RU2443504C2 - Method of producing metal strip - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metallurgy. Liquid metal is fed between two crystalliser rollers of two-roller casting machine. Powder reagents are fed from above into zone wherein crystalliser rollers bite liquid metal along strip drawing direction. Metal is fed in parallel flows on both sides of infeed of powder reagents. The latter represent loose powder, powder wire, powder tape. Liquid metal surface between crystalliser rollers and powder reagent feed assembly are arranged in isolated chamber filled with inert atmosphere.

EFFECT: higher physical and mechanical properties.

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Description

The present invention relates to metallurgy, namely the production of a metal strip.

There is a method of producing a metal strip, including pouring liquid metal into a crystallizer, treating it with powder reagents supplied laterally at an angle to the metal surface and drawing an ingot (see, for example, V.N. Gushchin, V.A. Ulyanov. Complex out-of-furnace steel processing during continuous casting // "Metallurgy for mechanical engineering", No. 2, 2007, p.3-7).

Its disadvantages include the uneven distribution of powder over the cross section of the ingot and, as a result, the heterogeneity of the finished product obtained.

There is also a method of producing a metal strip, including pouring liquid metal into the mold through a hollow glass with an annular cross section and treating the metal with a powder reagent fed through the central hole of the hollow pouring glass (see, for example, P. Naveau, J.-P. Fishbach, V .Flores et al., Industrial Tests of the Hollow Jet Nozzle on the ArcelorMittal ISBERGEUS Slab Caster // "CIT". 2008. October. C.513-519).

Its disadvantages include the high energy intensity and multi-stage process due to the large thickness of the cast ingot, determined by the need to introduce a submersible nozzle and carry out multi-stage rolling, uneven distribution of the modifying material over the cross section of the ingot after rolling into a thin strip, lack of distribution of reagents over the cross section, complexity and limited resistance submersible glass.

Of the known, the closest to the proposed technical essence and the achieved results is a method and device for the production of fiber reinforced composite material, in which the liquid metal is applied to the surface of two twin rolls rotating towards each other, cooled to a semi-solid state, a reinforcing fabric is introduced into the gap between the rollers and then combined into a composite material by rolling the layers between the rollers (see, for example, Patent No. JP 2005074491, 2005-03-24, Fujita Masa, Haga Toshio, Honda Motor Co. Ltd. Manufacturing Method and Appa ratus of Fiber Reinforced Composite).

Its disadvantages include the lack of distribution of the material introduced into the metal in the bulk of the metal, the insufficient interaction of the material introduced into the metal with the base metal due to the fact that the final structure is formed by mechanical combination of the semi-cured layers of the metal by rolling. The technical result of the proposed method for the production of a metal strip is to expand technological capabilities by continuously producing finished structural strips and improved physical and mechanical characteristics due to the introduction of various powder reagents into the liquid metal and uniform distribution over the strip width. The introduction of powder reagents into liquid metal cast on a twin roll casting machine can significantly reduce the energy intensity and duration of the process, enhance the interaction of components by introducing them into the liquid metal bath and at the same time solve a wide range of technological problems: obtaining materials with improved physical and mechanical characteristics and new properties as a result of alloying processes, structural modification, compensation of the harmful effects of impurities, change in abrasive, mechanical properties, magnetic properties, radio transparency, electrical, thermal conductivity, strength, etc., with obtaining a homogeneous structure.

The technical result is achieved by the fact that in the proposed method for the production of a metal strip, powder reagents are introduced into the liquid metal trapping area, while the metal is fed laterally in two parallel streams, in the presence of continuous casting of molten metal between rotating rolls-crystallizers of a two-roll casting machine, stretching the metal strip in the lower direction, its rolling with the supply of liquid metal to the zone of metal capture by roll crystallizers in two streams, with the formation of a bath with a level of below the upper edges of the mold rolls, and the reagent in the form of a powder, or flux cored wire, or flux-cored tape is introduced from above into the middle of the bath.

Ferroalloys, microalloying additives, iron powder, fusible reactive desulfurizers and other modifying additives introduced into liquid metal in the form of unpacked powder, a flux-cored wire or tape with inert gas protection can be used as powder reagents.

