Production process of center valve body casting of large engineering machinery

Abstract

The invention relates to a production process of a center valve body casting of a large engineering machine. Large sand cores of a first vertical flow channel, a second vertical flow channel, a third vertical flow channel and a fourth vertical flow channel and matched small sand cores of a vertical flow channel, a transverse flow channel, an arc-shaped flow channel and other flow channels are designed and manufactured according to the flow channel structure of a product. The invention has the advantages that the hollow 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 hollow core bar and the high-strength sand core; a high exothermic riser with the diameter of 120mm is used, a special chilling block is placed on the bottom surface, and meanwhile, a process of simultaneously pouring two sides of a side thin sprue is adopted, so that the phenomenon of overheating at the riser is avoided, the erosion of molten iron to a shell mold and a sand core is reduced, the pouring time is shortened, a good heat dispersion effect is achieved, and the defects of shrinkage cavities, shrinkage porosity and the like are avoided; the asbestos cloth is placed at one end of the large sand core of the main runner, and when a casting expands, a gap can endure the casting, so that the main runner is prevented from being bent.

Description

TECHNICAL FIELD

[0001] The present application relates to the valve body casting production field, and in particular to a production process of a large-scale engineering machinery center valve body casting. BACKGROUND

[0002] XIV32.01-1C center valve body is a large-scale engineering machinery main valve body jointly developed according to the requirements of Xugong Research Institute and market demand. Since the trial production of the project product, it has been tested and used by customers and inspected by the product quality inspection department for two years. The trial production is summarized as follows.

[0003] The valve body product has a large casting volume, a small main hole of the casting, and a difficult-to-guarantee straightness. The internal runner of the casting is complex, there are many heat-saving points, and local fracture and shrinkage are prone to occur. The main content of the project to be studied is to solve the straightness of the main hole of the large-scale complex runner multi-way valve and the shrinkage of the casting. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a production process of a large-scale engineering machinery center valve body casting, which is designed ingeniously, has perfect process, reasonable and compact structure, high straightness precision of the main runner, no fracture and no shrinkage.

