EP1203622A2 - Rotary drive for reciprocal roll-off roll grooves of a cold pilger mill - Google Patents

Abstract

The rolling curve of the drive pinions of ring rollers are adapted to the neutral zone in decreasing caliber of the ring rollers of a cold pilger rolling mill, by using circular pinions, which are positioned eccentrically on and fastened to the roller shaft. Sinusoidal toothed racks are used to drive pinions and ring rollers. If circular eccentric pinions are used, which mesh with sinusoidal racks, for parameters can be adapted to actual roller dimensions:- roller diameter, pinion reference circle, eccentricity, angular position of eccentricity relative to entrance dead center of roller stand.

Description

The invention relates to a method for adapting the rolling curve of the drive pinion from ring rollers to the neutral zone in the tapered caliber of Ring rolling of a cold pilger rolling mill.

Cold pilger rolling mills are suitable, extruded, hot-rolled or continuously cast, thick-walled metal slugs, especially copper slugs, in one operation with a comparatively large extension to long, thin-walled as well reduce ductile pipes with low eccentricity.

The cold pilger process used is a forming rolling process for metal pipes, in which in a large number of forming steps Diameter and wall thickness can be reduced.

There is a stationary mandrel that tapers in the rolling direction when rolling inside the tube. The rolling mandrel is attached to a long mandrel bar, which is clamped and held by a mandrel abutment.

A pair of rollers rolls back and forth over the one on the mandrel tubular rolling stock and stretching it, similar to a rolling pin when rolling out and Stretching dough.

The pair of rollers is in a reciprocating reciprocating roll stand stored and is connected by pinions connected to it with two fixed Combing racks, driven during the scaffolding movement. The roll Roll caliber back and forth in synchronism with the oscillating roll stand.

The rolling stand itself is moved like a motor piston by a crank mechanism moved here. The roller calibers are approximately circular and shrink in the usual execution according to the state of the art over the circumference of the roller. The decreasing or tapering cross section between rollers and Rolling mandrel simultaneously reduces the diameter and wall thickness of the rolling stock.

In the area of at least one of the two dead centers, the rollers briefly release the blank, which is advanced and / or rotated at the same time, for example by approximately 60 ° in each case. With this method, both the forward and the return stroke are used for the forming. The feed and angle of rotation in both dead centers depend on the pipe material and quality requirements. The deformation resistance of rolled pipes ranges from 400 N / mm ² to over 1,500 N / mm ² for special alloys.

A basic representation of the pipe rolling process described above is the purely schematic representation in Figures 2a to 2d. figure 2a shows a reduction in the forward stroke. Figure 2b shows in section A-B an exit cross section. Figure 2c shows a reduction in the return stroke and Figure 2d shows in section A-B an outlet cross section.

The combination of a cold pilger rolling mill with in-line reel device enables the production of coiled pipes e.g. 250 m length. It will be with incremental feed rotating back and forth from the cold pilger mill emerging pipe bent during the rolling process into a coil and directly into one for the subsequent pulling process filed required basket.

• er ergibt fallweise relativ große Querschnittsreduktionen von Durchmesser und Wanddicke, und eine
• erhebliche Verminderung der Exzentrizität infolge ausgleichenden Fließens in Umfangsrichtung, sowie eine
• Optimierung des Werkstoffgefüges infolge mechanischer Vergütung, bei
• Herstellung großer Rohrlängen.

The above-described forming process using the cold pilger process is of considerable advantage for numerous areas of application despite the relatively low production speed:

• in some cases it results in relatively large cross-sectional reductions in diameter and wall thickness, and one
• considerable reduction in eccentricity due to compensating flow in the circumferential direction, as well as a
• Optimization of the material structure due to mechanical tempering, at
• Manufacture of large pipe lengths.

• Erzielung enger Toleranzen für Durchmesser und Wanddicke beim Walzgut,
• kein prozeßbedingter Materialverlust,
• Anwendbarkeit auch für schwer umformbare Werkstoffe, mit
• hoher Wirtschaftlichkeit durch Einsatz großer Luppengewichte und -längen, sowie
• Herstellung unterschiedlicher Fertigproduktabmessungen aus einer Luppenabmessung.

The cold pilger process for the production of pipes results in an improved roundness, uniform tension homogeneity and roughness of the surface

• Achieving tight tolerances for diameter and wall thickness in the rolling stock,
• no process-related loss of material,
• Applicability even for difficult to form materials, with
• high cost-effectiveness through the use of large slab weights and lengths, as well
• Manufacture of different finished product dimensions from a blank dimension.

