DE2910049A1 - Wire rolling mill - with swivelling spray nozzles between stands and swivelling roll sets - Google Patents

Abstract

In a wire rolling mill, spray nozzles are arranged between the rolling mill stands and apply a coolant only to the sections where the preceding pass effected a maximum reduction ratio. The directions of the max. and min. redn. can be changed in a subsequent stand by turning a plate with the two roll pairs through half the angle between the perpendiculars to adjacent profile sides. Wire of given mechanical properties can be produced by this system from steel of difficult deformability and low ductility outside the temp. range where a deformation ageing process can occur.

Description

1. Magnitogorsky gorno-metallurgichesky institute imeni G.I.

Nosova, Magnitogorsk / USSR 2. VEB Heavy Machinery Combine "Ernst Thälmann'X, Magdeburg / GDR 3. Beloretsky metallurgichesky Kombat imeni M.I. Kalinina, Beloretsk / USSR Process for rolling wire and plant for carrying out the Process The present invention relates to the compression deformation of metal, in particular to a method of rolling wire, with the successive Work steps: unwinding, heating of the starting wire billet to a temperature, which is preferably below the recrystallization temperature, rollers with belt tension in at least two frames with multiple-sided compression of the wire knot to be deformed. local cooling over the circumference of the wire between the frames, as well as cooling of the wire before winding, as well as on a system for carrying out the process.

This invention can be particularly effective for the production of cold and hot-rolled wire, fine iron, single and shaped profiles made of difficult to deform and little plastic steels and alloys are used.

There are significant difficulties in the compression deformation of metal, especially in the manufacture of wire from steel and those alloys that have a high breaking strength and tend to become brittle. For forming of such steels and alloys is an all-round compression and a specific one Technological process management required that does not cause cracks in the products and which reduces the energy expenditure.

Various methods of rolling wire are known. Known is, for example, a method of hot rolling wire with a diameter of more than 5 mm in wire rolling mills, where the wire after hot rolling in stands with two-roller calibers before reeling and immediately afterwards in various Process is cooled (see. For example, GB-PS 1 412 423).

The manufacture of wire by this method with a diameter however, below 5 mm is difficult. When the cross-section is reduced, a Lowering the temperature as a result of a significant heat transfer to the rollers, especially when rolling in the last roll stands.

The deformation force increases, the strength of the profile in the Calibers are reduced and the production of the necessary cross-sections is made more difficult, especially when rolling steels that are difficult to deform and not very plastic, the opposite a change in the temperature control of the technological process are. To maintain a stable temperature control the use of heating devices is necessary in the last rolling passes, thereby making the technological process more complicated and causing high costs. In addition, strict requirements are placed on individual types of wire with regard to their strength properties and placed on the surface quality, which often cannot be met, because mill scale inevitably arises and solidification of the metal during hot rolling is missing.

A method for hot rolling wire with a is also known Diameter less than 5 mm, which combines the advantages of cold and hot rolling, and consists in the fact that a wire billet - as such serves wire with a diameter from 6 to 10 mm - heated to its recrystallization temperature and in frameworks is rolled with two-roll calibers.

The rolled wire is then cooled and fed to the reeling (See, for example, report by WNIIMETMASCH on topic no. 7O, 1.19.118-1 M, 1971).

The complicated production appears to be a disadvantage of this process of fine wire made of difficult to deform and poorly plastic steels and alloys with specified mechanical properties and a high surface quality.

This is due to the fact that when rolling steels and alloys with low plastic properties in known processes a low stretching per roll pass in every stand, substantial metal expansion during the deformation are recorded that lead to the development of tensile stresses and defects on the side edges of the respective profile.

When rolling stainless steels with known processes, the tend to spread intensely when heated, the Caliber, an adhesion of metal to the rollers and in connection with it also a Appear of defects on the surface of the rough rolled product. The initial temperature of wire increases as a result of the heat of plastic deformation, and the wire can in the last scaffolding down to temperature values that are higher than the critical Temperature, be heated. An intensive cooling of the wire after the The last framework before being reeled on leads to hardening and the formation of permanent ones Tensions that adversely affect mechanical and special properties of the material impact. This ind for the successful deformation of difficult to deform and little plastic steels a minimum width and a certain temperature range necessary.