[0005] The technical scheme of the present application is as follows: A production process of a large-scale engineering machinery center valve body casting, in the production process of the center valve body casting, the mold cavity in the sand box is made according to the product shape, then the first vertical runner, the second vertical runner, the third vertical runner, the fourth vertical runner, the fifth vertical runner, the sixth vertical runner, the first block-shaped runner and the second block-shaped runner are designed and manufactured according to the runner structure of the product, and the large sand core of the main runner and the small sand core of the rest of the runner are matched, then the large sand core of the main runner and the small sand core of the rest of the runner are placed in the mold cavity of the sand box, the sand box is closed, the molten iron is poured from the reserved pouring gate, after cooling, the sand box is opened, the valve body casting is taken out, the internal sand core is cleaned and removed, and the processing is completed. Before the large sand core of the main runner and the small sand core of the rest of the runner are placed into the sand box, a layer of water-based paint is coated on the front surface of the sand box; the large sand core of the main runner is horizontally placed in the sand box, and a layer of asbestos cloth is placed at one end of the large sand core; a high fever riser with a diameter of 120 mm is reserved in the middle of the sand box, and cold iron is placed at the bottom of the sand box; the pouring is carried out by using the side thin runner pouring process, after the pouring is completed, the molten iron in the high fever riser is stirred by using a metal stirring rod, a layer of heat preservation agent is scattered above the high fever riser after stirring for 1-2 minutes; the large sand core and the small sand core are made of high-strength HAGHD290 type sand core sand; a hollow core bone with a diameter of φ10 mm is arranged in the middle of the large sand core of the main runner. The center valve body casting comprises a main body, a first vertical flow channel, a second vertical flow channel, a third vertical flow channel, a fourth vertical flow channel, a fifth vertical flow channel, a sixth vertical flow channel, a first square flow channel and a second square flow channel, and the main body is in a rectangular body shape; The front face of the main body is designed with four flow channel openings, namely a first flow channel opening, a second flow channel opening, a third flow channel opening and a fourth flow channel opening; The rear face of the main body is designed with three flow channel openings, namely a first flow channel opening, a second flow channel opening and a third flow channel opening; The upper face of the main body is designed with nine flow channel openings, namely a first flow channel opening, a second flow channel opening, a third flow channel opening, a fourth flow channel opening, a fifth flow channel opening, a sixth flow channel opening, a seventh flow channel opening, an eighth flow channel opening and a ninth flow channel opening; The lower face of the main body is designed with six flow channel openings, namely a first flow channel opening, a second flow channel opening, a third flow channel opening, a fourth flow channel opening, a fifth flow channel opening and a sixth flow channel opening; The left face of the main body is designed with five flow channel openings, namely a first flow channel opening, a second flow channel opening, a third flow channel opening, a fourth flow channel opening and a fifth flow channel opening; The right face of the main body is designed with seven flow channel openings, namely a first flow channel opening, a second flow channel opening, a third flow channel opening, a fourth flow channel opening, a fifth flow channel opening, a sixth flow channel opening and a seventh flow channel opening; The first vertical flow channel, the second vertical flow channel, the third vertical flow channel, the fourth vertical flow channel, the fifth vertical flow channel and the sixth vertical flow channel in the main body are divided into two rows, the upper ends of the first vertical flow channel, the second vertical flow channel, the third vertical flow channel, the fourth vertical flow channel, the fifth vertical flow channel and the sixth vertical flow channel are communicated and penetrate through the first square flow channel, and the first vertical flow channel, the second vertical flow channel, the third vertical flow channel, the fourth vertical flow channel, the fifth vertical flow channel and the sixth vertical flow channel correspond to the first flow channel opening, the second flow channel opening, the third flow channel opening, the fourth flow channel opening, the fifth flow channel opening and the sixth flow channel opening at the upper end of the main body respectively; the lower ends of the first vertical flow channel, the second vertical flow channel, the third vertical flow channel, the fourth vertical flow channel, the fifth vertical flow channel and the sixth vertical flow channel are communicated and penetrate through the second square flow channel, and the first vertical flow channel, the second vertical flow channel, the third vertical flow channel, the fourth vertical flow channel, the fifth vertical flow channel and the sixth vertical flow channel correspond to the first flow channel opening, the second flow channel opening, the third flow channel opening, the fourth flow channel opening, the fifth flow channel opening and the sixth flow channel opening at the lower end of the main body respectively; The front right side of the first square flow channel and the second square flow channel is communicated through a first arc-shaped flow channel; the front left side of the first square flow channel is communicated with the first flow channel opening through a horizontal flow channel; the left front end of the first square flow channel is communicated with the first vertical small flow channel through a horizontal flow channel, and the upper end of the first vertical small flow channel is communicated with the seventh flow channel opening; the front left side of the second square flow channel is communicated with the fourth flow channel opening through a horizontal flow channel; The first vertical flow channel is sequentially provided with a first ring groove, a second ring groove and a third ring groove from top to bottom, the first ring groove is communicated with the front two flow channel openings through a horizontal flow channel, the front ends of the first ring groove and the third ring groove are communicated through a second arc-shaped flow channel, the middle of the second arc-shaped flow channel is communicated with the front two flow channel openings through a horizontal flow channel, and the lower left side of the second arc-shaped flow channel is communicated with the left flow channel opening through a horizontal flow channel; The second vertical flow channel is sequentially provided with a fourth ring groove and a fifth ring groove from top to bottom; The third vertical flow channel is sequentially provided with a sixth ring groove, a seventh ring groove and an eighth ring groove from top to bottom, the front end of the fifth ring groove is communicated with the front end of the seventh ring groove through a third arc-shaped flow channel, the lower right side of the second arc-shaped flow channel is communicated with the left side of the third arc-shaped flow channel, and the right side of the third arc-shaped flow channel is communicated with the right flow channel opening through a horizontal flow channel, the sixth ring groove is communicated with the right two flow channel openings through a horizontal flow channel, and the eighth ring groove is communicated with the right three flow channel openings through a horizontal flow channel; The fourth vertical flow channel is sequentially provided with a ninth ring groove, a tenth ring groove, an eleventh ring groove, a twelfth ring groove and a thirteenth ring groove from top to bottom; The fifth vertical flow channel is sequentially provided with a fourteenth ring groove, a fifteenth ring groove, a sixteenth ring groove, a seventeenth ring groove and an eighteenth ring groove from top to bottom; The fourth vertical flow channel is sequentially provided with a nineteenth ring groove, a twentieth ring groove, a twenty-first ring groove, a twenty-second ring groove and a twenty-third ring groove from top to bottom; The rear end of the second ring groove is communicated with the front end of the eleventh ring groove through a horizontal flow channel, the rear end of the fourth ring groove is communicated with the front end of the fifteenth ring groove through a flow channel, the rear end of the fifth ring groove is communicated with the front end of the seventeenth ring groove through a fourth arc-shaped flow channel, the left side of the fourth arc-shaped flow channel is communicated with the lower end of the second vertical small flow channel through a horizontal flow channel, and the lower left side of the second vertical small flow channel is communicated with the left two flow channel openings through a horizontal flow channel; The right middle of the first block-shaped flow channel and the right middle of the second block-shaped flow channel are communicated through a vertical rectangular flow channel, and the rear middle of the vertical rectangular flow channel is communicated with the twenty-first ring groove through a horizontal flow channel; The left side of the tenth ring groove and the left side of the twelfth ring groove are communicated through a fifth arc-shaped flow channel, the left middle of the fifth arc-shaped flow channel is communicated with the left three flow channel openings through a horizontal flow channel, the upper end of the third vertical small flow channel is communicated with the upper nine flow channel openings, and the middle of the third vertical small flow channel, the middle of the second vertical small flow channel and the lower end of the first vertical small flow channel are communicated through a horizontal flow channel; The right end of the fourteenth ring groove is communicated with the left end of the nineteenth ring groove through a horizontal flow channel, the right end of the eighteenth ring groove is communicated with the left end of the twenty-third ring groove through a horizontal flow channel, the right end of the twentieth ring groove is communicated with the right four flow channel openings through a horizontal flow channel, and the right end of the twenty-second ring groove is communicated with the right five flow channel openings through a horizontal flow channel; The left rear end of the first block-shaped flow channel is communicated with the rear fifth flow channel through a flow channel; the left rear end of the first block-shaped flow channel is communicated with the left fifth flow channel through a flow channel; The rear end of the ninth annular groove is communicated with the right sixth flow channel through the sixth arc-shaped flow channel; the rear end of the eleventh annular groove is communicated with the rear second flow channel through a horizontal flow channel; the rear end of the sixteenth annular groove is communicated with the left fourth flow channel through the seventh arc-shaped flow channel, and the seventh arc-shaped flow channel also communicates with the lower end of the horizontal flow channel of the rear end of the eleventh annular groove; the rear end of the thirteenth annular groove is communicated with the right seventh flow channel through the eighth arc-shaped flow channel. The rear end of the second block-shaped flow channel is communicated with the rear third flow channel through a flow channel; the rear end of the nineteenth annular groove and the rear end of the twenty-third annular groove are communicated through the ninth arc-shaped flow channel.