Nevertheless, the state of the art results from the geometric relationships Disadvantages from the fact that over the stroke length of a pilgrim rolling mill with unchanged radius of the drive wheels the rolling radius of the calibers Roll circulation changes in a wide range. These inevitably slip on the pipe to be rolled, thereby deteriorating its quality. The one there causing further disadvantageous axial thrust acting on the rolling stock a number of problems. So it becomes difficult or even impossible to have thin walls Roll blanks with the usual feed rates, since the end faces of the Wedges blanks into each other during rolling, which means the rolling mill performance accordingly is lowered. In addition, the rolling mill is in all its functional elements highly stressed and strained and subjected to forced wear. In particular, roller and mandrel breaks have to be taken care of, as well as others expensive damage to the rolling mill.

Another disadvantage of the prior art is that the return stroke of the Rolling mill can only be used to a limited extent for the forming work, since the highest rolling forces usually occur on the return stroke. This leads to a basically sensible, additional feed of the blanks in the outlet dead center area cannot be fully used and that therefore the possible production output is restricted.

Furthermore, the state of the art also enables the forming technology Reduced diameter reduction. It can be seen that with increasing Diameter reduction also the problem due to the locally not adapted Sprocket pitch circle increases. This also affects the economy of the cold pilgrim process. "

To remedy this, the state of the art includes known: an assignment of the pitch circle of round, centrally arranged pinions and the roller diameter to the current roll dimension. However, this can only be an unsatisfactory one Achieve improvement in the rolling process.

The document DE-OS 17 52 996 on the other hand suggests the use of spiral Pinions in front that mesh with an inclined, straight rack. The well-known The main disadvantage of this solution is that it allows usable caliber length is lost, and the rolling power is reduced. This solution is still on tied the straight shape of the rack. However, since the caliber processing is one Parabola of higher order follows, here too is the approximation to the target curve only possible to a very limited extent.

Starting from the aforementioned prior art, the object of the invention based on a method for driving the roller pair of a cold pilger rolling mill to indicate which is a significantly improved adjustment of the rolling curve of the pinion to the neutral zone in the tapered caliber of the ring rollers realized.

• Verminderung der Druckbelastung an den Vorschubschlitten,
• Vermeidung eines unkontrollierten Vorschubs durch Relativbewegungen zwischen Walzenprofil und Walzgut,
• Verschleißminderung im Walzenprofil,
• Reduktion des Energieverbrauchs durch verminderte Reibleistung,
• Anpassung der Abwälzkurve des Ritzels an die neutrale Zone im sich verjüngenden Kaliber der Ringwalzen,
• Vermeidung der noch bestehenden Nachteile vorbekannter Lösungen.

To achieve the object, the invention proposes that circular pinions are used to adapt the rolling curve of the drive pinion of ring rollers to the neutral zone in the tapered caliber of the ring rollers, and these are arranged and attached eccentrically on the roller axis. The following goals are achieved with the invention:

• Reduction of the pressure load on the feed carriage,
• Avoidance of an uncontrolled feed due to relative movements between roll profile and rolling stock,
• Wear reduction in the roll profile,
• Reduction of energy consumption through reduced friction,
• Adaptation of the pinion rolling curve to the neutral zone in the tapered caliber of the ring rollers,
• Avoiding the existing disadvantages of previously known solutions.

An embodiment of the invention consists in that for driving the pinion and so that the ring rolling - corresponding sinusoidal racks are used.

This solution according to the invention reduces or avoids the disadvantages of unsatisfactory methods and devices from the prior art, e.g. the sliding of the pair of rollers on the rolling stock with those described above Disadvantages for the rolled product and the rolling mill, or the reduced Production output.

• Walzendurchmesser
• Ritzelteilkreis
• Exzentrizität
• Winkellage der Exzentrizität zum Einlauftotpunkt des Walzgerüstes.

A further embodiment of the method according to the invention provides that when using circular eccentric pinions which mesh with corresponding sinusoidal racks, the following four parameters can be adapted to the current rolling dimension:

• Roll diameter
• Pinion pitch circle
• eccentricity
• Angular position of the eccentricity to the dead center of the roll stand.