Without a particular order in the alternation of directions maximum and minimum decreases in several scaffolding and without a maintenance the required temperature control during the deformation, it is not possible with the help of the known systems wire with given mechanical properties to manufacture.

A more perfect procedure appears from this point of view the following known method of hot rolling round and corrugated wire. This The process includes the following successive steps: unwinding of starting material, Heating and rolling in stands with three-roll calibers, cooling before reeling and reeling up the finished wire.

The rolling mill in which the process described is carried out has unwinding devices arranged one behind the other in horizontal respectively vertical design, guide devices, electrical heating devices, a straightening machine with default and seven rollers, roll stands, provided with interchangeable Cassettes with three-roller calibers, their rollers against each other in a plane which runs through the roller axes at an angle of 120, offset are.

The rolling mill also includes a drive for the stands, a system to cool the rolls, a straightening machine that is set up in front of a pair of scissors, a drum-type flying scissors and a reel. It can be a different one Number of mill remnants in a line depending on the respective rolling mill program can be used (see, for example, magazine "Draht Kaltwalzlagen" 1974, volume 25, No. 10, pages 550-551).

However, this known technical solution has a number of disadvantages afflicted that do not allow fine wire from difficult to deform and little plastic steels and alloys with specified properties and a high To produce surface quality. When rolling in one pass formed by three Rollers, there is a free spread in the direction of the roller openings, i.e., that a sufficiently large mass of metal is removed under the action of Tensile stress is located, and thereby the state of stress when compressing on all sides is not secured, which is necessary for the deformation of less plastic steels is. The temperature control is not regulated. Because of this, the warming can of the rolling stock when rolling, for example, high-strength reinforcing wire as a result of Heat of plastic deformation reach temperature values of deformation aging, whereby the plastic deformation resistance and the power consumption are significant increased and the plastic properties decreased.

The latter phenomena can be avoided if one carries out an adjustable selective cooling of the wire after each frame and that Rolling itself performs outside the temperature range of deformation aging.

However, it is not possible to have the required technological Operations run with the help of this known plant for rolling wire, because the distance between the scaffolding is small, and one does not have appropriate cooling devices can arrange.

This results in the need for such a plant for rolling of wire, with the help of which it would be possible to develop the necessary technology to realize.

A method for rolling rod material with heating is also known (See, for example, GB-PS 1 485 020), which also includes local cooling on the circumference of a wire billet in the time between the removals of the same to eliminate the provides for excess heating. The procedure is done with the help of atomizers realized with attachments that extend along the entire length of the intermediate framework on the Cross-sectional circumference of the wire billet are arranged.

The process described is carried out in a rolling mill with eighteen rolling stands realized. The scaffolding is arranged in four parallel streets. In the first A heating device and twelve scaffolds are set up on the street. in the second A scaffolding is set up on each of the third and third streets. Another four scaffolding are in the next parallel street.

After the twelfth and fourteenth stands are cooling devices assembled. Each cooling device is provided with atomizers and attachments.

Scissors are attached behind the eighth and eighteenth frames. The finished product is either cut and fed to a cooler or on a Reel wound up.

This method which is closest to the method according to the invention however, sees an even supply of coolant on the whole Circumference of the respective wire billet and takes into account an uneven distribution of heat across the cross-section and length of the wire billet due to the lack of a complete one Symmetry of the deformation zone with respect to the center of the wire billet as well as one No heat dissipation in the space between the frameworks. It therefore does not ensure the necessary complete control over the temperature of the rolling process.

The invention is based on the object of a method for rolling of wire as well as a system to carry out the process which is the production of wire (also form wire) from difficult to deform and little plastic steels with specified mechanical properties and implementation deformation at temperatures outside the deformation aging range as a result of the change in the technology of cooling and the distribution of stitches in rolling guaranteed by wire.

This object is achieved according to the invention in that the cooling between the roll stands selectively over the circumference of the wire by means of feed of coolant only to the sections with maximum decrease in the previous one Caliber takes place, and the direction of the maximum and minimum decreases in each next scaffolding by half the angle between the perpendiculars to the adjacent profile edges is changed.

