EP0845310A1 - Wire cooling - Google Patents

Abstract

The method concerns rolling of wire with use of at least one finish block with two-stand reduction stages in which the wire cross section is reduced to a specified degree through horizontal and vertical passes. The final rolling speed and the degree of reduction of each stage are determined according to the rolling temperature depending on material properties and rolling speed. The method is characterised by the fact that in order to increase the final rolling speed together with (if required) an increased degree of reduction at substantially unchanged rolling temperatures, the distances between the individual reduction stages of the finish block are increased, and intermediate cooling of the rolled product is applied at least over parts of these distances. Also claimed are a corresponding installation, and an application for finish rolling of wire, in particular, made of a special steel.

Description

The invention relates to a method and a system for Finishing rolling of wire in at least one finishing block two-stage reduction stages in which the Wire cross section through a horizontal and Vertical stitch reduced with a specified degree of reduction and the final rolling speed as well as the degree of reduction of each Level according to the depending on material quality and the rolling speed of the rolling temperature is determined. The invention further relates to a Use of the process or the system.

Rolling wire, for example from billet stock, is usually carried out in a rolling mill from a Vorstrasse, an Zwischenstrasse and one Finishing train. When entering the finishing train the rolling stock is already so largely pre-reduced that it has an approximately circular cross section. in the The rolling stock is then finished with a sequence two-stage reduction stages, each with a horizontal and Vertical stitch up to the specified final caliber finish rolled. This is a comparatively high one Final rolling speed reached, especially for the Rolling speeds of the rolled stock in the pre and Intermediate mill and thus overall for the rolling capacity of the entire rolling mill is decisive.

There is an urgent economic need that Final rolling speed of the rolling stock in the finished block if possible largely increase. The resulting problem however, is that according to the Rolling speed from reduction level to reduction level due to increased rolling work corresponding heating processes in Rolling stock take place, which eventually becomes a metallurgical unacceptable temperature rise.

It is basically known within a rolling mill Intermediate cooling of the rolling stock is required, however the cooling devices known in the prior art each a considerable increase in the space requirement of the system with considerable additional costs for investment and operation.

On the other hand, the compact design of known billets leads often to difficult employment relationships Conversion work, for example when changing the steel quality or the product. The same applies to renovations due to dimensional changes, which is a relatively high cost of assembly work.

US 4,182,148 discloses a finishing train for Fine steel profiles with one finished block, comprising four Units in two parallel rolling lines, each unit a double frame with one for each of the lines vertical / horizontal rolling stage. In front and behind the Blocks are provided in the direction of rolling, which Rolled material from a feed roller table into one or the other Turn in the line and at the outlet into a common one Steer the outlet roller table back. Each block has one Central drive with downstream branching gear for the two units. The rolling lines are for layered Operation designed, intermediate cooling is not provided.

DE 44 26 930 A1 discloses a fine steel rolling mill, especially wire rolling mill, for the optimization of Product quality and performance of the finishing train. With this can contribute with economic use of investment funds economical space requirement and without any noteworthy Production interruptions an increase in performance as well Modernization can be achieved by using the finishing train at least one two-stand standard bloom block is subordinate. Also with this system Intercooling not provided.

DE 42 07 296 A1 describes a high-performance / fine steel / wire mill with one each Mill stands / roughing units comprising rolling units, at least an intermediate street and subsequent finishing street, especially as a finishing block for single or multi-core Rolling out wire or rolled stock with a round cross-section Stainless steel or alloy steel. With a view to a higher one Throughput and for the purpose of better rolling stock quality the road with at least one two-stand finishing mill provided, which is arranged downstream of the finishing block, where between the finishing block and the roughing block Temperature-controlling cooling and compensation device for the rolling stock is interposed.

Based on this prior art, the invention lies Task based on a procedure and one for this suitable plant for finish rolling wire in at least to indicate a finished block of funds in order to Final rolling speed and thus the capacity of the whole Comparatively rolling mill without impermissible temperature increase significantly increase and at the same time the flexibility of the Rolling process when adapting a rolling program z. B. on different material qualities or rolling stock dimensions increase and, if necessary, the maximum engine power to reduce the previously determined dimensions.