Figur 1

im Diagramm die geometrischen Verhältnisse über der Hublänge eines Kaltpilgerwalzwerkes

Figur 2 a bis 2 d

ein Walzverfahren nach der Erfindung mit den Arbeitsschritten:

Figur 2a

eine Reduktion beim Vorhub mit exzentrisch angeordneten Ritzeln

Figur 2b

im Schnitt A-B einen Austrittsquerschnitt

Figur 2c

eine Reduktion beim Rückhub

Figur 2d

im Schnitt A-B einen Austrittsquerschnitt

Further details and features of the invention result from the claims and the following description of an embodiment of the invention shown in the drawings. Show it:

Figure 1

the diagram shows the geometric relationships over the stroke length of a cold pilger rolling mill

Figure 2 a to 2 d

a rolling process according to the invention with the steps:

Figure 2a

a reduction in the advance stroke with eccentrically arranged pinions

Figure 2b

in section AB an outlet cross section

Figure 2c

a reduction in the return stroke

Figure 2d

in section AB an outlet cross section

A cold pilgrim process known as such is shown in FIGS. 2a to 2d shown. It is used to manufacture or form a tube 12 by means of a pair of cold pilger rolls 10, 10 ', which is in a roll stand, not shown is stored. The pipe 12 to be machined is guided on a rolling mandrel 13. The Rolling stand makes an oscillating movement during the rolling process, stroke frequencies of up to 300 per minute and more are possible. The pipe 12 is brought into its finished shape or final contour by rolling calibres 11, 11 '; the rolling calibers 11, 11 'are in each other over the entire outer circumference opposite rollers 10 and 10 'cut and close in Roll gap (see FIGS. 2b and 2d) encloses the tube 12 circumferentially. The Rolling calibers 11 and 11 'have a different one according to their calibration Width and / or depth - in processing over the circumference of the roller seen- what with the hatched roller caliber contours 11 and 11 'in the figures 2a or 2c is indicated.

The tube 12 is moved in the conveying direction R during rolling. While The forward stroke, which is schematically sketched in FIG. 2a, rolls the complementary one Cold pilger roller pair 10 and 10 'in the conveying direction R on the tube 12, which in Roll gap is enclosed by the roll calibers 11 and 11 '. During the return stroke, that is schematically outlined in FIG. 2c, the roll pair is unrolled 10 and 10 'on the tube 12 against the conveying direction R (cf. in the Figures the arrows for the direction of rotation 14 and direction of translation 15).

In Figure 1, the geometric relationships over the stroke length of a cold pilger rolling mill are shown schematically in the form of diagrams. This is based on the following data or parameters of an exemplary embodiment as follows: Kupferwalzung 87 x 11 to 40 x 2 Roll diameter 375 mm Pinion pitch circle 336 mm Scaffold stroke 1,023 mm Reduzierkaliberlänge 600 mm Glättkaliberlänge 140 mm Ritzelexzentrizität 13 mm angular displacement 140 degrees

• aus der Zone 1, in der die Walzen das Walzgut zum Vorschieben und Drehen freigeben,
• aus der Reduktionszone 2, die einer Parabelfunktion folgt,
• aus der zylindrischen Glättzone 3,
• aus dem Übergang 4, in dem das Walzgut zusätzlich gedreht und/oder vorgeschoben werden kann.

The caliber processing as the basic caliber curve exists

• from zone 1, in which the rollers release the rolling stock for feeding and turning,
• from the reduction zone 2, which follows a parabolic function,
• from the cylindrical smoothing zone 3,
• from the transition 4, in which the rolling stock can also be rotated and / or advanced.

Curve 5 shows the neutral fiber, in which the longitudinal forces result from the different Neutralize transmission speeds.

The rolling stock share between the caliber base and the neutral fiber is relative lower speed, the proportion between roller diameter 6 and neutral Fiber 5 rolled over at a higher speed.

A pinion pitch circle, which could follow curve 5, would also neutralize the longitudinal forces that result from the rolling ratios that change over the caliber length. A round, centrally arranged pinion 7 can only imperfectly approach these requirements. Because:
The proportion of the circumferential speed that is too high predominates in the front caliber area, but is too low in the smoothing area of the smoothing zone 3. The conditions are only temporarily correct when the roll is unrolled at approx. 120 °.

However, the pinion is arranged eccentrically in a suitable manner according to the invention (8), it becomes an extremely extensive approximation to the desired curve 5 reached and the movement tendencies of the rolling stock are largely neutralized. The roller circumference can be used without restriction and the curve follows the target curve much better than is possible in the prior art is.

Claims (3)

Procedure for adjusting the rolling curve of the drive pinion of ring rollers to the neutral zone in the tapered caliber of the ring rollers of a Cold pilger rolling mill, using circular pinions for this and these are arranged and attached eccentrically on the roller axis. Method according to claim 1,
characterized in that correspondingly sinusoidal racks are used to drive the pinion - and thus the ring rollers. Method according to one of claims 1 or 2,
characterized in that when using circular eccentric pinions which mesh with corresponding sinusoidal racks, the following four parameters can be adapted to the current rolling dimension: Roll diameter Pinion pitch circle eccentricity Angular position of the eccentricity to the dead center of the roll stand.

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