Production process of high-precision anti-deformation main valve body casting for excavator

Abstract

In the production process, large sand cores of a first longitudinal runner, a second longitudinal runner, a third longitudinal runner and a fourth longitudinal runner and matched small sand cores of a vertical runner, a transverse runner, an arc-shaped runner and other runners are designed and manufactured according to the runner structure of a product. The invention has the advantages that the ceramic core bar is arranged in the large sand core of the main runner, and the high-strength sand core is adopted, so that the bending strength of the main hole is improved and the straightness is ensured through combination of the ceramic core bar and the high-strength sand core; the inner runner is free of sand core cracking and fin; the core support is added, so that the runner is not deformed after dissecting; the surface of the sand core is coated with the coating, sintering is prevented, and the surface quality of the runner is guaranteed; a high exothermic riser is used at the top and two auxiliary risers are added to effectively exhaust air, so that the casting is smooth in surface and free of slag inclusion; the special chilling block is placed on the bottom surface, so that the overheating phenomenon at the riser is avoided, the shell mold and the sand core are prevented from being scoured by molten iron, the pouring time is shortened, heat is well dispersed, and shrinkage cavity and shrinkage porosity are avoided.

Description

Technical Field

[0001] The present invention relates to the field of production of valve body castings, and particularly to a production process for a main valve body casting for an excavator with high precision and anti-deformation. Background Art

[0002] The ZYJFKZ-14-B-1MP valve body is an integral main valve body jointly developed with Zoomlion, mainly used in the excavator control system, and has a large market demand. The internal structure of the valve body casting is complex, and the production of the casting is difficult. It is very crucial to determine what kind of process to use. After research and analysis, it is determined to adopt the process of resin sand molding with coated sand shell mold. The internal structure of this valve body is complex, composed of multiple sand cores spliced together. The internal structure is complex, the sand cores emit a large amount of gas, the exhaust is not smooth, and defects such as porosity are easily formed; there are also a small amount of slag inclusion defects on the outer shape; the sand core holes are small, and they are prone to deformation at high temperature, and the internal dimensions are difficult to control, and the dimensional accuracy requirements are high. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention proposes a production process for a main valve body casting for an excavator with high precision and anti-deformation, which is ingeniously designed, has a perfect process, a reasonable and compact structure, a high straightness accuracy of the main runner, no deformation, no cracking, and no shrinkage porosity phenomenon.