[0006] The upper and lower front and rear ends of the main body are respectively designed with a rectangular boss, and the inner side of the four rectangular bosses is respectively provided with an L-shaped step groove; the left side of the four rectangular bosses is flush with the left side end surface of the main body, and the right side of the four rectangular bosses forms a gap with the main body; the rear side of the main body is provided with a double-layer step groove, and the double-layer step groove comprises a first layer step groove and a second layer step groove; the rear end of the first layer step groove is communicated with the rear end surface of the main body, the rear end of the first layer step groove is designed with the second layer step groove in the middle, and the rear end of the second layer step groove is communicated with the right side end surface of the main body; the left side of the upper end surface of the main body is provided with an L-shaped step groove, and the upper eighth flow channel and the upper ninth flow channel are respectively located at the positions close to the front and rear sides of the bottom of the L-shaped step groove.

[0007] The middle of the first block-shaped flow channel and the second block-shaped flow channel are designed with a support column.

[0008] The water-based paint is HA377 water-based paint, and a certain amount of graphite powder is added as the paint, and the Baume degree of the paint is adjusted to 35°Bé-42°Bé.

[0009] The thickness of the asbestos cloth is 1.5 mm.

[0010] The contour size of the center valve body casting is 430*330*320mm, and the weight reaches 200kg.

[0011] The advantages of the present application are: The hollow core is arranged in the large sand core of the main flow channel, and the high-strength sand core sand is used for sanding, so that the bending strength of the main hole is increased through the combination of the two, and the straightness is ensured; The surface of the sand core is coated with paint, and the Baume degree is set to 35°Bé-42°Bé, which can effectively prevent sintering and ensure the surface quality of the flow channel; Using a diameter of 120 mm high fever riser, bottom placed special cold iron, while using the side thin gate two sides pouring process, not only can directly avoid the phenomenon of overheating riser, but also can greatly reduce the molten iron flushing shell and sand core, reduce pouring time, so as to have a good dispersion of heat, no shrinkage porosity and other defects; After pouring, use metal rod in the riser stirring, prevent the formation of small pool can't make up, finally in the riser above a layer of insulation material, good let the riser played the role of make up; The main flow channel of the big sand core is placed on the asbestos cloth. When the casting expands, there will be a 1.5 gap tolerance, so as to prevent the bending of the main flow channel. Combined with the timely cooling of the bottom cold iron, the straightness of the main flow channel is ensured within 1.0 mm. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figures 1-2 is the front and rear perspective view of the invention.

[0013] Figures 3-7 is the front view of the invention from front to back in turn (internal flow channel display schematic diagram).

[0014] Figure 8 is the rear view of the invention close to the rear end (internal flow channel display schematic diagram).

[0015] Figure 9 is the side view of the invention close to the right end (internal flow channel display schematic diagram).

