Pouring method of casting

Abstract

According to the casting method, argon is filled into a casting cavity in advance, an argon medium is annularly distributed on the periphery of a liquid column between a casting ladle and a pouring cup, molten metal and the atmosphere are isolated, the risk of secondary oxidation during molten metal casting is eradicated, the content of inclusions in the casting is effectively reduced, and the defects of segregation, cracks and the like of the casting are avoided; and the pouring quality is improved. According to the casting method of the casting, the sliding nozzle is used, and flow opening, flow closure and flow control of the casting ladle are achieved through alignment or staggering of the first flow channel and the second flow channel; the elastic driving part establishes constant and uniform interface pressure on a movable interface between the upper sliding plate and the lower sliding plate, and the flow of molten metal is effectively controlled. The anti-oxidation device is designed to annularly distribute an argon medium, the annular body structure in a special shape has high matching degree with the sliding nozzle and the pouring cup, and the size and the weight of the anti-oxidation device are effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of casting technology, and particularly to a pouring method for castings. Background Art

[0002] Pouring is an important link in the production of castings and directly affects the quality of casting products. Currently, the general metal liquid pouring process in the industry is generally the bottom leakage type of ladle. Due to the requirement of drainage, there must be a distance between 200 mm and 300 mm between the lower water outlet of the ladle and the sprue cup. During the pouring process, when the metal liquid passes through this distance, it will directly contact the atmosphere, causing secondary oxidation of the metal liquid, forming a large amount of oxidation inclusions that enter the mold cavity along with the metal liquid. These oxidation inclusions are difficult to float out during the solidification process of the metal liquid, resulting in an increase in the content of secondary oxidation inclusions in the casting, and at the same time, defects such as segregation and cracks are generated. Especially for materials with more precise requirements for inclusion content and chemical composition, such as high alloy steel castings, the situation of the decline in the quality of castings caused by the secondary oxidation of metal liquid is more serious. Summary of the Invention

[0003] Based on this, it is necessary to provide a pouring method that can prevent secondary oxidation of castings for the above technical problems.

[0004] To solve the above problems, the present invention adopts the following technical solutions:

[0005] An embodiment of the present invention discloses a pouring method for castings. Before pouring, an anti-oxidation device is placed between the ladle and the sprue cup; argon is introduced into the anti-oxidation device; argon is introduced into the mold cavity of the casting mold; during pouring, the sliding gate of the ladle is opened, and the metal liquid in the ladle passes through the anti-oxidation device and flows into the sprue cup, and then is injected into the mold cavity of the casting mold.

[0006] In one of the embodiments, the sliding gate includes a gate seat, an upper gate, an upper slide plate, a lower slide plate, a lower gate, a fixed seat, and a sliding seat; the upper gate is arranged in the gate seat, the fixed seat is fixed at the bottom of the gate seat, and the upper slide plate is installed in the inner cavity of the fixed seat; a first flow channel communicating with each other is arranged in the gate seat, the upper gate, and the upper slide plate; the sliding seat is slidably arranged at the bottom of the fixed seat, and the lower slide plate and the lower gate are installed in the inner cavity of the sliding seat, and a second flow channel communicating with each other is arranged in the lower slide plate and the lower gate; when the sliding seat is in the first position, the first flow channel and the second flow channel are communicated; when the sliding seat is in the second position, the first flow channel and the second flow channel are not communicated.

[0007] In one embodiment, the sliding water gate further includes an elastic driving mechanism, which includes a driving member and an elastic connecting component, wherein one end of the elastic connecting component is connected to an output end of the driving member, and the other end is connected to the sliding seat.

[0008] In one embodiment, the anti-oxidation device includes a hollow ring structure, a plurality of gas outlet holes are evenly distributed on the inner side of the ring structure, and an argon gas inlet is arranged on the outer side of the ring structure.

[0009] In one embodiment, the ring structure includes a large circle segment, a small circle segment and two straight segments connected between the large circle segment and the small circle segment; the large circle segment matches the pouring cup, and the small circle segment matches the sliding gate; the length of the straight segment matches the sliding stroke of the sliding gate.

[0010] In one embodiment, the air outlet hole is axially inclined upward.

[0011] In one embodiment, the axial inclination angle of the air outlet is 45°.

