RU2491140C2 - Method of strip hot rolling and combination mill to this end - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy and may be used for strip hot rolling at combination mill. Proposed mill comprises heating furnaces, set of roughing stands, run-up table and run-off table, through heating furnace, set of finishing stands and reel. Slabs heated in heating furnaces are fed to roughing while produced thick sheets are fed via run-off table to edging or via run-out table to through heating furnace and to finishing. Thick sheets are fed to edging after roughing while loosely reeled coils from foundry-rolling unit are fed to finishing. Prior to feeding to through heating furnace said loosely coiled reels are unwound.

EFFECT: higher efficiency.

2 cl, 3 dwg

Description

The bulk of the strip metal in the iron and steel industry is produced on semi-continuous (3/4 continuous) hot rolling mills. In the past 20 years, a certain number of hot-rolled strips are produced at casting and rolling units.

Distinguish the production of hot rolled metal on conventional and combined semicontinuous mills.

A known method of hot rolling strips in a semicontinuous mill, including heating slabs, rough rolling, pre-heating, finishing rolling and winding strips into rolls (see, for example, JP 58122107 A, B21B 1/46 from 07.20.1983).

The main disadvantage of this method is the inability to produce thick sheets of reduced weight (2-4 tons) of special high alloy steels and alloys.

A known method of hot rolling of strips in a combined semicontinuous mill, including heating slabs, rough rolling of thick sheets with subsequent transfer of finished sheets from the production line of the mill in the section of the intermediate roller table for finishing, while maintaining the production of strips of rolled metal that is wound into an intermediate roll on the intermediate roller table unwind, carry out finish rolling and wrap the finished strip into a roll (see, for example, the production process of rolled products on a combined semi-continuous tane 2800/1700 of "Severstal" after installation thereon Coilbox. "On retooling rolling production Cherepovets plant." "Steel" Journal 1986, №5, s.57-58).

The main disadvantage of this method is the need for a complete replacement of heating furnaces and the draft group of the mill for the production of strips in rolls of increased mass.

There is a method of hot rolling strips in a combined semicontinuous mill, including heating slabs, rough rolling, pre-heating, finishing rolling and winding of the obtained strips into rolls (See, for example, Rolling production. Textbook for universities. 3rd ed. Polukhin P.I. . and others, Metallurgy, 1982, s. 389-392).

The described method is closest to the proposed, therefore, adopted as a prototype. However, this method has significant disadvantages.

Firstly, an integral part of hot rolling on a combined mill is the production of thick sheets of reduced weight from special steels and alloys.

Secondly, a number of strips of carbon steel grades of steels, as well as special steels and alloys, are rolled in the finishing group of stands and the finished strips are coiled.

The noted features of the implementation of the known method of hot rolling of strips in a combined semicontinuous rolling mill lead to a significant decrease in the productivity of the combined semicontinuous mill, since in the production of thick sheets a significant part of the equipment is idle (finishing group, discharge roller table, coilers).

The set of noted disadvantages of the known method of hot rolling on a combined semicontinuous mill in the proposed method is eliminated by breaking the single production line of this mill into independent two:

- to a line providing hot rolling from slabs of reduced mass of thick sheets;

- to a line providing only hot rolling of thin strips from slabs of increased mass with coiling of finished strips into a roll, and organizing the production of hot-rolled strips in both technological lines.

Implementation of the proposed method of hot rolling can significantly improve the performance of a combined semi-continuous mill by increasing the production of primarily thin strips in rolls on it, while maintaining the production of thick sheets.

An important advantage of the technical proposal is also that the indicated break in the unified technological line of the mill allows you to completely save (which is necessary for a number of steels and alloys) the possibility of using the existing method of rolling thin strips in rolls from slabs of reduced weight, i.e. using the finishing group, the discharge of the roller table and coilers.

