WO2003057383A1

WO2003057383A1 - Method and rolling stand for producing rods, bar stock or seamless tubes

Info

Publication number: WO2003057383A1
Application number: PCT/EP2003/000090
Authority: WO
Inventors: Manfred Leferink
Original assignee: Sms Meer Gmbh
Priority date: 2002-01-09
Filing date: 2003-01-08
Publication date: 2003-07-17
Also published as: BR0306683A; ATE296689T1; BR0306683B1; RU2274503C2; EP1463591B1; AU2003235800B2; EP1463591A1; PL369431A1; ES2243904T3; RU2004124048A; PL203879B1; AU2003235800A1

Abstract

The invention relates to a method for producing rods, bar stock or seamless tubes on a rolling stand for rolling hot metal material. Said rolling stand optionally comprises, when seen in the direction of rolling, a piercing-crossrolling mill, a multiple-stand stretch-rolling mill as the main stretching stage (4), a drawing mill (6), a finishing mill (10) and a rod rolling block (15) and devices, mounted upstream, intermediately or downstream thereof, such as a preheating furnace and a reheating furnace (11), roller tables (14) and a cooling bed (13). According to the inventive method, in the main stretching stage (4), a three-roller continuous rolling mill (3) is used both for rolling tubes and for massive rolling for producing bar stock, rods or the like. For massive rolling, the mandrel bar used for tube milling is brought out of the operative position and the provided bar stock rolls calibrated for a larger diameter reduction than used for tube milling are replaced by rolls calibrated for tube milling. A rolling mill suitable for carrying out the inventive method has, in the main stretching stage (4), a multi-stand three-roller continuous rolling mill (3) adapted to receive bar stock rolls or tube rolls and a device for removing the mandrel bar.

Description

Process and rolling plant for the production of wire, bars or seamless tubes

The invention relates to a method and a rolling plant for producing wire, rods or seamless tubes on a rolling plant for rolling heated metallic material, comprising optionally a perforated rolling mill, a multi-stand stretching rolling mill as the main drawing stage, a pull-out rolling mill, a finishing mill, viewed in the rolling direction and a wire rolling block as well as upstream, intermediate or downstream equipment such as a preheating and post-heating furnace, roller tables, separating devices and a cooling bed.

In order to enable better utilization of the rolling mill and to no longer need a rolling mill other than the manufacture of wire, rods or similar rolling stock for the production of pipes, it has become known from DE 199 35 647 A1 that the rolling of wire, bars or the same as well as the rolling of seamless tubes on the same rolling mill in two rolling lines, a part of the plant aggregates being used both in tube rolling (seamless tubes) and in solid rolling (wire, bars or the like). Although this can reduce the total number of units required, for example because existing furnaces, separators, the cooling bed and sections of the roller tables can be used universally in the rolling mill, there are one behind the furnace that heats the rolling stock to the rolling temperature and a transverse transport device downstream of it Rolling line required for wire or bars and one for pipes, ie two separate rolling lines in parallel. These are then combined in the material flow or in the rolling direction much later to form a common rolling line.

BESTATIGUNGSKOPIE The invention is therefore based on the object of providing a rolling method and a rolling installation of the type mentioned at the outset, which permit optimized operation with a further reduced outlay on equipment.

This object is achieved with a method according to the invention in that a 3-roll continuous rolling mill is used in the main stretching stage and is used both for tube rolling and for solid rolling in the production of bars, wire or the like, for which purpose a mandrel bar used for tube rolling in an out-of-operation position is brought and provided steel bar rolls with rolls calibrated for a large diameter reduction are exchanged for the rolls with their rolls calibrated for pipe rolling. By "continuous rolling mill", sometimes also called "continuous tube rolling mill", the person skilled in the art understands a rolling mill consisting of several consecutive rolling stands with an internal mandrel bar, as has become known, for example, from DE-Z "Berg- und Hüttenmännchen Monthly Bulletin 130 (1985) No. 7, pages 205 to 211. "

While in the known rolling mill the solid line is arranged separately from the tube rolling line, according to the invention a single line can be used for both purposes, which not only reduces the investment costs, but also the operating and maintenance costs. This is based on the consequent exploitation of the 3-roll technology, because it was recognized that despite the contradicting requirements - with pipe rolling, the outer diameter is usually changed little to avoid procedural disadvantages and the high elongation arises due to the central hole, while with solid rolling a large one Reduction in diameter must be ensured in order to achieve the required stretching - universal rolling is possible. This is also because, compared to conventional hole cross-rolling mills with 2-roll stands, there are no tensile stresses in the material core zone, but compressive stresses, which creates the risk of occurrence considerably restricted by internal defects. The stress behavior in the rolling stock when rolling in 2- or 3-roll cross-rolling mills is described in detail in "Manufacture of tubes", Verlag Stahleisen 1975, pp. 28 to 31.