[0012] In one of the embodiments, medium-high pressure argon gas is introduced into the anti-oxidation device, and the pressure of the medium-high pressure argon gas is 0.5MPa to 0.8MPa.

[0013] In one of the embodiments, medium-low pressure argon gas is introduced into the mold cavity of the casting mold, and the pressure of the medium-low pressure argon gas is 0.3MPa to 0.5MPa.

[0014] In one embodiment, the medium-low pressure argon gas is introduced into the mold cavity from the bottom of the mold.

[0015] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0016] The casting method disclosed in the present invention fills argon gas into the casting mold cavity in advance and distributes argon gas medium around the liquid column between the ladle and the pouring cup to isolate the molten metal from the atmosphere, thereby eliminating the risk of secondary oxidation during the pouring of the molten metal, effectively reducing the inclusion content of the casting, avoiding defects such as segregation and cracks in the casting, and improving the casting quality.

[0017] The casting method disclosed by the present invention uses a sliding water gate to realize the opening, blocking and flow control of the ladle by aligning or staggering the first flow channel and the second flow channel; and establishes a constant and uniform interface pressure at the movable interface between the upper and lower slide plates through an elastic driving component to effectively control the flow rate of the molten metal.

[0018] The casting pouring method disclosed by the present invention has an anti-oxidation device designed as a ring structure with a special shape. On the one hand, the anti-oxidation device has a high degree of matching with both the sliding nozzle and the pouring cup. On the other hand, it effectively reduces the volume and weight of the anti-oxidation device. The anti-oxidation device is ingeniously designed, simple in structure, and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is an assembly drawing of each device for pouring disclosed in the embodiment of the present invention;

[0020] Figure 2 It is a schematic structural diagram of the anti-oxidation device;

[0021] 110 - nozzle seat, 120 - upper nozzle, 121 - first runner, 130 - upper slide plate, 140 - lower slide plate, 150 - lower nozzle, 151 - second runner, 160 - fixed seat, 170 - sliding seat, 180 - elastic driving mechanism, 190 - mounting bracket;

[0022] 200 - anti-oxidation device, 210 - air cavity, 220 - access port, 230 - air outlet hole, 241 - large circular section, 242 - small circular section, 243 - straight section;

[0023] 300 - pouring cup. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0025] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right", "top", "bottom", "bottom end", "top end" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0027] An embodiment of the present invention discloses a casting pouring method, in which molten metal is poured into a mold cavity under an argon protection environment; during the pouring process, the high-temperature molten metal does not contact the atmosphere, effectively preventing secondary oxidation during the pouring of the high-temperature molten metal and reducing the inclusion content in the casting.

[0028] In this embodiment, taking the pouring process of a certain high-alloy steel casting as an example to illustrate the casting pouring method of the present invention, the pouring process may specifically include the following steps:

[0029] S1. 10 min to 30 min before pouring, use a hose with a diameter of 10 mm to 15 mm to introduce medium-low pressure argon into the mold cavity from the bottom of the mold, and the introduction time continues until pouring starts. During this period, the oxygen concentration content in the mold cavity can be measured to determine whether the argon is full, and an oxygen concentration detector can be selected as the measuring tool. The pressure of the medium-low pressure argon introduced into the mold cavity can be 0.3 MPa to 0.5 MPa.

[0030] S2. Before pouring, as Figure 1 shown, place the anti-oxidation device 200 on the pouring cup 300, connect medium-high pressure argon to the anti-oxidation device 200, and form an argon environment above the pouring cup 300. The pressure of the medium-high pressure argon introduced into the anti-oxidation device 200 can be 0.5 MPa to 0.8 MPa.

[0031] Specifically, as Figure 1 , 2 shown, the anti-oxidation device 200 is a hollow ring structure, a gas cavity 210 is arranged inside the wall of the ring structure, a plurality of air outlet holes 230 are evenly distributed on the inner wall of the ring structure, several inlets 220 can be arranged on the outer wall of the ring structure, the air outlet holes 230 and the inlets 220 are both communicated with the gas cavity 210, argon is introduced into the gas cavity 210 through a hose from the inlets 220 and flows out through the air outlet holes 230, so that the space inside the ring of the anti-oxidation device 200 is filled with argon, forming an argon isolation film that isolates the atmosphere.

