RU2038906C1 - Metal continuous casting mold - Google Patents

Abstract

FIELD: metallurgy. SUBSTANCE: mold for continuous casting of thin slabs has supporting plates with wide and narrow working walls, secured to the plates and forming a working cavity of the mold, having an upper funnel-type portion and a lower rectangular-shaped portion. The wide working walls of the funnel-like portion of the working cavity are curvilinear in a horizontal plane and have in their edges at a side of the narrow working walls flat portions, mutually spaced by a distance, equal to a width of the narrow walls. A width of the flat portions of the wide working walls is variable along a height of the funnel-like portion of the mold; it changes according to a rectilinear law from a minimum value on the upper end of the mold, equal to (0.02-0.05)a up to a maximum value, equal to (0.2-0.5)a in the lower portion of the funnel-like portion of the working cavity of the mold, where a a width of the narrow walls of the mold. EFFECT: enhanced quality of slabs. 1 cl, 4 dwg, 1 tbl

Description

 The invention relates to metallurgy, and more particularly to the continuous casting of thin slabs.

где а расстояние между узкими рабочими стенками, мм.A known mold for continuous casting of metals, including base plates with wide and narrow working walls fixed to them, forms a working cavity of the mold with the upper section of the funnel-shaped and lower section of a rectangular shape. The wide working walls are radially bent in the horizontal plane. Narrow working walls are installed with an inclination to each other and with an increase in the distance between them to the exit from the funnel-shaped section by an amount equal to 0.012-0.016 of the length of the radial section of the wide walls. The length of the radial section is 12.0-18.0 thickness of the rectangular section of the working cavity of the mold. In the direction from the upper end of the mold to the exit from the funnel-shaped section of its working cavity, the radial section of the wide working walls is made with a decrease in the value of arrow h from 0.1-1.4 of the thickness of the rectangular section of the working cavity and an increase in R depending on:
R

where a is the distance between the narrow working walls, mm

 There are no flat sections along the edges of wide walls. A disadvantage of the known mold is the unsatisfactory quality of flat continuously cast ingots. This is due to the fact that during casting, the bend of the corner of the ingot deforms at the place where the flat surface of the narrow working wall and the curved wide wall coincide. Under these conditions, the formation of angular cracks occurs in the corners of the ingot, which leads to the rejection of the ingots and breakthroughs of the metal under the mold.

 The closest in technical essence is a mold for continuous casting of metals, including base plates with wide and narrow working walls fixed to them with the formation of the working cavity of the mold with the upper section of the funnel-shaped and lower section of a rectangular shape. The wide working walls are curved in the working cavity in a horizontal plane along a curve.

 Narrow working walls are made rectilinear. The wide working walls in the areas adjacent to the narrow working walls have flat sections, the distance between which is equal to the distance between the straight sections of the wide working walls in the lower part of the mold or the width of the narrow working walls. The width of the flat sections of the wide working walls is constant along the length of the mold. A disadvantage of the known mold is the unsatisfactory quality of continuously cast ingots. This is because the width of the flat sections of the wide working walls has a constant value. Under these conditions, during continuous casting, the shell of the wide face of the ingot undergoes bending deformation at a distance from the surface of the narrow working wall in excess of the permissible value. Under these conditions, the shell of the ingot in the place of its bend when moving from a flat position to a curvilinear will depart from the surface of the wide working wall with the formation of a gap with it. In this case, the ingot surface will be heated in this place, which will cause the formation of longitudinal internal and external cracks. The foregoing causes the marriage of ingots and breakthroughs of the metal under the mold. Studies have established that the place of bending of the wide face of a flat ingot from a curved position to a rectilinear in the horizontal plane should be located at a certain and variable distance from the corner of the ingot. Under these conditions, the formation of both angular cracks in the ingot and the formation of a gap between the face of the ingot in the place of its bending from a flat to curved state are eliminated.

 The technical effect when using the invention is to improve the quality of continuously cast ingots and increase the productivity and stability of the process of continuous casting of metals.

 The specified technical effect is achieved in that the mold for continuous casting of metals includes base plates with wide and narrow working walls fixed to them with the formation of the working cavity of the mold with the upper section of the funnel-shaped and lower section of a rectangular shape. The wide working walls on the funnel-shaped portion of the working cavity are made curved in the horizontal plane, and also have flat sections along the edges of the narrow working walls, the distance between which is equal to the width of the narrow working walls. The width of the flat sections of the wide working walls is made variable in height of the funnel-shaped part of the mold and varies in a straightforward law, from a minimum value at the upper end of the mold equal to (0.02-0.05) ˙ a to a maximum value equal to (0.2-0 5) ˙а in the lower part of the funnel-shaped portion of the working cavity of the mold, where the width of the narrow working walls.