[0016] Figure 10 is the side view of the invention close to the left end (internal flow channel display schematic diagram). DETAILED DESCRIPTION

[0017] Referring to the accompanying Figures 1-10 A large-scale engineering machinery center valve body casting, the center valve body valve body casting in the production process, according to the product shape to make the cavity in the sand box, then according to the product flow channel structure design and manufacture of the first vertical flow channel 1, the second vertical flow channel 2, the third vertical flow channel 3, the fourth vertical flow channel 4, the fifth vertical flow channel 5, the sixth vertical flow channel 6, the first block flow channel 7 and the second block flow channel 8 big sand core and the matching vertical flow channel, horizontal flow channel, arc flow channel small sand core of the rest of the flow channel, then put the main flow channel of the big sand core and the small sand core of the rest of the flow channel in the cavity of the sand box, close the sand box, then pour the molten iron from the reserved pouring riser, wait for cooling, open the sand box, take out the valve body casting, then clean the internal sand core and export, complete the processing; The large sand core of the main channel and the small sand cores of the other channels are placed in the sand box and coated with a layer of water-based paint on the front surface; the large sand core of the main channel is placed horizontally in the sand box and a layer of asbestos cloth is placed on one end of the large sand core; a high-temperature riser with a diameter of 120mm is reserved in the middle of the upper part of the sand box, and a chiller is placed at the bottom of the sand box; the casting is carried out by a simultaneous casting process on both sides of the thin side gate. After the casting is completed, a metal stirring rod is used to stir the molten iron in the high-temperature riser. After stirring for 1-2 minutes, a layer of insulation is sprinkled above the high-temperature riser; the large sand core and the small sand core are made of high-strength HAGHD290 sand core sand; a hollow core bone with a diameter of φ10mm is set in the middle of the large sand core of the main channel; This invention utilizes a 120mm diameter high-heat riser with a dedicated chiller placed at the bottom. Simultaneous pouring from both sides of a thin side gate not only directly prevents overheating at the riser but also significantly reduces molten iron scouring the shell and core, shortening pouring time and effectively dispersing heat. After pouring, mechanical stirring is used to continuously stir the riser to prevent the formation of a small, unreplenishable molten pool. Finally, a layer of insulation material is sprinkled over the riser, effectively replenishing the riser. The casting was further sectioned and dissected, and color flaw detection was performed, revealing no defects such as shrinkage cavities or porosity. Other requirements also met the QT600-3 standard, and the casting's appearance was also excellent.