[0032] Among them, the ring structure is welded by steel plates about 4 mm thick, and 3 to 5 rows of air outlet holes 230 with a diameter of about 3 mm are arranged at equal intervals on the inner wall of the ring structure. Since the density of argon is slightly greater than that of air and it does not have the ability to rise in the atmosphere, all the air outlet holes 230 are designed to be axially inclined upward. By blowing argon obliquely upward, it is convenient to displace the air around the pouring spout of the ladle to achieve a better anti-oxidation effect. The axial upward inclination angle of the air outlet holes 230 is preferably 45°. 2 to 4 inlets 220 for argon are symmetrically arranged at the lower part of the outer wall of the ring structure, and the diameter of the inlets 220 can be about 13 mm.

[0033] In addition, a sliding nozzle can be installed at the bottom of the ladle to control the opening, intercepting, and flow rate of the molten steel during pouring. Correspondingly, the shape and size of the anti-oxidation device 200 should match those of the sliding nozzle and the pouring cup 300. As Figure 2 shown, the anti-oxidation device 200 can be a ring structure with an unconventional circular shape. The ring structure includes a large circular section 241, a small circular section 242, and straight sections 243. The large circular section 241 and the small circular section 242 are arranged opposite to each other, and the two straight sections 243 are smoothly connected between the large circular section 241 and the small circular section 242. The large circular section 241 matches the top surface of the pouring cup 300, the small circular section 242 matches the sliding nozzle, and the length of the straight section 243 matches the sliding stroke of the sliding nozzle. This design with an unconventional circular shape can, on the one hand, prevent the anti-oxidation device 200 from interfering with the sliding nozzle structure. On the other hand, the overall cooperation between the entire anti-oxidation device 200, the sliding nozzle, and the pouring cup 300 is more compact, reducing the overall size of the anti-oxidation device 200 and improving its anti-oxidation effect.

[0034] S3. After the ladle sliding nozzle stops draining, place the ladle above the anti-oxidation device 200. Adjust the submerged nozzle 150 to be on the side of the small circular section 242, and ensure that the orientation of the anti-oxidation device 200 is parallel to the sliding direction of the sliding nozzle. Start the sliding nozzle, and the submerged nozzle 150 slides to a position near the center of the large circular section 241 and the pouring cup 300 to start pouring. During pouring, continuously introduce argon into the anti-oxidation device 200.

[0035] In this step, the ladle can be slowly lowered until the submerged nozzle 150 is inside the anti-oxidation device 200. Combining with the argon environment in the mold cavity, the molten steel flowing out of the submerged nozzle 150 is completely in an argon protection environment.

[0036] In the embodiments disclosed in the present invention, as Figure 1As shown, the sliding nozzle may include a nozzle component made of refractory material, and a mounting frame 190, a fixed seat 160 and a sliding seat 170 for mounting the nozzle component, wherein the nozzle component includes a nozzle seat 110, an upper nozzle 120, an upper slide plate 130, a lower slide plate 140 and a lower nozzle 150. The nozzle seat 110 is arranged inside the ladle, and a mounting frame 190 is fixed to the lower end of the nozzle seat 110. An inner cavity connected up and down is arranged in the nozzle seat 110, and the upper nozzle 120 is tightly mounted in the lower half of the inner cavity. The fixed seat 160 is fixed to the bottom of the nozzle seat 110 through the mounting frame 190, and the part of the upper nozzle 120 exposed from the nozzle seat 110 is arranged in the upper half of the inner cavity of the fixed seat 160, and the upper slide plate 130 is tightly mounted in the lower half of the inner cavity of the fixed seat 160. The upper water inlet 120 and the upper slide plate 130 are both provided with a through hole coaxial with the inner cavity of the water inlet seat 110, and the inner cavity of the water inlet seat 110, the through hole of the upper water inlet 120 and the through hole of the upper slide plate 130 together constitute the first flow channel 121. The sliding seat 170 is slidably arranged at the bottom of the fixed seat 160 through the mounting frame 190, and the lower slide plate 140 is tightly mounted on the upper half of the inner cavity of the sliding seat 170, and the lower water inlet 150 is tightly mounted on the lower half of the inner cavity of the sliding seat 170. The lower slide plate 140 and the lower water inlet 150 are coaxially provided with mutually communicating through holes, and the through holes of the lower slide plate 140 and the lower water inlet 150 together constitute the second flow channel 151.

