rotate slowly while rolling, with the direction of rotation and also the angular velocity are indefinite. This is a peculiarity when skew rolling or planetary inclined rolls. If the outgoing pipe is to be wound up behind the rolling stand, must the torsion on exit from the rolling stand is taken into account, d. H. it should not turn.

To prevent this, it is out of the DE 101 26 411 B4 become known that the speed of the rotor and the rollers, which are driven by a two motors existing so-called. Overhead drive, are changed to each other. For this purpose, a sensor is mounted on the outlet side of the rolling mill, which can detect a rotation of the outgoing pipe. Turning the billet can be prevented only with great effort. It is usually not enough to change the speed of the rotor and the rollers against each other, but it would also be necessary to adjust the position of the rollers to the tube blank and the pipe. This is virtually impossible to do on the running machine.

To prevent the torsion in a simpler way, sees the DE 101 26 411 B4 in that the feeding of the tube blanks to be rolled into the roll gap is carried out continuously in bursts, whereby the respective tube blank following the roll gap is advanced with a rotation corresponding to the rotation of the tube end due to the torsion under the rolls. This process is complex and not always feasible.

By the GB 308,783 It has become known for a method of the type mentioned, to keep a constant ratio of certain geometric sizes during rolling. The sizes to be set are, on the one hand, a value as a radius from the axis of the pipe to be formed to its outer surface and, on the other hand, a distance from the axis of the pipe to be formed to the point where the radius jet intersects the roll axis.

Of the Invention is therefore the object of a method of the initially to create the type mentioned that prevents torsion in a simpler way. It is aimed at that over the entire forming length the torsion of the rolling stock is minimized, the forming process thus preferably runs without torsion. The "Ke gelgetriebe" should this over as possible size Parts of the forming length, preferably over the entire forming length, remain effective.

These The object is achieved by a Solved by the method of the type mentioned pingangs; that over at least a portion of the axial extent over which the rolls the rolling stock forming, between two successive rolling in the rolling direction The relationship the radius of the rolling stock is kept constant to the radius of the roll.

The Method is particularly preferred when skew rolling or planetary cross rolling for use.

The to be rolled long goods is preferably a doll or a pipe.

Further is further education provided that The relationship the radius of the rolling stock to the radius of the roller over the entire axial extent is kept constant over the rollers transform the rolling stock.

The Torsion of the rolling stock can with the proposed procedure without further measures minimized or eliminated. For this purpose, only the inventive calibration of Rollers required.

The Invention allows So by a roll calibration, along the nip nearly constant radius ratio from radius rolling stock and radius roller has.

Is possible it too, the change the direction of the velocity vector for complete elimination to consider the twist.

In order to is an improved deformation in particular of torsion sensitive Materials possible, as well as an improvement of the efficiency and a simplified Handling of the rolling stock, as neither in the inlet nor in the outlet area of the Rolling mill is a rotation of the rolling stock.

In the drawing are embodiments of Invention shown. Show it:

1 to be rolled long goods with the engaged rollers, viewed in the direction of the axis of the long goods, ie in the front view;

2 the long goods including rollers accordingly 1 in a side view;

3 the long goods including rollers accordingly 1 in perspective view;

4 the object according to 2 in an enlarged view; and

5 the course of the contour of the forming zone over the axial direction (z-axis) for different ratios for previously known solutions and for an inventive design of the roll caliber.

In the 1 to 4 is a rolling mill 2 to be seen in different views, being from the rolling mill 2 only the three rollers 3 . 4 and 5 a planetary cross rolling mill and the material to be rolled 1 is shown in the form of a tube blank. There is a roller 3 shown with solid lines, whereas the other two rollers 4 . 5 for the sake of clarity, are shown with dashed lines only.

The rolling stock 1 has in the direction of its longitudinal axis an axial extent z. Around the longitudinal axis, the rollers rotate in the planetary inclined rollers in a known manner. It is to this known technology to the above-mentioned publications DE 101 26 411 B4 and on the DE 30 30 052 C2 pointed.

Essential process parameters for planetary inclined rolls are the planetary radius r _Plan (s. 1 ), the head angle φ and the feed angle α. In the exemplary embodiment, the planetary radius r _Plan = 325 mm. The head angle φ is usually in the range between 30 ° and 50 °, the feed angle α is usually in the range between 6 ° and 11 °. Another important parameter for the planetary _{skew rolling process} is the gear ratio i _PSW . For this values between 0.5 and 1.5 are common.