 Improving the quality of flat continuously cast ingots will occur due to the implementation of flat sections of wide working walls of variable width with its change in the optimal range. Under these conditions, close contact of the shell of the ingot with the surface of the wide working wall will be ensured at the place of transition from a flat position to curved, which eliminates the formation of longitudinal cracks. In addition, when you remove the place of bending of the shell of the ingot from its angle, bending stresses decrease below acceptable values, which eliminates the formation of angular transverse cracks.

 The increase in productivity and stability of the process of continuous casting of metals will occur as a result of eliminating breakthroughs of metal under the mold due to a decrease in the formation of internal and external cracks in the ingots.

 The implementation of flat sections of wide working walls of variable width is explained by an increase in the thickness of the shell of the ingot along narrow and wide faces. The range of changes in the width of the flat sections of the wide working walls in the range (0.02-0.05) - (0.2-0.5) of the width of the narrow working walls is explained by the laws of increasing the thickness of the shell of the ingot along the height of the mold at different speeds of drawing. At lower values, cracks will form in the corners of the ingots, which will cause their marriage. At large values, a gap will form between the shell of the ingot and the surface of the working walls at the point of transition from a flat to a horizontal position, which will cause the formation of internal and external cracks.

 The specified range is set in inverse proportion to the working value of the speed of drawing a flat ingot and in direct proportion to the thickness of the ingot.

 Figure 1 shows a mold for continuous casting of metals, a longitudinal section; figure 2 is the same, a section aa in figure 1; figure 3 is the same, a section bB in figure 1; figure 4 is the same, a section bb in figure 1.

 The mold for continuous casting of metals consists of base plates 1 and 2, wide 3 and narrow 4 working walls, funnel-shaped 5 and rectilinear 6 parts of the mold cavity, flat 7 and curved 8 surfaces, border 9 of the funnel-shaped and rectilinear parts of the mold cavity, flat sections 10 wide working walls. Designated: a width of narrow working walls; b the width of the flat part of the wide walls, l the length of the funnel-shaped part of the mold.

 A mold for continuous casting of metals works as follows.

 PRI me R. In the process of continuous casting, 3sp steel is fed into the mold and a rectangular ingot with a variable speed is pulled from it. Water-cooled, respectively wide 3 and narrow 4 copper working walls, which form the working cavity of the mold with the upper section 5 of a funnel-shaped and the lower section 6 of a rectangular shape, are attached to the base plates 1 and 2 of the mold using studs. The wide working walls 3 on the funnel-shaped section 5 are made along curve 7 in the horizontal plane, for example, along the radius. In general, curve 7 can be made in a sinusoid or other smooth curve. In this example, the value of R varies from 3 m at the upper end of the mold to infinity on line 9.

 The wide working walls 3 have on the edges from the side of the narrow working walls 4 flat sections 10, the distance between which is equal to the width a of the narrow working walls 4.

 The width b of the flat sections 10 of the wide working walls 3 is made variable in height l of the funnel-shaped part 5 of the mold and varies in a straightforward manner from the minimum value b at the upper end of the mold equal to (0.02-0.05) a to the maximum value b equal to (0.2-0.5) a, in the lower part 9 of the funnel-shaped part 5 of the working cavity of the mold. The lower part of the mold 6 is formed by the rectilinear parts 8 of the wide faces 3.

 The table shows examples of the operation of the mold with various technological parameters.

 In the first example, angular cracks and breaks in the metal will form in the corners of the ingot due to the small width b of the flat section 10 of the wide working wall 3.

 In the fifth example, longitudinal surface and internal cracks will form in the ingot shell, as well as metal breaks, due to the large width b of the flat section 10 of the wide working wall 3.

 In the sixth example (prototype), corner and longitudinal cracks will form in the ingot due to the constancy and large width b of the flat section 10 of the wide working wall 3.

 In examples 2-4, during the casting process, there will be no angular and longitudinal cracks in the ingots due to a change in the width b of the flat section 10 of the wide wall 3 in the optimal range.

 In the General case, the plane of the narrow working walls 4 may have a different inclination to the longitudinal axis of the mold.

 The use of the proposed mold allows to reduce the marriage of ingots for cracks by 1.2% and also to reduce breakthroughs of metal by 2.8%

Claims (1)

 CRYSTALIZER FOR CONTINUOUS METAL CASTING, containing base plates with wide and narrow working walls fixed to them with the formation of the working cavity of the mold with the upper section of the funnel-shaped and lower section of the rectangular shape, while the wide working walls are made curved in the middle and with flat sections along the edges, characterized the fact that the flat sections of the wide working walls are made with a change in width in a straightforward law from the minimum value at the upper end of the mold, equal to (0.02 0.05) · a, to the maximum value in the lower part of the funnel-shaped portion of the working cavity of the mold, equal to (0.2 0.5) · a, where a is the width of the narrow working walls.

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