Gas protection device matched with molten steel pouring

Abstract

The invention relates to a gas protection device matched with molten steel pouring. An annular air pipe is additionally arranged on the periphery of a molten steel flowing nozzle in a traditional molten steel pouring system and communicated with an inert gas pipeline, a plurality of downward air holes are formed in the pipe wall of the air pipe, inert gas is sprayed out of the air holes, an inert gas cylindrical air film is formed, and air on the periphery of the molten steel flowing nozzle is isolated from molten steel. A two-position three-way valve is arranged on the inert gas pipeline, and a passage of the two-position three-way valve is switched through linkage of the handle and the lower sliding plate. When molten steel is injected, an inert gas pipeline is communicated with the annular gas pipe to form a cylindrical gas protection film; and when pouring is suspended, the inert gas pipeline is communicated with the grate steel meshes to form an air cushion to prevent the molten steel from being cooled and solidified in the molten steel channel. Molten steel can smoothly flow out of the steel ladle, and the molten steel is prevented from being polluted by air in the flowing process.

Description

Technical Field

[0001] The invention relates to a gas protection device, in particular to a gas protection device for preventing secondary contamination of molten steel during the molten steel pouring process, and belongs to the technical field of metal casting. Background Art

[0002] During the pouring process of molten steel, the molten steel flows out of the ladle, enters the pouring cup after a certain distance downward, and then is injected into the mold from the steel flow channel through the steel flow brick outlet. Since the molten steel is in direct contact with the air, the molten steel may bring air into the mold. The secondary pollution caused by air to the molten steel will have many adverse effects on the castings, resulting in an increase in impurities in the steel. In particular, after air enters the molten steel, the hydrogen content in the steel increases significantly, which will destroy the continuity of the steel and reduce the mechanical properties of the steel, such as strength, toughness and plasticity. When subjected to force, stress concentration is easily generated around the impurities, forming cracks and reducing the service life of the steel. Therefore, it is necessary to optimize the process and improve the equipment to reduce the impact of secondary pollution on steel quality. Summary of the invention

[0003] The invention provides a gas protection device for molten steel pouring, in which an annular inert airflow curtain and a linkage reversing valve are added to the molten steel pouring system to ensure that the molten steel flows out of the ladle smoothly and prevent the molten steel from being polluted by air during the flow process.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a gas protection device for molten steel pouring, comprising: a ladle and a steel pouring system, wherein the ladle contains molten steel; the steel pouring system comprises: an upper slide, a lower slide, an inert gas pipeline, a pouring cup, a steel flow channel and a mold, wherein the upper slide is fixed to the bottom surface of the ladle and forms a moving pair with the lower slide; steel flow holes are respectively provided on the bottom of the ladle and the upper slide, and the lower slide is provided with a grate steel mesh and a steel flow port, and the grate steel mesh is connected to the connecting port of the inert gas pipeline. When the lower slide moves to the right to the set limit position, the steel flow holes on the bottom of the ladle and the upper slide seat communicate with the grate steel mesh holes on the lower slide plate to form an air injection channel, and the inert gas is sprayed into the steel flow holes on the upper slide seat. When it moves to the left to the set limit position, the steel flow holes on the bottom of the ladle and the upper slide seat communicate with the steel flow outlet on the lower slide plate to form a molten steel channel. The steel flow outlet on the lower slide plate is opposite to the pouring cup, and the molten steel is injected into the mold through the steel flow channel. A splash guard is arranged between the lower slide plate and the pouring cup, and the steel flow outlet passes downward through the splash guard, characterized in that:

[0005] An annular air pipe is arranged above the splash shield, the annular air pipe is closely attached to the splash shield, and a plurality of downward air holes are arranged on the pipe wall;

[0006] The splash guard is provided with a ventilation net;

[0007] The inert gas pipeline is provided with a two-position three-way valve, whose valve core is linked with the lower slide plate. The lower slide plate slides left and right under the action of external force, driving the valve core to move and control the connection or disconnection of the molten steel channel, and at the same time switching the inert gas passage;

[0008] When the molten steel channel is connected, the two-position three-way valve simultaneously switches the inert gas pipeline to be connected to the annular air pipe, and the gas ejected from the air hole passes through the ventilation net to form an inert gas cylindrical air film to isolate the air outside the molten steel column from the molten steel;

[0009] When the molten steel channel is disconnected, the two-position three-way valve simultaneously switches the inert gas pipeline to be connected to the grate steel mesh.

