DE102021205431A1 - Plant and process for the production of bar-shaped steels - Google Patents

Abstract

The present application relates to a plant (1) and a method for the thermomechanical rolling of long steel semi-finished products (2), comprising a first rolling device (5); a first thermomechanical sizing block (8) arranged downstream of the first rolling means (5); a first cooling device (6) arranged between the first rolling device (5) and the first thermomechanical sizing block (8); a separating device (14) arranged downstream of the first thermomechanical sizing block (8); a second cooling device (11) arranged between the first thermomechanical sizing block (8) and the separating device (14); and a coil winding device (13) arranged downstream of the separating device (14) in the transport direction.

Description

The present invention relates to a plant for the thermomechanical rolling of long steel semi-finished products, a method for producing rod-shaped steels, preferably structural steels, from the long steel semi-finished products, in particular with a yield point of at least 300 MPa, preferably with a yield point of at least 400 MPa, and a rod-shaped steel product , Which is preferably obtainable by the process according to the invention.

In the conventional production of bar-shaped steel products, it is provided that the corresponding steels are first hot-rolled over a plurality of roll stands and then quenched after the rolling train. Due to the large drop in temperature, a martensite ring forms over the circumference, giving the material the required strength. The resulting steel products are then cut to a length of up to 12 m, cooled as evenly as possible on a cooling bed from 650 °C to 100 °C and then combined into bundles that can be transported and processed further.

As an alternative to cooling on a cooling bed, such steel products can also be coiled into compact coils. In contrast to the conventional procedure, however, the wound coil has highly inhomogeneous cooling conditions, which cause increased scattering of the mechanical properties and which then have a negative effect during further processing, such as drawing over a die.

From the WO 2004/104237 A1 a method for winding metal rods is known, for example. According to the disclosed method, the finish-rolled bars are slowly cooled to a temperature in the range of 600 to 700 °C in a cooling and equalizing section, which is arranged downstream of the rolling device in the transport direction and comprises several water tanks, and then fed to a coil winding device. This results in only a microstructure with a core of ferrite and pearlite surrounded by a ring-shaped structure of martensite and larger portions of bainite.

The present invention is therefore based on the object of providing a system for thermomechanical rolling of long steel semi-finished products and a method for producing bar-shaped steel products, in particular structural steels, with which bar-shaped steel products, in particular structural steels, with a low scattering of the mechanical material properties and/or can be produced with consistent quality in terms of their microstructure.

According to the invention, the object is achieved by a system having the features of patent claim 1 and a method having the features of patent claim 10 .

The plant according to the invention for the thermomechanical rolling of long steel semi-finished products comprises a first rolling device; a first thermomechanical sizing block disposed downstream of the first rolling means; a first cooling device disposed between the first rolling device and the first thermomechanical sizing block; a separator arranged downstream of the first thermomechanical sizing block; a second cooling device disposed between the first thermomechanical sizing block and the separator; and a coil winding device arranged downstream of the separating device in the transport direction.

In the same way, the invention relates to a method for producing bar-shaped steels from long steel semi-finished products, in particular with a yield point of at least 300 MPa, preferably with a yield point of at least 400 MPa, even more preferably with a yield point of at least 500 MPa, and most preferably with a yield strength of at least 600 MPa, with the long steel semi-finished product, optionally heated to a temperature of at least 900 °C, preferably to a temperature of at least 950 °C, first being pre-rolled in a first rolling device and then to a temperature in a subsequent first cooling device is cooled to at least 850 °C; is then finish-rolled in a first thermomechanical sizing block arranged downstream of the first cooling device in the transport direction to form bar-shaped steel, which is cooled to a temperature in the range of 400 °C to 600 °C in a second cooling device downstream of the first thermomechanical sizing block; subsequently prefabricated in a separating device arranged downstream of the second cooling device in the transport direction; and is then fed to a coil winding device arranged downstream of the separating device in the transport direction and is wound into vertically and/or horizontally wound coils.

As part of the development of the present invention, it has been shown that a coordinated process control produces vertically and/or horizontally wound coils of a bar-shaped steel product which, on the one hand, have a specific pearlitic-bainitic microstructure, and on the other hand have a reduced scatter of the mechanical material values. The bar-shaped steel products preferably have a scatter of the mechanical material values, in particular the yield point Re of <25 MPa, more preferably a scatter of the yield point Re of ≦20 MPa, even more preferably a scatter of the yield point Re of ≦15 MPa, and most preferably one Scatter of the yield point Re of ≤ 10 MPa, whereby the strength levels specified in the respective standards based on DIN 488 and other material values are partially improved.