The deformation is over by the procedure according to the invention the cross-section of the wire balanced. At the same time there is also the excess heat compensated at the particularly stressed sections, creating uniform mechanical Properties can be achieved via the wire cross-section.

The wire should expediently be run at a speed of 50-1200C cooled down every second. The cooling should be done with a quantity of coolant from 0.25 to 0.4 l / sec in each interframe space.

The procedure according to the invention makes it possible to produce fine profiles Hardly deformable and little plastic steels to be rolled and the quality of products to be manufactured by regulating the temperature and speed to control the rolling process.

In addition, the produced by the method according to the invention has Wire has high plastic properties. The wire has lower values with respect to on the strength and the yield point compared to one produced without cooling Wire.

The procedure according to the invention enables the type dimensions to roll simple fine and shaped profiles in a wide range.

The set task is also carried out with an attachment of the method according to the invention solved, one after the other in the production sequence direction arranged and interconnected unwinding and heating devices, at least two roll stands of the cassette type with roller drive, cooling devices, for example Atomizer with attachments that are in the cross-sectional plane of the respective wire billet are arranged continuously in the interframe space, and a winding device are included, according to the invention the attachments of the atomizer in the form of hollow detachable telescopic cones are designed, each of which consists of at least two Assembled segments that are connected with elastic Eiementen, and into one conical housing with the possibility of an autonomous axis offset of each cone in with respect to the housing can be installed, whereby the regulation of the cross-section of the Cooling jet in a range from 0.4 to 0.6 of the cross section of the respective Wire is secured.

The inventive arrangement of the atomizer allows in the event the change in the dimensions and shapes of the cross-section of a billet of wire during the rolling process the cross section of the cooling jet as required Operationally regulate the interval. It is not necessary to shut down the rolling mill. The downtime is reduced and the utilization coefficient of the equipment is reduced will be raised. In the case of different production programs in one rolling mill it is not necessary to use cooling devices, the atomizers of which are different Have exit cross-sections.

Other objects and advantages of the invention will be apparent from the following Description of the embodiment shown in the accompanying drawings. 1 shows an overall view of the technological line of the invention Plant, FIG. 2 shows a plan view of the plant according to FIG. 1, FIG. 3 shows an overall view a unwinder with a memory, FIG. 4 is a plan view of the arrangement according to FIG Fig. 3, Fig. 5 an overall view of a roll stand with four-roll calibers, Fig. 6 shows a view of FIG. 5 in the direction of arrow B, FIG. 7 shows an overall view of a Cooling device according to the invention for the intermediate framework space, FIG. 8 a Section in the plane VIII-VIII of FIGS. 7, 9 an atomizer according to the invention in longitudinal section, and FIG. 10 shows an overall view of a section cooling device.

The plant shown for rolling wire has an unwinding device 1 (Fig. 1 and 2) for unwinding wire from spools and coils. The unwinder 1 is provided with a memory 2 (Fig. 1, 2 and 3), which can be swiveled out in the form of a Guide cone 3 (Fig. 3, 4) with a hydraulic cylinder 4 (Fig. 3) and one Limit switch 5 is executed. The end switch 5 is directly with the guide cone 3 coupled. In a store 2, a supply of wire is created, which at normal During the rolling process, the rolling train is continuously fed with metal guaranteed and in emergency situations - i.e. when the wire windings cross, as can happen when rolling fine cross-sections - but it allows the to reduce dynamic loads on the unwinding device 1 and in good time shut down the rolling mill.

In addition to the unwinding device 1, a butt welding device 6 (Fig. 2 and 4). Such an arrangement of the butt welding device allows welding wire ends together without shutting down the rolling mill. Behind the memory 2 is a guide device 7 (Fig. 1 and 2) arranged, which is made in the form of a pair of vertical and horizontal rollers, whose profile corresponds to the basic shape of the wire with specified parameters.