The technical result is achieved by the fact that in the method of hot rolling of strips on a combined semicontinuous mill, including heating slabs, rough rolling, pre-heating, finishing rolling and winding of the obtained strips into rolls, according to the proposal for finishing rolling, a tack is supplied in the form of thick sheets after heated rolling slabs or tackles in the form of loose-rolled coils coming from the casting and rolling unit, while maintaining the production of thick sheets that are transferred to the finish after rough rolling, etc. and this, before heating the rolled metal coming from the casting and rolling unit, rolls are unwound.

A known casting and rolling installation for the manufacture of a steel strip containing a continuous casting machine, scissors, a tunnel furnace located in line with a tunnel furnace, a broadband slab hot rolling mill with a thickness of 120-400 mm with heating furnaces and a number of combinations of the location of the above equipment (see, for example, RU 2301120 C2 (CMC DEMAG AKTSIENGESELLSHAFT) dated 06/20/2007).

The main disadvantage of the known installation is the direct location of the continuous casting machine and a continuous tunnel kiln. If there is a feed-through heating furnace on the intermediate roller table of a combined semicontinuous mill, this arrangement of equipment is unnecessary, because, firstly, it increases the capital costs for a tunnel tunnel furnace, and secondly, the operating costs for heating the metal in this furnace increase.

A well-known universal casting and rolling mill arranged with series-parallel placement of procurement and roughing equipment and sequential placement of finishing and finishing equipment (see, for example, RU 2217247 C2 (OJSC "Artyomovsk non-ferrous metals processing plant") from 11/27/2003).

The main disadvantage of the well-known universal casting and rolling mill is the lack in its layout, immediately after casting the workpiece, of an installation for winding the workpiece into an intermediate roll, which excludes the possibility of the known casting and rolling mill for solving a technical problem, the description of which is described in the hot rolling method.

Known (see the specified textbook, table 26 on page 390, mill 2300/1700 ChelMZ) is a combined semicontinuous mill containing heating furnaces in the production line, a roughing and finishing group of stands, connected by an intermediate roller table, an outlet roller table and coilers, while on the intermediate the roller table has a section for transferring finished thick sheets from the processing line of the mill for finishing; the intermediate rolling table also includes a continuous heating furnace located between the section for transferring finished thick sheets in for finishing and the finishing group of stands, and in this case, the production line of the mill closes the discharge roller table and coiler.

The described well-known combined semicontinuous mill is the closest analogue, therefore, adopted as a prototype. However, the well-known combined semicontinuous mill has a significant drawback consisting in the inability to simultaneously produce thick sheets and thin strips in rolls on the mill, which significantly reduces the overall operation efficiency of the mill. The aforementioned is due to the fact that the equipment of the well-known combined semicontinuous mill excludes the possibility of breaking a single production line of the combined mill into independent two and the organization in both lines of simultaneous production of thick sheets from slabs of reduced mass in one of them and hot rolling from intermediate rolls of increased mass of thin strips with reeling them into a roll.

This technical proposal provides for the elimination of this disadvantage of a combined semi-continuous mill, adopted as a prototype.

The technical result is achieved due to the fact that the combined semicontinuous mill, containing heating furnaces, a roughing and finishing group of stands, connected by an intermediate roller table, draining the roller table and coilers, while on the intermediate roller table there is a section for transferring finished thick sheets from the processing line of the mill for finishing, and also a continuous heating roller furnace located between the transfer section of finished thick sheets for finishing and the finishing group of stands, according to the proposal between ASTK transmission thick sheet for the finishing and the beginning of the continuous furnace a heating coil located receiver coupled to the vehicle engine coagulation casting and rolling machine.

For the technical implementation of the proposed method of hot rolling, the location of the casting and rolling unit relative to the combined semi-continuous mill is not of fundamental importance. At the same time, we note four options for this arrangement:

1. The parallel arrangement of the production line of the combined semicontinuous mill and the production line of the casting and rolling unit (MPA) with the organization of the movement of the metal flow in the MPA towards the metal flow rolled in the finishing group of stands.

