Universal casting system and process for blank pressing of round gray iron compressor and manufactured casting

Abstract

The invention discloses a universal casting system and process for blank pressing of a round gray iron compressor and a manufactured casting, and belongs to the technical field of pouring. The casting system comprises a pouring cup; the cross gate is positioned below the sprue cup; and the vertical pouring gate is connected below the transverse pouring gate and comprises one or more vertical pouring gate bodies which are used for receiving the pouring liquid from the transverse pouring gate and a mold cavity. Through reasonable design of the runner area, the obtained casting system is suitable for casting of blank pressing of various circular gray iron compressors, the flow design accuracy of each layer of the circular gray iron compressors is improved, repeated mold flow adjustment is not needed, the size design of the casting system and adjustment of the pouring process and components are utilized, and the production efficiency is improved. The casting prepared by using the casting system can obtain stable high yield, and the casting prepared by using the casting system can obtain stable high yield.

Description

Technical Field

[0001] The invention belongs to the technical field of casting, and more specifically, relates to a universal casting system, process and obtained casting of a round grey iron compressor press edge. Background Art

[0002] The shapes and sizes of the products of the round gray iron compressor press edge are mostly similar. At the beginning of the design, mature processes can be used as a reference, which can effectively improve the mold design and product trial production, thereby improving production efficiency. It can also be flexibly used between different products to improve the stability of product quality. The existing flow channels include three standard flow channel shapes, among which the simple trapezoidal flow channel is used as a vertical flow channel, the slender trapezoidal flow channel is used as a horizontal flow channel, and the high trapezoidal flow channel is used as an upper horizontal flow channel. The flow channel cross-sectional area varies according to the shape of the different flow channels.

[0003] For example, patent CN220372152U discloses an air-conditioning compressor cylinder casting system structure for a vertical casting production line, including an external pouring gate, the external pouring gate is connected to a cross runner, the cross runner is connected to a straight runner riser, the cross runner and the straight runner riser are staggered in front and back, and are connected and conducted by a connecting pressure edge, the upper section of the straight runner riser is the runner part, and the lower section is the riser part, and the side of the straight runner riser is provided with a cavity for pouring annular air-conditioning compressor cylinder castings.

[0004] For another example, patent CN118305273A discloses a pouring device and casting method for special-shaped castings, wherein the special-shaped castings include an upper cavity, a lower cavity and a middle cavity, and also include a casting system that is simultaneously connected to the upper cavity, the lower cavity and the middle cavity; the casting system includes a casting mechanism 1, the casting mechanism 1 includes a first runner, an upper pouring port, a second runner, a middle pouring port and a lower pouring port, the first runner is located at the upper end of the second runner and is interconnected, and the first runner maintains a horizontal direction between the first runner and the second runner for pouring. The pouring device for the special-shaped casting is designed with a pouring port and a cross-sectional area of ​​the runner to prevent molten steel from forming sand in the cavity.

[0005] However, conventional flow channel design formulas have the problem of inaccurate flow calculation, especially in vertical flow channels. Since the molten iron is poured from top to bottom, the flow rate of the upper flow channel is usually calculated to be too large, which is easy to wash away sand, while the flow rate of the lower layer is too small, which leads to slow filling and seriously affects the quality of castings. In order to ensure the quality of castings, it is necessary to adjust the flow rate of each layer of the casting system by adjusting the flow channel cross-sectional area to obtain a filling speed suitable for mass production. Summary of the invention

[0006] 1. Problem to be solved

[0007] Aiming at the problem that the flow rate design of each layer of the existing circular gray iron compressor is inaccurate and requires repeated mold flow adjustment, the first object of the present invention is to provide a universal casting system for the edge of a circular gray iron compressor, which can realize the accurate design of the flow rate of each layer;

[0008] The second object of the present invention is to provide a casting process and a casting obtained by using the above-mentioned casting system, wherein the process can obtain a stable high output rate.

