DD202251A5 - METHOD FOR ROLLING TUBES - Google Patents

Abstract

While the aim of the invention lies in a labor productivity increase in the rolling of pipes, the object is to provide a method with which it is possible optimal performance increase over the cold pilgrim method by significantly increasing the total rolling work during cold rolling of pipes and thus a corresponding increase to create the output of the rolling mill. The solution now envisages that the overwhelming part of the total rolling work done during the reciprocation of the rolling mill stand on the forward stroke d. Walzgeruestweges u. d. smaller part d. Total rolling is provided on the Rueckwaertshub the Walzgeruestweges and that the total rotation of the rolling material with each reciprocating movement of Walzgeruestes is about 50 to 70%, the angle of rotation in the inlet dead center about 20 to 40 degrees and the rotation angle in the outlet dead center about 20 to 40 degrees.

Description

236920 0

Method of rolling pipes Field of application of the invention

The invention relates to a method of rolling tubes in which two oppositely arranged calibrated rolls mounted on a roll stand are reciprocated on a tubular rolling stock disposed on an axially fixed conical mandrel, the rotary driven rolls being at their ends Circumferential surfaces have tapered, adapted to the shape of the conical mandrel working caliber, the rolling material on the. Roll out the mandrel, with the y / alzen at the ends of the working caliber. Release rolling stock in both dead centers of Walzgerüstweges for the purpose of Vorschuberzeugung and rotation.

Characteristic of the known technical solutions

A known method for rolling tubes is that on an axially fixed conical mandrel, the tube material to be processed is stretched out by means of reciprocating and calibrating reciprocating rollers mounted in a rolling stand. In the inlet dead center (dead center on the inlet side of the rolling material of the rolling stand), the tube material is released from the ring rollers, - so that in this period there is the possibility to carry out the advance of the tube material and the rotation of the tube material by a certain required rotation angle.

In this known rolling process, the feed of the

Rolled material in the inlet dead center, d. h »generated before the forward stroke of the roll stand. The necessary rotation of the rolling material - the rotation angle is in the range of 50 ° to 70 ° - takes place in this rolling process also in the inlet dead center of the roll stand ·

236920 0

3 · 3 ·· 1982

60 011/27/37

Since in this known rolling process practically only on the forward stroke of the roll stand 'the effective rolling work is done, this method has been called "cold pilgering process". »No rolling work was done on the backward stroke of the rolling stand.

^ -, _N from the DT-OS 16 02 036 it is already known, the advance of the rolling material 100% or most of the Auslauftotpunkt of the mill way to generate that before the Rückwärt shubes and the rotation of the roll material of approximately · 60 ° both at the inlet dead center and at the outlet dead center of the rolling stand stroke

In DE-OS 16 02 O36 is mentioned that the more expedient, more favorable deformation of the rolling material is present, if the Verwalzung takes place on the return stroke. This proposal is disadvantageous for the following reasons:

When rolling on the backward stroke with large feeds produced at the exit dead center, the rolling stock must flow opposite to the direction of movement of the work rolls. This results in very large axial back pressure forces on the mandrel, on the mandrel rod with mandrel abutment and the feed slide · Since these axial backpressure forces must be perfectly controlled by the cold rolling mill and this a certain load limit can not be exceeded, so is the size of the feed generated in the discharge dead center can be limited. For these reasons, only relatively small feeds can be realized in the discharge dead center. "Thus, the proposal according to DE-OS 16 02 O36 does not bring any improvements compared to the known cold pilger method. This proposal was made without any practical experience at that time.

236920 0

03/03/1982

60 011/27/37

theoretical basic technical knowledge of the proposed rolling technique.

Furthermore, it is proposed in DE-OS 16 02 O36 to make the proposed sole Vorschuberzeugung at the outlet dead center additional Vorschuberzeugung in Einlauftotpunkt · This brings no significant increase in the total feed (main feed in the discharge dead center, and additional feed in Einlauftotpunkt), as by the additional Vorschuberzeugung in Einlauftotpunkt with thereby necessary shift stroke in Einlauftotpunkt, - due to the now shortened working caliber length and the. As a result, increased roller pressure forces increase the axial back pressure forces on the return stroke. As a result, the size of the allowable feed in the outlet dead center must again be reduced so far that the proposal no performance increase over the practiced Kaltpilgerwalzverfahren results.

