DE617468C - Method and apparatus for producing pipes with inwardly thickened ends - Google Patents

Description

Method and device for producing pipes with inside thickened ends In the known process for the production of raw materials with after internally thickened ends by pilgrimage of a cylindrical hollow block on a The offset mandrel provides the correct shape of the pipes at the transition point difficulties between the thick-walled and the thinner part. These difficulties are eliminated by the method according to the invention.

The method according to the invention is essentially characterized by that at the beginning of the rolling out of the transition, the mandrel in the mandrel holder is released is, so that he in the further rolling out of the transition by the stretching of the Workpiece in the stretching direction, i.e. opposite to the rolling direction, for so long is taken until the rolling of the transition is completed.

The device used to carry out the method is The mandrel is slidably arranged in the mandrel holder and is secured by a removable locking piece, on the one hand against the wall of the mandrel holder, on the other hand against the head of the thorn, temporarily secured against displacement.

The device is shown on the drawing in Figs.

The in the mandrel holder b displaceable mandrel a, which is a stepped End a1 and has a conical transition part d = can in its extreme left Position by a fork-shaped locking piece d (Fig. 3), which is against the head e supports the mandrel bar, prevents movement in the mandrel holder in the stretching direction (Fig. i to 4).

The rolling process (see Figs. 8, 9, io of the drawing) is as follows: In the rolling section I, in which the rolling of the thickened pipe end (tail end) takes place, the mandrel a is rigidly connected to the mandrel holder b by the holding fork d. The hollow block c rests firmly against the mandrel holder b.

The direction of rolling is determined by the rotation of the pilger rolls h and directed from the pilgrim rollers towards the mandrel holder b. The rolling direction is not to be equated with the stretching direction. The latter is opposite to the rolling direction.

The moment the pilgrim rollers let go of the hollow block, it moves .the hollow block, driven by some kind of power source, moves against the roller. When they collide, the mouth of the pilgrim roller h pinches a small wave of material c 'from the hollow block. During this process, the hollow block has the same movement as accepted the roller. The roller exerts a pushing back force on the hollow block, which causes the tension of the propulsion means (air or spring) in the pilgrim's chariot. The push-back pressure is transmitted through the hollow block c via the mandrel holder b on the connecting rod b1.

Due to the special shape of the pilger roller h, the material wave becomes cl opposite to the rolling direction, i.e. in the stretching direction, stretched, at the same time being ironed onto the mandrel.

This creates a friction force between the hollow block and the mandrel, which causes a large tensile force in the mandrel in the stretching direction. Because the The mandrel head e is held in place by the fork d, the mandrel cannot achieve this tensile force follow. The rolled out material shaft cl slides in the stretching direction over the mandrel surface away.

The rolling of the conical transition takes place in Walzabs.chnitt II.

If one were to keep the rigid connection between mandrel a and mandrel holder b , according to what has been said about the first rolling section, the rolled material would slide over the firmly coupled mandrel a and the conical part of the tube would detach from the conical mandrel part and form a cavity m (Fig. zo). The material would be pressed into this cavity by the pressure of the pilger rollers h and form an undesired material wave c2.

The invention now aims to eliminate this drawback and Achieving a smooth transition.

To this end, when the rolling process is close to the conical The transition is reached when: that is, the thick-walled pipe part f (Fig. 5) is completed is, by removing the fork d, the rigid connection between the mandrel and mandrel holder solved. The mandrel can now follow the tensile force that occurs. Because of the friction Tube and mandrel form a complete whole. So the thorn wanders through them Friction with the direction of stretching of the material, thereby creating the cavity at the transition a ° (Fig. 8) and thus also the formation of material waves is avoided will. The material hugs the conical part of the mandrel without loosing itself forms a cavity.

In the rolling section III the rolling of the thin pipe part takes place.

The gradual wandering out of the mandrel is determined by the shape of the Mandrel holder b limited. The mandrel can only move around the stretching egg (Fig. 5) and then leans firmly with his head e against the end of the mandrel holder b (Fig. 7). The hollow block c is supported against the mandrel holder b, and the same occur again Conditions as in rolling section I. The thickened pipe end and the conical one Transition part g detach from the mandrel.

Claims (2)

PATENT CLAIMS: T. Process for the production of pipes with after ends thickened on the inside by pilgrimage over a stepped thorn, characterized in that at the beginning of the rolling out of the transition, the mandrel in the mandrel holder is released is, so that he will continue to roll out the transition by stretching the workpiece It is carried along in the stretching direction until the rolling of the transition: ends is. 2. Device for carrying out the method according to claim r, characterized in gel # r-, indicates, .that the mandrel (a) is slidably arranged in the mandrel holder (b) and through a removable locking piece (d), which on the one hand is against the wall of the mandrel holder, on the other hand against the head (e) of the mandrel (a), temporarily against displacement is secured.