[0004] The technical solution of the present invention: A production process for a main valve body casting for an excavator with high precision and anti-deformation, During the production of the main valve body casting for an excavator, the cavity in the sand box is made according to the shape of the product, and then the large sand cores of the first longitudinal runner, the second longitudinal runner, the third longitudinal runner, and the fourth longitudinal runner and the small sand cores of the vertical runners, horizontal runners, and arc runners that match the runner structure of the product are designed and manufactured. Then, the large sand core of the main runner and the small sand cores of the other runners are placed in the cavity of the sand box as specified, the sand box is closed, and then the molten iron is poured from the reserved pouring riser. After waiting for cooling, the sand box is opened, the valve body casting is taken out, and then the internal sand cores are cleaned and exported to complete the processing; A layer of water-based coating is applied to the front surface of the large sand core of the main runner and the small sand cores of the other runners before they are put into the sand box; a high-heat-generating riser is reserved in the middle above the sand box and two auxiliary risers are added, and chill blocks are placed at the bottom of the sand box; the side thin gate is used for simultaneous pouring from both sides for pouring, and the large sand cores and small sand cores are made of high-strength sand core sand; a ceramic core bone with a diameter of Φ3*115mm is provided in the middle of the large sand core of the main runner; The main valve body casting for an excavator includes a main body, a first longitudinal runner, a second longitudinal runner, a third longitudinal runner, and a fourth longitudinal runner. The main body is in a rectangular shape, There are 4 runner openings designed on the front of the main body, namely the front first runner opening, the front second runner opening, the front third runner opening, and the front fourth runner opening; There are 4 flow ports designed behind the main body, namely the rear first flow port, the rear second flow port, the rear third flow port, and the rear fourth flow port; There are 7 flow ports designed on the main body, namely the upper first flow port, the upper second flow port, the upper third flow port, the upper fourth flow port, the upper fifth flow port, the upper sixth flow port, and the upper seventh flow port; There is 1 flow port designed on the left side of the main body, namely the left first flow port; There are four longitudinal flow channels designed in the front and back of the middle of the main body. From left to right, they are the first longitudinal flow channel, the second longitudinal flow channel, the third longitudinal flow channel, and the fourth longitudinal flow channel; The first longitudinal flow channel is successively designed with five annular grooves from front to back, namely the first annular groove, the second annular groove, the third annular groove, the fourth annular groove, and the fifth annular groove; the front end of the first longitudinal flow channel is connected to the front first flow port, and the rear end of the first longitudinal flow channel is connected to the rear first flow port; a first arc-shaped flow channel is designed above the first longitudinal flow channel. The front and rear ends of the first arc-shaped flow channel are respectively connected to the upper ends of the first annular groove and the fifth annular groove. The front and rear ends of the first arc-shaped flow channel are also respectively connected to the positions near the orifices of the front and rear ends of the first longitudinal flow channel through an auxiliary arc-shaped flow channel; a rectangular groove is also designed on the left side of the fifth annular groove, and a rectangular groove is also designed on the right side of the first annular groove and the fourth chute respectively; a first vertical flow channel is arranged on the left side of the first annular groove and the second annular groove of the first longitudinal flow channel. The left side of the third annular groove is connected to the rear end of the first vertical flow channel near the middle position through a second arc-shaped flow channel. The upper end of the first vertical flow channel is connected to the upper first flow port, and the lower left end of the first vertical flow channel is connected to the left first flow port through a transverse flow channel; The second longitudinal flow channel is successively designed with three annular grooves from front to back, namely the sixth annular groove, the seventh annular groove, and the eighth annular groove; the front end of the second longitudinal flow channel is connected to the front second flow port, and the rear end of the second longitudinal flow channel is connected to the rear second flow port; a third arc-shaped flow channel is designed below the second longitudinal flow channel. The front end of the third arc-shaped flow channel is connected to the lower end of the seventh annular groove, and the rear end of the third arc-shaped flow channel is connected to the position below the rear end of the second longitudinal flow channel near the orifice; a second vertical flow channel is arranged above the sixth annular groove of the second longitudinal flow channel. The lower end of the second vertical flow channel is connected to the upper end of the sixth annular groove through an L-shaped flow channel, and the upper end of the second vertical flow channel is connected to the upper second flow port; The left side of the seventh annular groove is connected to the right side of the second annular groove through a transverse flow channel; The third longitudinal flow channel is successively designed with five annular grooves from front to back, namely the ninth annular groove, the tenth annular groove, the eleventh annular groove, the twelfth annular groove, and the thirteenth annular groove; the front end of the third longitudinal flow channel is connected to the front third flow port, and the rear end of the third longitudinal flow channel is connected to the rear third flow port; a fourth arc-shaped flow channel is designed on the right side of the third longitudinal flow channel. The front end of the fourth arc-shaped flow channel is connected to the right side of the ninth annular groove, and the rear end of the fourth arc-shaped flow channel is connected to the right side of the thirteenth annular groove; The left side of the eleventh annular groove is connected to the right side of the eighth annular groove through a transverse flow channel; The fourth longitudinal flow channel is designed with five annular grooves in sequence from front to back, namely the fourteenth annular groove, the fifteenth annular groove, the sixteenth annular groove, the seventeenth annular groove, and the eighteenth annular groove; the front end of the fourth longitudinal flow channel is connected to the front four flow ports, and the rear end of the fourth longitudinal flow channel is connected to the rear four flow ports; a fifth arc-shaped flow channel is designed below the fourth longitudinal flow channel, the front end of the fifth arc-shaped flow channel is connected to the lower end of the fourteenth annular groove, the rear end of the fifth arc-shaped flow channel is connected to the lower end of the eighteenth annular groove, and the front and rear ends of the fifth arc-shaped flow channel are respectively connected to the lower ends near the orifices of the front and rear ends of the fourth longitudinal flow channel through an auxiliary arc-shaped flow channel; The left side near the orifice of the front end of the fourth longitudinal flow channel is connected to the right side near the orifice of the front end of the third longitudinal flow channel through a transverse flow channel; A third vertical flow channel is arranged above the fourteenth annular groove of the fourth longitudinal flow channel, the upper end of the third vertical flow channel is connected to the upper six flow ports, and the lower end of the third vertical flow channel is connected to the upper end of the fifteenth annular groove through an L-shaped flow channel; A fourth vertical flow channel is arranged above and to the left of the eighteenth annular groove of the fourth longitudinal flow channel, the upper end of the fourth vertical flow channel is connected to the upper five flow ports, the upper end of the sixteenth annular groove is connected to the position near the lower end of the fourth vertical flow channel through a sixth arc-shaped flow channel; the lower end of the fourth vertical flow channel is connected to the lower end of the second vertical flow channel through a large L-shaped flow channel; a fifth vertical flow channel is designed at the upper end of the corner position of the large L-shaped flow channel, the upper end of the fifth vertical flow channel is connected to the upper three flow ports, and the lower end of the fifth vertical flow channel is connected to the upper end of the corner position of the large L-shaped flow channel; a sixth vertical flow channel is designed at the upper middle of the fourth arc-shaped flow channel, the lower end of the sixth vertical flow channel penetrates and is connected to the large L-shaped flow channel and then connected to the upper middle of the fourth arc-shaped flow channel, and the upper end of the sixth vertical flow channel is connected to the upper four flow ports; A seventh vertical flow channel is designed at the upper right rear of the fourth longitudinal flow channel, the upper end of the seventh vertical flow channel is connected to the upper seven flow ports, and the lower end of the seventh vertical flow channel is connected to the right side of the seventeenth annular groove through an L-shaped flow channel.