2. Similarly to paragraph 1 of the location of the processing lines of the combined mill and mill, but with the organization of the movement of the metal flow in the mill, coinciding with the movement of the metal flow, rolled in the finishing group of the combined semicontinuous mill.

3. The perpendicular arrangement of the production line of the combined semicontinuous mill and the processing line of the medical facility.

4. Inclined to the location of the processing line of the combined semicontinuous mill location of the processing line LPA.

The implementation of paragraphs 2-4 requires the presence of a rotary table roll, which naturally leads to complication of the articulation of the combined mill and LPA.

Therefore, it is preferable to join the mill and LPA according to claim 1, however, ultimately this is determined by the location of the workshop with the combined semi-continuous broadband mill on the master plan of the plant and the possibility of organizing the supply of liquid metal to the mold of the casting and rolling unit.

Hot rolling method: and a combined semi-continuous mill for its implementation are explained in figures 1-3.

The combined semicontinuous mill contains (Fig. 1) the main production line 1, on which the following equipment is installed: 2 - a group of heating methodical furnaces, 3 - a draft group of stands, containing a vertical descaler and two reversible universal quarto stands (the first stand can be universal duo), 4 - the correct machine, 5 - the mechanism (Schlepper) transfer finished thick sheets from line 1 of the mill for further processing, 6 - receiver rolls, 7 - through passage heating roller furnace with lower and upper Heated, 8 - finishing group of stands, containing flying scissors, finishing descaler and six finishing stands of quarto (maybe five), forming a continuous group, 9 - discharge roller table, 10 - group (maybe one) of coilers. A casting and rolling unit 11 is adjacent to the combined mill, comprising a mold 12, a rolling machine 13, a roll conveyor 14.

The casting and rolling unit (figure 2) along with the mold 12 contains a secondary metal cooling zone 15, which implements metal cooling and soft compression in rolling stands of quarto 16 (up to 3 stands installed with a minimum distance along the axes), flying scissors 17 for cutting the cast metal transversely, a rolling machine 13, in which a mechanism for raising and lowering the roll is provided in the form of plates covering the roll 18 (in Figures 2 and 3, the arrows show the direction of action of this mechanism). The mechanism for raising and lowering the roll in the form of plates covering the roll 18 (FIGS. 2 and 3) is also an integral part of the conveyor 14 (FIG. 1), on which the roll is provided with a stable position during its transfer from the medical device. The mechanism of lowering and raising the roll in the area of formation of the roll 13 in the LPA, during transportation along the conveyor 14 and during operation of the receiver 6 is identical and contains a number of plates covering the roll 13 (in the form of a roll) 18, which are equipped with a drive to move them to / from the roll ( shown by arrows in figure 2 and 3).

In the process of forming a roll 13 (figure 2) and its gradual unwinding of figure 3 (figure 1, receiver 6), the roll rests on rollers 19, which are made drive.

An integral part of the receiver 6 in FIG. 3 is a bending device 20 (of a known construction) of the front end of the roll for organizing the movement of the tackle in direction 21 into the feed-through furnace 7 and into the finishing group of stands 8 in FIG. In this case, as noted, the roll 13 is based on the drive rollers 19.

The method of hot rolling on a combined semi-continuous mill is as follows.

For rolling thick sheets, the slabs are heated in furnaces 2 (Fig. 1) and unloaded into the production line 1 of the mill, where the slab passes the draft group of stands 3 to obtain a thick sheet of the required thickness. The resulting finished sheet is corrected in the correct machine 4 and the slapper 5 is removed from the processing line 1 of the combined mill for further processing, including heat treatment.