A further advantage of thermomechanical rolling and the resulting grain refinement effects in the bar-shaped steel products is that the use of manganese or other strength-enhancing micro-alloying elements can be reduced or saved, which has a beneficial effect on production costs.

Furthermore, the winding of the bar-shaped steel products into vertically and/or horizontally wound coils has further advantages with regard to transport and space requirements.

Further advantageous refinements of the invention are specified in the dependently formulated claims. The features listed individually in the dependent claims can be combined with one another in a technologically meaningful manner and can define further refinements of the invention. In addition, the features specified in the claims are specified and explained in more detail in the description, with further preferred configurations of the invention being presented.

It should be noted that the temperatures given here represent the average temperatures over the cross-section of the rolling stock and therefore cannot be equated with surface temperatures.

In the context of the present invention, the term “long steel semi-finished products” is understood to mean steel semi-finished products which are suitable for producing the bar-shaped steels or steel products according to the invention, in particular structural steels. Such semi-finished long steel products are also referred to as billets and usually have a square or rectangular cross-section.

In the context of the present invention, the term "rod-shaped steel products" refers to steel products or steel bars, in particular structural steels, which have a round cross-section with a diameter in the range from 6.0 to 50 mm, preferably 6.0 to 32 mm, and whose surface is ribbed and /or is smooth. Such bar-shaped steel products are also known as “rebars”.

The first rolling device, in which the long steel semi-finished product, which has previously been heated to a temperature of at least 900° C., preferably to a temperature of at least 950° C., is pre-rolled, can be formed from a large number of standless rolling stands. Advantageously, the first rolling means comprises at least ten, more preferably at least twelve, even more preferably at least fourteen, and most preferably sixteen of these standless rolling stands.

In addition or as an alternative, the first rolling device can comprise hydraulically adjustable roll stands instead of the roll stands without stands.

The first cooling device is arranged downstream of the first rolling device in the direction of transport in a first section which extends between the first rolling device and the first thermomechanical sizing block. The first cooling device can comprise one, or more preferably two, water tanks, which are then arranged at a distance from one another in the first section. By means of the cooling device, a temperature reduction is achieved in the rolling stock before the thermomechanical rolling step.

The cooling capacity of the water tanks of each cooling device can be adjusted based on the volume flow of the cooling water, the number of active cooling pipes per water tank, the cooling pipe diameter and/or the cooling water pressure and, if necessary, the cooling water temperature. The specifications can typically be predetermined using specific process models and adjusted by online regulation.

An example channel box may have a channel box length of 6500mm and include six cooling tubes each 750mm long. Such a water box then typically has a maximum cooling water quantity of 230 m ³ /h and a controllable cooling water pressure range from 1.5 to 6.0 bar.

In addition, the first section is preferably selected in such a way that the rolling stock is also given sufficient time for adequate temperature equalization over the cross section. The temperature in the rolling stock is equalized by conduction from the core to the surface. To keep the temperature as even as possible over the entire cross In order to achieve a cut of the rolling stock, it is particularly preferred that a temperature gradient of at most 100 °C, more preferably a temperature gradient of at most 80 °C, even more preferably a temperature gradient of at most 60 °C, and most preferably a temperature gradient of at most 50 °C is set. The homogenization of the cross-section temperatures can be controlled indirectly between the respective stations by measuring the surface temperatures of the rolled long steel semi-finished product. In addition, corresponding process models can also be used.

The first section can have a length of 80 to 120 m, more preferably a length of 90 to 100 m.

The rolled long steel semi-finished product, cooled to a temperature of at least 850 °C in the first cooling device, is then fed to the first thermomechanical sizing block, in which it is finish-rolled to the desired or specified final diameter.

In a particularly advantageous embodiment variant, it is provided that the rolled long steel semi-finished product is fed to the first thermomechanical sizing block at a temperature of at least 700 °C, preferably at a temperature of at least 730 °C, more preferably at a temperature of at least 750 °C, even more preferably at a temperature of at least 760°C, and most preferably at a temperature of at least 770°C. However, the temperature of the rolled long steel semi-finished products must not be too high, otherwise the lowest possible temperature gradient between the surface and core temperatures required for the metallurgical recrystallization processes and the associated grain refinement effects cannot be set. Therefore, the temperature at which the rolled long steel semi-finished product is fed to the first thermomechanical sizing block is limited to 850°C, preferably to 840°C, more preferably to 820°C, and most preferably to 800°C. Provision is very particularly preferably made for rolled semi-finished long steel products to be fed to the first thermomechanical sizing block at a temperature of 780°C.

