Pouring system of thin-wall square-tube-shaped blanking groove casting

Abstract

A pouring system of a thin-wall square-tube-shaped blanking groove casting belongs to the field of casting industry and comprises a blanking groove casting cavity and a transverse pouring gate longitudinally arranged on the upper surface of the cavity, a plurality of parallel right-angle branch transverse pouring gates are symmetrically connected to the two sides of the transverse pouring gate respectively and are parallel to the outer surface of the cavity, and the transverse pouring gate is arranged on the outer surface of the cavity. Spaces are reserved between the transverse pouring gates and the cavity and between the branch transverse pouring gates and the cavity, the spaces are communicated through a plurality of inner pouring gates, the straight pouring gates and the risers are arranged at the two ends of the cavity, and during pouring, one end of the cavity of the blanking groove casting provided with the risers is higher than the other end of the cavity of the blanking groove casting provided with the risers. The casting quality of the blanking groove is improved, the using effect of the blanking groove is improved, the service life of the blanking groove is prolonged, and user requirements are met.

Description

Technical Field

[0001] The utility model relates to a sand mold for a lower thin-walled tubular casting and a pouring system thereof, in particular to a pouring system for a thin-walled square tubular trough casting, and belongs to the field of casting industry. Background Art

[0002] In the foundry industry, the fluidity of molten steel in steel castings is worse than that of molten iron in iron castings. In particular, thin-walled steel castings are prone to cold shuts, insufficient pouring, and porosity defects during pouring. For steel castings with larger dimensions, the traditional production process sets the pouring system on the side of the casting. No matter how the pouring system is set, the flow distance of molten steel from one side of the casting to the other is long, and the molten steel cools down more during the flow. When the molten steel flows to the far end of the runner, the temperature will drop, and the temperature difference between the two ends is large, which is bound to cause cold shuts, insufficient pouring, and porosity defects. One such casting is the chute casting, made of high-alloy, heat-resistant, and wear-resistant ZG45Cr20Ni12Mo cast steel. This casting serves as the chute for the steel mill's sintering system. Operating under the conditions of continuous high-temperature heat and friction from 900-1000°C charge flowing through the chute's center hole, the chute has a wall thickness of 15-18 mm, a length of 3500-4500 mm, and weighs 1000-1500 kg. Initially, the chute exhibited numerous surface defects, including cold shuts, insufficient pouring, and porosity, requiring extensive welding repairs, which impacted its performance and service life.

[0003] Although there are some reports on pouring systems for thin-walled castings, none of them are suitable for the production of the feed trough described herein. For example, CN118403925A discloses a sand casting molding device and pouring method for special-shaped thin-walled castings. During pouring, the molten metal fills the mold at various locations within the mold cavity simultaneously. The molten metal is too dispersed and cools down quickly, making it unsuitable for the production of the feed trough casting described in the present utility model. CN115635044A discloses a pouring system for hollow thin-walled castings, CN113664162A discloses a pouring system for thin-walled castings with a length of 650 mm, and CN216680104U discloses a pouring system for thin-walled castings. These three patents all belong to lost wax casting for small castings and are not suitable for the production of large thin-walled castings.

[0004] How to solve the cold shut, insufficient pouring and porosity defects formed during the casting process of large thin-walled castings and ensure the performance and service life of the products is a major issue facing the company in the manufacturing process. Summary of the Invention

[0005] In view of the problem that thin-walled square trough steel castings are prone to defects such as cold shut, insufficient pouring and air holes during pouring, the utility model provides a pouring system for thin-walled square tubular trough castings. Its purpose is to eliminate the casting defects caused by the trough castings in the production process by designing a reasonable pouring system, improve the quality of the trough castings, and improve the performance and service life of the trough to meet user requirements.

[0006] The technical solution of the utility model is: a pouring system for a thin-walled square tubular trough casting, comprising a casting, a sprue arranged outside the casting, a runner connected below the sprue, and an inner runner on the runner connected to the casting. The pouring system for the trough casting comprises a square tubular trough casting cavity, a runner arranged along the length direction above the center line of the upper part of the trough casting cavity, and a plurality of sub-runners parallel to each other are symmetrically connected on both sides of the runner. The plurality of sub-runners include a sprue connected to the upper surface of the trough casting cavity. A parallel upper runner and a side runner parallel to the side of the trough casting cavity; a gap is left between the runner and the branch runner and the trough casting cavity; the runner and the branch runner are connected to the trough casting cavity through an ingrown runner; a sprue is provided above the runner, and a pouring cup is provided above the sprue; a plurality of risers connected to the trough casting cavity are provided above the end edge of the trough casting cavity; during pouring, one end of the trough casting cavity provided with the risers is higher than the other end;

[0007] Furthermore, the riser is higher than the sprue and lower than the highest point of the pouring cup. The sprue is arranged at one end of the casting cavity close to the trough, and the riser is arranged at the edge of the opposite end.