A drive straightening machine 8 is located behind the guide device 7 attached, consisting of a group of drive rollers with a horizontal axis of rotation composed. The wire is aligned with the aid of the straightening machine 8 and introduced into the roll stands 9 (Fig. 1, 2, 5 and 6), which are at a common Frame 10 (Fig. 1 and 2) are mounted. In each roll stand 9 there are rolls 11 (Fig. 5 and 6), which are driven individually by an electric motor 12. The torque is from the electric motor 12 to a bevel gear, which consists of gears 13 and 14 (Fig. 6) is transmitted.

The driven gear 14 is together with a central gear 15 of a spur gear arranged on a shaft.

The spur gear in turn operates four gears 16. The bevel and spur gears are arranged on a stand 17 of the roll stand 9. the Gears 16 are on one and the same shaft with drive wheels 18 of bevel gears 19 attached, which are attached outside of the stand 17 of the roll stand 9. The torque of a gear 20 is with the help of a shaft 21 and a clutch 22 transferred to the rolling mill roller 11.

The rolling mill rolls 11 are housed in a removable frame 23, which is attached to an indexable plate 24. The turning plate 24 rotates around the rolling axis such that the interchangeable frame 23 together with the rolling mill rolls 11 a WeLi ^ bigç iebc Ste'lurls in relation to the immovable stand 17 in one Can occupy an angle range of 0-90 °.

This will be in accordance with the chosen calibration plan ensures the change in the direction of compression, and the finished product has a uniform intensity of solidification over the entire circumference.

Be at a minimum allowable distance from the deformation zone Roller guides 25 (FIGS. 1 and 2) are arranged on the removable frame 23. Before the first Roll stand 9 is mounted a heating device 26, which has a maximum heating temperature of 680 ° C.

To maintain the temperature of the pre-rolled rolling mill certain types of steel outside the deformation age range are used in the distances between the roll stands 9 cooling devices 27 with coolers, for example atomizers 28 (Figs. 7 and 8) mounted in the plane of each pair the rollers 11 (Figs. 5 and 6) are arranged. The atomizers 28 (Figs. 7 and 8) included Attachments designed in the form of hollow detachable telescopic cones 29 (Fig. 9) are. Each of these cones is composed of at least two segments, the are connected to elastic elements 30, and in a conical housing 31 with the possibility of an autonomous axis displacement of each cone 29 with respect to the conical housing 31 are installed. The atomizers 28 are provided with a cooling liquid through a pipe 32 (Fig. 7) with a reversing throttle for regulating the Consumption fed to coolant. Turning the cooling device 27 is guaranteed with the help of a worm gear 33 (Fig. 8). To the Cooling of the finished product to the specified temperature before winding a section cooling device is behind the last frame 9 (Fig. 1 and 2) 34 arranged, which can consist of six sections, for example, on stands 35 (Fig. 10) are mounted. The coolant becomes each section fed via a telescope line to which the feed line 32 is connected which ends with the atomizer 28. The liquid is drained through a drain pipe communicating with the drain highway and having an adjustment valve is provided. A temperature sensor is located behind the last stand 9 in the direction of the production flow 36 (Fig. 2) set up. Immediately behind the section cooling device 34 is one Rotary shears 37 (Figs. 1 and 2) for cutting wire at the moment of filling one of the spools of a winder 38 (Figs. 1 and 2) attached. Behind the scissors 37 guides and distribution devices 39 and 40 are set up, which make it possible to wind up wire without stopping the rolling train perform a free spool.

An example of a concrete implementation of the invention is given below described: Before starting the rolling train, the frame 23 (Fig. 6) with the Rolling mill rolls 11 on the rolling of the predetermined profile outside the rolling train set up, then they are set up and attached to the plates 24. By The rotation of the plates 24, the frame 23 with the rolling mill rolls 11 around the required angle rotated by the specified calibration plan to the Rolling the predetermined profile is determined.

After the change frame 23 has been turned over, the plates 24 are fixed and rigidly connected to the uprights 17 of the roll stands 9. The frame 23 of each roll stand 9 is rotated through an appropriate angle such that an edge of the profile is excluded in the course of the rolling process.

Then the electric motors of the roller straightening machine 8 (Fig. 1 and 2) the rolling stands 9 switched on, the rollers 11 of which are moving at puncture speed turn.

The rolling process starts with the supply of wire from the unwinding device 1 started from a bobbin or a bundle.