The problem is solved with a method of Preamble of claim 1 type with the invention in that to achieve comparatively higher Final rolling speeds with a preferably increased degree of reduction and approximately constant rolling temperature increased between individual reduction stages of the finished block and at least in the area of part of these distances Intercooling of the rolling stock is carried out.

The method according to the invention is surprising in achieved that simply and economically by dissolving a finished block in several two-stage reduction stages or units the sum of the heating in the stitches is significantly reduced. This is extremely important on the one hand for achieving higher final rolling speeds, but also on the other hand, to certain rolling stock qualities to be able to roll faster than before in the prior art.

An advantageous embodiment of the method provides that it is carried out with at least two finished blocks, between which comparatively large distances are set and the rolling stock is intense in the area of these distances is cooled.

It also provides an advantageous embodiment of the method before that to achieve a comparatively higher Flexibility in the reduction coordination of the individual stages or units among themselves at least one two-stand Unit, and preferably the last one, as "sizing level" is operated. These measures make it better End product tolerances reached. With the higher one Flexibility can also simplify calibration and the number of calibers compared to a finished block conventional design can be reduced, e.g. B. if Rolling families are torn apart.

The dissolution of a known finished block according to the Invention into several two-stand units can be one Specially selectable engine or transmission design for the individual units - like tearing apart Rolling families - make them unnecessary.

Another advantage of the invention is that that individual of the two-stand units only in use when they are needed and until then (e.g. when rolling thick dimensions) for "maintenance" To be available. In such a case, the Conversion time of a prefabricated block with additionally available standing mill stands or units significantly reduced be what is essential to the availability and Overall performance of the rolling mill contributes. Furthermore, in In such a case, the guides are calmer and more precise to be assembled.

The setting work can be carried out by using individual blocks this at least partially using electromotive Adjustment means are carried out. Blocks not used can, for example, next to the rolling line for a next one Dimensions can be prepared without wasting time. And still can by appropriate coordination of the purchase conditions among themselves the engine performance of the individual blocks be optimized.

In addition, the overall system is more flexible because the Decrease between the individual levels or units in one relatively wide range, for example in the reduction of cross sections in the rough and intermediate street, changed or can be adapted to each other. This can be an advantage can also be used to maximize engine performance to reduce the determining dimensions.

A system for finish rolling wire in at least one Multi-stand prefabricated block with two-stand units as Reduction levels, each with a horizontal and Vertical scaffolding, especially for performing the method according to the invention, provides that the units between them have comparatively increased distances, and that in Range of at least some of these distances Local cooling of the rolling stock is available.

It can advantageously be provided that individual stages or units, and preferably the last unit, as Sizing level is trained or used.

And finally, the invention provides a use of the Procedure and the system provided for its implementation especially for finish rolling wires Stainless steel quality.

The inventive method and the system enable Increasing the productivity of a wire rolling mill.

In the drawings are temperature diagrams for the rolling of Wire in one from Vorstrasse, Zwischenstrasse and Finished block existing rolling mill depending on different configurations, in particular the Finishing blocks and different rolling speeds shown. The length in meters is on the abscissa indicated on the ordinate the temperature in degrees Celsius. Each diagram shows three recorded one below the other Curves the temperature course in the core, the course of the Average temperature over the entire cross section and the Temperature curve on the surface of the rolling stock.

Fig. 1

Temperaturkurven für Walzgut im Durchlauf durch Vor- und Zwischenstraße sowie einen mehrgerüstigen Fertigblock, Eintrittsgeschwindigkeit (EG) = 0,53 m/s, Endwalzgeschwindigkeit (EWG) = 105 m/s;

Fig. 2

Temperaturkurven bei gleicher Anlage und gleichem Walzprogramm, jedoch mit teilweise auseinandergezogenem Fertigblock und Zwischenkühlung, EG = 0,53 m/s, EWG = 105 m/s;

Fig. 3

Temperaturkurven bei Anlage und Walzprogramm gemäß Fig. 1, jedoch mit EWG = 150 m/s;