[0037] The sliding nozzle also includes an elastic drive mechanism 180 for driving the sliding seat 170 to slide back and forth. When the elastic drive mechanism 180 drives the sliding seat 170 to slide to the first position, the first flow channel 121 and the second flow channel 151 are coaxial, and the molten steel in the ladle is in a completely open flow state; when the elastic drive mechanism 180 drives the sliding seat 170 to slide to the second position, the first flow channel 121 and the second flow channel 151 are completely staggered, and the molten steel in the ladle is in a completely cut-off state; the elastic drive mechanism 180 drives the sliding seat 170 to slide between the first position and the second position, controls the degree of connectivity between the first flow channel 121 and the second flow channel 151, and further controls the flow rate of the molten steel out of the ladle.

[0038] Furthermore, the elastic drive mechanism 180 may include a drive member and an elastic connection component, wherein the drive member is mounted on the mounting frame 190, the output end of the drive member is connected to the elastic connection component, and the end of the elastic connection component away from the drive member is connected to the sliding seat 170. Under the action of the drive member, an active interface is formed between the upper slide 130 and the lower slide 140; through the elastic connection component, the active interface can establish a constant and uniform liquid surface pressure to improve the casting quality. Among them, the drive member can be a hydraulic cylinder, and the elastic connection component can be a spring connection member.

[0039] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A casting method, characterized in that: Before pouring, an anti-oxidation device is placed between the ladle and the pouring cup; argon gas is introduced into the anti-oxidation device; argon gas is introduced into the mold cavity of the casting mold; During pouring, the sliding water nozzle of the ladle is opened, and the molten metal in the ladle passes through the anti-oxidation device and flows into the pouring cup and is injected into the cavity of the casting mold.

2. The casting method according to claim 1, characterized in that: The sliding water gate comprises a water gate seat, an upper water gate, an upper slide plate, a lower slide plate, a lower water gate, a fixed seat and a sliding seat; The upper water inlet is arranged in the water inlet seat, the fixed seat is fixed to the bottom of the water inlet seat, and the inner cavity of the fixed seat is installed with an upper slide plate; the water inlet seat, the upper water inlet and the upper slide plate are all provided with a first flow channel; The sliding seat is slidably arranged at the bottom of the fixed seat, the inner cavity of the sliding seat is provided with the lower slide plate and the lower water outlet, and the lower slide plate and the lower water outlet are both provided with a second flow channel; When the sliding seat is in the first position, the first flow channel is connected to the second flow channel; when the sliding seat is in the second position, the first flow channel is not connected to the second flow channel.

3. The casting method according to claim 2, characterized in that: The sliding water gate also includes an elastic driving mechanism, which includes a driving member and an elastic connecting component. One end of the elastic connecting component is connected to the output end of the driving member, and the other end is connected to the sliding seat.

4. The casting method according to claim 2, characterized in that: The anti-oxidation device comprises a hollow ring structure, a plurality of gas outlet holes are evenly distributed on the inner side of the ring structure, and an argon gas inlet is arranged on the outer side of the ring structure.

5. The casting method according to claim 4, characterized in that: The ring structure includes a large circle segment, a small circle segment and two straight segments connected between the large circle segment and the small circle segment; The large circle segment matches the pouring cup, and the small circle segment matches the sliding gate; the length of the straight segment matches the sliding stroke of the sliding gate.

6. The casting method according to claim 4, characterized in that: The air outlet hole is axially inclined upward.

7. The casting method according to claim 6, characterized in that: The axial inclination angle of the air outlet is 45°.

8. The casting method according to any one of claims 1 to 7, characterized in that: The anti-oxidation device is fed with medium- and high-pressure argon gas, and the pressure of the medium- and high-pressure argon gas is 0.5 MPa to 0.8 MPa.

9. The casting method according to any one of claims 1 to 7, characterized in that: Medium-low pressure argon gas is introduced into the mold cavity of the casting mold, and the pressure of the medium-low pressure argon gas is 0.3MPa-0.5MPa.

10. The casting method according to claim 9, characterized in that: The medium and low pressure argon gas is introduced into the mold cavity from the bottom of the mold.

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