RU1677926C - Method of continuous casting of flat ingots and device for its realization - Google Patents

Abstract

FIELD: metallurgy. SUBSTANCE: method of continuous casting of flat ingots includes their cobbing in the solid-liquid state in the spray cooling chamber with the aid of rolls. The change of the cobbing value along the ingot length is carried out along the broken line consisting of separate rectilinear segments. The length of these segments makes up (0.5-0.20) of the common length of the ingot cobbing zone. The value of the ingot cobbing in the place of jointing the broken line segments makes up (0.1-0.3) of the total value of the cobbing as viewed from each wide side of the ingot relative to the preceding place of the segment jointing. Along the spray cooling chamber length the rolls are grouped together into links. The axis of each roll located on the link butt is mounted in the slide blocks able to travel in the guides under the action of hydraulic cylinders. EFFECT: enhanced quality of the continuously cast flat ingots and simpler control system of the roll displacement. 2 cl, 4 dwg, 1 tbl

Description

 The invention relates to metallurgy, namely to the continuous casting of flat ingots in the conditions of their compression in a solid-liquid state in the secondary cooling zone.

 The purpose of the invention is improving the quality of the ingots and simplifying the control system for the movement of the rollers.

 The method of continuous casting of flat ingots involves feeding metal into the mold, pulling the ingot from it at a variable speed, compressing the ingot in a solid-liquid state from the side of wide faces in the secondary cooling zone using rollers with changing the amount of ingot compression along its length from the minimum value under the mold to the maximum values at the end of the compression zone.

 The change in the amount of compression along the length of the ingot is made along a broken line consisting of separate straight sections, the length of which is set within (0.5-0.2) of the total length of the deformation zone of compression of the ingot, while the amount of compression of the ingot at the junction of sections of the broken line is set within (0.1-0.3) of the total amount of compression from the side of each wide facet of the ingot relative to the previous joint sites.

 Figure 1 shows a device, a longitudinal section; figure 2 section aa in figure 1; figure 3 section BB in figure 2; figure 4 section bb in figure 2.

 A device for implementing the method of crimping flat ingots during continuous casting consists of a mold 1, links 2, rollers 3 and 4, axles 5, sliders 6, guides 7, frames 8, hydraulic cylinders 9, holes 10 with sliders 11 forming gaps 12.

In FIG. the following designations are accepted: 13 ingot shell, 14 liquid metal, l length of the straight section of the broken line of the ingot compression or the length of the link with rollers, L length of the compression zone of the ingot, N thickness of the ingot at the outlet of the mold, N thickness of the ingot after compression, ΔН total amount of compression ingot, ΔН _{i is the} size of the ingot compression at the junction of the straight sections of the broken line, i is the number of the junction of the straight sections of the broken line of the compression of the ingot, i 1,2,3.n.

 The quality improvement of flat continuously cast ingots will occur due to an increase in the accuracy of the installation of the rollers relative to the ingot during its reduction along the broken line and the grouping of the rollers in separate links along the length of the secondary cooling zone. In this case, the degree of deformation at the crystallization front along the length of the ingot will not exceed the permissible values, which will lead to a decrease in the marriage of ingots along internal cracks.

 The length range of straight sections within (0.05-0.2) of the total length of the compression zone of the ingots is explained by the need to maintain the degree of deformation at the crystallization front of the ingot shell within acceptable limits. At large values, the degree of deformation at the crystallization front of the shell at the joints of the rectilinear sections of compression of the ingot will exceed the permissible values, which will cause the marriage of the ingots along internal cracks. At lower values, the accuracy of the installation of the rollers will be underestimated due to an increase in the number of controlled hydraulic cylinders, which will cause the marriage of ingots by internal cracks and will complicate the control system of hydraulic cylinders.

 The specified range is set in direct proportion to the length of the deformation zone of compression of the ingot.

 The range of change in the size of the compression of the ingot at the junction of sections of the broken line within (0.1-0.3) of the total value of compression on the side of each wide face of the ingot relative to the previous joint is explained by the allowable strain on the crystallization front of the shell of the ingot. At large values, the degree of deformation at the crystallization front of the shell of the ingot will exceed the permissible values, which will cause the marriage of ingots along internal cracks. At lower values, it will be necessary to increase the number of straight sections or links, which will necessitate the use of a large number of hydraulic cylinders. In this case, the accuracy of adjusting the position of the rollers decreases, which will lead to the rejection of ingots by internal cracks. In addition, in this case, the control system of hydraulic cylinders will be complicated.

 The specified range is set in inverse proportion to the carbon content of the cast steel, since the degree of permissible deformation at the crystallization front is inversely proportional to the same carbon content.

 The method of continuous casting of flat ingots is carried out and the device operates as follows.

