CN101168186A - Continuously Lubricated Mold for Semi-continuous Casting of Aluminum Alloy - Google Patents

Abstract

The invention relates to a continuous lubrication crystallizer used for casting aluminum alloy semi-continuously, wherein the inner wall of the crystallizer is inlaid with a graphite lining, a top cover of the crystallizer is internally provided with an independent oil cavity, the graphite lining presents up-down symmetric construction with a taper, a body of the crystallizer is provided with a top water cavity and a lower cavity which are independent, the top water cavity and the lower cavity are respectively opened with an independent water inlet and are respectively provided with a splash plate, the bottom of the top water cavity is provided with a row of water passing ports, the bottom of the lower water cavity is also provided with a row of water passing ports, the angel of the water passing ports of the top water cavity is different from and presents interlaced shape with the water passing ports of the lower water cavity's, when casting, a layer of continuous oil film forms via infiltrating oil forming the oil cavity to the graphite lining, which has effects of heatproof, reducing once cooling of ingot casting at the same time when improving graphite lubricating oil effects, two independent water cavities realize the independent or double water-cavity water supply, which improves the aftercooling effect on the premise of ensuring heat cracks not to appear at the early stage of aluminum alloy ingot casting, thereby realizing a low liquid level on the inner portion of the crystallizer, and distinctively improving surface quality of the ingot casting.

Description

Continuously Lubricated Mold for Semi-continuous Casting of Aluminum Alloy

technical field

The invention relates to a crystallizer for semi-continuous casting of aluminum alloys, in particular to a lubricable crystallizer for semi-continuous casting of aluminum alloys, and belongs to the technical field of semi-continuous casting of aluminum alloys.

Background technique

During the semi-continuous casting process of aluminum alloy, the heat transfer of the side wall of the mold has an important influence on the surface quality of the aluminum alloy billet. In the traditional semi-continuous casting process, the crystallizer is usually made of copper alloy. During the casting process, the copper inner wall is in direct contact with the liquid aluminum alloy melt, and the casting resistance is large. Usually, smooth casting is achieved by manually applying lubricating oil. Therefore, the surface quality of the ingot is poor, and a large amount of turning is required to meet the requirements of subsequent thermal deformation. At present, there are many advanced casting processes to improve the surface quality of aluminum alloy ingots, including electromagnetic casting technology, hot top casting technology, air slide (air curtain) casting technology, low liquid level casting technology, etc.

Electromagnetic casting technology can produce aluminum alloy round ingots and flat ingots with bright surfaces, but this technology requires large equipment investment, complex equipment, high operation and maintenance requirements, and cannot achieve multi-mode production, so this technology has only achieved small-scale production in industrial production. application. Since the hot top casting technology came out in the 1970s, due to the stable low mold casting and the same level casting, the surface quality and production efficiency of the ingot have been greatly improved. widely used. However, the hot-top casting technology requires skilled operators. When the process parameters are not well adjusted, the ingot will have unique lap joints and sweat-like surface defects.

Air sliding (air curtain) casting technology is an extension of aluminum alloy hot top casting technology. It adds an oil-air lubrication system on the basis of hot top casting, which reduces the friction of the ingot and the inner wall of the crystallizer while reducing the The primary cooling strength improves the surface quality of aluminum alloy ingots. Air sliding (air curtain) casting technology can significantly improve the surface quality of aluminum alloy ingots, and is generally used for round bar production. However, the structure of the air-sliding (air curtain) crystallizer is relatively complicated, and there is no self-designed crystallizer and related equipment for commercialization.

Low liquid level casting technology is a new type of aluminum alloy casting technology developed by western developed countries in the 1990s. This technology does not use the traditional insulation cap-hot top casting method, but inlays a layer of graphite on the inner wall of the traditional crystallizer. The plate and graphite plate are lubricated with continuous penetration. The casting process uses a liquid level control system to precisely control the height of the metal liquid level in the mold. The surface of the ingot produced by this technology is bright and smooth, and even the surface quality of some ingots can be comparable to that of moldless electromagnetic casting. However, the equipment of low liquid level casting technology is very expensive, and the requirements for the control system are relatively strict, and the structure and design of the crystallizer are kept secret.

Contents of the invention

Aiming at the problems of complex structure and expensive equipment of existing aluminum alloy advanced casting crystallizers, the present invention provides an advanced, realistic and feasible continuous lubricating crystallizer which can greatly improve the surface quality of aluminum alloy ingots, and is suitable for aluminum alloy round ingots and Flat ingot casting.

The purpose of the present invention is achieved through the following technical solutions:

Continuous lubricating crystallizer for aluminum alloy semi-continuous casting, including crystallizer body and upper cover. The inner wall of the mold is inlaid with graphite lining. Symmetrical structure with taper. The crystallizer body is provided with two independent water chambers, the upper water chamber and the lower water chamber. The upper water chamber has an independent water inlet, and the lower water chamber has an independent water inlet. A water baffle is installed in the cavity, and a water baffle is also installed in the lower water cavity. A row of water spray holes is set at the bottom of the upper water cavity, and a row of water spray holes is also set at the bottom of the lower water cavity. The water spray holes of the upper water cavity The angle of the nozzle is inconsistent with the angle of the spray hole of the lower water chamber, and is in a staggered shape.