In the thermomechanical sizing block, the highest deformation or the highest reduction, which can preferably be 30 to 80%, takes place. The thermomechanical sizing block can have one, preferably two, more preferably four, even more preferably six, and most preferably eight stands.

In a further advantageous embodiment variant, the system can comprise a second thermomechanical sizing block between the first thermomechanical sizing block and the second cooling device, which also has one, preferably two, more preferably four, even more preferably six, and most preferably eight stands can be trained. In this context, it is particularly preferred that an intermediate cooling device is provided between the two thermomechanical sizing blocks, which comprises one or two water tanks spaced apart from one another. For example, in a first advantageous embodiment variant, the first thermomechanical sizing block can have four stands and the second thermomechanical sizing block can have two stands. In a further advantageous embodiment variant, the first thermomechanical sizing block can, for example, have four stands and the second thermomechanical sizing block can also have four stands. Any other combination is possible and conceivable with regard to the division of the stands between the two thermomechanical sizing blocks.

A thermomechanical sizing block designed in a basic design, for example a six-stand thermomechanical sizing block, could also be divided into six single-stand thermomechanical sizing blocks, with within the entire cascade of, for example, six single-stand thermomechanical sizing blocks between two of these six one-stand thermomechanical sizing blocks are each to be provided with an intermediate cooling device with at least one water box.

The thermomechanical sizing blocks are known in principle and are sold by the applicant under the brand name MEERdrive®.

In the direction of transport behind the first, possibly second, thermomechanical sizing block, the second cooling device is then arranged in a second line section, in which the long steel semi-finished products finish-rolled to bar-shaped steels are cooled in order to stop further grain growth.

The second cooling device can comprise four to nine water boxes, more preferably five to eight water boxes. In a further embodiment variant, the second cooling device can comprise at least two, more preferably three, even more preferably four, and most preferably five water tanks, via which the rod-shaped steels are cooled, on the one hand to equalize the temperature and on the other hand to form to prevent hardened microstructures in the form of martensite or bainite.

The second section, which extends between the first or second thermomechanical sizing block, or the last stand of the sizing block, and the coil winding device, is preferably selected in such a way that the rolling stock is given enough time for adequate temperature equalization across the cross section. Preferably, therefore, a temperature gradient of at most 100 °C, more preferably a temperature gradient of at most 80 °C, even more preferably a temperature gradient of at most 60 °C, and most preferably a temperature gradient of at most 50 °C in the long steel semi-finished product finish-rolled to form rod-shaped steel set.

The second route section can advantageously have a transport length of 200 to 350 m, more preferably a transport length of 250 to 300 m. In this context, it has been shown to be particularly preferable that cooling, which starts as quickly as possible immediately after the last pass, i.e. after the first or second thermomechanical sizing block or the last stand of the sizing block, for the control of the recrystallization processes and a high fine grain size, preferably with a average grain diameter of less than 12.0 µm, more preferably with an average grain diameter of less than 10.0 µm, even more preferably with an average grain diameter of less than 8.0 µm, and most preferably with an average grain diameter in the range of 5.0 to 6.5 µm.

Advantageously, it is therefore provided that the rod-shaped steels, which have a temperature in the range from 800° C. to 950° C., preferably a temperature in the range from 800° C. to 900° C., after the last pass, after a maximum of 100 ms, preferably after a maximum of 90 ms, even more preferably after a maximum of 80 ms, more preferably after a maximum of 70 ms, and most preferably after a maximum of 60 ms of the second cooling device, in particular the first water tank of the second cooling device.

In order to prevent further grain growth, the rod-shaped steels are cooled to such an extent that an inlet temperature in the coil winding temperature range of 400 °C to 600 °C, preferably an inlet temperature in the coil winding device of 450 °C to 550 °C, is achieved.

In a further advantageous embodiment variant, the system can have a microstructure sensor device arranged between the second cooling device and the separating device, via which a martensitic microstructure that may be present, in particular a martensite proportion in area percentage (A.%), in the thermomechanically rolled rod-shaped steel product in the ongoing process directly can be determined. The microstructure sensor device according to the invention, which is arranged in the second section, can advantageously be arranged in the direction of transport directly in front of the coil winding device, directly in front of the cutting device, and/or in the direction of transport, possibly directly behind the second cooling device, in particular behind the last water tank of this. An arrangement between two water tanks of the plurality of water tanks in the second cooling device is also possible.