Subsequently, the guide device 7 is through the wire storage 2 through and the wire is introduced into the roller straightening machine 8. With the help of Roller straightener 8 is the wire through the heating device 26 of the group the roll stands 9 supplied. The wire produced is passed through the section cooling device 34 passed through and with the help of the guide and distribution devices 39 and 40 wound onto a metal-free spool of the winder 38.

After the wire has been pierced through the rolling train with the puncture speed - if necessary - the heating devices 26 switched on, which is a heating of the metal depending on steel brands in a range of 20 to 6800C. The rolling of wire from a certain steel grade takes place in a certain temperature range (for a steel with a carbon content of about 0.5 can be the temperature of the initial heating 200 to 230 C). To maintain the required temperature control, i.e. for the dissipation of the additional heat resulting from the plastic deformation is generated, the wire rod between the decreases in the stands 9 with the help of the cooling devices 27, which are set up in the intermediate framework spaces are.

The choice of temperature values outside the range of deformation aging is due to the fact that the simultaneous action of heating and Deformation in metal develops a process of deformation aging. For the majority The deformation aging process begins with carbon-containing steels and alloys at temperatures from 250 to 450 C. In a temperature range from 250 to 4500C there is an intensive solidification of the metal and its Embrittlement, which has an extremely unfavorable effect on the plastic properties. It increases the deformation and consequently the energy expenditure for the implementation increases deformation, which is not practical from an economic point of view. at the deformation above 4500C and up to 7000C becomes the deformation aging process completed, the plasticity increases and the strength properties decrease. This temperature range (450 to 7000C) is also suitable for rolling those that are difficult to deform and less plastic types of steel are advantageous.

Calculations of the temperature of the wire after each roll stand 9 and Experimental studies showed that the heating of wire in one stroke 50 to 600C. That is why it was used to compensate for the warmth caused by the plastic Deformation occurs, controlled cooling at a rate of 50 to 12000C per second created in the interframe space. The lower limit corresponds to the rate of cooling in the first interstand space at a rolling speed up to 1 m / sec, and the upper limit in the last intermediate stand space at a rolling speed up to 20 m / sec. To ensure the specified conditions of cooling was the consumption of cooling liquid that was supplied to the cooling device 27 0.25 to 0.4 l / sec (heat dissipation coefficient oL = 7500 kcal / h / m in each space between the scaffolding).

The cooling liquid passes through the supply pipe 32 (FIG. 7) to the cooling device 27 (FIG. 1) with the atomizers 28. With the aid of the atomizers 28 (FIG. 8), the cooling liquid is supplied to the profile sections with a maximum decrease in the previous caliber. The required exit cross-section of the detachable cone 29 (FIG. 9) is set as a function of the dimensions and the shape of the wire profile. The direction of the maximum and minimal decrease is changed in each subsequent frame 9 by half the angle between the perpendiculars to the adjacent profile edges by turning the plate 24 (FIG. 6) with the removable frame 23. The temperature control is carried out with the temperature sensor 36 (FIG. 1), which is arranged behind the last stand 9 of the rolling train. This is done by entering a control signal for the consumption of coolant. Furthermore, the speed increases up to the working speed of the rolling train and the process is carried out according to the same schedule as when operating the train at the piercing speed.

To ensure stable heat control of the rolling process the welding together of wire ends with the help of the butt welding device 6 (Fig. 2) made. In addition, the unwinding device 1 is provided for the same purposes, which contains four mandrels 41 (Figs. 3 and 4) onto which the bundles of starting wire billets to be abandoned. The winding of finished wire takes place on the double winding device 38 (Fig. 1).

In a system according to the invention, a wire with a round cross-section was used with a diameter of 5.5 mm from a wire with a diameter of 8 mm rolled from steel with a carbon content of about 0.62. A special The deformation characteristic of this steel is the formation of a "peak" of deformation aging in a temperature range of 250 to 4000C. In this context it was rolling according to the calibration plan and the pass plan (Table 1) in two procedural Processes carried out: a) with an initial heating of the respective wire billet up to 200 C and then maintaining the temperature control achieved at the expense of heat dissipation which develops during rolling, and with an intensive cooling of the wire in the spaces between the framework, b) with Initial heating up to a temperature of 2000C and subsequent rolling without Cooling of the wire in intermediate scaffolding spaces.