[0010] Preferably, the pore diameter is greater than 0.3 mm and less than 1 mm.

[0011] Preferably, the working pressure of the inert gas is set at 0.15-0.25 MPa.

[0012] Furthermore, the inner cross-sectional area of ​​the annular air tube is greater than 1.3 times the total cross-sectional area of ​​the plurality of air holes.

[0013] Furthermore, the annular diameter of the annular air pipe is set to 1.2-1.5 times the diameter of the pouring cup.

[0014] The present invention adds an annular air pipe to the traditional steel casting system. The inert gas in the annular air pipe is ejected from the air hole to form an inert gas cylindrical air film to isolate the air outside the molten steel column from the molten steel. A two-position three-way valve is arranged on the inert gas pipeline, and the valve is switched in conjunction with the lower slide plate. When pouring molten steel, the inert gas pipeline is connected to the annular air pipe to form a cylindrical gas protective film; when suspending pouring, the inert gas pipeline is connected to the grate steel mesh to form an air cushion to prevent the molten steel from cooling and solidifying in the molten steel channel. The molten steel is ensured to flow out of the ladle smoothly, and air pollution is avoided during the flow of the molten steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 This is a schematic diagram of the present invention when the molten steel channel is disconnected.

[0016] Attached Figure 2 This is a schematic diagram of the molten steel channel of the present invention when it is connected.

[0017] Attached Figure 3 For attachment Figure 1 The enlarged view of the structure of part Ⅰ,

[0018] Attached Figure 4 For attachment Figure 2 The enlarged diagram of the structure of part II.

[0019] Attached Figure 5 For attachment Figure 3 A-axis structure enlarged schematic diagram,

[0020] Attached Figure 6 For attachment Figure 5 Schematic diagram of the cross-sectional structure of the BB section.

[0021] In the accompanying drawings, 1 is a ladle, 2 is molten steel, 3 is a steel pouring system, 4 is a pouring cup, 5 is a steel flow channel, 6 is a mold, 301 is an upper slide, 302 is a lower slide, 303 is a handle, 304 is a connecting rod, 305 is a two-position three-way valve, 306 is an annular air pipe, 307 is a cylindrical air film, 308 is an air hole, 309 is a splash guard, 310 is a ventilation net, a and b are inert gas pipelines, c and d are steel flow holes, e is a grate steel mesh hole, f is a molten steel flow outlet, and p is a pressure air inlet. DETAILED DESCRIPTION

[0022] The present invention will be further explained below in conjunction with the accompanying drawings;

[0023] As attached Figure 1 , 2 As shown in Figures 3 and 4, the steel pouring system 3 includes: an upper slide 301, a lower slide 302, inert gas pipelines a and b, a pouring cup 4, a steel flow channel 5 and a mold 6. The upper slide 301 is fixed to the bottom surface of the ladle 1 and forms a moving pair with the lower slide 302; the bottom of the ladle 1 and the upper slide 301 are respectively provided with steel flow holes c and d, the lower slide is provided with a grate steel mesh e and a steel flow outlet f, and a splash guard is provided between the lower slide 302 and the pouring cup 4. Plate 309, the molten steel flow outlet f passes downward through the splash baffle 309, the annular air pipe 306 is closely attached to the splash baffle 309, and a plurality of downward air holes 308 are provided on its wall; a ventilation net 310 is provided on the splash baffle 309, and a two-position three-way valve 305 is provided on the inert gas pipeline, and its valve core is linked with the lower slide plate 302, and the pressure air inlet p of the valve is connected with the grate steel mesh e on one way, and is connected with the annular air pipe 306 on the other way.