[0009] 2. Technical solution

[0010] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0011] The first object of the present invention is to provide a universal casting system for a round gray iron compressor press edge, the casting system comprising:

[0012] Pouring cup: located at the top of the casting system;

[0013] Horizontal runner: Located below the pouring cup, the pouring flows from the pouring cup to the horizontal runner, which plays the role of buffering the pouring liquid and flowing to the vertical runner;

[0014] Vertical runner: connected below the horizontal runner, including one or more vertical runners, receiving the pouring liquid from the horizontal runner and guiding the pouring liquid through the water inlet into the cavity.

[0015] And the mold cavity is connected with the vertical pouring channel and distributed on both sides of the vertical pouring channel. A shrinkage feed riser is arranged between the mold cavity and the vertical pouring channel, and the mold cavity and the vertical pouring channel are connected through a water inlet.

[0016] Furthermore, the vertical runners are connected by overlapping, which plays a role of sand blocking and buffering in the casting system, thereby preventing sand from being drawn into the casting to form sand holes due to too fast filling.

[0017] Furthermore, a filter residue sheet is provided between the horizontal runner and the vertical runner. Preferably, the thickness of the filter residue sheet is 3-4 mm, preferably 3 mm, which can effectively block the residue.

[0018] Furthermore, the size of the pouring cup is selected according to the size of the product. If the pouring cup is too large, it will affect the pouring state of the product. If the cup mouth is too small, it will be difficult for the pouring personnel to find the water outlet, affecting the production efficiency. The pouring cup is preferably 55mm-65mm in height and the cup mouth size is 100mm (length) * 100mm (width).

[0019] Furthermore, the height of the shrinkage feeding riser is determined according to the material of the casting, preferably 10 mm-30 mm, which can pull out the internal heat node of the casting and prevent the shrinkage and depression of the casting.

[0020] Furthermore, the overlap is provided with a pressing edge with a thickness of 1.0mm-2.0mm, preferably 1.5mm, and a pressing edge length of 20mm-50mm. The pressing edge length is designed according to the product weight and the designed casting speed to ensure automatic separation of the product, no residue and lack of meat at the gate, and reduce the amount of product grinding.

[0021] It is worth noting that the design criteria for the flow channel area itself are obtained based on our company's empirical formula:

[0022]

[0023] Where S is the cross-sectional area of ​​the flow channel (mm) 2 ; μ is the influencing factor coefficient, which is related to the material. When the pouring liquid is gray iron, μ is 2000; G is the total weight of metal flowing through section S during the entire pouring process; T is the filling time, unit s, H is the static pressure head height, that is, the height from the upper surface of the metal in the pouring cup to the pressurized section, unit cm.

[0024] Among them, the influencing factor coefficient loss coefficient μ describes the overall reduction effect on the speed or flow rate of the metal in the casting system. In the present invention, μ is controlled to be 2000. According to experience, μ is affected by the metal flow energy and metal speed. The metal speed mainly depends on the metal type, pouring temperature and metal composition. Therefore, this application adjusts the μ value in combination with the metal type, pouring temperature and metal composition, and finally determines that the value of μ is 2000.

[0025] The second object of the present invention is to provide a universal casting process for a round grey iron compressor press edge, which is cast using the above casting system and comprises the following steps:

[0026] a) Smelting: heating and melting the pig iron 0-15%, scrap steel 50%-70%, recycled materials 30%-45% and antimony alloy 1%-5% by mass at a melting temperature of 1500-1580°C for 0.5-1h to obtain molten iron.

[0027] The molten iron in front of the furnace enters a pit-type treatment bag, and is added with a spheroidizer for spheroidization. The spheroidizer adopts an alloy spheroidizer with a Mg content of less than 15%, and is spheroidized by a pit-type flushing method, so that the composition of the molten iron after the furnace is C 2.0%-4.0%, Si 1.5%-2.8%, Mn 0.3%-0.8%, Sb <0.2%, P <0.15%, S <0.15%, Cu <0.8%, Cr <0.3%, Sn <0.08%, Al <0.02%, Zn <0.02%, and the rest is Fe and unavoidable impurities.

