CN201470880U - An argon protective device for mold casting - Google Patents

Abstract

An argon protection device for mold casting, which is arranged between the ladle nozzle and the casting center injection pipe; includes a fixed bracket; a protective sleeve, which is in the shape of a cone with a large bottom and a small top, and is connected with the fixed bracket. The upper port is sleeved on the outside of the ladle nozzle, and the upper and lower ports are respectively connected with an annular ventilation pipe, and the two ventilation pipes are connected through a connecting pipe. The wall of the ventilation pipe is opened with a number of air outlet holes downward; Below the fixed bracket, argon gas is injected into one end, and the other end communicates with the vent tube at the lower port of the protective sleeve. The utility model guides the argon flow formed by the air outlet hole of the ventilation pipe to both sides along the inner wall of the protective sleeve, completely covers the space between the ladle nozzle and the casting middle injection pipe, isolates the exposed steel flow from contacting the air, and greatly enhances the argon protection The effect is high, the purity of molten steel is high, and the gas content is low; and it has the characteristics of simple structure, repeated use, and low cost of use.

Description

An argon protective device for mold casting

Field

The utility model belongs to the mold casting technology in the field of metallurgy, in particular to an argon protection device for mold casting.

Background technique

In iron and steel metallurgy, the method of casting and solidifying molten steel can be generally divided into: continuous casting and die casting. Although the production method of die casting has the disadvantage of low yield compared with continuous casting, it has the characteristics of low equipment investment cost, simple method and strong adaptability. There are some special steel types that cannot be produced by continuous casting (casting difficulty High, the quality does not meet the requirements, etc.), die casting provides a guarantee of production. However, compared with continuous casting, which can take the advantage of fully enclosed protective casting, it is particularly important to provide argon protection and prevent secondary oxidation during die casting production.

In die casting production, there is a distance between the nozzle of the ladle and the upper edge of the pouring pipe (using the lower injection method) or the upper edge of the ingot mold (using the upper injection method), where the steel flow is exposed to the air. How to protect this section of steel flow , to avoid its secondary oxidation is the key to ensure product quality. Nowadays, argon blowing protection is often used to form an argon protective gas film between the steel flow and the air to avoid contact oxidation between the air and the molten steel. Most of the current argon protection devices are to install an argon sealing ring made of refractory material on the center injection pipe to form gas mist during casting. This kind of method has a narrow protection range and a small argon flow rate, so it is still unavoidable. For secondary oxidation, when the argon gas flow rate is large, it is easy to generate gas (argon gas) involved in the steel flow, and subcutaneous bubbles may be formed during the ingot solidification process, and after the argon gas flow rate is large, due to the forced flow of argon gas flow too fast , the heat absorption of the exposed steel flow is serious, and the temperature of the molten steel drops too fast, forming nodules. Therefore, how to effectively control the argon flow, fully and effectively avoid secondary oxidation, and at the same time not affect the casting, is a problem to be considered in the design of the argon protection device.

Chinese Patent No. CN02266115.8 discloses a mold-casting fully enclosed argon-protected pouring device. A connecting sleeve is used between the ladle and the middle injection pipe, and argon is blown on the upper part of the inner cavity of the sleeve and the ring-shaped bracket supporting the sleeve. , better improve the conditions of argon protection in casting. However, due to the argon blowing position of the metal ring bracket, this method is far away from the exposed steel flow after exiting the sleeve, and because of its flat structure, the direction of the airflow is not stable (as mentioned earlier, the argon flow cannot too large), so there are certain defects.

Contents of the invention

The purpose of this utility model is to design an argon protection device for mold casting, so that when the high-temperature molten steel is cast from the nozzle at the bottom of the ladle into the sprue of the middle injection pipe, it is under good fully enclosed argon protection casting conditions, thereby It avoids secondary oxidation when the casting stream is exposed, and improves the purity of molten steel and the quality of ingots.

The technical scheme of the present utility model is,

An argon gas protection device for mold casting, which is arranged between the ladle nozzle and the pouring pipe; it includes: a fixed bracket; The upper port is sleeved on the outside of the ladle nozzle, and the upper and lower ports are respectively connected with an annular ventilation pipe, and the two ventilation pipes are connected through a connecting pipe. The wall of the ventilation pipe is opened with a number of air outlet holes downward; Below the fixed bracket, argon gas is injected into one end, and the other end communicates with the vent tube at the lower port of the protective sleeve.

Further, the taper of the protective sleeve is tangent to the outer edge of the casting center injection pipe.

Also, the number of air outlets of the vent pipe at the lower port of the protective sleeve is greater than that of the vent pipe at the upper port: in order to fully ensure the airtight protection of the exposed molten steel, the argon flow rate of the vent pipe at the lower port of the protective sleeve is greater than that of the vent pipe at the upper end. Flow rate to ensure the complete protection of the lower mouth to the exposed molten steel. By controlling the number of outlet holes in the upper argon tube and the lower argon tube wall, the ratio of the number of outlet holes between the upper argon tube and the lower argon tube is 1: (4~5), that is, the argon gas flow rate of the upper argon tube and the lower argon tube It is about 1: (4~5), and the argon flow rate is 20~40Nm ³ /hour, so as to ensure sufficient argon protection and the effect of sealing the steel flow.

