EP0876856B1 - High performance wire rolling mill - Google Patents

Abstract

The installation includes a continuous casting unit or casting wheel (1), a rolling mill and a buffer furnace (3) for smoothing production differences and smaller disturbances. There is also a compact preliminary section (4) and an intermediate section I (5), as well as calibrating means for the sections (4, 5). There is a 180 degrees turn (6) behind the intermediate section I followed by an intermediate section II (7) and a finish section (8). Both of these sections are designed for quick roll stand changing. The section (8) is arranged in a production line (9) parallel to the section (II). Additionally there is a water cooling section (11) which is common to both the production lines (9, 10), and is laterally movable from one to the other. Finally there is coiling unit (12) which is movable between the two production lines.

Description

• einer CC-Anlage bzw. einem CC-Gießrad für hohe Produktion,
• einer Direktanbindung von CC-Anlage bzw. -Gießrad an das Walzwerk,
• einem Puffer-Ofen zwischen der CC-Anlage bzw. dem -Gießrad und dem Walzwerk zum Ausgleich von Produktionsunterschieden sowie kleineren Walzwerksstörungen,
• einer kompakten Vor- und Zwischenstraße I
• mit einer Einheitskalibrierung für die Straßenabschnitte.

The invention relates to a high-performance wire rolling mill comprising a wire and / or bar mill for rebar and simple carbon steels with:

• a CC system or a CC casting wheel for high production,
• a direct connection of the CC system or casting wheel to the rolling mill,
• a buffer furnace between the CC system or the casting wheel and the rolling mill to compensate for production differences and minor rolling mill disruptions,
• a compact Vorstrasse and Zwischenstrasse I
• with a uniform calibration for the road sections.

High-performance wire rod mills with the generic features in the aforementioned preamble of claim 1 are in the prior art known. This includes individual components of the system concept described, but these are not yet sufficient to in terms of the desired layout for minimized space requirements and investment costs to implement a convincing new concept.

The special print from Klepzik Fachberichte 82 (1974) 11, pp. 427/430 with the title "Single-core Morgan Siemag wire mill", author Heinz Bachmann describes the planning principles for a new wire rod mill at the Diemlach (Austria) plant, where - due to the very tight Space - a space-saving solution had to be found. Taking into account the local conditions and with the goal The only solution was one of the lowest possible investment costs compact single-core wire rod in U-shape. For heat treatment The wire became an elongated Morgan Street for two layers Operation. With a targeted heat treatment be achieved that the wire emerging from a wire mill after cooling, good drawing properties and as uniform as possible The course of the strength over the entire length of the wire and over has the wire cross-section.

A detailed discussion of the problems and the prior art of water cooling behind wire lines can be found in the special print from "DRAHT" 29 (1978) 6, pp. 286/89. The first stage of controlled cooling from the rolling heat is usually water cooling immediately behind the finishing block. Often, several cooling zones are assigned to the wire, which cool it down in stages to the desired laying temperature. Recreational routes have been set up between the individual cooling zones, which should give the wire the opportunity to equalize its temperature over the course of the cross-section. In conventional cooling sections that work with water pressures between 5 and 15 bar, heat transfer coefficients of up to 50,000 W / m ² ° C can occur at a rolling speed of 60 m / sec in the area of the nozzle. Average heat transfer coefficients are 30,000 to 40,000 W / m ² ° C. The wire surface is strongly supercooled when it exits the cooling section, while the core of the wire has remained much hotter depending on the cooling intensity and cooling time. This paper also takes into account the fact that when the wire tip enters a water-filled pipe, considerable forces can act on the wire tip, which in some cases cause the wire tip to break away.

Learn more about heat treating steel wire with over 0.4% lying carbon contents from the rolling heat are the DE-AS 1 583 411. The invention described therein lies the The task is based on a method for the heat treatment of steel wire from the rolling heat, the steel after exiting the last Scaffold intermittently quenched and through Temperature compensation with a core cross section is heated again and in the pearlite transformation region with a medium temperature from 600 to 650 ° C occurs in such a way that the previous usual lengths, which are considerable at increased rolling speeds which can significantly reduce cooling distances. This will be after this Document reached by quenching the wire surface intermittently up to 70 ° C above the martensite transformation temperature, at least to 400 ° C, is cooled, and that the wire of intermittent cooling for a time from 0.6 to 0.7 seconds is exposed. This takes place in a manner known per se Way, water cooling quenching and temperature compensation under air cooling.

The special print from "Stahl und Eisen" 108 (1988), Eisenhüttentag Pages 75 to 80 under the title "Temperature controlled rolling of Bar steel and wire ", the expert takes note that the Finishing roll temperature is easier to achieve and also a better one Temperature compensation becomes possible if only one cooling section is used a long temperature compensation section is used. A Temperature reduction in the finishing train with many cooling sections, e.g. a cooling section behind each scaffold does not bring the desired one Success, but increases the system length and is in the practical operation difficult to set. It goes on to say: The The selected plant regulations require that, contrary to the previous usual rolling practice all finished dimensions in the last two Stands are rolled and the stands in front of them during rolling thicker cross sections are omitted. The cooling section behind The task of the finishing stand is to recrystallize the austenite area to prevent, what to aim for a temperature of about 650 ° C. is. This leaves the fine-grained quality achieved by the forming of the structure preserved.

