CN110523934A - A Combined Repairable Billet High-speed Casting Mold - Google Patents

Abstract

The invention provides a combined repairable billet high-speed crystallizer, which relates to the technical field of iron and steel metallurgy. It not only has a strong heat exchange capacity, but also facilitates the close bonding between the billet shell and the crystallizer, and can ensure that the crystallizer The heat exchange efficiency and the uniformity of the slab shell meet the quality requirements of the slab; the mold includes four copper plates, which are used to assemble a strip-shaped mold shell, and the inner cavity section of the mold shell is square; The water tank is set on the outer surface of the crystallizer shell to increase the contact area between the crystallizer and the cooling water; the chamfer is set on the inner corner of the joint between two adjacent copper plates to facilitate slag removal and reduce casting slab Corner defects; taper, the inner surface of the mold shell is tapered to compensate for the solidification shrinkage of the slab. The technical scheme provided by the invention is suitable for the process of billet crystallization.

Description

A Combined Repairable Billet High-speed Casting Mold

【Technical field】

The invention relates to the technical field of iron and steel metallurgy, in particular to a combined repairable billet high-speed crystallizer.

【Background technique】

Ordinary tubular billet crystallizer adopts water seam and copper tube contact heat exchange, which can meet the requirements of conventional speed-drawing continuous casting production. However, under the conditions of high-speed continuous casting production, the residence time of the billet in the mold is shortened, so that the thickness of the solidified billet shell is reduced, and the friction between the billet shell and the mold is increased; Type crystallizer, its cooling capacity is insufficient, the solidified billet shell formed is relatively thin, and there is not enough strength to resist the hydrostatic pressure of molten steel, which is easy to cause steel breakout accidents. Therefore, the production of high-speed continuous casting requires that the mold has sufficient cooling strength and uniform heat conduction, so as to ensure that the billet shell at the exit of the mold has a certain safe thickness to resist the hydrostatic pressure without deformation and steel breakout.

Chinese patent CN106825465A discloses a crystallizer for preventing defects. The water tank is provided with a water inlet chamber and a plurality of water outlet chambers. The cooling water tank communicates with the water inlet chamber and the water outlet chamber. The cross-sectional area of the cooling water tank becomes smaller in the meniscus area, and The water outlet chamber can be connected with a valve, and the water flow in the meniscus area can be adjusted by controlling the water flow, thereby reducing the cooling intensity of the meniscus area of the crystallizer, effectively preventing or reducing cracks in the continuous casting slab, and improving the quality of the continuous casting slab. However, the above-mentioned patents did not consider the shape, size and distribution of the cooling water tank, and did not design the copper plate water tank at the corner of the billet. The part is affected by two-dimensional heat transfer and cools faster, and it is easy to form corner defects such as depressions and cracks.

Chinese patent CN207642259U discloses a high-speed, balanced and high-efficiency heat transfer crystallizer copper tube. By slotting the cold surface of the common billet or rectangular billet crystallizer copper tube, the convective heat transfer of the cast slab is enhanced, and the different positions of the mold The groove width, depth and density are adjusted to make the temperature and stress of the slab uniform, which can effectively avoid defects caused by uneven temperature and stress of the slab, and improve the quality of the slab while increasing the casting speed. However, the crystallizer adopts an integrated copper tube design and cannot be disassembled. When the inner wall of the copper tube is damaged to a certain extent, it needs to be replaced with a new crystallizer, which cannot be repaired. It has only one service life and cannot be used repeatedly.

Chinese patent CN206763871U discloses a uniform cooling high-speed crystallizer for steelmaking and continuous casting. The crystallizer is a square or rectangular copper tube. Enhancing the convective heat transfer of the slab in the off-angle area can effectively avoid defects such as dents and cracks in the corners of the slab and the off-angle area, and improve the quality of the slab. However, after the four corners of the lower part of the copper tube of the mold are cut off, the rigidity of the copper tube is reduced, and it cannot play a good supporting role in the cast slab. Deformation and steel leakage; In addition, the crystallizer is designed with an integrated copper tube, which cannot be disassembled. When the inner wall of the copper tube is damaged to a certain extent, a new crystallizer needs to be replaced, and it cannot be repaired. It has only one service life and cannot be repeated many times. use.