[0005] The water-based coating is HA377 water-based coating and a certain amount of graphite powder is added as the coating, and the Baume degree of the coating is adjusted to 35°Bé - 42°Bé.

[0006] The large sand core of the main flow channel and the small sand cores of the other flow channels are produced by using high-strength GHD170 sand to make cores.

[0007] The contour dimensions of the main valve body casting for the excavator are 76*96*190 mm, and the weight reaches 13 kilograms.

[0008] In the core-making process of the large core of the main runner and the small cores of the remaining runners, a rectangular frame core and four portal frame cores are also designed. The front and rear ends of the large cores of the four longitudinal runners are respectively connected to the inner middle of the rectangular core. At the same time, the four portal frame cores are respectively supported and connected to both sides of the upper end of the rectangular core. From left to right, they are the first portal frame core, the second portal frame core, the third portal frame core, and the fourth portal frame core. The lower part of the inner side of the leftmost first portal frame core is connected to the upper end of the small core of the first vertical runner. The lower part of the inner side of the second portal frame core is connected to the upper end of the small core of the second vertical runner. The lower part of the inner side of the third portal frame core is connected to the upper ends of the small cores of the fifth and sixth vertical runners. The lower part of the inner side of the fourth portal frame core is connected to the upper end of the small core of the seventh vertical runner. A transverse core is connected between the upper ends of the third portal frame core and the fourth portal frame core, and the lower end of this transverse core is connected to the upper end of the small core of the fourth vertical runner; vertical plate-shaped cores are respectively designed on both sides of the lower end of the rectangular frame core, and the left end of the small core of the first transverse runner is connected to the inner side of the left vertical plate-shaped core; a core support is placed above the small core of the sixth arc-shaped runner, and the upper end of the core support supports on the inner top of the sand box.

[0009] The advantages of the present invention are as follows: A ceramic core bone is arranged in the large core of the main runner, and high-strength core sand is used for core-making. The combination of the two increases the bending strength of the main hole and ensures straightness; after using a special high-strength binder, there are no defects such as core cracking and flash in the inner runner; due to core deformation, core supports are added, and there is no deformation in the runner after dissection; Coating the surface of the core with paint and setting the Baume degree at 35°Bé - 42°Bé can effectively prevent sintering and ensure the surface quality of the runner; 3. Using a high-heat riser at the top and adding two auxiliary risers for effective exhaust. The castings poured out with increased exhaust are smooth on the surface and have no defects such as slag inclusion; special chill blocks are placed on the bottom surface, and at the same time, the side thin gate and double-sided pouring process are adopted. This can not only directly avoid the overheating phenomenon at the riser, but also greatly reduce the erosion of the molten iron on the shell mold and the core, reduce the pouring time, and thus has a good effect of dispersing heat, and there are no defects such as shrinkage cavities and porosity; after process improvement, the qualified rate of the castings reaches more than 95%. Description of the Drawings

[0010] Figure 1-2 are the front and rear three-dimensional schematic diagrams of the present invention.

[0011] Figure 3 is the transverse sectional top view schematic diagram at the longitudinal runner of the present invention.

[0012] Figure 4 is the vertical sectional side view schematic diagram at the first vertical runner of the present invention.

[0013] Figure 5It is a schematic vertical sectional side view of the first longitudinal flow channel of the present invention.

[0014] Figure 6 It is a schematic vertical sectional side view of the second longitudinal flow channel of the present invention.

[0015] Figure 7 It is a schematic vertical sectional side view of the third longitudinal flow channel of the present invention.

[0016] Figure 8 It is a schematic vertical sectional side view of the fifth and sixth vertical flow channels of the present invention.

[0017] Figure 9 It is a schematic vertical sectional side view of the fourth vertical flow channel of the present invention.

[0018] Figure 10 It is a schematic vertical sectional side view of the fourth longitudinal flow channel of the present invention.

[0019] Figure 11 It is a schematic vertical sectional side view of the seventh vertical flow channel of the present invention.

[0020] Figure 12 It is a schematic horizontal sectional top view of the large L-shaped flow channel of the present invention.