In an advantageous embodiment variant, the system comprises a microstructure sensor device according to the invention behind each of the plurality of water tanks that are arranged within the second cooling device in the second section. As a result, each of the plurality of water tanks can be adjusted individually and the formation of martensitic structures in the specific water tanks can be assigned.

The martensitic structure, in particular a proportion of martensite in A%, in the rod-shaped steels can be identified online in the ongoing process via the structure sensor device. In principle, all techniques known to the person skilled in the art at the time of filing can be used as measurement methods. Advantageously, however, it is provided that the microstructure sensor device for identifying the undesired martensite has an ultrasonic measuring device, an X-ray measuring device, a radar beam measuring device and/or an electromagnetic measuring device.

The microstructure sensor device can advantageously be coupled to a control and/or regulation device, via which active interventions in the respective process steps can be undertaken, possibly with the aid of appropriate algorithms, in order to set the desired microstructure.

In a further aspect, the present invention also relates to a rod-shaped steel product, preferably produced by the method according to the invention, in particular with a yield point of at least 300 MPa, more preferably with a yield point of at least 400 MPa, even more preferably with a yield point of at least 500 MPa, and most preferably having a yield strength of at least 600 MPa, having a martensite content of at most 15.0 A%, preferably a martensite content of at most 10.0 A%, more preferably a martensite content of at most 8.0 A%, even more preferably one March 6.0 A.% maximum, and most preferably 5.0 A.% maximum martensite.

The bar-shaped steel, in particular structural steel, preferably has the following composition in % by weight: Carbon: 0.04 to 0.35, Silicon: 0.10 to 0.80, Manganese: 0.40 to 1.60 Phosphorus: maximum 0.06 Sulfur: maximum 0.06, Nitrogen: maximum 0.012;
and the remainder iron, possibly other accompanying elements, and unavoidable impurities.

The bar-shaped steel can include the following elements individually and/or in combination as additional accompanying elements (in % by weight): Chrome: maximum 0.40, Molybdenum: maximum 0.20, Nickel: maximum 0.90, Copper: maximum 1.0, Lead: maximum 0.25, Tin: maximum 0.07,

Provision is particularly preferably made for the bar-shaped steel, in particular structural steel, to have a carbon equivalent (Ceq) of ≦0.60, more preferably a carbon equivalent (Ceq) of ≦0.50.

• 1 eine Ausführungsvariante der erfindungsgemäßen Anlage,
• 2 ein Temperaturprofil eines ersten Ausführungsbeispiels des erfindungsgemäßen Verfahrens,
• 3 ein Temperaturprofil eines zweiten Ausführungsbeispiels des erfindungsgemäßen Verfahrens, sowie
• 4 ein Temperaturprofil eines dritten Ausführungsbeispiels des erfindungsgemäßen Verfahrens.

The invention and the technical environment are explained in more detail below with reference to figures and examples. It should be pointed out that the invention should not be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and findings from the present description and/or figures. In particular, it should be pointed out that the figures and in particular the proportions shown are only schematic. The same reference symbols designate the same objects, so that explanations from other figures can be used as a supplement if necessary. Show it:

• 1 an embodiment of the system according to the invention,
• 2 a temperature profile of a first exemplary embodiment of the method according to the invention,
• 3 a temperature profile of a second embodiment of the method according to the invention, and
• 4 a temperature profile of a third embodiment of the method according to the invention.

In 1 an embodiment variant of the system 1 according to the invention for the thermomechanical rolling of long steel semi-finished products 2 is shown in a schematic block diagram. Such long steel semi-finished products or starting billets 2, which are thermomechanically rolled in plant 1 to form bar-shaped steels 3, can have a quadrilateral (square) cross-section with the dimensions of 160×160 mm. The correspondingly finish-rolled bar-shaped steels 3 can have a diameter in the range from 6.0 to 32 mm.

To produce the corresponding bar-shaped steels 3, the long steel semi-finished products 2 are first fed to a reheating furnace 4, in which the long steel semi-finished products 2 to be rolled are heated to a temperature of 900° C. to 1000° C.

The then heated long steel semi-finished products 2 are fed to a first rolling device 5, in which they are pre-rolled hot in a cascade of sixteen standless roll stands (not shown). Here, a decrease in the range of 20 to 40% per pass is achieved in the respective roll stand. The average temperature of the rolling stock in the first rolling device 5 is 850°C to 1000°C.