[0008] Furthermore, a sand core is provided in the middle of the cavity of the chute casting, the length of the sand core is greater than the length of the chute casting, a center hole is provided at the center of the sand core, the end of the center hole is connected to the outside, and the center hole is a vent hole of the sand core;

[0009] Furthermore, the sprue, runner, sub-runner, top ingrown gate and side ingrown gate are all ceramic tubes, which are arranged in the corresponding sand mold;

[0010] Furthermore, the proportional relationship between the cross-sectional areas of the sprue, runner, sub-runner and the sum of the cross-sectional areas of a group of inner runners is: A 直 :A 横 :2A 分横 :A 内和 =1.4:1:1.2:1.2, which is a semi-closed structure;

[0011] Furthermore, a plurality of sub-cross runners and a plurality of ingrowns are evenly distributed on both sides of the chute casting, and a plurality of ingrowns are connected to the bottom surface of the upper cross runner and the upper surface of the chute casting.

[0012] The positive effects of the present invention are as follows: by arranging a runner along the length direction on the center line above the trough casting cavity, and arranging a plurality of branch runners parallel to the upper surface and side surfaces of the trough casting cavity on both sides of the runner, and arranging a plurality of ingates connected to the cavity below the runner and inside the branch runners, molten steel can be poured into the cavity in the shortest time, the shortest process, and at the maximum flow rate. During pouring, by raising one end of the trough casting cavity provided with a riser higher than the other end, the low-position ingates and the cavity can be filled with molten steel first, thereby discharging the gas in the cavity along the rising flow of the molten steel to one end of the riser and then out of the riser, ensuring that the casting will not produce cold shuts, insufficient pouring, and air holes. This structure can eliminate casting defects generated during the production process of the trough casting, improve the quality of the trough casting, and improve the performance and service life of the trough, thus meeting user requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is an oblique side view of the chute casting and pouring system structure.

[0014] Figure 2 It is a schematic diagram of the end of the chute casting and the pouring system structure.

[0015] Explanation of the numbers: 001—side wall of the chute, 002—cross runner, 003—chute casting, 004—sand core, 005—sand core vent hole, 006—cross runner, 007—pouring cup, 008—upper surface of the chute, 009—riser, 010—sprue, 011—top ingrown runner, 012—side wall ingrown runner. DETAILED DESCRIPTION

[0016] The following is a detailed description of the technical solution of the present invention with reference to the accompanying drawings. The side wall of the feed chute indicated in the accompanying drawings is consistent with the cavity structure of the sand mold. Figure 1 and Figure 2 The chute casting referred to in the figure is the cavity structure formed in the sand mold. In order to facilitate the explanation of the problem, the structure of the sand mold around the casting is directly removed in the attached figure. Therefore, the sprue, runner, branch runner, and inner runner buried in the sand mold are all exposed.

[0017] The utility model is a pouring system for thin-walled square tubular trough castings. Figure 1 It is an oblique side view of the chute casting and pouring system structure. Figure 2Schematic diagram of the end structure of the trough casting and the pouring system, the pouring system of the trough casting 003 includes a square tubular trough casting 003 cavity, the upper surface of the trough casting 003 cavity, namely: a runner 006 arranged along the length direction above the center line of the trough upper surface 008, and a plurality of sub-runners 002 parallel to each other are symmetrically connected on both sides of the runner 006, the plurality of sub-runners 002 include an upper part runner parallel to the upper surface of the trough casting 003 cavity (the trough upper surface 008), and a side part runner parallel to the side surface of the trough casting cavity, namely the trough side wall 001, the runner 006, the sub-runner 002 (upper part runner, side part runner) and the lower There is a gap between the cavities of the trough casting 003. The runner 006, the sub-runner 002 (the upper runner and the side runner) are connected to the cavity of the trough casting 003 through the top endogate 011 and the side wall endogate 012 respectively. A sprue 010 is provided above the runner 006, and a pouring cup 007 is provided above the sprue 010. A plurality of risers 009 connected to the cavity of the trough casting 003 are provided above the end of the cavity of the trough casting 003. The sprue 010 is provided at one end close to the cavity of the trough casting 003, and the riser 009 is provided at the edge of the opposite end. During pouring, the end of the cavity of the trough casting 003 with the riser 009 is higher than the other end. The riser 009 is higher than the sprue 010 and lower than the highest point of the pouring cup 007, and is inclined at 8-30 degrees. In order to ensure that the molten steel slag in the pouring cup 007 does not flow into the mold cavity, the pouring cup 007 must be large enough. A thin steel sheet can be used to cover the pouring cup outlet before pouring.