[0021] Figure 13-14 It is a schematic front and rear three-dimensional view of the overall sand core of the present invention. Detailed implementation manners

[0022] Refer to the attached Figure 1-14 , the production process of the main valve body casting for high-precision anti-deformation excavators, The main valve body casting for excavators includes a main body 1, a first longitudinal flow channel 11, a second longitudinal flow channel 12, a third longitudinal flow channel 13, and a fourth longitudinal flow channel 14. The main body 1 is in a rectangular shape. There are 4 flow ports designed on the front of the main body 1, namely the front first flow port 21, the front second flow port 22, the front third flow port 23, and the front fourth flow port 24; There are 4 flow ports designed on the rear of the main body 1, namely the rear first flow port 31, the rear second flow port 32, the rear third flow port 33, and the rear fourth flow port 34; There are 7 flow ports designed on the top of the main body 1, namely the top first flow port 41, the top second flow port 42, the top third flow port 43, the top fourth flow port 44, the top fifth flow port 45, the top sixth flow port 46, and the top seventh flow port 47; There is 1 flow port designed on the left side of the main body 1, namely the left first flow port 51; There are four longitudinal flow channels designed in the middle front and rear of the main body 1, which are the first longitudinal flow channel 11, the second longitudinal flow channel 12, the third longitudinal flow channel 13, and the fourth longitudinal flow channel 14 from left to right; The first longitudinal flow channel 11 is designed with five annular grooves in sequence from front to back, namely the first annular groove 101, the second annular groove 102, the third annular groove 103, the fourth annular groove 104, and the fifth annular groove 105; the front end of the first longitudinal flow channel 11 is connected to the front flow port 21, and the rear end of the first longitudinal flow channel 11 is connected to the rear flow port 31; above the first longitudinal flow channel 11, a first arc-shaped flow channel 61 is designed. The front and rear ends of the first arc-shaped flow channel 61 are respectively connected to the upper ends of the first annular groove 101 and the fifth annular groove 105. The front and rear ends of the first arc-shaped flow channel 61 are also respectively connected to the positions near the mouths at the front and rear ends of the first longitudinal flow channel 11 through an auxiliary arc-shaped flow channel; on the left side of the fifth annular groove 105, a rectangular groove is also designed, and rectangular grooves are also respectively designed on the right sides of the first annular groove 101 and the fourth chute; on the left sides of the first annular groove 101 and the second annular groove 102 of the first longitudinal flow channel 11, a first vertical flow channel 71 is provided. The left side of the third annular groove 103 is connected to the rear end of the first vertical flow channel 71 near the middle position through a second arc-shaped flow channel 62. The upper end of the first vertical flow channel 71 is connected to the upper flow port 41, and the lower left end of the first vertical flow channel 71 is connected to the left flow port 51 through a transverse flow channel; The second longitudinal flow channel 12 is designed with three annular grooves in sequence from front to back, namely the sixth annular groove 106, the seventh annular groove 107, and the eighth annular groove 108; the front end of the second longitudinal flow channel 12 is connected to the front second flow port 22, and the rear end of the second longitudinal flow channel 12 is connected to the rear second flow port 32; below the second longitudinal flow channel 12, a third arc-shaped flow channel 63 is designed. The front end of the third arc-shaped flow channel 63 is connected to the lower end of the seventh annular groove 107, and the rear end of the third arc-shaped flow channel 63 is connected to the position below the rear end of the second longitudinal flow channel 12 near the mouth; above the sixth annular groove 106 of the second longitudinal flow channel 12, a second vertical flow channel 72 is provided. The lower end of the second vertical flow channel 72 is connected to the upper end of the sixth annular groove 106 through an L-shaped flow channel, and the upper end of the second vertical flow channel 72 is connected to the upper second flow port 42; The left side of the seventh annular groove 107 is connected to the right side of the second annular groove 102 through a transverse flow channel; The third longitudinal flow channel 13 is designed with five annular grooves in sequence from front to back, namely the ninth annular groove 109, the tenth annular groove 110, the eleventh annular groove 111, the twelfth annular groove 112, and the thirteenth annular groove 113; the front end of the third longitudinal flow channel 13 is connected to the front third flow port 23, and the rear end of the third longitudinal flow channel 13 is connected to the rear third flow port 33; on the right side of the third longitudinal flow channel 13, a fourth arc-shaped flow channel 64 is designed. The front end of the fourth arc-shaped flow channel 64 is connected to the right side of the ninth annular groove 109, and the rear end of the fourth arc-shaped flow channel 64 is connected to the right side of the thirteenth annular groove 113; The left side of the eleventh annular groove 111 is connected to the right side of the eighth annular groove 108 through a transverse flow channel; The fourth longitudinal flow channel 14 is designed with five annular grooves in sequence from front to back, namely the fourteenth annular groove 114, the fifteenth annular groove 115, the sixteenth annular groove 116, the seventeenth annular groove 117, and the eighteenth annular groove 118; the front end of the fourth longitudinal flow channel 14 is connected to the front four flow ports 24, and the rear end of the fourth longitudinal flow channel 14 is connected to the rear four flow ports 34; a fifth arc-shaped flow channel 65 is designed below the fourth longitudinal flow channel 14, the front end of the fifth arc-shaped flow channel 65 is connected to the lower end of the fourteenth annular groove 114, the rear end of the fifth arc-shaped flow channel 65 is connected to the lower end of the eighteenth annular groove 118, and the front and rear ends of the fifth arc-shaped flow channel 65 are respectively connected to the lower ends near the orifices of the front and rear ends of the fourth longitudinal flow channel 14 through an auxiliary arc-shaped flow channel; The left side near the orifice of the front end of the fourth longitudinal flow channel 14 is connected to the right side near the orifice of the front end of the third longitudinal flow channel 13 through a transverse flow channel; A third vertical flow channel 73 is arranged above the fourteenth annular groove 114 of the fourth longitudinal flow channel 14, the upper end of the third vertical flow channel 73 is connected to the upper six flow ports 46, and the lower end of the third vertical flow channel 73 is connected to the upper end of the fifteenth annular groove 115 through an L-shaped flow channel; A fourth vertical flow channel 74 is arranged above and to the left of the eighteenth annular groove 118 of the fourth longitudinal flow channel 14, the upper end of the fourth vertical flow channel 74 is connected to the upper five flow ports 45, and the upper end of the sixteenth annular groove 116 is connected to a position near the lower end of the fourth vertical flow channel 74 through a sixth arc-shaped flow channel 66; the lower end of the fourth vertical flow channel 74 is connected to the lower end of the second vertical flow channel 72 through a large L-shaped flow channel 81; a fifth vertical flow channel 75 is designed at the upper end of the corner position of the large L-shaped flow channel 81, the upper end of the fifth vertical flow channel 75 is connected to the upper three flow ports 43, and the lower end of the fifth vertical flow channel 75 is connected to the upper end of the corner position of the large L-shaped flow channel 81; a sixth vertical flow channel 76 is designed at the upper middle of the fourth arc-shaped flow channel 64, the lower end of the sixth vertical flow channel 76 penetrates and is connected to the large L-shaped flow channel 81 and then connected to the upper middle of the fourth arc-shaped flow channel 64, and the upper end of the sixth vertical flow channel 76 is connected to the upper four flow ports 44; A seventh vertical flow channel 77 is designed at the upper right rear of the fourth longitudinal flow channel 14, the upper end of the seventh vertical flow channel 77 is connected to the upper seven flow ports 47, and the lower end of the seventh vertical flow channel 77 is connected to the right side of the seventeenth annular groove 117 through an L-shaped flow channel.