Fig. 4

Temperaturkurven bei gleicher Anlage und gleichem Walzprogramm gemäß Fig. 2, jedoch mit EWG = 150 m/s;

Fig. 5

Temperaturkurven, Anlage und Walzprogramm gemäß Fig. 4, jedoch mit erheblich weiter auseinandergezogenem Fertigblock, EWG = 150 m/s;

Fig. 6

Temperaturkurven einer Edelstahlstraße, EG = 2,4 m/s, EWG = 20 m/s;

Fig. 7

Temperaturkurven gemäß Fig. 6, jedoch EWG = 30 m/s;

Fig. 8

Temperaturkurven gemäß Fig. 6, jedoch EWG = 40 m/s;

Fig. 9

Temperaturkurven gemäß Fig. 8, jedoch mit auseinandergezogenem Fertigblock und verstärkter Zwischenkühlung;

Fig. 10

einen Fertigblock gemäß Fig. 5 in Form eines Stammbaums.

The individual shows:

Fig. 1

Temperature curves for rolling stock as it passes through the roughing and intermediate mill and a multi-stand finishing block, entry speed (EG) = 0.53 m / s, final rolling speed (EWG) = 105 m / s;

Fig. 2

Temperature curves for the same plant and the same rolling program, but with the finished block partially pulled apart and intermediate cooling, EG = 0.53 m / s, EWG = 105 m / s;

Fig. 3

Temperature curves for the plant and rolling program according to FIG. 1, but with EEC = 150 m / s;

Fig. 4

Temperature curves for the same plant and the same rolling program according to FIG. 2, but with EEC = 150 m / s;

Fig. 5

Temperature curves, system and rolling program according to FIG. 4, but with the finished block being considerably further apart, EEC = 150 m / s;

Fig. 6

Temperature curves of a stainless steel mill, EG = 2.4 m / s, EWG = 20 m / s;

Fig. 7

6, but EEC = 30 m / s;

Fig. 8

6, but EEC = 40 m / s;

Fig. 9

8, but with the finished block pulled apart and increased intermediate cooling;

Fig. 10

5 in the form of a family tree.

In Figures 1 to 4 is the temperature profile for rolls of tire wire in a roughing area of the plant area between 0 and 50 m, then in an intermediate street between 50 and 150 m in length, as well as in an eight-stand Prefabricated block with two-stand units between 150 and 200 m length shown. The final diameter is 5.5 each mm.

The core temperature reaches according to Figure 1 when the Rolled goods at 1000 ° C in the first roughing stand at the beginning of the Intermediate rolling at approx. 66 m a temperature peak of 1050 ° C, after which the wire emerges from the last The core temperature drops to approx. 825 ° C and in the eight-stand prefabricated block at approx. 169 m at 1035 ° C increases and by means of cooling when exiting the last Scaffolding is lowered to approx. 855 ° C. The strongest Temperature fluctuations naturally occur with Surface temperatures with difference amounts of approximately 300 ° C of individual cooling levels.

According to Figure 2 are boundary conditions and total length of the road with Fig. 1 up to 150 m length of the rough and intermediate road identical. However, in contrast to Fig. 1, the finished block broken down into five two-stand blocks with intermediate cooling. The core temperature in the rolling stock is thus around on average about 70 ° C, namely from 1035 ° C of FIG. 1 to 965 ° C 2. The final temperatures at 225 m length are 855. 835, 825 ° C (core temperature, average temperature, Surface temperature). The temperature curves of FIGS. 1 and 2 correspond to a final rolling speed under otherwise the same Material quality and rolling program parameters of 105 m / s.

In contrast, Figures 3 and 4 show temperature curves same rolling program, starting material and end product, however with 150 m / s rolling speed. It is in the Intermediate road reaches a maximum temperature of 1070 °, when the rolling stock enters the finished block to 870 ° C (Core), 845 ° C (average temperature) and 830 ° C (Surface temperature) is reduced in several cooling stages. By dissolving the finished block in two-stand units with Intercooling is achieved at the same Production parameters the maximum core temperature in Finished block with a system length of approx. 180 m not above 1060 ° C increases. Surrendered after leaving the last finishing stand for the core temperature 960 ° C, for the Average temperature 940 ° C and for that Surface temperature 925 ° C.