In the direction of transport behind the first rolling device 5, a first cooling device 6 is arranged in a first section 7, which in the present case comprises two water tanks (not shown) in order to reduce the temperature of the 850 °C to 1000 °C hot rolling stock before the subsequent step of thermomechanical rolling achieve. The first section 7, which extends between the last roll stand without stands of the first rolling device 5 and a first thermomechanical sizing block 8, is also selected in such a way that the rolling stock is given enough time for a sufficient temperature equalization in addition to the temperature reduction. The first section can have a length of 90 m to 100 m.

The pre-rolled and cooled long steel semi-finished product 2, which is now a round and / or has an oval cross-section, is then fed to the first thermomechanical sizing block 8 at a temperature in the range of 760° C. to 820° C. and finish-rolled to the desired or specified final diameter, which can be 8 mm, 12 mm or 25 mm, for example. For this purpose, the first thermomechanical sizing block 8 can be designed with six stands in one embodiment variant, with a reduction of 22 to 27% being achievable per pass in the individual stands.

In a further embodiment variant, the first thermomechanical sizing block 8/8.1 can be supplemented by a second thermomechanical sizing block 8.2, which can also have a multi-stand design. In this embodiment variant, an intermediate cooling device 10 with two water tanks (not shown) is provided in an intermediate section 9 formed between the two thermomechanical sizing blocks 8.1, 8.2. This intermediate section 9 also has a specific distance of 72 m, for example, in order to allow the rolling stock enough time for an adequate temperature equalization between the two thermomechanical rolling steps.

The second cooling device 11 is then arranged in a second section 12, which extends between the first or the second thermomechanical sizing block 8, 8.1, 8.2 and a coil winding device 13, downstream of the first or the second thermomechanical sizing block 8, 8.1, 8.2. In the second cooling device 11, the long steel semi-finished products 2, which have been finish-rolled into rod-shaped steels 3 and have a temperature of 800° C. to 900° C., are cooled by a cascade of four water tanks spaced one behind the other in order to prevent further grain growth and the formation of hardened grains To prevent microstructures in the form of martensite or bainite. This requires cooling to start as quickly as possible immediately after the last pass in order to be able to control the recrystallization processes and to achieve a high degree of fineness with an average grain diameter in the range of 6.0 to 10.0 µm. In order to allow the rolling stock enough time for a sufficient temperature equalization on the way to the last station, the second section 12 is also chosen to be correspondingly long. This can have a length of 250 to 300 m, for example.

The rod-shaped steels 3 are, after prefabrication in a cutting device 14, then fed to the coil winding device 13, which is designed as a vertical coil winding device, at a coil winding temperature of 450° C. to 500° C.

Since the entire cooling process is unstable in relation to the respective target temperatures, and martensitic microstructures can therefore form suddenly during the course of the process, the system 1 can also include a microstructure sensor device 15, which is arranged in the second section 12.

The formation of the martensitic structure, in particular a proportion of martensite in A%, in the rod-shaped steels 3 produced can be identified online in the ongoing process via the structure sensor device 15 . To identify the undesired martensite, the microstructure sensor device 15 can comprise, for example, an ultrasonic measuring device, an X-ray measuring device, a radar beam measuring device and/or an electromagnetic measuring device.

The possible positions of the structure sensor device 15 in the second section 12 are shown via the dashed arrows. For example, this can be arranged in the direction of transport in front of the second cooling device 11, immediately in front of the separating device 14 or immediately in front of the coil winding device 13. An arrangement between the water tanks of the plurality of water tanks in the second cooling device 11 or in the intermediate section 9 is also possible.

In the 2 until 4 3 shows three different temperature profiles (average temperatures) 16, 17, 18 of three steel rods 3 with different diameters, which have been produced according to an embodiment variant of the method according to the invention. For this purpose, billets of quality C20D with a quadrangular (square) cross-section with dimensions of 160 x 160 mm were produced in a plant 1, which had a reheating furnace 4, a first rolling device 5 with sixteen standless rolling stands (not shown), a first cooling device 6 with two Water tanks, a six-stand sizing block 8, a second cooling device 11 with four water tanks and a coil winding device 13, thermomechanically to bar steel 3 with a diameter of 8 mm ( 2 ), 12mm ( 3 ) and 25 mm ( 4 ) rolled.