Another note on the design of wire mills with integrated The expert takes a continuous caster from a translation the publication from MPT (Verlag Stahl Eisen, Düsseldorf) Vol. 15 (1992) No. 3, pp. 52/58 with the title "Connection of the continuous casting plant to fine steel or wire rod mills "by the author U. Svejkovsky. It particularly emphasizes the difficulty of harmonization between the continuous caster and the fine steel or wire rolling mill noted that these rolling mills have a wide range of products have many different dimensions and qualities as well as small lot sizes. In addition, the different Dimensions rolled in very different quantities because of the production quantity especially with small dimensions, very different from the Rolling speed is determined. That means the relative constant casting production with small dimensions not can be completely removed and for larger finished dimensions the performance of the rolling mill is greater.

For the best possible remedy, i.a. a warm operation according to the EHC process (indirect hot charging). With this The billets coming from the continuous caster are processed not fed directly to the rolling mill furnace, but rather the thermal energy the billet is used for this, the billets coming from a warehouse to warm up, exchanging heat in a heater is carried out. It is a two-storey heat store. In this are cold billet batches from the warehouse come and put together according to the rolling program, above the billet batch coming from the continuous caster in Countercurrent transported. This involves heat transfer preferably over heat radiation.

Based on this prior art, the invention lies The task is based on known individual components of the aforementioned plant concepts to be combined with new device elements in such a way that the considerable hitherto usual at increased rolling speeds Lengths of the cooling section can be significantly reduced, so that in their functional interaction the concept of a particularly space-saving design of the system can be realized can.

• einer Zwischenstraße II zur Erzeugung dicker Fertigabmessungen bzw. Vorquerschnitte, in Konzeption für schnellen Gerüstwechsel,
• einer Fertigstraße, ebenfalls in Konzeption für schnellen Gerüstwechsel, mit
• der Anordnung der Fertigstraße in einer zur Zwischenstraße II parallelen Fertiglinie, mit
• der Zuordnung einer gemeinsamen und zwischen diesen beiden parallelen Fertiglinien verschiebbaren Wasserkühlstrecke und
• der Zuordnung einer zwischen beiden Fertiglinien verschiebbaren Wickelspulenanordnung anstelle einer nachgeordneten Ausgleichstrecke.

This object is achieved in a high-performance wire rolling mill of the type described in the preamble of claim 1 with

• an intermediate line II for the production of thick finished dimensions or pre-sections, designed for quick scaffolding changes,
• a finishing train, also designed for quick scaffolding changes, with
• the arrangement of the finishing train in a finishing line parallel to Zwischenstrasse II, with
• the assignment of a common water cooling section which can be moved between these two parallel finished lines and
• the assignment of a winding spool arrangement that can be moved between the two finished lines instead of a downstream compensation section.

With great advantage is the arrangement of a single and comparatively generously designed water cooling section a very intensive cooling of the wire is reached after the finishing train and compared to systems for intermittent cooling, for example considerable reduction in system length achieved.

The fact that two parallel finishing lines have a common and is assigned between these slidable water cooling section considerably saved on investment volume and a very economical one Construction of the system allows.

• Ersetzen des Stelmor-Transportbandes durch die Aufwickelstation;
• Ersetzen des Kühlbettes durch die Aufwickelstation, bzw.
• Ersetzen einer Garett-Anlage durch die Aufwickelstation.

The fact that instead of a subordinate compensation section is assigned to a winding line arrangement that can be displaced by two finished lines, a longer air cooling section is avoided and thus contributes in a special way to shortening the system length and the space requirement. Depending on the inlet temperature of the wire from the cooling section into the winding spool arrangement, the wire, with an assumed base weight of 5 t, for example, has the possibility of forming a predeterminable microstructure per unit of time with a predetermined decrease in temperature of the coil. This is made possible by the use of cooling technology by means of cooling to the transition temperature for reinforcing steel and simple carbon steels, whereby the wire has already completed the structural transformation before winding and therefore temperature control, such as on the Stelmor conveyor belt, is no longer necessary. A considerable reduction in costs is achieved through:

• Replacement of the Stelmor conveyor belt by the winding station;
• Replacing the cooling bed with the winding station or
• Replacing a Garett system with the take-up station.

With this technology, design in conjunction with the direct use of a CC-casting plant or a CC-casting wheel for high production (CC stands for C ontinuous C asting) is an extremely compact overall system by increasing the coil weights of, for example, 2 t 5 t possible.

An embodiment of the system provides that the winding coil arrangement for wire from 6 to 16 mm and for round steel from 18 to 40 mm is designed.

The winding spools can advantageously in a winding station be arranged and they can be inside the take-up station Means for moving the winding spools between the finished lines have.