[0018] The larger inclination of the sand mold combined with the above-mentioned pouring system can ensure that the molten steel fills the mold gradually from the bottom of the mold cavity upward during pouring, avoiding the simultaneous entry of molten steel into multiple places in the mold cavity. In this way, for each part, the molten steel fills the mold quickly, the process is short, and the temperature drops less, so it is not easy to have cold shut, insufficient pouring and porosity defects.

[0019] A sand core 004 is provided in the middle of the cavity of the chute casting 003. The length of the sand core 004 is greater than the length of the chute casting 003. A center hole is provided at the center of the sand core 004. The end of the center hole is connected to the outside. The center hole is the sand core exhaust hole 005.

[0020] The sprue 010 , runner 006 , branch runner 002 , top ingrown runner 011 and sidewall ingrown runner 012 are all ceramic tubes, which are arranged in the corresponding sand mold.

[0021] The relationship between the cross-sectional area of ​​the sprue 010, the runner 006, the sub-runner 002 and the total cross-sectional area of ​​a group of ingates is: 直 :A 横 :2A 分横 :A内和 =1.4:1:1.2:1.2, which is a semi-closed structure;

[0022] There are one or more inner runners connecting the cavity of the feed trough casting 003 and the side cross runners on both sides, and the distances between the multiple inner runners on both sides are equal. In this embodiment, there are three inner runners arranged between each side cross runner and the cavity, which are respectively located at the upper, middle and lower positions of the side cross runner, and the intervals between them are equal.

[0023] Specific implementation steps:

[0024] ①Analyze and evaluate the casting process, conduct PFMEA analysis of potential failure modes and consequences of the product production process, identify possible casting defects, and determine the preventive measures that need to be taken;

[0025] ② According to Article ①, formulate APQP, design production process drawings and mold drawings;

[0026] ③ Purchase various materials, make molds, prepare sand boxes and other tooling accessories;

[0027] ④Shaping, painting, drying, core removal and box closing;

[0028] ⑤Smelting molten steel simultaneously with the implementation of item ④;

[0029] ⑥Pouring;

[0030] ⑦ Wait for enough time to keep warm. When the temperature of the casting in the sand mold drops below 300 degrees, open the box and remove the sand.

[0031] ⑧Cleaning and polishing of castings;

[0032] ⑨Heat treatment;

[0033] ⑩Inspection and storage after passing the inspection. Specific embodiments

[0035] One type of trough we produce is used in the sintering system of a metallurgical plant. Made of high-alloy, heat-resistant, and wear-resistant cast steel ZG45Cr20Ni12Mo, the trough features a 16mm wall thickness, is 3700mm long, and weighs 1250kg. These troughs operate under the dual effects of high-temperature heat and friction on the trough's thin walls, subjecting them to both high-temperature heat and constant friction. At the start of production, the troughs exhibited numerous surface defects, including cold shuts, insufficient pouring, and porosity, requiring extensive welding repairs that shortened their service life. Later, the company launched a scientific research project on "a pouring system structure for thin-walled cylindrical castings". The project results were applied to the production of the castings, and the pouring system structure described in the utility model was fully applied. A cross runner 006 was set in the length direction of the top of the trough casting 003, 11 top endocasting channels 011 were set below the cross runner 006, and 11 branch cross runners 002 were symmetrically set on both sides of the cross runner 006. The branch cross runners 002 on both sides were parallel to the top and side surfaces of the casting. A side wall endocasting channel 012 was set on the inner side of the vertical part of the branch cross runner 002, and the side wall endocasting channel 012 was parallel to the side wall of the casting. Connected, the sub-runner 002 and the side wall ingrown 012 are arranged in 11 groups on both sides of the casting, the straight runner 010, the cross runner 006, the sub-runner 002 and the top ingrown 011 and the side wall ingrown 012 are all ceramic tubes, the inner diameter of the straight runner 010 ceramic tube is Ø60mm, the inner diameter of the cross runner 006 ceramic tube is Ø50mm, the inner diameter of the sub-runner 002 ceramic tube is Ø40mm, the inner diameter of each ingrown ceramic tube is Ø20mm, the cross-sectional area of ​​the straight runner 010, the cross runner 006, the sub-runner 002 and the cross-sectional area of ​​the total of a group of ingrows are proportional to each other: A 直 ;A 横 ;2A 分横 ;A 内和 =1.4:1:1.2:1.2, a semi-enclosed design. The sprue 010 and pouring cup 007 are located above one end of the casting, near its length, but above the end. The riser 009 is located at the edge of the other end. During pouring, the sand mold is tilted at a steep 25-degree angle, with the riser 009 positioned high and the sprue 010 at a low point. A larger pouring cup 007 is positioned above the sprue 010, ensuring that the top surface of the pouring cup 007 is higher than the top surface of the riser 009 located at the other end of the casting. The application of this utility model has resulted in subsequent production of this type of trough, which no longer suffers from cold shuts, insufficient pouring, or porosity defects. The quality has been significantly improved, and has received positive reviews from users.