[0018] The central valve body casting includes a main body 10, a first vertical flow channel 1, a second vertical flow channel 2, a third vertical flow channel 3, a fourth vertical flow channel 4, a fifth vertical flow channel 5, a sixth vertical flow channel 6, a first block-shaped flow channel 7 and a second block-shaped flow channel 8. The main body 10 is in a rectangular shape. The front of the main body 10 is designed with four flow channels, namely the front first flow channel 11, the front second flow channel 12, the front third flow channel 13, and the front fourth flow channel 14; There are three flow channels designed at the rear of the main body 10, namely the rear first flow channel 21, the rear second flow channel 22, and the rear third flow channel 23; The main body 10 is designed with 9 flow channels, namely, an upper first flow channel 31, an upper second flow channel 32, an upper third flow channel 33, an upper fourth flow channel 34, an upper fifth flow channel 35, an upper sixth flow channel 36, an upper seventh flow channel 37, an upper eighth flow channel 38, and an upper ninth flow channel 39; Six flow channels are designed below the main body 10, namely, a lower flow channel 41, a lower second flow channel 42, a lower third flow channel 43, a lower fourth flow channel 44, a lower fifth flow channel 45, and a lower sixth flow channel 46; The left side of the main body 10 is designed with five flow channels, namely the first left flow channel 51, the second left flow channel 52, the third left flow channel 53, the fourth left flow channel 54, and the fifth left flow channel 55; The right face of the main body 10 is designed with seven flow channel openings, which are right one flow channel opening 61, right two flow channel opening 62, right three flow channel opening 63, right four flow channel opening 64, right five flow channel opening 65, right six flow channel opening 66 and right seven flow channel opening 67 respectively. The first vertical flow channel 1, the second vertical flow channel 2, the third vertical flow channel 3, the fourth vertical flow channel 4, the fifth vertical flow channel 5 and the sixth vertical flow channel 6 in the main body 10 are divided into two rows, the upper ends of the first vertical flow channel 1, the second vertical flow channel 2, the third vertical flow channel 3, the fourth vertical flow channel 4, the fifth vertical flow channel 5 and the sixth vertical flow channel 6 are communicated and penetrate through the first square flow channel 7 and correspond to the upper one flow channel opening 31, the upper two flow channel opening 32, the upper three flow channel opening 33, the upper four flow channel opening 34, the upper five flow channel opening 35 and the upper six flow channel opening 36 of the upper end of the main body 10 respectively, the lower ends of the first vertical flow channel 1, the second vertical flow channel 2, the third vertical flow channel 3, the fourth vertical flow channel 4, the fifth vertical flow channel 5 and the sixth vertical flow channel 6 are communicated and penetrate through the second square flow channel 8 and correspond to the lower one flow channel opening 41, the lower two flow channel opening 42, the lower three flow channel opening 43, the lower four flow channel opening 44, the lower five flow channel opening 45 and the lower six flow channel opening 46 of the lower end of the main body 10 respectively. The front right side of the first square flow channel 7 and the second square flow channel 8 is communicated through the first arc-shaped flow channel 20, the front left side of the first square flow channel 7 is communicated through a horizontal flow channel to the front one flow channel opening 11, the left front end of the first square flow channel 7 is communicated through a horizontal flow channel to the first vertical small flow channel 81, the upper end of the first vertical small flow channel 81 is communicated to the upper seven flow channel opening 37, the front left side of the second square flow channel 8 is communicated through a horizontal flow channel to the front four flow channel opening 14. The first vertical flow channel 1 is sequentially provided with the first ring groove 71, the second ring groove 72 and the third ring groove 73 from top to bottom, the first ring groove 71 is communicated to the front two flow channel opening 12 through a horizontal flow channel, the front ends of the first ring groove 71 and the third ring groove 73 are communicated through the second arc-shaped flow channel, the middle of the second arc-shaped flow channel is communicated to the front two flow channel opening 12 through a horizontal flow channel, the lower left side of the second arc-shaped flow channel is communicated to the left one flow channel opening 51 through a horizontal flow channel. The second vertical flow channel 2 is sequentially provided with the fourth ring groove 74 and the fifth ring groove 75 from top to bottom. The third vertical flow channel 3 is sequentially provided with the sixth ring groove 76, the seventh ring groove 77 and the eighth ring groove 78 from top to bottom, the front end of the fifth ring groove 75 is communicated to the front end of the seventh ring groove 77 through the third arc-shaped flow channel, the lower right side of the second arc-shaped flow channel is communicated to the left side of the third arc-shaped flow channel, the right side of the third arc-shaped flow channel is communicated to the right one flow channel opening 61 through a horizontal flow channel, the sixth ring groove 76 is communicated to the right two flow channel opening 62 through a horizontal flow channel, and the eighth ring groove 78 is communicated to the right three flow channel opening 63 through a horizontal flow channel. The fourth vertical flow channel 4 is sequentially provided with the ninth ring groove 79, the tenth ring groove 710, the eleventh ring groove 711, the twelfth ring groove 712 and the thirteenth ring groove 713 from top to bottom. The fifth vertical flow channel 5 is sequentially provided with a fourteenth annular groove 714, a fifteenth annular groove 715, a sixteenth annular groove 716, a seventeenth annular groove 717, and an eighteenth annular groove 718 from top to bottom; The fourth vertical flow channel 4 is sequentially provided with a nineteenth annular groove 719, a twentieth annular groove 720, a twenty-first annular groove 721, a twenty-second annular groove 723, and a twenty-third annular groove 724 from top to bottom; The rear end of the second annular groove 72 is communicated with the front end of the eleventh annular groove 711 through a horizontal flow channel, the rear end of the fourth annular groove 74 is communicated with the front end of the fifteenth annular groove 715 through a flow channel, the rear end of the fifth annular groove 75 is communicated with the front end of the seventeenth annular groove 717 through a fourth arc-shaped flow channel, the left side of the fourth arc-shaped flow channel near the middle position is communicated with the lower end of the second vertical small flow channel 82 through a horizontal flow channel, and the left side of the lower end of the second vertical small flow channel 82 is communicated with the left two flow channel port 52 through a horizontal flow channel; The right middle of the first block-shaped flow channel 7 and the right middle of the second block-shaped flow channel 8 are communicated through a vertical rectangular flow channel 30, and the middle of the rear side of the vertical rectangular flow channel is communicated with the twenty-first annular groove 721 through a horizontal flow channel; The left side of the tenth annular groove 710 and the left side of the twelfth annular groove 712 are communicated through a fifth arc-shaped flow channel, the middle of the left side of the fifth arc-shaped flow channel is communicated with the left three flow channel port 53 through a horizontal flow channel, the upper end of the horizontal flow channel is communicated with the lower end of the third vertical small flow channel 83, the upper end of the third vertical small flow channel 83 is communicated with the upper nine flow channel port 39, and the middle of the third vertical small flow channel 83, the middle of the second vertical small flow channel 82, and the lower end of the first vertical small flow channel 81 are communicated through a horizontal flow channel; The right end of the fourteenth annular groove 714 is communicated with the left end of the nineteenth annular groove 719 through a horizontal flow channel, the right end of the eighteenth annular groove 718 is communicated with the left end of the twenty-third annular groove 724 through a horizontal flow channel, the right end of the twentieth annular groove 720 is communicated with the right four flow channel port 64 through a horizontal flow channel, and the right end of the twenty-second annular groove 723 is communicated with the right five flow channel port 65 through a horizontal flow channel; The left side of the rear end of the first block-shaped flow channel 7 is communicated with the rear flow channel port 21 through a flow channel, and the left side of the rear end of the first block-shaped flow channel 7 is communicated with the left five flow channel port 55 through a flow channel; The rear end of the ninth annular groove 79 is communicated with the right six flow channel port 66 through a sixth arc-shaped flow channel, the rear end of the eleventh annular groove 711 is communicated with the rear two flow channel port 22 through a horizontal flow channel, the rear end of the sixteenth annular groove 716 is communicated with the left four flow channel port 54 through a seventh arc-shaped flow channel, and the seventh arc-shaped flow channel is also communicated with the lower end of the horizontal flow channel of the rear end of the eleventh annular groove 711, and the rear end of the thirteenth annular groove 713 is communicated with the right seven flow channel port 67 through an eighth arc-shaped flow channel; The left side of the rear end of the second block-shaped flow channel 8 is communicated with the rear three flow channel port 23 through a flow channel, and the rear end of the nineteenth annular groove 719 and the rear end of the twenty-third annular groove 724 are communicated through a ninth arc-shaped flow channel.