[0023] During the production process of the main valve body casting for an excavator, the cavity in the sand box is made according to the product shape, and then the large sand cores of the first longitudinal flow channel, the second longitudinal flow channel, the third longitudinal flow channel, and the fourth longitudinal flow channel and the small sand cores of the vertical flow channels, transverse flow channels, and arc-shaped flow channels that match them are designed and manufactured according to the flow channel structure of the product. Then, the large sand core of the main flow channel and the small sand cores of the remaining flow channels are placed in the cavity of the sand box as specified, the sand box is closed, and then the molten iron is poured from the reserved pouring riser. After waiting for cooling, the sand box is opened, the valve body casting is taken out, and then the internal sand cores are cleaned and exported to complete the processing; Before the large core of the sprue and the small cores of the remaining runners are placed in the sand box, a layer of water-based coating is applied to the front surface of the sand box; a high-heat riser is reserved in the middle above the sand box and two auxiliary risers are added, and chill blocks are placed at the bottom of the sand box; the side thin gate is used for casting with simultaneous pouring from both sides. The large core and small cores are made of high-strength core sand. A ceramic core bone with a diameter of Φ3*115mm is provided in the middle of the large core of the sprue. In order to prevent the core from bending, a ceramic core bone of Φ3*115mm is used. Due to the large volume of the valve body, a top heat riser is used and the molten iron enters from the middle. After the valve body casting is dissected, the inner cavity basically meets the requirements, but there are a small amount of slag inclusions on the outer shape. By adding two auxiliary vent risers, this defect disappears; for core production, HA high-strength GHD170 sand is used to make the core. The main core is assembled by multiple cores. It is required that there is no gap at the assembly interface. After the core is assembled, it must be repaired and inspected. After ensuring no defects, it is coated and baked. Otherwise, flash will be generated in the casting and it will be scrapped. After the core is baked, it is shelled. The inner runner of this valve body is complex and the main hole is small. During pouring, the runner bends and deforms at high temperature. Chill blocks are placed at the bottom of the sand box in the process to ensure that the straightness of the core is within the required range. After shelling is completed, molding is carried out. Considering the high requirements for the runner size of this valve body, the size must be controlled within the range of ±0.3mm. The resin sand buried shell process is adopted. The resin sand has high strength and is easy to control the size. The valve body has a large volume, and chill blocks are added to the bottom surface to increase the chill of the casting. After using a special high-strength binder, there are no defects such as core cracking and flash in the inner runner. Due to core deformation, core supports are added. After dissection, the runner is not deformed. The surface of the casting with increased exhaust pouring is smooth and there are no defects such as slag inclusions. After process improvement, the qualified rate of the casting reaches more than 95%.