For rolling thin strips, a heating feed roller furnace 7, a finishing group of stands 8, a discharge roller 9 and coilers 10 are used. Rolling for rolling thin strips is fed in the form of a roll 13 by a conveyor 14 to an uncoiler 6 in the production line of mill 1. A roll 13 is received at a foundry rolling unit 11 (figure 1). On this unit, liquid metal is fed (see arrow in FIG. 2) to the mold 12, after passing through which slabs are obtained with a thickness of 90 ... 100 (110) mm (but not less than 50 and not more than 150 mm). After the slab exits the crystallizer 12 as it moves, gently compress the slab 15 in a two-phase region in a known manner, after which, in the solid state, the slab is fed to the rolling stand group 16, in which the slab is crimped to 15-25 mm (in the range of 30-35 mm). The group of rolling stands 16 contains up to three 4 roll stands that are installed close to each other (analogy to the technical solution at the Crevedon plant of Arvedi company). At the exit from the group of stands 16 with flying scissors 17, the cutting is rolled into measured lengths (measured length means the ability of the equipment operating after the scissors 17 to process the resulting metal roll, including the corresponding mass). The resulting tackle is wound into a loosely wound roll 13. Preferably, the specific gravity of the obtained roll is equal to a maximum of 27-28 t / (m width). By conveyor 14, roll 13 is transferred to the mill production line 1, while for stability of the roll, supports 18 are provided, equipped with a drive to move to / from the roll (in Fig. It is not considered in detail, since it does not determine the essence of the proposed rolling method). Roll 13 is fed to the receiver 6 (figure 1).

In the receiver 6, the roll 13 is rotated using the support drive rollers 19 (FIGS. 2 and 3), while the front end of the roll using the bending device 20 (FIG. 3) is bent and fed in the direction 21, towards the feed roller furnace 7 and the finishing group 8 in FIG. Supports 18 and rollers ensure the stability of the roll 13 (figure 2 and 3).

When implementing the proposed method of hot rolling, partial thermal insulation of the roll 13 is possible, which additionally preserves the temperature of the metal (Cremona furnace).

During the passage of the through-hearth furnace 7 with a roller hearth (the length of the furnace is about 50 m), the speed of tackle movement in the passage-type furnace varies within the feed rate of the tackle to the first stand F _{0 of the} finishing group and cutting on the flying scissors of the finishing group of stands 8.

Since rolling technology on a combined semi-continuous mill can provide rolling in the finishing group of rolled stands up to 50 mm thick (see, for example, “Technical passport” of a sheet rolling workshop with a combined mill 2300/1700 Chelyabinsk, 2000, p. 25 ), in the proposed method of hot rolling and a combined semicontinuous mill for its implementation, it is envisaged to preserve in the draft group a combined semicontinuous mill for the production of rolled products up to 50 mm thick, its passage through receiver 6 (Fig. 1), feed roller furnace 7 and rolling in the finishing group of stands 8.

Similarly, in the proposed method of hot rolling of strips and a combined mill for its implementation, the possibility of operation of a continuous roller furnace 7 with a delay of rolling in the furnace by its "rocking" is preserved. In this case, rolling draft 3 is provided in draft group 3 of the combined semicontinuous mill (in Fig. 1), which, through the intermediate roller table (through receiver 6), enters the continuous roller furnace 7, in which the rolling is heated with its "rocking" and the subsequent rolling is heated tackle in the finishing group of stands 8.

In both cases considered, the operation of the combined semicontinuous mill at the casting and rolling complex 11 reduces the rate of metal casting, thereby the receiver 6 freely passes the tackles coming from the roughing group of the combined semi-continuous mill, while the tackles are rolled in the roughing group from the slabs.

Example 1. Rolling in the finishing group of the combined mill 1700 hot rolled strips with a thickness of 2 ... 6 mm. In the mold 12 of the LPA in figure 2, molten steel is poured 90 mm thick. In the secondary cooling zone 15, the slab is compressed by 16 mm and the metal with an average temperature of 1140 ° C enters a compact continuous group of stands 16, where it is deformed in height to a roll with a thickness of 16 ... 24 mm, depending on the size of the finished thin strips produced at the exit from stands F ₀ -F ₆ , (8 in FIG. 1). From the group of stands 16, the metal leaves with an average temperature of 980 ° C.