[0019] The upper and lower ends of the main body 10 are respectively designed with a rectangular boss 9, and the inner side of the middle of the four rectangular bosses 9 is respectively provided with an L-shaped step 91, the four rectangular bosses 9 are all arranged to be flush with the left side end surface of the main body 10, and the right side of the four rectangular bosses 9 and the main body 10 form a gap; the middle of the rear side of the side end surface of the main body 10 is provided with a double-layer step groove 101, the double-layer step groove 101 comprises a first layer step groove and a second layer step groove, the rear end of the first layer step groove is communicated with the rear end surface of the main body 10, the middle of the rear end of the first layer step groove is designed with the second layer step groove, and the rear end of the second layer step groove is communicated with the right side end surface of the main body 10; the middle of the left side of the upper end surface of the main body is provided with an L-shaped step groove, and the upper eight flow channel opening and the upper nine flow channel opening are respectively located at the positions close to the front and rear sides of the bottom of the L-shaped step groove.

[0020] The middle of the first block-shaped flow channel 7 and the second block-shaped flow channel 8 is designed with a support column.

[0021] The water-based paint is HA377 water-based paint, and a certain amount of graphite powder is added as the paint, and the Baume degree of the paint is adjusted to 35°Bé-42°Bé. For this design, because the flow channel of the casting is dense and complex, the heat is dense during pouring, and it is easy to cause defects such as sintering, so the paint requirement for the sand core is also very important, the application adopts HA377 water-based paint, and a certain amount of graphite powder is added as the paint, and the Baume degree of the paint is adjusted to 35°Bé-42°Bé, if the Baume degree is too high, the paint is easy to accumulate, if the Baume degree is too low, the paint cannot play a role, therefore, the Baume degree of the paint of the application is set to 35°Bé-42°Bé, which is the most reasonable, and can effectively prevent sintering and ensure the surface quality of the flow channel.

[0022] The thickness of the asbestos cloth is 1.5 mm. Because the expansion force of the casting is large, the box is easy to expand, and the main hole is easy to bend because the core support cannot be placed, in order to ensure that the straightness of the casting is less than 1.0 mm, the core bone is increased to control the bending degree, and the core support is placed at the place where the core support can be placed, but the result is not very ideal, although the bending degree is small, but the problem of bending of the main hole of the casting cannot be completely solved. Therefore, the application places the asbestos cloth with a gap of 1.5 mm at all core heads of the main hole, when the casting expands, there is a 1.5 mm gap to tolerate, thereby preventing the bending of the main hole, and combining with the timely cooling of the bottom cold iron, the straightness of the main hole is ensured to be within 1.0 mm.

[0023] The center valve body casting has a profile size of 430*330*320mm, and a weight of 200kg.

[0024] The main index parameters of the valve body are determined: The material is QT600-3. 2) Tensile strength of the body: ≥ 550 Mpa; 3) Yield strength: ≥ 340 Mpa; 3) HB hardness: 190-270; 4) Spheroidization grade: 1-3 grade; 5) The metallographic structure shall meet the evaluation of GB / T 9441-2009; 6) Graphite size grade: 6-8 grade; 7) No slag inclusion, pore, shrinkage hole, shrinkage porosity and other casting defects; 8) Valve body weight: 200 KG.