Further, in the continuous lubricating crystallizer for aluminum alloy semi-continuous casting, the graphite lining has a taper, and the taper angle ranges from 174° to 179°.

Furthermore, in the continuous lubricating crystallizer for aluminum alloy semi-continuous casting, the angle range of the water spray hole in the upper water chamber is 15°-35°, and the angle range of the water spray hole in the lower water chamber is 40°-60°.

The outstanding substantive features and remarkable progress of the technical solution of the present invention are mainly reflected in:

① The upper cover of the crystallizer is equipped with an independent oil chamber, which keeps the liquid level of the aluminum alloy melt below the center line of the graphite lining during the casting process. The surface of the high-strength graphite lining itself is not easily wetted by the molten metal and has self-lubricating properties. In addition, The oil cavity on the upper wall of the crystallizer continuously leaks oil into the inner wall of the graphite, forming a continuous oil film between the graphite and the melt, which increases the lubricating effect and reduces the primary cooling intensity of the ingot; The height of the liquid level inside is low, and the range of variation is 6-15mm. While reducing the primary cooling of the ingot, the surface quality of the ingot has also been greatly improved;

②The graphite lining has a tapered design, which can reduce the contact friction between the aluminum alloy melt and graphite during the casting process; the graphite lining adopts a symmetrical design up and down, and the graphite lining can be turned over to continue to use when worn, extending the graphite lining service life;

③The crystallizer body is designed with independent double water chambers. During casting, one water chamber can be used for water supply or two water chambers can be used for water supply at the same time. When the two water chambers supply water at the same time, most of the splash (reflection splash) formed by the cooling water in the lower water chamber hitting the surface of the ingot can be eliminated by the cooling water in the upper water chamber, and the secondary cooling effect of the ingot is significantly enhanced.

④Compared with the existing aluminum alloy advanced casting crystallizer, the crystallizer of the present invention has a novel structure and low equipment cost, is suitable for casting aluminum alloy round ingots and flat ingots, and has excellent popularization and application value.

Description of drawings

Below in conjunction with accompanying drawing, technical solution of the present invention will be further described:

Fig. 1: the structural representation of continuous lubricating crystallizer of the present invention;

Figure 2: A schematic diagram of the application of the continuous lubrication crystallizer of the present invention.

See the table below for the meanings of the symbols in the figure:

reference sign meaning Reference signs meaning reference sign meaning 1 Sheung Shui Chamber 2 Sewer cavity 3 oil cavity 4 Graphite lining 5 upper cover 61 Upper water chamber water baffle 62 Downpipe water baffle 71   Water inlet of the upper water chamber 72 water inlet

Reference signs meaning Reference signs meaning Reference signs meaning 8   Crystallizer body 9 water outlet hole 10 drain hole 11 lower lid 12 Melt level 13 melt 14   Liquid-solid two-phase region 15 Ingot 16 oil film 17 Cooling water 18 base

Detailed ways

As shown in Figure 1, the continuous lubricating crystallizer for aluminum alloy semi-continuous casting includes a crystallizer body 8, an upper cover 5 and a lower cover 11; the inner wall of the crystallizer is inlaid with a graphite lining 4, and an independent The oil chamber 3 and the graphite lining 4 have a vertical symmetrical structure with a taper, and the taper angle ranges from 174° to 179°; the crystallizer body 8 is equipped with two independent water chambers, namely the upper water chamber 1 and the lower water chamber 2. An independent water inlet 71 is opened on the upper water chamber 1, and an independent water inlet 72 is opened on the lower water chamber 2. A water retaining plate 61 is installed in the upper water chamber 1, and a water retaining plate 62 is installed in the lower water chamber 2. A row of water spray holes 9 is set at the bottom of the upper water chamber 1, and the angle range of the water spray holes 9 is 15° to 35°. A row of water spray holes 10 is set at the bottom of the lower water chamber 2, and the angle range of the water spray holes 10 is 40°～60°, the angles of the water spray holes 9 and the angles of the water spray holes 10 are inconsistent to form a staggered shape.

The upper cover 5 of the crystallizer is designed with an independent oil chamber 3, which continuously and automatically leaks oil to the graphite lining 4 during casting, so as to increase the lubricating effect of the mold. The graphite lining 4 is made of high-strength and high-toughness graphite for casting. The graphite lining 4 adopts a taper design, and the taper angle ranges from 174° to 179°, which can reduce the contact friction between the aluminum alloy melt and graphite during the casting process. The graphite lining 4 adopts a symmetrical design up and down. When the graphite below is worn due to excessive casting time, the graphite can be turned over and continued to be used. The service life of the graphite can be doubled compared with the asymmetric design.