In the proposed in DE-OS 16 02 O36 rotating the Walzmateriäls by the specified angle of rotation for the WaIzmaterial, thorn mi.t mandrel and inlet and outlet chuck of about 60 ° - both in the inlet dead center and in the outlet dead center of Walzgerüstweges is also for turning in the discharge dead center requires a considerable shift stroke. Compared to the Kaltpilgerverfahren, takes place at the feed and rotation in Einlauftotpunkt, this shift stroke the working caliber length and thus the rolling work length lost · Since basically the feed size is simply proportional to the working caliber length, a significant reduction in the working caliber length means a significant reduction in the feed size, so that in this Proposal even a reduction in performance compared to the previously practiced cold pilgrimage would occur.

236920 0 -

03/03/1982

60 011/27/37

Object of the invention

The aim of the invention is a labor productivity increase when rolling tubes ·

Explanation of the essence of the invention

The invention has for its object to provide a method for rolling ¹ of tubes of the type described, with which it is possible to achieve optimum performance over the cold pilgrim method by significantly increasing the total rolling during cold rolling of pipes and thus a corresponding increase in the output of To create a rolling mill.

To solve the problem, it is proposed according to the invention that the majority of the total rolling work done during the reciprocating movement of the roll stand is provided on the forward stroke of the roll stand path and the smaller part ΓΖ of the total rolling work on the reverse stroke of the rolling mill stand and that the total rotation of the Rolling material with each reciprocating movement of the roll stand - approx. 50 to 70 % , wherein the angle of rotation in the inlet dead center is approx. 20 to 40 ° and the angle of rotation in the outlet dead center is approx. 20 to 40 °.

When carried out rolling tests, it has been found that in an exclusively in. Approximately half of the total rolling work is split halfway down to the subsequent backward stroke of the rolling mill stand and to the subsequent forward stroke of the rolling mill stand. "

The rolling method according to the invention, in which the predominant

236920 G

3 · 3 · 1982

βΟ 011/27/37

Proportion of the rolling work of the rolling stock on the forward stroke and the smaller proportion takes place on the backward stroke, brings an optimal performance increase with respect to the cold pilgering method, since both the forward stroke and the reverse stroke are loaded with so much rolling work that the elements of the cold rolling mill, in particular Torschub- and Turning mechanism, mandrel abutment and rolling mill with the calibrated rolls compared to the cold pilger rolling mill with the cold pilger rolling process are not charged higher and thus need not be changed. In the proposed method, the smaller part of the total rolling work assumes a size which represents a significant rolling work on the backward stroke, thus allowing a substantial increase in the total feed rate contrary to the cold pilgering method. "

This notable size smaller proportion of the total rolling work on the return stroke is possible, that existing in the inventive roll method angle of rotation for the rolling material in both the Einlauftotpunkt and in Auslauftotpunkt be about 20 to 40 °, since at these NEN angles of rotation during the rolling small to the axial back pressure on the mandrel, mandrel bar, mandrel abutment and "feed slide. are substantially smaller than the known angle of rotation of about 50 ° to 70 ° both in the infeed and in the discharge dead center. The broadening of the rolling in the roll gap occurring during rolling becomes Presence of the small angles of rotation in the inlet and outlet dead center of about 20 to 40 ° on the next forward stroke and on the next backward stroke distributed, thus resulting in a significant reduction of the axial back pressure forces.

Moreover, the rolling method according to the invention results in an improvement of the tube tolerances, a reduction of the differences of the tangential and longitudinal inner

235920 0 -

3 · 3 · 1982

βO 011/27/37

Stresses of the cold-rolled tubes and a substantial extension of the life of the rolling tools ·

When cold pilgering of copper pipes with feed and rotation in Einlauftotpunkt often desired large Luppengewichten (about 400 to 500 kg) occur in the last part each -x doll at the end of the working caliber large deceleration forces in the rolling stock, whereby there is a risk that the rolling material unwanted Movements in the discharge direction · If you wanted to avoid this, you were sometimes forced to reduce the working speed of the rolling mill in the last area of each billet, which meant a reduction in output.