Another also advantageous embodiment provides that the Water cooling section Means for moving them to the finished lines has. The means for moving can be a great advantage the winding coils and the means for moving the water cooling section be synchronously coupled with each other. Overall, with the Concept of plant layout according to the invention achieved that the The entire system can be accommodated in an area of approximately 30 x 150 m.

Details, features and advantages of the invention result from the following explanation of a schematic in the drawing illustrated embodiment.

The purely schematically shown family tree of the system according to the invention, For example, for approx. 600,000 JATO reinforcing steel or simple carbon steels 2 shows a CC system or CC casting wheel 1 for high production. As I said, CC is an abbreviation for continuous Casting. With the preferred connection of the CC system 1 to the Rolling mill is the installation of a buffer furnace 3 to compensate for Production differences between the CC system 1 and rolling mill as well provided to compensate for smaller mill malfunctions. Following then a compact pre-4 and Intermediate road I 5, which are designed so that a roll change is only required in the weekly repair shift, where, for example, the stands with two-caliber rollers for mutual Caliber insert are equipped. The scaffolds have through short bale length, high rigidity.

This is followed by a detour 6 by 180 ° in the family tree shown behind the intermediate road I 5, then an intermediate road II 7 to Generation of thick finished dimensions or pre-sections (e.g. 18-40 mm diameter) for the finishing train, designed for the fastest Stand changing. After the intermediate road II 7 branches off the Finishing line 10 from a parallel finishing line 9 in which the finishing train 8 (e.g. for 6-16 mm rolling stock diameter) is arranged. In The water cooling section is located in the following outlet section 11 with means 15 for displacement between the finished lines 9 and 10 is equipped. This is subordinate to the Slidable winding spool assembly 12, which also with means 14 within the winding station 13 for moving between the Finished lines 9 and 10 is equipped.

Like the concept of the plant with a layout for minimized needs in space and investment costs according to the family tree shown reveals a compact system with a maximum of 30 x 150 m Space requirements and with comparatively low investment costs realized in particular in that the usually arranged Stelmor cooling section through a relatively short water cooling section is replaced. To increase the coil weights, it is proposed that to use the winding station 13 instead of the Garett system. On System concept with the interaction of all of the aforementioned individual components 1 to 15 according to the invention is the wide range not to be deduced from the technology. Therefore, the invention solves in an optimal way Wise the task at the beginning.

Claims (9)

1. A heavy-duty wire rolling mill, comprising a wire and/or steel rod train for concrete steel and simple C-steels, with

   a CC-system or a CC-casting wheel (1),

   a direct connection between the CC-system or casting wheel (1) and the rolling mill,

   a buffer furnace (3) between the rolling mill and the CC-system or casting wheel (1) in order to compensate production inconsistencies, as well as slight rolling mill defects,

   a compact preliminary (4) and intermediate train I (5), as well as a unified calibration for the train sections (4 and 5), and

   a deflection (6) by 180° after the intermediate train I (5),

   characterized by

   an intermediate train II (7) for respectively producing thick finished dimensions or preliminary cross sections which is designed for a fast roll stand exchange,

   a finishing train (8) that is also designed for a fast roll stand exchange,

   the arrangement of the finishing train (8) in a finishing line (9) that runs parallel to the intermediate train II (7),

   the allocation of a common water cooling section (11) that can be displaced between the two parallel finishing lines (9, 10), and

   the allocation of a wind-up spool arrangement (12) that can be displaced between both finishing lines (9, 10) instead of a downstream compensation section.
2. The wire rolling mill according to Claim 1, characterized by the fact that the wind-up spool arrangement (12) is designed for wires (2) between 6 and 16 mm and for round steel (2) between 18 and 40 mm.
3. The wire rolling mill according to Claim 1 or 2, characterized by the fact that the wind-up spool arrangement (12) is arranged in a winding station (13).
4. The wire rolling mill according to at least one of Claims 1 - 3, characterized by the fact that the wind-up spool arrangement (12) which is arranged in the winding station (13) comprises means (14) for displacing the wind-up spools between the finishing lines (9, 10).
5. The wire rolling mill according to at least one of Claims 1 - 4, characterized by the fact that the water cooling section (11) comprises means (15) for being displaced between the finishing lines (9, 10).
6. The wire rolling mill according to at least one of Claims 1 - 5, characterized by the fact that the means (14) for displacing the wind-up spools (12) and the means (15) for displacing the water cooling section (11) are synchronously coupled to one another.
7. The wire rolling mill according to at least one of Claims 1 - 6, characterized by the fact that the entire system can be accommodated within an area of approximately 30 x 150 m.
8. The wire rolling mill according to at least one of Claims 1 - 7, characterized by the fact that the preliminary (4) and the intermediate train I (5) are constructively designed in such a way that a roll exchange is only required during a weekly repair shift.
9. The wire rolling mill according to at least one of Claims 1 - 8, characterized by the fact that the roll stands of the mill trains, in particular, the compact preliminary and intermediate train (4, I 5), are equipped with dual-groove rollers, wherein the grooves can be alternately utilized.

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