There are upper and lower independent water chambers in the crystallizer body, which are upper water chamber 1 and lower water chamber 2 respectively. The two water chambers are respectively supplied with water by two independent water inlet pipes to realize water supply to the ingot separately or simultaneously. Water baffles are respectively installed in the two water cavities to evenly distribute the cooling water in the two water cavities. Two rows of water spray holes with different angles are staggered at the bottom of the two water chambers. When the two water chambers supply water at the same time, the splash (reflection splash) formed by the cooling water in the lower water chamber hitting the surface of the ingot can be mostly absorbed The cooling water in the water cavity is eliminated, and the secondary cooling effect of the ingot is enhanced.

During semi-continuous casting of aluminum alloy, as shown in Figure 2, the upper oil chamber 3 of the crystallizer is first opened, and oil is continuously and evenly leaked into the mold, so that a thin layer of uniform oil film 16 is formed on the surface of the graphite lining 4; the aluminum alloy melt After 13 enters the crystallizer, it firstly fills the cavity formed by the base 18 and graphite, and solidifies under the primary cooling of the base 18 and the graphite lining 4. Since the metal melt is not in direct contact with the relatively strong heat-conducting graphite, but is separated by a layer of oil film, the primary cooling intensity of the melt is greatly reduced. When the liquid level 12 of the melt in the crystallizer rises close to the centerline of the graphite lining, the base 18 begins to move down at a certain speed, and the partly solidified ingot is separated from the mold and subjected to secondary cooling by cooling water impacting the surface at a certain angle As a result, the ingot 15 and the cooling water 17 undergo intense heat exchange, and the entire ingot is gradually solidified and formed. During the casting process, the liquid level height of the molten metal in the crystallizer ranges from 6 to 15mm.

Different brands of aluminum alloys have different casting processes. At the beginning of casting, for hard aluminum alloys that are relatively easy to crack, such as 2××× and 7×××, you can choose to only open the upper water chamber 1 to reduce the secondary cooling intensity of the ingot, and when the ingot enters the stable stage Open the lower water chamber 2 again to realize the water supply of the two water chambers. For aluminum alloys with better casting performance, such as 1××× and 3×××, two water chambers can be opened at the beginning of casting to realize simultaneous water supply of the two water chambers. Compared with the traditional conventional crystallizer, the two water chambers of this crystallizer supply water at the same time, which can avoid the "reflection splash" formed by the cooling water on the surface of the ingot when the water is supplied by a single water chamber, and enhance the heat exchange effect between the ingot and the cooling water , to increase the secondary cooling intensity. Under the premise that the secondary cooling intensity is enhanced, the shape of the ingot liquid cavity is smoother, which can ensure that no leakage occurs even if the melt level in the mold is low.

To sum up, in the semi-continuous casting process of aluminum alloy, the oil seeps continuously and evenly into the graphite lining through the oil chamber, and forms a continuous oil film on the graphite surface, which not only increases the lubricating effect of graphite, but also plays a role in heat insulation and reduction. The role of the primary cooling of the ingot. At the same time, the two independent water chambers of the crystallizer can be independently adjusted according to the casting properties of different aluminum alloys during the casting process, so as to realize the simultaneous water supply of single or double water chambers, and ensure that no heat occurs in the initial stage of aluminum alloy ingot casting. Under the premise of cracks, the secondary cooling effect is increased to achieve a low liquid level inside the crystallizer, and the liquid level height is 6-15mm, thereby greatly improving the surface quality of aluminum alloy ingots and bringing excellent technical significance and benefits to production. significant economic effect.

The above are only specific application examples of the present invention, and do not constitute any limitation to the protection scope of the present invention. All technical solutions formed by equivalent transformation or equivalent replacement fall within the protection scope of the present invention.

Claims (3)

1. continuous lubricating crystallizer for aluminum alloy semi-continuous casting, comprise crystallizer body (8) and loam cake (5), the inwall of crystallizer is inlaid with graphite liner (4), it is characterized in that: in loam cake (5), be provided with independently oil pocket (3), described graphite liner (4) is up and down symmetrical structure and has tapering, crystallizer body (8) is provided with two independent water cavities up and down, be upper water cavity (1) and following water cavity (2), have independently water inlet (71) on the upper water cavity (1), have independently water inlet (72) on the following water cavity (2), water fender (61) is installed in the upper water cavity (1), water fender (62) is installed in the following water cavity (2), establishes row's hole for water spraying (9) in the bottom of upper water cavity (1), establish row's hole for water spraying (10) in the bottom of following water cavity (2), two row's hole for water sprayings (9,10) angle does not wait, and is staggered.

2. continuous lubricating crystallizer for aluminum alloy semi-continuous casting according to claim 1 is characterized in that: graphite liner (4) has tapering, and its cone angle scope is at 174 °～179 °.

3. continuous lubricating crystallizer for aluminum alloy semi-continuous casting according to claim 1 is characterized in that: the angular range of upper water cavity hole for water spraying (9) is at 15 °～35 °, and following water cavity hole for water spraying angular range is at 40 °～60 °.

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