In 4 can be seen that the contact area between roller 3 . 4 . 5 and rolling stock 1 extends over an axial extent z ₀ . At least one region of the axial extent z ₀ defined by two points a and b exists, in which the rolls 3 . 4 . 5 the rolling stock 1 deform and for which applies that the ratio V of the radius r _{1 of} the rolling stock 1 to the radius r _{3 of} the roller 3 . 4 . 5 remains constant.

The forming zone contains a diameter decrease in the inlet area and a less pronounced increase in the outlet area. This is best in 4 to recognize. The roll axis runs skewed past the rolling stock axis and has a minimum distance to the rolling stock axis at a defined point. Before this point, as the rolling direction progresses, a decrease in the center distance occurs, and behind the point, the distance increases as it progresses in the rolling direction.

The Roller calibration is done so that in the area of the closest point the smoothing zone lies. Thus, the course of the center distance qualitatively the Forming geometry dar.

According to the above situation, optimum torsion freedom is given in relation to the ratio V when the ratio V of the radius r _{1 of} the rolling stock along the flow-dividing sheath is 1 to the radius r _{3 of} the roller 3 . 4 respectively. 5 remains constant. To simplify, for the calculation, instead of the flow-divide, the outflow line can be considered, which is defined purely geometrically.

By specifying the translation of the Planetenschrägwalzprozesses i _PSW , the head angle φ and the feed angle α, it follows a roll caliber with a constant radius ratio. By varying these three parameters, almost any calibration can be achieved.

In 5 a diagram is shown, which indicates the course of Umformgeometrie, ie the course of the forming zone, for varying translations i _PSW between 0.5 and 1.5. For comparison, the forming geometry of a conventional calibration is shown (curves A). It should be noted that the torsion-free roll calibration (curve B) remains locally (in the z-direction) well behind the original calibration.

In the illustration according to 5 the planetary radius r _{plan is} 325 mm, the head angle φ is 40 °, the feed angle α is 8.0 °. The head angle φ has an influence on the forming geometry. If the pitch diameter, which is mainly influenced by the feed angle α, is maintained at different head angles φ, the forming length varies. By changing the head angle φ the Forming geometry shifted axially.

As can be seen, with a suitable choice of the ratio i _PSW of approximately 0.8, there is a good overlap of the two forming geometries, ie the curves A and B are most similar. The pitch diameter and the forming length are approximately coincident in the original and the torsion-free roll caliber.

The roll caliber determining parameters i _PSW , φ and α allow different calibrations. In this case, the resulting roll diameter is to be considered, since this may not be too small due to the load in combination with the roll length. By specifying a high Planetenschrägwalz- translation of the roll diameter is increased. The roller diameter is limited by the adjacent rollers upwards, so that no collision of the rollers occurs.

1

Langgut (Pipe, tube billet)

2

rolling mill

3

roller

4

roller

5

roller

z

axial direction

z ₀

axial extension

a

first Job

b

second Job

V

relationship

r ₁

radius of the rolling stock

r ₃

radius the roller

_Plan

Planet radial head angle

φ

head angle

α

feed angle

i _PSW

ratio

A

previously known curve

B

curve according to embodiments of the invention

Claims (4)

Method for rolling a long product ( 1 ) in a rolling mill ( 2 ), wherein several over the circumference of the rolling stock ( 1 ) arranged rollers ( 3 . 4 . 5 ) over an axial extent (z) the rolling stock ( 1 contact and reshape, characterized in that over at least part of the axial extension (z ₀ ) over which the rollers ( 3 . 4 . 5 ) the rolling stock ( 1 ), the ratio (V) of the radius (r ₁ ) of the rolling stock (a, b) between two successive rolling points (a, b) ( 1 ) to the radius (r ₃ ) of the roller ( 3 . 4 . 5 ) is kept constant. Method according to claim 1, characterized in that the long goods ( 1 ) is rolled by means of a transverse rolling process. Method according to claim 1, characterized in that the long goods ( 1 ) is rolled in the planetary cross rolling process. Method according to one of claims 1 to 3, characterized in that the ratio (V) of the radius (r ₁ ) of the rolling stock ( 1 ) to the radius (r ₃ ) of the roller ( 3 . 4 . 5 ) is kept constant over the entire axial extent (z ₀ ) over which the rollers ( 3 . 4 . 5 ) the rolling stock ( 1 ) transform.