[0036] The utility model sets a cross runner 006 on the center line above the cavity of the trough casting 003 in the longitudinal direction, and sets a plurality of sub-cross runners 002 on the left and right sides of the cross runner, which are parallel to the upper surface of the cavity of the trough casting 003 and the side surfaces of the cavity of the trough casting 003. A plurality of top endocastors 011 and side wall endocastors 012 connected to the cavity can be set below the plurality of cross runners 006 and inside the sub-cross runners 002. Molten steel can be poured into the cavity with the maximum flow rate in the shortest time and the shortest process. When pouring, one end of the cavity of the trough casting 003 provided with a riser is higher than the other end, so that the sand mold is tilted. When the inclination of the sand mold is combined with the above-mentioned pouring system, it can ensure that the pouring cup is full so that the slag in the molten steel does not enter the cavity, and can also ensure that the molten steel enters the cavity and flows upward in an orderly manner from the lowest part of the cavity. Fill the cavity. Before the lower runner and cavity are filled, molten steel will not flow into the upper runner and cavity, avoiding molten steel entering multiple places in the cavity at the same time, reducing the filling speed of molten steel in each runner and cavity, pouring in an inclined state can speed up the speed of molten steel entering the local cavity, shorten the time, shorten the process, and ensure that it enters the cavity at high temperature. The shorter the pouring process, the less cold shut, insufficient pouring and air hole defects will occur. First fill the low-level runner and cavity with molten steel, so that the gas and slag in the cavity can be discharged to one end of the riser along the rising of the molten steel and discharged from the riser, ensuring that the casting will not produce cold shut, insufficient pouring and air holes. This structure can eliminate the casting defects generated by the chute casting in the production process, improve the quality of the chute casting, improve the performance and service life of the chute, and meet user requirements.

Claims

1. A pouring system for a thin-walled square tubular trough casting, comprising a casting, a sprue disposed outside the casting, a runner connected below the sprue, and an endogate on the runner connected to the casting, characterized in that: The pouring system of the trough casting includes a horizontal runner arranged in the length direction of the upper center line of the square tubular trough casting, and a plurality of mutually parallel branch horizontal runners are symmetrically connected on both sides of the horizontal runner. The plurality of branch horizontal runners include an upper part horizontal runner parallel to the upper surface of the trough casting and a side part horizontal runner parallel to the side of the trough casting. There is a gap between the horizontal runner and the branch horizontal runner and the trough casting cavity. The horizontal runner and the branch horizontal runner are connected to the trough casting cavity through an inner runner respectively. A straight runner is arranged above the horizontal runner, and a pouring cup is arranged above the straight runner. A plurality of risers connected to the trough casting cavity are arranged above the end edge of the trough casting cavity. During pouring, one end of the trough casting cavity provided with the riser is higher than the other end.

2. A pouring system for a thin-walled square tubular trough casting according to claim 1, characterized in that: The riser is higher than the sprue and lower than the highest point of the pouring cup. The sprue is arranged at one end close to the casting cavity of the trough, and the riser is arranged at the edge of the opposite end.

3. The pouring system for a thin-walled square tubular trough casting according to claim 1, characterized in that: A sand core is provided in the middle of the cavity of the chute casting. The length of the sand core is greater than the length of the chute casting. A center hole is provided at the center of the sand core. The end of the center hole is connected to the outside. The center hole is a sand core exhaust hole.

4. The pouring system for a thin-walled square tubular trough casting according to claim 1, characterized in that: The sprue, runner, branch runner, top ingrown runner and side wall ingrown runner are all ceramic tubes, and the ceramic tubes are arranged in the corresponding sand mold.

5. The pouring system for a thin-walled square tubular trough casting according to claim 1, characterized in that: The proportional relationship between the cross-sectional area of ​​the sprue, runner, sub-runner and the sum of the cross-sectional area of ​​a group of ingates is: 直 :A 横 :2A 分横 :A 内和 =1.4:1:1.2:1.2, which is a semi-closed structure.

6. The pouring system for a thin-walled square tubular trough casting according to claim 1, characterized in that: A plurality of sub-cross runners and a plurality of inner gates are evenly distributed on both sides of the lower trough casting, and a plurality of inner gates are connected to the bottom surface of the upper cross runner and the upper surface of the lower trough casting.

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