[0024] The water-based coating is HA377 water-based coating with a certain amount of graphite powder added as the coating, and the Baume degree of the coating is adjusted to 35°Bé - 42°Bé. For this design, due to the dense and complex runner of the casting, heat is concentrated during pouring and it is very easy to have defects such as molding sintering. Therefore, the coating requirements for the core are also crucial. The present invention uses HA377 water-based coating with a certain amount of graphite powder added as the coating, and the Baume degree of the coating is adjusted to 35°Bé - 42°Bé. If the Baume degree is too high, it is very easy to form coating accumulation. If the Baume degree is too low, the coating function cannot be achieved. Therefore, it is most reasonable to set the Baume degree of the coating of the present invention at 35°Bé - 42°Bé, which can effectively prevent sintering phenomenon and ensure the surface quality of the runner.

[0025] The large core of the sprue and the small cores of the remaining runners are produced using high-strength GHD170 sand to make the core.

[0026] The contour dimensions of the main valve body casting for the excavator are 76*96*190mm, and the weight reaches 13 kilograms.

[0027] In the core making process of the large core of the main runner and the small cores of the remaining runners, a rectangular frame core 2 and four portal frame cores are also designed. The front and rear ends of the large cores of the four longitudinal runners are respectively connected to the inner middle of the rectangular core. At the same time, the four portal frame cores are respectively supported and connected to both sides of the upper end of the rectangular core. From left to right, they are the first portal frame core 3, the second portal frame core 4, the third portal frame core 5, and the fourth portal frame core 6. The lower part inside the leftmost first portal frame core 3 is connected to the upper end of the small core of the first vertical runner. The lower part inside the second portal frame core 4 is connected to the upper end of the small core of the second vertical runner. The lower part inside the third portal frame core 5 is connected to the upper ends of the small cores of the fifth and sixth vertical runners. The lower part inside the fourth portal frame core 6 is connected to the upper end of the small core of the seventh vertical runner. A transverse core 9 is connected between the upper ends of the third portal frame core 5 and the fourth portal frame core 6, and the lower end of the transverse core 9 is connected to the upper end of the small core of the fourth vertical runner. Vertical plate-shaped cores 7 are respectively designed on both sides of the lower end of the rectangular frame core 2. The left end of the small core of the first transverse runner is connected to the inner side of the left vertical plate-shaped core 7. A core support 8 is placed above the small core of the sixth arc-shaped runner, and the upper end of the core support 8 supports the inner top of the sand box. The inner surface of the sand box is designed with grooves that match the rectangular frame core, the portal frame cores, and the vertical plate-shaped cores. Grooves for placing chill blocks are opened at the bottom of the sand box. The sand box is designed into two upper and lower boxes, and the upper and lower boxes are buckled on the outside of the whole core. After using a special high-strength binder, there are no defects such as core cracking and flash in the inner runner. At the same time, through the cooperation of the rectangular frame core 2 and the four portal frame cores, the overall core is stable. Ceramic core bones are added to the large cores, and combined with the use of additional core supports, the runner is not deformed after dissection.

[0028] Main technical parameters Material: HT300, tensile strength ≥ 300 MPa, hardness 190 - 230 HB, dimensional tolerance controlled within ±0.3, no shrinkage porosity and shrinkage cavity inside the casting, and the runner is smooth.