Claims

1. A production process for a central valve body casting of a large-scale engineering machinery, characterized in that: During the production process of the central valve body casting, a cavity in the sand box is made according to the product shape. Then, large sand cores for the first vertical flow channel, the second vertical flow channel, the third vertical flow channel, the fourth vertical flow channel, the fifth vertical flow channel, the sixth vertical flow channel, the first block-shaped flow channel, the second block-shaped flow channel, and the corresponding small sand cores for the vertical flow channel, the horizontal flow channel, the arc-shaped flow channel, and the remaining flow channels are manufactured according to the flow channel structure design. 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. The sand box is closed, and molten iron is poured in from the reserved pouring riser. After cooling, the sand box is opened, the valve body casting is taken out, and the internal sand cores are cleaned and discharged to complete the processing. The large sand core of the main channel and the small sand cores of the other channels are placed in the sand box and coated with a layer of water-based paint on the front surface; the large sand core of the main channel is placed horizontally in the sand box and a layer of asbestos cloth is placed on one end of the large sand core; a high-temperature riser with a diameter of 120mm is reserved in the middle of the upper part of the sand box, and a chiller is placed at the bottom of the sand box; the casting is carried out by a simultaneous casting process on both sides of the thin side gate. After the casting is completed, a metal stirring rod is used to stir the molten iron in the high-temperature riser. After stirring for 1-2 minutes, a layer of insulation is sprinkled above the high-temperature riser; the large sand core and the small sand core are made of high-strength HAGHD290 sand core sand; a hollow core bone with a diameter of φ10mm is set in the middle of the large sand core of the main channel; The central valve body casting includes a main body, a first vertical flow channel, a second vertical flow channel, a third vertical flow channel, a fourth vertical flow channel, a fifth vertical flow channel, a sixth vertical flow channel, a first block-shaped flow channel and a second block-shaped flow channel. The main body is in a rectangular shape. There are 4 flow ports designed in front of the main body, namely the front first flow port, the front second flow port, the front third flow port, and the front fourth flow port; There are three flow outlets designed at the back of the main body, namely the rear first flow outlet, rear second flow outlet, and rear third flow outlet; There are 9 flow outlets designed on the main body, namely the upper first flow outlet, upper second flow outlet, upper third flow outlet, upper fourth flow outlet, upper fifth flow outlet, upper sixth flow outlet, upper seventh flow outlet, upper eighth flow outlet, and upper ninth flow outlet; There are 6 flow outlets designed under the main body, namely the lower flow outlet, the lower second flow outlet, the lower third flow outlet, the lower fourth flow outlet, the lower fifth flow outlet, and the lower sixth flow outlet; There are 5 flow outlets designed on the left side of the main body, namely the left first flow outlet, the left second flow outlet, the left third flow outlet, the left fourth flow outlet, and the left fifth flow outlet; There are 7 flow outlets designed on the right side of the main body, namely right first flow outlet, right second flow outlet, right third flow outlet, right fourth flow outlet, right fifth flow outlet, right sixth flow outlet, right seventh flow outlet; The first vertical flow channel, the second vertical flow channel, the third vertical flow channel, the fourth vertical flow channel, the fifth vertical flow channel and the sixth vertical flow channel in the main body are divided into two rows, front and back. The upper ends of the first vertical flow channel, the second vertical flow channel, the third vertical flow channel, the fourth vertical flow channel, the fifth vertical flow channel and the sixth vertical flow channel are connected and pass through the first block-shaped flow channel, and respectively correspond to the upper flow channel opening, the upper second flow channel opening, the upper third flow channel opening, the upper fourth flow channel opening, the upper fifth flow channel opening and the upper sixth flow channel opening connected to the upper end of the main body. The lower ends of the first vertical flow channel, the second vertical flow channel, the third vertical flow channel, the fourth vertical flow channel, the fifth vertical flow channel and the sixth vertical flow channel are connected and pass through the second block-shaped flow channel, and respectively correspond to the lower flow channel opening, the lower second flow channel opening, the lower third flow channel opening, the lower fourth flow channel opening, the lower fifth flow channel opening and the lower sixth flow channel opening connected to the lower end of the main body. The front right sides of the first block-shaped flow channel and the second block-shaped flow channel are connected through a first arc-shaped flow channel; the front left side of the first block-shaped flow channel is connected to the previous flow channel opening through a horizontal flow channel; the front left side of the first block-shaped flow channel is connected to the first vertical small flow channel through a horizontal flow channel, and the upper end of the first vertical small flow channel is connected to the upper seven flow channel openings; the front left side of the second block-shaped flow channel is connected to the first four flow channel openings through a horizontal flow channel; The first vertical flow channel is provided with a first annular groove, a second annular groove, and a third annular groove in sequence from top to bottom. The first annular groove is connected to the front two flow channel openings through a transverse flow channel. The front ends of the first annular groove and the third annular groove are connected through a second arcuate flow channel. The middle of the second arcuate flow channel is connected to the front two flow channel openings through a transverse flow channel. The left side of the lower end of the second arcuate flow channel is connected to the left flow channel opening through a transverse flow channel. The second vertical flow channel is provided with a fourth annular groove and a fifth annular groove in sequence from top to bottom; The third vertical flow channel is provided with a sixth annular groove, a seventh annular groove, and an eighth annular groove in order from top to bottom; the front end of the fifth annular groove is connected to the front end of the seventh annular groove through the third arcuate flow channel, the right side of the lower end of the second arcuate flow channel is connected to the left side of the third arcuate flow channel, and the right side of the third arcuate flow channel is connected to the right first flow channel opening through a transverse flow channel; the sixth annular groove is connected to the right second flow channel opening through a transverse flow channel, and the eighth annular groove is connected to the right third flow channel opening through a transverse flow channel; The fourth vertical flow channel is provided with a ninth ring groove, a tenth ring groove, an eleventh ring groove, a twelfth ring groove, and a thirteenth ring groove in order from top to bottom; The fifth vertical flow channel is provided with a fourteenth ring groove, a fifteenth ring groove, a sixteenth ring groove, a seventeenth ring groove, and an eighteenth ring groove in order from top to bottom; The fourth vertical flow channel is provided with a nineteenth annular groove, a twentieth annular groove, a twenty-first annular groove, a twenty-second annular groove, and a twenty-third annular groove in order from top to bottom; The rear end of the second annular groove is connected to the front end of the eleventh annular groove via a transverse flow channel, and the rear end of the fourth annular groove is connected to the front end of the fifteenth annular groove via a flow channel. The rear end of the fifth annular groove is connected to the front end of the seventeenth annular groove via a fourth arcuate flow channel. The left side of the fourth arcuate flow channel, near the middle, is connected to the lower end of the second vertical small flow channel via a transverse flow channel, and the left side of the lower end of the second vertical small flow channel is connected to the left second flow channel outlet via a transverse flow channel. The middle of the right side of the first block-shaped flow channel and the middle of the right side of the second block-shaped flow channel are connected through a vertical rectangular flow channel, and the middle of the rear side of the vertical rectangular flow channel is connected to the twenty-first annular groove through a horizontal flow channel; The left side of the tenth annular groove is connected to the left side of the twelfth annular groove through a fifth arcuate flow channel; the middle of the left side of the fifth arcuate flow channel is connected to the left third flow channel opening through a transverse flow channel, and the upper end of the transverse flow channel is connected to the lower end of the third vertical small flow channel, and the upper end of the third vertical small flow channel is connected to the upper ninth flow channel opening; the middle of the third vertical small flow channel, the middle of the second vertical small flow channel, and the lower end of the first vertical small flow channel are connected through a transverse flow channel; The right end of the fourteenth annular groove is connected to the left end of the nineteenth annular groove through a transverse flow channel, the right end of the eighteenth annular groove is connected to the left end of the twenty-third annular groove through a transverse flow channel, the right end of the twentieth annular groove is connected to the right fourth flow channel opening through a transverse flow channel, and the right end of the twenty-second annular groove is connected to the right fifth flow channel opening through a transverse flow channel; The left side of the rear end of the first block-shaped flow channel is connected to the rear first flow channel through the first flow channel, and the left side of the rear end of the first block-shaped flow channel is connected to the left fifth flow channel through the first flow channel; The rear end of the ninth annular groove is connected to the right sixth flow channel through the sixth arc flow channel; the rear end of the eleventh annular groove is connected to the rear second flow channel through a transverse flow channel; the rear end of the sixteenth annular groove is connected to the left fourth flow channel through the seventh arc flow channel, and the seventh arc flow channel is also connected to the lower end of the transverse flow channel at the rear end of the eleventh annular groove; the rear end of the thirteenth annular groove is connected to the right seventh flow channel through the eighth arc flow channel; The left side of the rear end of the second block-shaped flow channel is connected to the rear three flow channel openings through a flow channel; the rear end of the nineteenth annular groove is connected to the rear end of the twenty-third annular groove through a ninth arc-shaped flow channel.