Reference List

1

attachment

2

semi-finished long steel products

3

bar-shaped steel / bar steel

4

oven

5

first rolling device

6

first cooling device

7

first section

8th

first sizing block

8.1

first sizing block

8.2

second sizing block

9

intermediate section

10

intermediate cooling device

11

second cooling device

12

second section

13

coil winding device

14

separator

15

microstructure sensor device

16

temperature profile

17

temperature profile

18

temperature profile

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2004/104237 A1 [0004]

Claims (15)

Plant (1) for the thermomechanical rolling of long steel semi-finished products (2), comprising a first rolling device (5); a first thermomechanical sizing block (8) arranged downstream of the first rolling means (5); a first cooling device (6) arranged between the first rolling device (5) and the first thermomechanical sizing block (8); a separating device (14) arranged downstream of the first thermomechanical sizing block (8); a second cooling device (11) arranged between the first thermomechanical sizing block (8) and the separating device (14); and a coil winding device (13) arranged downstream of the separating device (14) in the transport direction. Annex (1) according to claim 1 , further comprising a second thermomechanical sizing block (8.2) arranged between the first thermomechanical sizing block (8) and the second cooling device (11), optionally with an intermediate cooling device (10) arranged between the two sizing blocks (8.1, 8.2). Annex (1) according to claim 1 or 2 , wherein the first cooling device (6) comprises at least one water tank, preferably two water tanks. Plant (1) according to one of the preceding claims, wherein the second cooling device (11) comprises at least two water tanks, preferably at least three water tanks, even more preferably at least four water tanks, which are each arranged at a distance from one another. Plant (1) according to one of the preceding claims, wherein each of the thermomechanical sizing blocks (8.1, 8.2) is constructed with one, two, four, six and/or eight stands. Plant (1) according to one of the preceding claims, wherein the coil winding device (13) is designed as a vertical coil winding device. Plant (1) according to one of the preceding claims, further comprising a structure sensor device (15) which, in the direction of transport, is located directly in front of the coil winding device (13); immediately before the separator (14); and/or is arranged in the direction of transport, possibly directly behind the second cooling device (11). Annex (1) according to claim 7 , wherein the structure sensor device (15) has an ultrasonic measuring device, an X-ray measuring device, a radar beam measuring device and/or an electromagnetic measuring device. Annex (1) according to claim 7 or 8th , wherein the microstructure sensor device (15) is equipped with a control and/or regulating device for setting the temperature in the cooling devices (6, 10, 11), the rolling temperature and/or the rolling speed in the respective rolling units (5, 8, 8.1, 8.2) the system (1) is coupled. Process for the production of bar-shaped steels (3) from long steel semi-finished products (2), in particular with a yield point of at least 300 MPa, preferably with a yield point of at least 400 MPa, wherein first the long steel semi-finished product, optionally heated to a temperature of at least 900 °C, is heated (2) pre-rolled in a first rolling device (5) and cooled to a temperature of at least 850 °C in a subsequent first cooling device (6); is then finish-rolled in a first thermomechanical sizing block (8) arranged downstream of the first cooling device (6) in the transport direction to form the bar-shaped steel (3), which is heated to a temperature in a second cooling device (11) adjoining the first thermomechanical sizing block (8). is cooled in the range of 400 °C to 600 °C; subsequently prefabricated in a separating device (14) arranged downstream of the second cooling device (11) in the transport direction; and is then fed to a coil winding device (13) arranged downstream of the separating device (14) in the transport direction and is wound into vertically and/or horizontally wound coils. procedure after claim 10 , wherein the long steel semi-finished product (2) is finish-rolled at a temperature in the range from 700 to 850 °C. procedure after claim 10 or 11 , wherein the bar-shaped steel product (3) is wound up on a mandrel of the coil winding device (13) at a temperature in the range from 450 to 550 °C. Bar-shaped steel (3), preferably produced by a method according to one of Claims 10 until 12 , in particular with a yield point of at least 300 MPa, preferably with a yield point of at least 400 MPa, having a maximum martensite content of 15.0 A%. Bar-shaped steel (3) according to Claim 13 , comprising the following composition in % by weight: Carbon: 0.04 to 0.35 Silicon: 0.10 to 0.80 Manganese: 0.40 to 1.60 Phosphorus: maximum 0.06 Sulfur: maximum 0.06 Nitrogen: maximum 0.012, Remainder iron, possibly other accompanying elements, as well as unavoidable impurities. Bar-shaped steel (3) according to Claim 13 or 14 , having a carbon equivalent (Ceq) of < 0.60.)

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