[0024] As attached Figure 1 , 3 As shown, the external force connecting rod 304 drives the lower slide plate 302 to slide on the bottom surface of the upper slide seat 301 to the right limit setting position, the steel flow hole c and the grate steel mesh hole e are opposite, and at the same time drives the handle 303 to switch the two-position three-way valve pressure inlet p to connect with the inert gas pipeline a and disconnect from the inert gas pipeline b. The inert gas is sprayed into the ladle 1 through the grate steel mesh hole e, the steel flow hole c and d to spray a certain pressure of inert gas into the ladle 1, so that the molten steel 2 above the steel flow hole c is suspended in the ladle 1, thereby preventing the molten steel 2 from solidifying in the molten steel channel c.

[0025] As attached Figure 2 , 4As shown, the external force connecting rod 304 drives the lower slide plate 302 to slide on the bottom surface of the upper slide seat 301 to the left limit setting position, and the steel flow holes c and d are connected with the steel water flow outlet f. At the same time, the handle 303 is driven to switch the two-position three-way valve air inlet p to communicate with the inert gas pipeline b. The molten steel 2 in the ladle 1 flows out through the steel flow holes c and d and the steel water flow outlet f to form a molten steel column. The molten steel column enters the pouring cup 4 and then enters the mold 6 through the steel flow channel 5. At the same time, the inert gas in the annular air pipe 306 is sprayed out through the air hole 308 and the ventilation net 310 on the splash baffle 309, forming a cylindrical air film 307 on the periphery of the molten steel column to isolate the molten steel column from the air.

[0026] Attached Figure 5 , 6 The structure, shape and positional relationship of the annular air pipe 306, the air hole 308, the splash guard 309, the ventilation net 310 and the water inlet f are illustrated.

Claims

1. A gas protection device for molten steel pouring, include: A ladle and a steel pouring system, wherein the ladle contains molten steel; The steel pouring system comprises: an upper slide, a lower slide, an inert gas pipeline, a pouring cup, a steel flow channel and a mold, wherein the upper slide is fixed to the bottom surface of the ladle and forms a moving pair with the lower slide; steel flow holes are respectively provided on the bottom of the ladle and the upper slide, and a grate steel mesh and a steel water flow outlet are provided on the lower slide, and the grate steel mesh is communicated with the connecting port of the inert gas pipeline; when the lower slide moves to the right to the set limit position, the steel flow holes on the bottom of the ladle and the upper slide are communicated with the grate steel mesh on the lower slide, and the inert gas is sprayed into the steel flow holes on the upper slide, and when it moves to the left to the set limit position, the steel flow holes on the bottom of the ladle and the upper slide are communicated with the steel water flow outlet on the lower slide to form a steel water channel, and the steel water flow outlet on the lower slide is opposite to the pouring cup, and the molten steel is injected into the mold through the steel flow channel, and a splash guard is arranged between the lower slide and the pouring cup, and the steel water flow outlet passes downward through the splash guard, characterized in that: An annular air pipe is arranged above the splash shield, the annular air pipe is closely attached to the splash shield, and a plurality of downward air holes are arranged on the pipe wall; The splash guard is provided with a ventilation net; The inert gas pipeline is provided with a two-position three-way valve, whose valve core is linked with the lower slide plate. The lower slide plate slides left and right under the action of external force, driving the valve core to move and control the connection or disconnection of the molten steel channel, and at the same time switching the inert gas passage; When the molten steel channel is connected, the two-position three-way valve simultaneously switches the inert gas pipeline to be connected to the annular air pipe, and the gas ejected from the air hole passes through the ventilation net to form an inert gas cylindrical air film to isolate the air outside the molten steel column from the molten steel; When the molten steel channel is disconnected, the two-position three-way valve simultaneously switches the inert gas pipeline to be connected to the grate steel mesh.

2. A gas protection device for molten steel pouring according to claim 1, Features: The pores have a diameter greater than 0.3 mm and less than 1 mm.

3. A gas protection device for molten steel pouring according to claim 1, Features: The inner cross-sectional area of ​​the annular air tube is greater than 1.3 times the total cross-sectional area of ​​the plurality of air holes.

4. A gas protection device for molten steel pouring according to claim 1, Features: The working pressure of the inert gas is set between 0.15 and 0.25 MPa.

5. A gas protection device for molten steel pouring according to claim 1, Features: The annular diameter of the annular air pipe is 1.2 to 1.5 times the diameter of the pouring cup.

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