[0028] Creeping and inoculation are carried out at the wire feeding station. The inoculant is a silicon-iron-aluminum composite inoculant, whose components include Si 74%-79%, Ca 0.5%-1%, Al 0.8%-1.6%, and the rest is iron and inevitable impurities. After the wire feeding is completed, molten iron is poured.

[0029] b) The pouring liquid is injected into the cavity through the pouring cup, the clamping force is 1300-1500Kp, and the extrusion pressure is 10-12Kp / cm 2 The pouring temperature is 1400-1470℃, the pouring time is 8-10 seconds, and the casting is unpacked after natural cooling in the cavity.

[0030] Gray cast iron is an alloy with a high carbon content. It has low hardness and wear resistance, but good toughness and plasticity, and has high requirements for product appearance and processing performance. By setting the parameters of the molding machine, the pouring temperature is 1400-1470℃, and by adjusting the strength of the molding sand and the pouring temperature, it is ensured that the mold does not stick to the sand during demolding and that qualified castings are cast.

[0031] The internal casting defect standards of the produced castings meet ASTM-E446: metallographic and tensile sampling areas are free of defects;

[0032] In the casting, the graphite size is 3-6; the pearlite is ≤85%, and the cementite is <3%.

[0033] The tensile strength Rm (N / mm 2 )≥250MPa (sample rod diameter 30mm), hardness: 200-238HBW.

[0034] The yield rate of round grey iron compression parts manufactured by the above process can reach more than 75%, meeting the national standard performance of FC-250.

[0035] 3. Beneficial effects

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) A universal casting system for a circular gray iron compressor pressure edge of the present invention is suitable for casting a variety of circular gray iron compressor pressure edges through reasonable design of the flow channel area, thereby improving the accuracy of the flow design of each layer of the circular gray iron compressor component without repeated mold flow adjustment;

[0038] (2) The universal casting process for a circular gray iron compressor press edge of the present invention can achieve a stable high yield of the castings produced by the size design of the casting system and the adjustment of the pouring process and components. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0040] Figure 1 It is a structural schematic diagram of the casting system of the present invention;

[0041] In the figure: 1. pouring cup; 2. horizontal runner; 3. vertical runner; 4. feeding riser; 5. water inlet; 6. overlap; 7. cavity;

[0042] Figure 2 A graphite image of a casting made according to the present invention;

[0043] Figure 3 The metallographic structure diagram of the casting obtained by the present invention. DETAILED DESCRIPTION

[0044] The following detailed description of exemplary embodiments of the present invention refers to the accompanying drawings, which form a part of the description, and in which exemplary embodiments of the present invention that can be implemented are shown as examples. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be implemented and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but is only for the purpose of illustrating and not limiting the description of the characteristics and features of the present invention, so as to propose the best mode for performing the present invention and to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0045] It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention. As used herein, the terms "parallel" and "perpendicular" are not limited to their strict geometric definitions, but include tolerances for reasonable and inconsistent machining or human errors.

[0046] Example 1

[0047] A universal casting system for a round gray iron compressor press edge of the present invention, the casting system is as follows Figure 1 As shown, including:

[0048] Pouring cup 1: located at the top of the casting system;

[0049] Horizontal runner 2: Located below the pouring cup 1, the molten iron flows from the pouring cup 1 to the horizontal runner 2, which plays the role of buffering the molten iron and flowing to the vertical runner 3;

[0050] The vertical runner 3 is connected below the horizontal runner 2 and includes three vertical runners 3 . The vertical runners 3 receive the molten iron from the horizontal runner 2 and guide the molten iron into the mold cavity through the water inlet 5 . The vertical runners 3 are connected by overlaps 6 .

[0051] And the cavity 7 is connected to the vertical runner 3 and distributed on both sides of the vertical runner 3. A feeding riser 4 is provided between the cavity 7 and the vertical runner 3. The cavity 7 and the vertical runner 3 are connected through a water inlet 5.

[0052] A filter residue sheet with a thickness of 3 mm is provided between the horizontal runner 2 and the vertical runner 3 .