Claims

1. The production process of the main valve body casting for high-precision deformation-resistant excavators is characterized in that during the production of the main valve body casting for excavators, the cavity in the sand box is made according to the product shape, and then the large sand cores of the first longitudinal runner, the second longitudinal runner, the third longitudinal runner, and the fourth longitudinal runner and the small sand cores of the vertical runners, horizontal runners, and arc runners that match the remaining runners are designed and manufactured according to the runner structure of the product. Then, the large sand core of the main runner and the small sand cores of the remaining runners are placed in the cavity of the sand box as specified, the sand box is closed, and then the molten iron is poured from the reserved pouring riser. After waiting for cooling, the sand box is opened, the valve body casting is taken out, and then the internal sand cores are cleaned and exported to complete the processing; a layer of water-based coating is applied to the front surface of the large sand core of the main runner and the small sand cores of the remaining runners before they are placed in the sand box; a high-heat riser is reserved in the middle above the sand box and two auxiliary risers are added, and chill blocks are placed at the bottom of the sand box; the side thin gate is used for simultaneous pouring from both sides for pouring, and the large sand core and small sand cores are made of high-strength core sand; a ceramic core bone with a diameter of Φ3*115mm is provided in the middle of the large sand core of the main runner; the main valve body casting for excavators includes a main body, a first longitudinal runner, a second longitudinal runner, a third longitudinal runner, and a fourth longitudinal runner, and the main body is in a rectangular shape 4 runner openings are designed on the front of the main body, which are the front first runner opening, the front second runner opening, the front third runner opening, and the front fourth runner opening respectively; 4 runner openings are designed on the back of the main body, which are the back first runner opening, the back second runner opening, the back third runner opening, and the back fourth runner opening respectively; 7 runner openings are designed on the top of the main body, which are the top first runner opening, the top second runner opening, the top third runner opening, the top fourth runner opening, the top fifth runner opening, the top sixth runner opening, and the top seventh runner opening respectively; 1 runner opening is designed on the left side of the main body, which is the left first runner opening; 4 longitudinal runners are designed in the front and back of the middle of the main body, which are the first longitudinal runner, the second longitudinal runner, the third longitudinal runner, and the fourth longitudinal runner from left to right respectively; 5 annular grooves are designed in sequence from front to back on the first longitudinal runner, which are the first annular groove, the second annular groove, the third annular groove, the fourth annular groove, and the fifth annular groove respectively; the front end of the first longitudinal runner is connected to the front first runner opening, and the back end of the first longitudinal runner is connected to the back first runner opening; a first arc runner is designed above the first longitudinal runner, and the front and back ends of the first arc runner are respectively connected to the upper ends of the first annular groove and the fifth annular groove, and the front and back ends of the first arc runner are also respectively connected to the positions near the mouths of the front and back ends of the first longitudinal runner through an auxiliary arc runner; a rectangular groove is also designed on the left side of the fifth annular groove, and rectangular grooves are also designed on the right sides of the first annular groove and the fourth chute respectively; a first vertical runner is provided on the left sides of the first annular groove and the second annular groove of the first longitudinal runner, the left side of the third annular groove is connected to the back end of the first vertical runner near the middle position through a second arc runner, the upper end of the first vertical runner is connected to the top first runner opening, and the lower end left side of the first vertical runner is connected to the left first runner opening through a horizontal runner; The second longitudinal flow channel is designed with three annular grooves in sequence from front to back, namely the sixth annular groove, the seventh annular groove, and the eighth annular groove; the front end of the second longitudinal flow channel is connected to the front second flow port, and the rear end of the second longitudinal flow channel is connected to the rear second flow port; a third arc-shaped flow channel is designed below the second longitudinal flow channel, the front end of the third arc-shaped flow channel is connected to the lower end of the seventh annular groove, and the rear end of the third arc-shaped flow channel is connected to the lower part of the position near the mouth of the rear end of the second longitudinal flow channel; a second vertical flow channel is arranged above the sixth annular groove of the second longitudinal flow channel, the lower end of the second vertical flow channel is connected to the upper end of the sixth annular groove through an L-shaped flow channel, and the upper end of the second vertical flow channel is connected to the upper second flow port; The left side of the seventh annular groove is connected to the right side of the second annular groove through a transverse flow channel; The third longitudinal flow channel is designed with five annular grooves in sequence from front to back, namely the ninth annular groove, the tenth annular groove, the eleventh annular groove, the twelfth annular groove, and the thirteenth annular groove; the front end of the third longitudinal flow channel is connected to the front third flow port, and the rear end of the third longitudinal flow channel is connected to the rear third flow port; a fourth arc-shaped flow channel is designed on the right side of the third longitudinal flow channel, the front end of the fourth arc-shaped flow channel is connected to the right side of the ninth annular groove, and the rear end of the fourth arc-shaped flow channel is connected to the right side of the thirteenth annular groove; The left side of the eleventh annular groove is connected to the right side of the eighth annular groove through a transverse flow channel; The fourth longitudinal flow channel is designed with five annular grooves in sequence from front to back, namely the fourteenth annular groove, the fifteenth annular groove, the sixteenth annular groove, the seventeenth annular groove, and the eighteenth annular groove; the front end of the fourth longitudinal flow channel is connected to the front fourth flow port, and the rear end of the fourth longitudinal flow channel is connected to the rear fourth flow port; a fifth arc-shaped flow channel is designed below the fourth longitudinal flow channel, the front end of the fifth arc-shaped flow channel is connected to the lower end of the fourteenth annular groove, the rear end of the fifth arc-shaped flow channel is connected to the lower end of the eighteenth annular groove, and the front and rear ends of the fifth arc-shaped flow channel are respectively connected to the lower positions near the mouths of the front and rear ends of the fourth longitudinal flow channel through an auxiliary arc-shaped flow channel; The left side near the mouth of the front end of the fourth longitudinal flow channel is connected to the right side position near the mouth of the front end of the third longitudinal flow channel through a transverse flow channel; A third vertical flow channel is arranged above the fourteenth annular groove of the fourth longitudinal flow channel, the upper end of the third vertical flow channel is connected to the upper sixth flow port, and the lower end of the third vertical flow channel is connected to the upper end of the fifteenth annular groove through an L-shaped flow channel; A fourth vertical flow channel is arranged above and to the left of the eighteenth annular groove of the fourth longitudinal flow channel, the upper end of the fourth vertical flow channel is connected to the upper fifth flow port, the upper end of the sixteenth annular groove is connected to the position near the lower end of the fourth vertical flow channel through a sixth arc-shaped flow channel; the lower end of the fourth vertical flow channel is connected to the lower end of the second vertical flow channel through a large L-shaped flow channel; a fifth vertical flow channel is designed at the upper end of the corner position of the large L-shaped flow channel, the upper end of the fifth vertical flow channel is connected to the upper third flow port, and the lower end of the fifth vertical flow channel is connected to the upper end of the corner position of the large L-shaped flow channel; a sixth vertical flow channel is designed at the upper middle of the fourth arc-shaped flow channel, the lower end of the sixth vertical flow channel penetrates and is connected to the large L-shaped flow channel and then connected to the upper middle of the fourth arc-shaped flow channel, and the upper end of the sixth vertical flow channel is connected to the upper fourth flow port; A seventh vertical flow channel is designed at the upper right of the rear end of the fourth longitudinal flow channel, the upper end of the seventh vertical flow channel is connected to the upper seventh flow port, and the lower end of the seventh vertical flow channel is connected to the right side of the seventeenth annular groove through an L-shaped flow channel.