Therefore, it is necessary to study a combined repairable billet high-speed crystallizer to deal with the deficiencies of the prior art, so as to solve or alleviate one or more of the above-mentioned problems.

【Content of invention】

In view of this, the present invention provides a combined repairable billet high-speed crystallizer, which not only has a strong heat exchange capacity, but also facilitates the close fit of the billet shell and the crystallizer, and can ensure the replacement of the crystallizer. The thermal efficiency and the uniformity of the slab shell meet the quality requirements of the slab.

On the one hand, the present invention provides a combined repairable billet high-speed crystallizer, characterized in that the crystallizer includes:

Four copper plates are used to assemble a strip-shaped crystallizer shell, and the inner cavity section of the crystallizer shell is square;

The water tank is arranged on the outer surface of the crystallizer shell, and is used to increase the contact area between the crystallizer and the cooling water;

Chamfering, which is set at the inner corner of the connection between two adjacent copper plates, is used to facilitate slag removal and reduce corner defects of the slab;

The inner surface of the crystallizer shell is tapered to compensate for the solidification shrinkage of the slab.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the thickness H of the copper plate is 40-65 mm.

According to the foregoing aspect and any possible implementation manner, an implementation manner is further provided, wherein the water tanks are evenly or unevenly distributed on the copper plate.

According to the above-mentioned aspect and any possible implementation mode, an implementation mode is further provided, the maximum width of the water tank is 2-10 mm, the depth of the water tank is 5-30 mm, and the distance between two adjacent water tanks 5-20mm; the minimum distance between the bottom of the water tank and the inner surface of the copper plate where it is located is 15-35mm.

According to the foregoing aspect and any possible implementation manner, an implementation manner is further provided, wherein the water tank has a cross-sectional shape of rectangle, trapezoid, hexagon, circle or ellipse.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, when the cross-sectional shape of the water tank is a rectangle, the root of the rectangle is provided with a circular arc.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the length of the crystallizer is 800-1000 mm.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the taper of the crystallizer adopts single taper, double taper or triple taper.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the size of the taper is 0.5%-2.5%.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, wherein the chamfering is a circular arc with a radius of 1/4 of 3-35 mm.

Compared with the prior art, the present invention can obtain the following technical effects: the crystallizer of the present invention uses four copper plates to form the inner cavity of the crystallizer for the billet, and the crystallizer and cooling water are increased by opening a water tank on the outer surface of the copper plate. The heat exchange area is larger, and the heat exchange capacity of the mold is enhanced, so that the molten steel can form a certain thickness of safe solidified billet shell in the mold under the condition of high pulling speed, so as to resist the static pressure of the molten steel and avoid deformation and steel breakout; at the same time , The copper plate has a taper, which makes the crystallizer and the slab shell in good contact, which is conducive to improving the heat exchange efficiency of the mold; the narrow copper plate has chamfers, which can reduce the corner defects of the slab.

Of course, implementing any product of the present invention does not necessarily need to achieve all the technical effects described above at the same time.

【Description of drawings】

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort.

Figure 1 is a perspective view of a combined repairable billet high-speed crystallizer provided by an embodiment of the present invention;

Fig. 2 is a sectional view of a combined repairable billet high-speed crystallizer provided by an embodiment of the present invention;

Fig. 3 is a top view of a combined repairable billet high-speed crystallizer provided by an embodiment of the present invention;

Fig. 4 is a partial view of a copper plate water tank provided by an embodiment of the present invention;

Fig. 5 shows six shapes of cross-sections of water tanks of a high-speed crystallizer provided by an embodiment of the present invention.

Among them, in the figure:

1-wide copper plate; 2-narrow copper plate; 3-sink; 4-chamfer; 51-first taper; 52-second taper; 53-third taper.