The main advantage of the utility model is:

The utility model is used for the argon gas protection device for mold casting by controlling the argon flow to guide the flow along the inner wall of the protective sleeve to both sides, so that the argon flow strand impacts on the upper edge of the bell mouth of the casting injection pipe, completely covering the ladle nozzle and the casting injection The unconnected space between the tubes isolates the exposed steel stream from contact with the air, avoids secondary oxidation when the casting stream is exposed, and greatly enhances the effect of argon protection. It has the characteristics of simple operation, reasonable design, good protection effect, high purity of molten steel, and low gas content, and the device has a simple structure, can be used repeatedly, and has low cost of use.

Description of drawings

Fig. 1 is the structural representation of the utility model argon protection device;

Fig. 2 is a schematic diagram of the layout of vent pipe vents in the argon protection device of the present invention;

Fig. 3 is a schematic diagram of the installation position of the argon protection device of the present invention.

Detailed ways

Referring to Fig. 1 to Fig. 3, the argon protection device for mold casting of the present utility model is arranged between the ladle nozzle 1 and the pouring pipe 2 during casting, including: a fixed bracket 3; a protective sleeve 4, which is as large as The upper small cone, the outer wall is connected with the fixed bracket 3, the upper port is sleeved on the outside of the ladle nozzle 1, and the upper and lower ports are respectively connected with annular ventilation pipes 401 and 402, and the ventilation pipe 401 and the ventilation pipe 402 pass through a The connecting pipe 403 is connected, and the pipe walls of the air pipes 401, 402 are respectively provided with a number of outlet holes 4011, 4021 downwards; the air inlet pipe 5 is connected to the bottom of the fixed bracket 3, and one end is connected to the argon gas, and the other end is connected to the The ventilation pipe 402 of the lower port of the protection sleeve 4 communicates.

When performing mold casting and casting operations, the ladle is in place on the ladle car, and the protective sleeve 4 is set on the outside of the ladle nozzle 1, and the ladle car moves to the top of the gate of the pouring pipe 2 in the casting, and the distance between the upper edge of the gate and the protective sleeve 4 The lower port is about 80mm, centered; open the argon gas valve and let the argon gas flow through the intake pipe 5, the argon gas enters the vent pipe 402 from the intake pipe 5, and then enters the vent pipe 401 through the connecting pipe 403, forming an argon loop, and the argon gas Shot from the air outlet holes 4021, 4011 arranged on the pipe wall of the air pipe 402 and the air pipe 401, on the one hand, a downward argon air curtain is formed under the air pipe 402, and the argon flow rushes to the outer edge of the casting center injection pipe 2 , forming protection; on the other hand, a uniform argon flow is formed downward in the ventilation pipe 401 and an outward trumpet-shaped airflow is formed along the inner wall of the protective sleeve 4. After the argon flow is heated and expanded, it rushes to the upper edge of the casting center injection pipe 2, and to A protective airflow (see Figure 3) is formed outside to isolate the air and prevent the exposed steel flow 6 from inhaling and forming secondary oxidation inclusions. In this embodiment, the flow rate of argon gas is controlled to 23Nm ³ /hour to ensure that while preventing secondary oxidation, it is also possible to prevent argon gas from being involved in the molten steel and causing tumbling.

Referring to FIG. 2 , air outlet holes 4011 and 4021 are uniformly arranged on the pipe walls of the ventilation pipes 401 and 402 respectively. In this embodiment, the ratio of the number of air outlet holes 4011 to air outlet holes 4021 is 1:4.

Claims (4)

1. an argon protective device that is used for the die casting casting is arranged between ladle nozzle and the casting feed trumpet; It is characterized in that, comprising: fixed support; Protection sleeve is the big little taper of, is connected with fixed support, its upper port is sheathed on the ladle nozzle outside, its upper and lower port respectively is connected with a loop draught pipe, and this two breather pipe is connected by a connecting pipe, and described breather pipe tube wall offers some ventholes downwards; Air inlet pipe, an end feeds argon gas, and the other end is communicated with the breather pipe of described protection sleeve lower port.

2. the argon protective device that is used for the die casting casting as claimed in claim 1 is characterized in that, the tapering of described protection sleeve is tangent with casting feed trumpet outer.

3. the argon protective device that is used for the die casting casting as claimed in claim 1 or 2 is characterized in that the venthole quantity that described protection sleeve lower port breather pipe is offered is greater than upper port breather pipe quantity.

4. the argon protective device that is used for the die casting casting as claimed in claim 3 is characterized in that the breather pipe of described protection sleeve upper port is 1: 4～1: 5 with the breather pipe venthole quantity ratio of lower port.

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