In the transition from one type of rolling to the other, different rolls are provided according to the invention for tube rolling and solid rolling, in which the cross-section is different due to the adapted, different calibration, but the outer shape is constant, so that a simple exchange can be carried out , The specific number of 3-roll arrangements or stands in the main stretching stage is based on the desired degree of stretching, the stitch decreases or the decrease distribution for steel bars differing from that when rolling pipes. The measures to be taken for this, which depend on the insert or hollow block and the respective material properties, are known.

An advantageous embodiment of the method according to the invention provides that a 3-roll cross-rolling mill is also used for the perforating mill upstream of the main stretching stage, the perforated rollers for solid rolling with removed piercing mandrel bar being exchanged for provided steel bar rollers with rollers calibrated for diameter reduction. The 3-roll cross-rolling mill according to the invention in a perforated rolling mill then enables the production of different bar steel diameters in the sense of a pre-reduction, i.e. with a piercing rod moved away for solid rolling. a proportional reduction in cross-section based on the total reduction of all operated rolling mills. The piercing mill also fulfills a universal function.

According to the invention, in the main stretching stage, a rolling mill for carrying out the method has a multi-stand 3-roll continuous rolling mill designed to hold steel bar rolls or tube rolls and a device for removing the mandrel bar. The continuous rolling mill or the main stretching stage takes on either the one or the other stands or sets of rolls, each consisting of three rolls, on a frame. Corresponding stands can be provided in addition to the continuous rolling mill, which can then be brought into the operating position after the previous stands have been pulled out of the frame. Alternatively, a cassette construction or the exchange of only the rollers with the scaffold housings remaining in the frame is possible. In the simplest case, the mandrel bar can be moved to a non-operating position with the aid of the dome bar holding device when converting the 3-roll continuous rolling mill to solid rolling. This also applies to the perforated dome rod of the cross-rolling mill optionally upstream of the main stretching stage, which according to one embodiment of the invention is also designed as a universally usable 3-roll cross-rolling mill.

A preferred embodiment of the invention provides that a speed control is assigned to the 3 Λ / valve continuous rolling mill of the main stretching stage. This advantageously enables the different rolling speeds to be achieved in tube and bar rolling.

If the pull-out rolling mill arranged behind the main stretcher advantageously has two stand units which are arranged at a distance from one another and have end shears which can be inserted between them, bad ends can be easily cut off before further rolling in solid rolling. On the other hand, the use of scissors is not necessary for tube rolling.

The pull-out rolling mill is advantageously followed by a reheating furnace. From there, the heat-treated steel bars or, for example, alloyed or unalloyed steel pipes reach the finishing mill. This can include a sizing mill, a reducing mill or a stretch-reducing mill or a combination of these units. If a steel bar is to be rolled into wire, a roller table leading to the wire block is arranged behind the cooling bed.

Further details of the invention result from the embodiment drawing, which shows in a single figure in a very schematic manner a rolling mill according to the invention in plan view.

The universal rolling mill shown in the system diagram processes in one line, i.e. deviating from the drawing, the plant part shown in the lower half of the figure linearly joins the plant parts of the upper half of the drawing, which is indicated by the meandering line, an input material (insert block) either to seamless tubes or to bars, wire or similar solid rolled material.

In the figure is a furnace 1 with a loading device 2 for the raw material or blocks to be rolled, e.g. from continuous casting material, shown, in the furnace, the blocks are heated to rolling temperature. In the exemplary embodiment, a heated insert block is fed from there to a perforated cross-rolling mill designed as a 3-roll cross-rolling mill 3, where the block is guided in an inlet channel and rolled onto a mandrel bar provided with a piercing mandrel to form a hollow block in preparation for the subsequent rolling out to a seamless one Tube is deformed. Such a cross roll mill 3 in three-roll construction is known in the manufacture of pipes. If it is not pipes but rods or wire that are to be rolled, the 3-roll cross-rolling mill 3 is used with the mandrel rod held back or removed from the rolling line. massively reducing the block and compacting the structure instead.