【Detailed ways】

In order to better understand the technical solutions of the present invention, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

It should be clear that the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. As used in the embodiments of the present invention and the appended claims, the singular forms "a", "said" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

The present invention provides a crystallizer that can be used for billet high-speed continuous casting production. As shown in Figure 1, four combined copper plates are used to form a square inner cavity of the crystallizer. The inner surface of the copper plate is in contact with molten steel, and the outer surface The surface is in contact with cooling water. The outer surface of the copper plate is provided with several water tanks 3, and the water tanks 3 are in contact with the cooling water, which can greatly increase the contact area between the copper plate and the cooling water, thereby enhancing the heat exchange capacity of the crystallizer, so that the molten steel can be cooled at a small speed even at a high casting speed. A safe billet shell with a certain thickness is formed in the billet crystallizer to resist the hydrostatic pressure without deformation and steel breakout. In addition, the inner cavity of the crystallizer is designed with taper and chamfer 4, which can make the billet shell and the mold fit closely, which is beneficial to ensure the heat exchange efficiency of the mold and the uniformity of the billet shell, and meet the quality requirements of the billet.

The shape and distribution of the crystallizer copper plate water tank 3 have different designs according to the steel type, section and casting speed of the cast slab. Generally, there are no water tanks 3 on the outer surface of the copper plate of the crystallizer, and the water tanks 3 are evenly distributed or periodically distributed on the copper plate, as shown in Fig. 3 and Fig. 4 . The cross-sectional shape of the tank 3 is an open rectangle, and an arc can be set at its root. The bottom of the water tank of the crystallizer copper plate (that is, the bottom of the root arc of the cross-sectional shape, or the bottom of the rectangular root if no arc is set) has a certain thickness from the inner surface of the crystallizer, so that the copper plate can be ground many times Repeated use, increase the amount of steel passing and save costs. The minimum distance δ between the bottom of the water tank 3 and the inner surface of the copper plate where it is located is 15-35 mm. The width W of the water tank is 2-10 mm, the depth h of the water tank is 5-30 mm, and the distance S between adjacent water tanks is 5-20 mm. The shape and depth of the sinks on the same copper plate can be different. A water tank is not provided near the chamfer 4 of the crystallizer or a water tank is provided that is smaller than the average water tank depth of the copper plate where it is located, as shown in Figure 3.

The cross-sectional shape of the tank can also be other shapes, such as trapezoidal, hexagonal, circular or elliptical, as shown in FIG. 5 .

The crystallizer is composed of two wide copper plates 1 and two narrow copper plates 2, the thickness H of the copper plates 1 and 2 are both 40-65mm. The width of the wide copper plate is greater than that of the narrow copper plate, and the two wide copper plates are arranged in parallel, and the two narrow copper plates are arranged between the two wide copper plates, and are arranged vertically to the wide copper plates. The wide copper plate and the narrow copper plate have the same length, and the length L is 800-1000mm.

An arc-shaped chamfer 4 is provided at the inner corner connecting the wide-faced copper plate 1 and the narrow-faced copper plate 2 of the crystallizer, which facilitates slag removal and reduces corner defects of the slab. The arrangement of the chamfer 4 is specifically to provide a chamfer along the entire length direction of the crystallizer. The radius of the chamfer is 1/4 and the arc is 3-35mm. The inner cavity of the crystallizer has a taper, which can compensate the solidification shrinkage of the billet shell in time, and play a good role in heat transfer and support for the billet shell; when the optimal taper is set, the four copper plates have the same taper at the same time. The definition of taper in this application is: the inner surface of the copper plate has an inclination relative to the vertical direction, so that the inner space of the entire crystallizer has one or several truncated cone shapes.

The taper on the entire length of the same copper plate can be single taper, double taper or triple taper. The first taper 51 uses the second taper 52, and the three tapers use the first taper 51, the second taper 52 and the third taper 53 in sequence throughout the entire length. The sizes of the first taper 51 , the second taper 52 and the third taper 53 are all 0.5%-2.5%.

The molten steel is cooled in the mold to form a billet shell, and then shrinks away from the inner wall of the mold, forming an air gap between the billet shell and the inner wall of the mold. In order to reduce the air gap, improve the thermal conductivity of the crystallizer, and accelerate the growth of the billet shell, when designing the crystallizer, the lower section of the mold is usually made slightly smaller than the upper section, which is called the mold taper. The solidification shrinkage of the slab at different heights of the mold is different, and the air gap generated in the upper part of the mold is larger than that in the lower part. Therefore, double taper or even triple taper is adopted in the design of the mold, that is, the taper of the upper part of the mold is increased to compensate for the shrinkage of molten steel during solidification. It is more conducive to reducing the air gap and increasing the heat transfer capacity.