2. The production process of a main valve body casting for a high-precision deformation-resistant excavator according to claim 1, characterized in that, The water-based coating described is HA377 water-based coating with a certain amount of graphite powder added as the coating, and the Baume degree of the coating is adjusted to 35°Bé - 42°Bé.

3. The production process of a main valve body casting for a high-precision deformation-proof excavator according to claim 1, characterized in that, The large sand core of the main runner and the small sand cores of the remaining runners are produced using high-strength GHD170 sand for core making.

4. The production process of a main valve body casting for a high-precision deformation-resistant excavator according to claim 1, characterized in that, The contour dimensions of the main valve body casting for the excavator are 76*96*190 mm, and the weight reaches 13 kilograms.

5. The production process of a main valve body casting for a high-precision deformation-resistant excavator according to claim 1, characterized in that, During the core-making process of the large sand core of the main runner and the small sand cores of the remaining runners, a rectangular frame sand core and four portal frame sand cores are also designed. The front and rear ends of the large sand cores of the four longitudinal runners are respectively connected to the middle inner side of the rectangular sand core. At the same time, the four portal frame sand cores are respectively supported and connected to both sides of the upper end of the rectangular sand core. From left to right, they are the first portal frame sand core, the second portal frame sand core, the third portal frame sand core, and the fourth portal frame sand core. The lower end of the first portal frame sand core on the leftmost side is connected to the upper end of the small sand core of the first vertical runner. The lower end of the second portal frame sand core is connected to the upper end of the small sand core of the second vertical runner. The lower end of the third portal frame sand core is connected to the upper ends of the small sand cores of the fifth and sixth vertical runners. The lower end of the fourth portal frame sand core is connected to the upper end of the small sand core of the seventh vertical runner. A transverse sand core is connected between the upper ends of the third portal frame sand core and the fourth portal frame sand core, and the lower end of this transverse sand core is connected to the upper end of the small sand core of the fourth vertical runner. Vertical plate-shaped sand cores are respectively designed on both sides of the lower end of the rectangular frame sand core, and the left end of the small sand core of the first transverse runner is connected to the inner side of the left vertical plate-shaped sand core. A core support is placed above the small sand core of the sixth arc-shaped runner, and the upper end of the core support supports on the inner top of the sand box.

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