Substituting the rolling process according to the invention in the management of copper pipes with corresponding large Luppengewichten, the deceleration forces during rolling are significantly reduced, so that a reduction in the operating speed of the cold rolling mill is avoided »

In the method according to the invention, the force for producing thrust (the mandrel release force) is substantially reduced at the small angles of rotation of about 20 ° to 40 ° and in the distribution of total rolling work according to the invention on the forward and backward stroke. As a result of the small mandrel release forces and the small back pressure forces shows that in the rolling method according to the invention, the cold rolling mill runs much quieter than when using the known Kaltpilgerwalzverfahrens · The noise level in the cold rolling mill with the rolling process according to the invention is significantly reduced.

236920 0 -

03/03/1982

60 011/27/37

Ea has been shown that the proposed rolling process is used particularly favorable when, for carrying out the method, a cold pilgering mill with annular caliber rolls is used, in which a device is provided, by means of which the angle of rotation (Gesamtabrollwinkel) of the annular caliber rolls used, based on the pitch circle diameter roller axle pinion during each forward or backward stroke is greater than 330 °. That is, the shift stroke for feed and / or rotation of the rolling stock in the discharge dead center in the caliber mouth of the ring rolls and thus at feed or rotation in the discharge dead center, the working caliber length of the ring rolls is not affected.

In addition, cold rolling mills of this type, as described for example in the patent application P 23 29 526 · 3, a mechanical rotating device for generating the rotation of the rolling material, in which the necessary switching time is proportional to the angle of rotation angle to be generated.

When registering the method according to the invention in such a cold rolling mill, the following advantages result!

Since the angle of rotation in the inlet dead center is only approx. - 20 to 40 ° with respect to the angle of rotation of 50 to 70 ° in the cold pilger method, the switching time at the inlet dead center can also be reduced to about half. This results in a überpropor.tionale shortening of the shift stroke in Einlauftotpunkt and thus the working caliber length can be extended accordingly (about 15 to 20 %) without the roll diameter of the ring rolls, as it was used in conventional long-stroke cold pilger mills, is changed. This results in a particularly long stroke,

236920 0

3 · 3 · 1982

60 011/27/37

with the help of which a corresponding increase in the total feed, ie. the total rolling work of the rolling material is made possible with each reciprocation of the rolling stand.

Since the rotational angle size at the discharge dead center in the new rolling process is about 20 to 40 °, the required elongation of the rolling mill stand in a cold rolling mill using the method of the present invention is superior to the rolling mill stand using the cold pilgering method in the long-stroke cold pilger mill (eg DE-OS 23 29 526) only about 5 to 10 %, Thus, the main mechanical drive of a cold rolling mill for use of the method according to the invention must be only insignificantly increased, making the entire cold rolling mill is only slightly heavier · In contrast, however, results in a total performance increase of approx · 40 to 50% compared to the performance of the known cold pilgering mill.

Claims (1)

236920 0 ' 3 · 3 · 1982 60 011/27/37 invention claim A method of rolling tubes in which two oppositely arranged calibrated rolls mounted on a rolling stand are reciprocated on a tubular rolling stock disposed on an axially fixed conical mandrel, the rotationally driven rolls tapering at their peripheral surfaces, having working calibers adapted to the shape of the conical mandrel, which roll the rolling stock on the mandrel, the rollers at the ends of the working caliber releasing the rolling stock at both dead centers of the rolling mill path for the purpose of feed and rotation, characterized in that the majority of in the reciprocating motion of the rolling stand, total rolling work is performed on the forward stroke of the rolling mill stand and the smaller part of the total rolling work is performed on the backward stroke of the rolling mill stand, and that the total rotation of the rolling stock at each reciprocation of the rolling stand is about 50 to 70 % , wherein the angle of rotation in the inlet to tp.unkt ca · 40 ° and the rotation angle in the outlet dead center ca · 20 to 40 ° amount.