2. The production process of a large-scale engineering machinery central valve body casting according to claim 1 is characterized in that: The water-based paint is HA377 water-based paint and a certain amount of graphite powder is added as the paint, and the Baume degree of the paint is adjusted to 35°Bé-42°Bé.

3. The production process of a large-scale engineering machinery central valve body casting according to claim 1 is characterized in that: The thickness of the asbestos cloth is 1.5 mm.

4. The production process of a large-scale engineering machinery central valve body casting according to claim 1 is characterized in that: The central valve body casting has an outline size of 430*330*320mm and weighs 200 kilograms.

5. The production process of a large-scale engineering machinery central valve body casting according to claim 1 is characterized in that: A rectangular boss is designed at the front and rear ends of the upper and lower parts of the main body respectively, and an L-shaped step groove is provided in the middle of the inner side of each of the four rectangular bosses. The four rectangular bosses are set so that the left side is flush with the left end face of the main body, and a gap is formed between the right side of the four rectangular bosses and the main body; a double-layer step groove is provided in the middle of the rear side of the side end face of the main body, and the double-layer step groove includes a first-layer step groove and a second-layer step groove. The rear end of the first-layer step groove is connected to the rear end face of the main body, and a second-layer step groove is designed in the middle of the rear end of the first-layer step groove, and the rear end of the second-layer step groove is connected to the right end face of the main body; an L-shaped step groove is provided in the middle of the left side of the upper end face of the main body, and the upper eight flow channel openings and the upper nine flow channel openings are respectively located at the bottom of the L-shaped step groove near the front and rear sides.

6. The production process of a large-scale engineering machinery central valve body casting according to claim 1 is characterized in that: Support columns are designed in the middle of the first block-shaped flow channel and the second block-shaped flow channel.

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