The invention is illustrated by examples of its implementation in the accompanying drawings, where

- figure 1 shows a diagram of the implementation of the proposed method with the supply of powder reagents in the form of unpacked powder in an inert gas stream;

- figure 2 shows a section aa in figure 1;

- figure 3 presents a section bB in figure 2;

- figure 4 shows a variant of the implementation of the proposed method for supplying unpacked powder through several feed heads;

- figure 5 shows a section of a cored wire;

- figure 6 shows a section of a powder tape;

- Fig.7 shows a diagram of the implementation of the proposed method with a tribamer for introducing powdered reagents in the form of a cored wire or tape;

- in Fig.8 shows a section GG in Fig.7 (option 1 - the implementation of the node supply for cored wire);

- figure 9 shows a section GG in figure 7 (option 2 - the implementation of the node supply for powder tape).

The method is as follows:

To obtain a metal strip in the tank 1 pour molten metal 2 (figure 1). It is possible that the metal is melted directly in the tank 1 using an inductor 3. The rotation mechanism and the cooling system of the mold rolls 4, 5 are turned on (fig. 5, position 5 is not visible and symbolically indicated) of a two-roll casting machine. The molten metal 2 is released into a metal wire 6, which is made of heat-resistant material in the form of an inclined groove 7 and a receiving tank 8, while a refractory bridge 11 is made in the groove 7 opposite the input unit 9 of the modifying material 10 to separate the flow of molten metal into two streams. The molten metal 2 enters the receiving tank 8, formed by two side walls 12, 13 (in Fig. 1, pos. 13 is not visible and is conventionally marked) adjacent to the forming of the mold rolls 4, 5 and two end walls 14, 15, with cutouts repeating the profile of the rolls-crystallizers 4, 5. The molten metal 2 is fed to the rolls-molds 4, 5 in two parallel streams 16, 17 (figure 2) on both sides of the input unit 9 of the powder reagents 10, made in the form of a hopper 18 with a slit-shaped feed head 19 located in the capture zone that metal 20 formed between the mold rolls. For a uniform distribution of the incoming metal across the width of the formed strip with the upper supply of metal on the inner sides of the side walls of the receiving tank can be made of refractory shelves 21, 22 (Fig.2, 3).

After the beginning of the exit of the crystallized portion of the strip from the rolls 4, 5 vertically downwards and entering it into the secondary cooling zone through the input unit 9 of the powder reagent 10, the powder reagents 10 are fed into the metal bath formed in the capture zone 20 of the liquid metal 2 by the rolls-crystallizers 4, 5 , while they are preheated by a heating device 23 and protected by a protective atmosphere by means of a device for creating a protective atmosphere 24 with protective casings 25. I dissolve the powder reagents 10 in the capture zone 20 of the liquid metal 2 Xia in the liquid metal and form an improved structure in the solidifying metal. After the passage of the initial powder-treated section of the strip 26 with the improved structure through the secondary cooling zone, it is crimped by rollers 27, the strip is additionally cooled by nozzles 28, the strip is cut into measured lengths using scissors 29 and the strip 26 is finally rolled by rollers 30. Process control is carried out a change in the height of the metal level 2 in the capture zone 20 by the rolls of crystallizers 4, 5, the rotation speed of the rolls of crystallizers 4, 5, the modes of supply of powder reagents 10 in hard metal 2 and cooling according to the temperature sensors and strip thickness 31, 32.

Powder reagents are fed through one common slotted feed head 19 or through several feed heads 33 with a common collector or with individual leads and with the possibility of independent movements (figure 4).

Powder reagents in the form of a flux-cored wire 34 (Fig. 5) or a flux-cored wire 35 (Fig. 6) are supplied by the tribamer 36 (Fig. 7) through round 37 (Fig. 8) or rectangular 38 (Fig. 9) feed heads.

For the use of powder reagents in the form of unpacked powder in an inert gas stream, powder reagents are loaded into the reagent supply device. The metal is loaded into a smelting tank and melted in a protective atmosphere. They include rotation and a cooling system for rolls of crystallizers, molten metal is poured into the intermediate tank using metal feeding devices, and a system for feeding and heating powder reagents is turned on. In this case, the supplied powder reagents and the metal surface are protected with a protective atmosphere. Powder reagents in the liquid metal trapping zone dissolve in the liquid metal and form an improved structure in the solidified metal. After the beginning of the exit of the crystallized strip from the rolls, a secondary cooling device is turned on. After the strip passes through the secondary cooling zone, a stream is measured in the characteristics of the formed structure: thickness, width, density using sensors and the strip is crimped by rolls, the characteristics are measured a second time and the strip characteristics are refined using the heat treatment device, additional deformation and cooling. After that, the strip is cut in the stream using a cutting device, the surface is cleaned and protected from oxidation and packaged in a packaging device for supply to the warehouse.