PRI me R. During continuous casting, steel 14 with a different carbon content is fed into the mold 1 with a length of 0.8 m and an ingot 13 is drawn from it with a thickness of H and a width of 1.0 m at a speed of V m / min. In the secondary cooling zone under the mold 1, the compression of the ingot 13 is deformed and in the solid-liquid state in thickness from H to h using the rollers 3 and 4. The compression value ΔН _{i of the} ingot 13 is changed along its length from the minimum value under the mold 1 to the maximum value of ΔН at the end of the compression zone of length L.

The change in the amount of compression ΔН along the length of the compression zone is made along a broken line consisting of separate rectilinear sections of length l. The length of sections l is set within (0.05-0.2) the length of the compression zone L. In this case, the amount of compression ΔН _{i of the} ingot 13 at the junction of sections of the broken line is set within (0.1-0.3) of the total amount of compression ΔН on the side of each wide facet of the ingot relative to the previous joint section.

 The rollers 3 and 4 along the length of the secondary cooling zone are grouped and installed in separate rectilinear links 2, the length of which corresponds to the rectilinear sections l of the broken line of compression reduction of the ingot 13. The axis 5 of each roller 4, located at the junction of the links 2, is mounted in the sliders 6, with the ability movement in frames made in the form of guides 7. The bearings of the rotation of the rollers 4 are mounted in frames 8 connected to hydraulic cylinders 9 and having the possibility of reciprocating movement.

 The links 2 are mounted using oval holes 10 through the sliders 11 on the axes 5 of the rollers 4. In this case, the ends of the sliders 11 form gaps 12 with the links 2, which allows relative relative movement of the links 2 and the change in their total total length during compression of the ingot. The diameter of the rollers is 100 mm.

In the process of continuous casting with a change in ΔН _i , the rollers 4 are moved using hydraulic cylinders 9, controlled by a special system using a computer system (not shown). In this case, the rollers 4 and the rollers 3 together with the links 2 occupy the necessary position relative to the ingot, which ensures its compression without the formation of internal cracks.

In examples 1-5, the rollers 4 in one link 2 have the maximum values ΔH _{i max} respectively under the numbers: i 13 and i 10 at the end of the first links, i 15 at the end of the 3rd link, i 21 at the end of the 7th link, i in end of the 9th link (numbering of rollers and links is made from the bottom end of the mold).

On the other rollers 4, the values of ΔH _{i are} less than the corresponding value of ΔH _{i max}

In Example 1, 3-4 cracks are formed in the ingots due to the large ΔН _{13max value} . In example 5, internal cracks of 3-3.5 points are formed due to inaccurate installation of a large number of controlled pairs of rollers and hydraulic cylinders (26). At the same time, the control system of hydraulic cylinders is complicated.

 In the prototype example, the number of pairs of hydraulic cylinders is equal to the number of pairs of rollers (45), which leads to a violation of the accuracy of their installation.

 Under these conditions, internal cracks of 3-4 points are formed in the ingots. At the same time, the control system of hydraulic cylinders is complicated.

 The inaccuracy of the installation of the rollers in the case of a large number of them is 0.0001-0.0002 mm.

In examples 2-4, the _{ΔНimax values} are within acceptable limits, which leads to a decrease in the score of internal cracks to 0.5-1.0. In addition, a small number of hydraulic cylinders simplifies the automatic control system.

 In the General case, the length l of the links 2 may be different.

 The application of the proposed method and device can reduce the rejection of flat ingots by internal cracks by 3.5%. The system of automatic control of hydraulic cylinders for moving rollers is simplified.

Claims (2)

 1. A method of continuous casting of flat ingots, including feeding liquid metal into the mold, drawing an ingot from it at a variable speed, compressing the ingot in a solid-liquid state from the side of wide faces in the secondary cooling zone using rollers with changing the amount of ingot compression along its length from the minimum value under the mold to a maximum value at the end of the compression zone, characterized in that, in order to improve the quality of the ingots and simplify the control system for the movement of the rollers, changing the value of compression along the length of the ingot is performed along a broken line consisting of separate straight sections whose length is (0.05 0.20) the total length of the compression zone of the ingot, while the compression value of the ingot at the junction of sections of the broken line is (0.1 0, 3) the total amount of compression from the side of each wide facet of the ingot relative to the previous joint sites.  2. A device for the continuous casting of flat ingots containing a mold, rollers located in the secondary cooling zone, mounted in the frame and equipped with hydraulic cylinders, characterized in that, in order to improve the quality of the ingots and simplify the control system for moving the rollers, the rollers along the length of the secondary cooling zone are grouped and installed in separate rectilinear links, while the axis of each roller located at the junction of the links is mounted in sliders that can be moved in frames, They are made in the form of guides, and the holes in the links under the axis of the rollers common to two adjacent links are made in the form of ovals, the major axis of which is located along the links, and the supports of the rollers common to two adjacent links are mounted in movable frames connected to the hydraulic cylinders.

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