The formula for calculating crystallizer taper is as follows

In the formula

▽——Mold taper, unit is %/m;

l ₁ - Dimensions of the upper opening of the crystallizer, in m;

l ₂ - Dimensions of the lower opening of the crystallizer, in m;

H _m - the length of the crystallizer (that is, the length of the taper set on the crystallizer), the unit is m.

The billet crystallizer of the invention can meet the demand of billet high-speed continuous casting production, increase the output of steel billets, increase the amount of steel passing through the crystallizer, and save costs.

The combined repairable billet high-speed crystallizer provided by the embodiment of the present application has been introduced in detail above. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation and application scope. To sum up, the contents of this specification should not be understood as limiting the application.

Certain terms are used, for example, in the description and claims to refer to particular components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in name as a way to distinguish components, but use the difference in function of components as a criterion for distinguishing. As mentioned throughout the specification and claims, "comprising" and "comprising" are open-ended terms, so they should be interpreted as "comprising/including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred implementation mode for implementing the application, but the description is for the purpose of illustrating the general principles of the application, and is not intended to limit the scope of the application. The scope of protection of this application should be defined by the appended claims.

It should also be noted that the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a good or system comprising a set of elements includes not only those elements but also includes items not expressly listed. other elements of the product, or elements inherent in the commodity or system. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the article or system comprising said element.

It should be understood that the term "and/or" used herein is only an association relationship describing associated objects, which means that there may be three relationships, for example, A and/or B, which may mean that A exists alone, and A and B exist simultaneously. B, there are three situations of B alone. In addition, the character "/" in this article generally indicates that the contextual objects are an "or" relationship.

The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various Various other combinations, modifications and environments, and can be modified by the above teachings or the technology or knowledge in the related field within the scope of the application concept described herein. However, changes and changes made by those skilled in the art do not depart from the spirit and scope of the present application, and should all be within the protection scope of the appended claims of the present application.

Claims (10)

1. a kind of combined type can repair the high pulling rate crystallizer of small billet, which is characterized in that the crystallizer includes:

Four pieces of copper sheets, for being combined into the crystallizer shell of strip, the intracavity section of the crystallizer shell is rectangular；

Sink, set on the outer surface of the crystallizer shell, for increasing the contact area of crystallizer and cooling water；

Chamfering, the interior angle set on adjacent two pieces of copper sheet junctions, for facilitating slag and reducing slab corner defect；

Four inner surfaces of the crystallizer shell are with tapered, for compensating the solidification shrinkage of slab.

2. combined type according to claim 1 can repair the high pulling rate crystallizer of small billet, which is characterized in that the copper sheet Thick H is 40~65mm.

3. combined type according to claim 1 can repair the high pulling rate crystallizer of small billet, which is characterized in that the sink exists It is uniformly distributed on copper sheet or uneven distribution.

4. combined type according to claim 3 can repair the high pulling rate crystallizer of small billet, which is characterized in that the sink Maximum width is 2~10mm, and the depth of the sink is 5~30mm, and the spacing between two neighboring sink is 5~20mm；Institute The minimum range for stating the bottom of sink and the inner surface of copper sheet where it is 15~35mm.

5. combined type according to claim 3 or 4 can repair the high pulling rate crystallizer of small billet, which is characterized in that the water The cross-sectional shape of slot is rectangle, trapezoidal, hexagon, round or ellipse.

6. combined type according to claim 5 can repair the high pulling rate crystallizer of small billet, which is characterized in that the sink When cross-sectional shape is rectangle, the root of the rectangle is equipped with circular arc.

7. combined type according to claim 1 can repair the high pulling rate crystallizer of small billet, which is characterized in that the crystallizer Length be 800~1000mm.

8. combined type according to claim 1 can repair the high pulling rate crystallizer of small billet, which is characterized in that the crystallizer Taper using single taper, double tapered or three tapers.

9. combined type according to claim 8 can repair the high pulling rate crystallizer of small billet, which is characterized in that the taper Size is 0.5%~2.5%.

10. combined type according to claim 1 can repair the high pulling rate crystallizer of small billet, which is characterized in that the chamfering The circular arc for being 3~35mm for 1/4 radius.