On flying scissors 17 (Fig. 17), they cut the front end of the roll (if necessary) and the finished roll at a temperature of 970 ° C (depends on the thickness of the slab 15 at the exit from the secondary zone of the LPA) is wound into a loosely wound roll 13 (Fig. 1- 3). When reeling, the roll 13 is supported on the drive rollers 19 (FIGS. 2 and 3) and forms a roll due to the action of the guide plates 18 and the mechanism of their movement.

The guides 18 raise the roll 13 above the rollers 19 and conveyor 14 (chain or plate, it does not matter) transfer to the receiver 6, where they are lowered onto the rollers 19, rotate and the front end are unbent 20 and rolled out in the direction 21 (in the furnace 7 and to the finishing group 8 in figure 1). In the process of winding the roll and transferring it from the injection unit to the production line 1 (Fig. 1), it is preferable to insulate the surface of the roll (the form of roll insulation is not considered here).

In the furnace 7, the tackle enters at a temperature of about 970 ° C. Passing the furnace 7, the metal is heated to 1100 ... 1150 ° C (the heating level determines the thickness of the rolled 16 ... 24 mm and the speed of its passage through the finishing group 8 of the combined mill and, accordingly, furnace 7). Basically, the temperature of the end of rolling strips in the finishing group 8 is 820 ... 870 ° C (depending on the grade of steel and the thickness of the finished strip). On the discharge roller table 9, the laminar system of the strip is cooled to 680 ... 700 ° C (determined by the grade of rolled steel) and reeled up by coilers 10 into a finished roll.

Example 2. On a combined mill 2300/1700 carry out rolling of thick sheets (up to 6.0 mm) while using as a workpiece slabs, including continuously cast. For their heating, furnace 2 is used (in FIG. 1), the slabs are deformed in draft group 3 (in FIG. 1). The finished sheet with a slapper 5 (Fig. 1) is removed from the processing line of the combined mill for finishing. When implementing this technology at the 2300/1700 mill, the technological instructions TI-GL1-2008 and TI-GL2-2008, TI-GL7-2008 and TI-GL6-2008, Chelyabinsk are used.

Example 3. On a combined mill 2300/1700 from slabs carry out rolling of thick (up to 6.0 mm) strips with coiling. In this case, the rate of steel casting is reduced at the MPA and the rolled rolled in the rough group of the 2300 mill is transported along the intermediate roller table up to the finishing group of stands 8, after rolling and cooling on the discharge roller table 9 the strip is wound onto a roll on a coiler 10.

Thus, on the combined mill for hot rolling of strips all the technologies for the production of thick sheets and thin strips are preserved. At the same time, the main production of thin strips in rolls is carried out using the proposed method of hot rolling on a combined semi-continuous mill, which significantly increases the productivity of the mill.

Claims (2)

1. The method of hot rolling of strips on a combined semicontinuous mill, including heating slabs, rough rolling, pre-heating, finishing rolling and winding of the obtained strips into rolls, characterized in that the rolling is fed in the form of thick sheets obtained after rough rolling of heated slabs , or tackle in the form of loosely wound rolls coming from the casting and rolling unit, while maintaining the production of thick sheets that are transferred to the finish after rough rolling, while the tackle is heated before heating and coming from a casting and rolling unit, rolls are unwound. 2. Combined semi-continuous mill for hot rolling of strips, comprising heating furnaces, a group of roughing stands, an intermediate roller table, a discharge roller table, a continuous heating furnace, a finishing mill group and a coiler, characterized in that a roll receiver is connected in front of the continuous heating furnace and connected by a conveyor to a rolling the machine of the casting and rolling unit, and between the group of roughing stands and the receiver of rolls there is a section for transferring thick sheets for finishing.

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