Table 1 The calibration schedule and the pass schedule for rolling Wire with a diameter of 5.5 mm made of steel with a carbon content of about 0.6%.

No. of the framework I II III IV V Shape of the octagon not on the octagon not filled circle caliber filled filled square square degree of compression 4-5 28 # 30 4 + 5 28.30 18 + 19 From the comparison of the results of the mechanical test of wire (see table 2), which according to the technological processes ("a" and "b" j was rolled, as well as the forces (P) necessary to carry out the deformation , it can be seen that with controlled cooling in interframe spaces (a) wire produced had higher plastic properties. This wire showed lower Values of the breaking strength ## and the yield strength ##) compared to a wire, which is produced in the second technological process ("b" without cooling became, at the Waiz temperature of the wire in the area of deformation aging for the to testing steel lay. Thereby the force (P) increases for the implementation of the technological Rolling process without controlled cooling by 14 to 16% compared to the first technological one Process ("a").

Table 2 Mechanical properties of wire and pressure of metal on the rolls during hot rolling in stands with four-roll calibers with controlled and uncontrolled cooling Variants temperature according to mechanical properties Printing of the tech- stitches of steel wire, 0 5.5 mm biological ZU ß 2 2 process 1 2 3 4 5 kg / mm2 kg / mn2 Br% gt P, kg a 200 210 205 215 230 112 110 8 2 4 100 b 200 260 320 380 430 120 118 41-1.5 4800 The procedure according to the invention enables it is to roll fine profiles made of difficult to deform and not very plastic steels and the quality of the manufactured products at the expense of a controllable temperature and to control the speed control of the rolling process. Plus, the performance a rolling mill by 10 to 15% by reducing the downtimes of the mill increased when switching to a new profile.

Pauses when changing bobbins in the winders omitted. With the application of the invention it becomes possible to have type dimensions of to roll simple files and shaped profiles in a wide range.

Claims (4)

1. Magnitogorsky gorno-metallurgichesky institute imeni G.I. Nosova, Magnitogorsk / USSR 2nd VEB heavy machinery construction combine "Ernst Thälmann",; Ntagdeburg / GDR 3. Beloretsky metallurgichesky Kombat imeni M.I. Kalinina, Beloretsk / USSR procedure for rolling wire and system for performing the method claims Method for rolling wire, with the following work steps: unwinding, Heating the starting billet of wire to a temperature preferably below that Recrystallization temperature is, rolling with strip tension in at least two stands with multi-sided compression of the wire billet to be deformed, local cooling over the circumference of the wire between the scaffolding, as well as cooling the wire before kufwickeln, thereby showing that the cooling between the Roll stands (9) selectively over the circumference of the wire by means of supply of cooling liquid only for the sections with maximum decrease in the previous caliber takes place, and the direction of the maximum and minimal decreases in each subsequent scaffold (9) by half the angle between the verticals to the adjacent profile edges is changed. 2. The method according to claim 1, characterized in that g e k e n n -z e i c h n e t, that the wire between the frames (9) at a speed of 50-12000C is cooled down every second. 3. The method according to claim 2, characterized in that g e k e n n -z e i c h n e t, that the cooling of the wire in each interframe space with an amount of cooling liquid from 0.15-0.4 l / sec. is carried out. 4. Plant for carrying out the method according to claims 1, 2, and 3 in the one behind the other in the production flow direction and with one another connected unwinding and heating devices, at least two roll stands from Cassette type with roller drive, cooling devices, for example with atomizers Attachments that are continuous in the cross-sectional plane of the respective wire billet are arranged in the interframe space and contain a winding device, characterized in that the attachments of the atomizer (28) in the form are made of hollow detachable telescopic cones (29), each of which is made up composed of at least two segments, which are connected with elastic elements (30) are, and in a conical housing (31) with the possibility of an autonomous axis offset each cone with respect to the housing (31) can be installed, whereby the regulation of the cross section of the cooling jet in a range of 0.4-0.6 of the cross section of the respective wire is secured.