Figure 5 shows a typical course of the core average and Surface temperatures with positive effects of Method and the system according to the invention. Here are in Area of the finished block a total of five two-stand 10 in an extension of 150 to 350 m arranged at intervals of 40 m on average and with Intercooling equipped. This ensures that the Core temperature at the top, for example at 280 m 865 ° C does not exceed and the average temperature itself settles at approximately 800 ° C. The other system parameters correspond to the course of the curves from FIGS. 1 to 4, however, the rolling speed is 150 m / s.

Figure 6 shows the temperature simulation of a stainless steel mill when rolling a Ni-based alloy with a Rolling speed of 20 m / s. Here is the Temperature peak in the finished block at approx. 275 m in the range from 1270 ° C.

Figure 7 shows the same rolling process as Fig. 6, but with a final rolling speed of 30 m / s. Here is the Temperature peak in the finished block at approx. 275 m in the range from 1340 ° C.

With a further increase in the final rolling speed 40 m / s according to FIG. 8 result in the intermediate street at approx. 125 m core temperatures of 1305 and at approx. 170 m of 1310 ° C. In the finished block there is a temperature peak at approx. 270 m reached with 1360.

In contrast, FIG. 9 shows the same rolling parameters and one with three two-stand units with cooling more powerful exploded finished block a reduction in Peak temperature at 240 m at 1275 ° C. That is the proof provided that a realization is comparatively higher Final rolling speeds with possibly increased Degree of reduction and almost constant rolling temperature or reduced rolling temperature succeeds if after the Invention the distances between individual reduction stages or units of a finished block increased and at least in Area of part of these distances an intermediate cooling of the Rolled good is made. It becomes essential Production increase with the use of effective economic Medium reached, with the Vorstraße and Zwischenstrasse slightly be adapted and substantially preserved.

Figure 10 shows a in the form of a block diagram Prefabricated block (1) with five two-stand units (2a) vertical, (2b) horizontal to (6a) vertical, (6b) horizontal. Each of these units (2 to 6) is a cooling or Downstream cooling section (20, 30, 40, 50, 60). The after the Invention thus achievable temperature curve for core, Average and surface is favorably lowered and corresponds approximately to the curve diagram of FIG. 5. With this Designing a prefabricated block will be an optimal solution achieved the task set at the beginning.

Claims (7)

Process for the final rolling of wire in at least one finishing block with two-stand reduction stages, in which the wire cross-section is reduced by a horizontal and vertical pass with a predetermined degree of reduction, and the final rolling speed and the degree of reduction of each stage are determined in accordance with the rolling temperature that is established as a function of material quality and rolling speed , characterized in that, in order to achieve comparatively higher final rolling speeds with a possibly increased degree of reduction and approximately constant rolling temperature, the distances between individual reduction stages of the finished block are increased and intermediate cooling of the rolling stock is carried out at least in the region of a part of these distances. A method according to claim 1, characterized in that the sum of the heating processes in the stitches is reduced by dissolving a multi-stage finished block in individual reduction stages spaced apart. Method according to claim 1 or 2, characterized in that it is carried out with at least two finishing blocks, between which comparatively large distances are set and the rolling stock is intensively cooled in the area of these distances. Method according to one or more of claims 1 to 3, characterized in that in order to achieve greater flexibility in the reduction coordination of individual stages, a two-stage or unit, and preferably the last, is operated as a sizing stage. Plant for the final rolling of wire in at least one multi-stand finishing block (1) with two-stand units (2a, 2b to 6a, 6b), each comprising a horizontal (2a - 6a) and vertical stand (2b - 6b), in particular for carrying out the method according to the preceding claims, characterized in that the units (2a, 2b - 6a, 6b) have comparatively increased distances between them, and in the area of at least some of these distances devices (20, 30, 40, 50) for intermediate cooling of the rolling stock passing through available. System according to claim 5, characterized in that individual units and preferably the last unit are designed or used as a sizing level. Use of the method and the system according to the Claims 1 to 6 for finish rolling wires in particular with stainless steel quality.

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