From the 3-roll cross-rolling mill 3, the hollow blocks or the solid blocks are loaded into the downstream rolling devices. These include a main drafting stage 4, which here as a 6-stand 3-roll Continuous rolling mill 5 is formed. However, other scaffolding numbers are also possible. This is followed by a pull-out rolling mill 6, which here has two stand units 6a, 6b arranged at a distance from one another. Insertable end shears 8, 9 are provided both between the multi-stand 3-roll continuous rolling mill 5 and the pull-out rolling mill 6 and between the two stand units 6a, 6b of the pull-out rolling mill 6.

During tube production, a hollow block is stretched in the 6-stand 3-roll continuous rolling mill 5 and, after pulling out the mandrel bar, which is carried out by a back and forth mandrel bar holding device, reduced as a slug in the two stand units 6a, 6b of the pull-out rolling mill 6, while at Solid rolling, even the 6-stand 3-roll continuous rolling mill 5, like the pull-out rolling mill 6, reduces the bar steel by reducing the diameter. Before the reduced blanks or the reduced steel bars in one dimension or Stretch-reducing mill 10 is finished rolled into a tube or a rod, the rolling stock is brought to the required temperature in a reheating furnace 11.

A cropping saw 12 arranged on the outlet side of the sizing or stretching reduction mill 10 divides the finished tube or the finished rolled steel bar into the desired lengths. The finished lengths are then transferred to a cooling bed 13. If, on the other hand, the bar steel is to be rolled into wire, the bar steel is fed to a wire block 15 via an extension of the cooling bed roller table 14.

The universal rolling mill described thus allows seamless pipes as well as bars or wire to be rolled in one line. For this purpose, in the case of solid rolling in the 6-stand 3-roll continuous rolling mill 5, the rolls which have been calibrated for the pipe rolling are previously exchanged for rolls calibrated for a solid rolling and the mandrel rod is brought drive position, for example by moving the mandrel rod holding device into its retracted starting position.

Claims

claims:

1. Method for producing wire, rods or seamless tubes on a rolling mill for rolling heated metallic material, comprising optionally a perforated mill, viewed in the rolling direction, a multi-stand stretching mill as the main stretching stage, a pull-out mill, a finish rolling mill and a wire rolling block as well as Intermediate or downstream devices such as a preheating and post-heating furnace, roller tables and a cooling bed, characterized in that in the main stretching stage (4) a 3-roll continuous rolling mill (3) is used and both for hole rolling in pipe production and for solid rolling the production of bars, wire or the like is used, for which purpose a mandrel bar used for perforated rolling is brought into a non-operating position in the case of solid rolling and provided steel bar rolls with rolls calibrated for a larger diameter reduction than those used for pipe rolling are exchanged for the rolls calibrated for the pipe rolling the.

2. The method according to claim 1, characterized in that a 3-roll continuous rolling mill (3) is also used for a perforating mill connected upstream of the main stretching stage (4), the perforated rolling of which for solid rolling with a removed mandrel bar against provided steel bar rolls with for a diameter reduction customary for bar steel rolling calibrated rollers can be replaced.

3. Rolling plant for rolling heated metallic material into wire, rods or seamless tubes, comprising optionally a perforated rolling mill when viewed in the rolling direction, a multi-stand stretching rolling mill as the main fe, a pull-out rolling mill, a finishing mill and a wire rolling block, as well as upstream, intermediate or downstream devices such as a preheating and a post-heating furnace, roller tables and a cooling bed, characterized in that the main stretching stage (4) is designed to accommodate bar steel rollers or tube rollers, Multi-stand 3-roll continuous rolling mill (5) and a device (7) for removing the mandrel bar.

4. Rolling plant according to claim 3, characterized in that the upstream of the main stretching stage (4) perforated rolling mill (3) is designed as a 2-roll cross-rolling mill or 3-roll cross-rolling mill for receiving steel bars or perforated rolls and with a device for removing the piercing rod is provided.

5. Rolling plant according to claim 3 or 4, characterized in that the 3-roll continuous rolling mill (5) of the main stretching stage (4) is assigned a speed control which regulates both the roll speeds customary in tube and bar rolling.

6. Rolling plant according to one of claims 3 to 5, characterized in that the pull-out rolling mill (6) has two spaced-apart stand units (6a, 6b) with end shears (9) which can be inserted between them.

7. Rolling plant according to one of claims 3 to 6, characterized by a retracting furnace (11) following the pull-out rolling mill (6).

8. Rolling plant according to one of claims 3 to 7, characterized by a dimensioning and / or stretch-reducing mill arranged behind the reheating furnace (11) as a finishing mill (10) for pipes and steel bars.

9. Rolling plant according to one of claims 3 to 8, characterized by a behind the cooling bed (13) arranged to the wire block (15) leading roller table extension (14).