For the use of powdered reagents in the form of flux-cored wire or tape, material in the form of coils or rolls is loaded into the tribamer. The metal is loaded into a smelting tank and melted in a protective atmosphere. They include a system for heating powdered reagents, rotation and a cooling system for rolls of crystallizers, molten metal is poured into the intermediate container using metal feeding devices, and a system for feeding powder reagents into the region of liquid metal between the rolls is included. After the beginning of the exit of the crystallized strip from the rolls, a secondary cooling device is turned on. As the strip passes through the secondary cooling zone, a measurement is made of the characteristics of the formed structure in the stream: thickness, width, density with the help of sensors and the strip is compressed by rolls, the characteristics are measured again and the strip characteristics are modified using the heat treatment device, additional deformation and cooling. After that, the strip is cut in the stream using a cutting device, the surface is cleaned and protected from oxidation and packaged in a packaging device for supply to the warehouse.

An example implementation of the method. Upon receipt of a steel strip with an improved structure, the steel is melted and heated to a temperature of 1550-1600 ° C in an induction furnace, a melt is fed to the metal capture zone of a two-roll casting machine with lower strip stretching, water-cooled crystallizer rolls with a diameter of 500 mm begin to rotate at a peripheral speed 1-6 m / s and after pulling the front end of the cast strip from the rolls into the molten metal through the slit-like dispenser, iron powder is first fed, preheated to a temperature of 0.4-0.5 The temperature of the cast metal melting in an amount of 0.01-0.005 mg / kg melt. In the molten metal, the powder dissolves, forming a microcrystalline structure with improved properties. The structure parameters are determined by the cooling rate and the peripheral speed of rotation of the mold rolls, the corresponding strip drawing speed, as well as the position of the nozzle, the flow rate of the powder reagent, and the height of the receiving bath. The total thickness of the strip is determined by the solution of rolls-crystallizers, which can vary within 1-5 cm. The width of the strip, determined by the distance between the end walls of the receiving tank, can be up to 1.1 m.

The strip emerging from the rolls-crystallizers is subjected to soft reduction by 5–10% in thickness, additional water-air cooling, and continuous monitoring of the main parameters in the stream, after which it is cut into measured lengths and rolled to the final thickness.

Compared with the best known methods for producing a high-quality strip using the processing of cast metal by powder reagents, the proposed method can significantly reduce the energy intensity and duration of the process and at the same time solve a wide range of technological problems: obtaining materials with improved physical and mechanical characteristics and new properties as a result of alloying processes, modifying the structure, compensating for the harmful effects of impurities, changing abrasive, mechanical properties PTS magnetic properties of radio, electrical, thermal conductivity, strength, etc. with a homogeneous composition, due to the supply of metal from the side in two parallel streams, in the presence of continuous casting of molten metal between the rotating rolls-crystallizers of a two-roll casting machine, stretching the strip of metal in the lower direction, its rolling with the supply of liquid metal to the metal capture zone by rolls-crystallizers in two streams , with the formation of a bath with a level not lower than the upper edges of the rolls of crystallizers, while the reagent in the form of a powder, or flux-cored wire, or flux-cored tape is introduced from above into the middle part of the bath.

Claims (7)

1. A method of manufacturing a metal strip, including pouring molten metal between the rotating mold rolls of a two-roll casting machine, stretching the strip in the lower direction and rolling it, the liquid metal being fed into the metal capture zone by the mold rolls in two streams, characterized in that the metal is treated with powder reagents that are introduced from above into the zone of metal capture by rolls in the direction of stretching the strip, while the metal is supplied, in parallel flows on both sides from the introduction of powder reagents. 2. The method according to claim 1, characterized in that the powder reagents are used in the form of unpacked powder. 3. The method according to claim 1, characterized in that the powder reagents are used in the form of a cored wire. 4. The method according to claim 1, characterized in that the powder reagents are used in the form of a powder tape. 5. The method according to claim 1, characterized in that the melting point of the powder reagents does not exceed the melting point of the base metal. 6. The method according to claim 1, characterized in that the powder reagents are preheated. 7. The method according to claim 1, characterized in that the surface of the molten metal between the mold rolls and the powder reagent introduction unit is placed in an isolated chamber filled with an inert atmosphere.

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