[0053] The height of the pouring cup 1 is 60 mm, and the cup mouth size is 100 mm*100 mm;

[0054] The height of the feeding riser 4 is 10mm-30mm;

[0055] The overlap 6 is provided with a pressing edge with a thickness of 1.5 mm and a pressing edge length of 20 mm-50 mm, which ensures automatic separation of the product, no residue or lack of meat at the gate, and reduces the amount of product grinding.

[0056] The flow channel area satisfies:

[0057]

[0058] Where S is the cross-sectional area of ​​the flow channel (mm) 2 ; μ is the influencing factor coefficient, and if the pouring liquid is molten iron, μ is 2000; G is the total weight of metal flowing through section S during the entire pouring process; T is the filling time, unit s, and H is the static pressure head height, that is, the height from the upper surface of the metal in the pouring cup to the pressurized section.

[0059] Example 2

[0060] A universal casting process for a round grey iron compressor press edge, using the casting system of Example 1 for casting, comprises the following steps:

[0061] a) Smelting: heat and melt 500kg of pig iron, 2000kg of scrap steel and 1500kg of recycled materials at a smelting temperature of 1550±30℃ for 0.5h to obtain molten iron.

[0062] The molten iron in front of the furnace enters a pit-type treatment bag, and is added with a spheroidizer for spheroidization. The spheroidizer adopts an alloy spheroidizer with a Mg content of less than 15%, and is spheroidized by a pit-type flushing method, so that the composition of the molten iron after the furnace is C 2.6%, Si 1.9%, Mn 0.7%, Sb 0.2%, P 0.13%, S 0.12%, Cu 0.6%, Cr 0.2%, Sn 0.05%, Al 0.01%, Zn 0.01%, and the rest is Fe and unavoidable impurities.

[0063] Creeping and inoculation are carried out at the wire feeding station. The inoculant is a silicon-iron-aluminum composite inoculant, whose components include Si 75%, Ca 0.8%, Al 1.1%, and the rest is iron and inevitable impurities. After the wire feeding is completed, molten iron is poured.

[0064] b) The pouring liquid is injected into the cavity through the pouring cup, the clamping force is 1500Kp, and the extrusion pressure is 10Kp / cm 2 The pouring temperature is 1420±20℃, the pouring time is 11 seconds, and the casting is unpacked after natural cooling in the cavity.

[0065] like Figure 2 and Figure 3 As shown, in the obtained casting, the average graphite size is 6; the pearlite is 75%, and the cementite is less than 3%.

[0066] The tensile strength Rm (N / mm 2 ) is 268MPa, (sample rod diameter 30mm), hardness (cross section): 220-238HBW.

[0067] The yield rate of round grey iron compression parts manufactured by the above process can reach more than 75%, meeting the national standard performance of FC-250.

[0068] Example 3

[0069] A universal casting process for a round grey iron compressor press edge, using the casting system of Example 1 for casting, comprises the following steps:

[0070] a) Smelting: heat and melt 500kg of pig iron, 2000kg of scrap steel and 1500kg of recycled materials at a smelting temperature of 1550±30℃ for 0.5h to obtain molten iron.

[0071] The molten iron in front of the furnace enters a pit-type treatment bag, and is added with a spheroidizer for spheroidization. The spheroidizer adopts an alloy spheroidizer with a Mg content of less than 15%, and is spheroidized by a pit-type flushing method, so that the composition of the molten iron after the furnace is C 2.9%, Si 2.1%, Mn 0.6%, Sb 0.1%, P 0.12%, S 0.11%, Cu 0.5%, Cr 0.15%, Sn 0.04%, Al 0.01%, Zn 0.01%, and the rest is Fe and unavoidable impurities.

[0072] Creeping and inoculation are carried out at the wire feeding station. The inoculant is a silicon-iron-aluminum composite inoculant, whose components include Si 75%, Ca 0.8%, Al 1.1%, and the rest is iron and inevitable impurities. After the wire feeding is completed, molten iron is poured.

[0073] b) The pouring liquid is injected into the cavity through the pouring cup, the clamping force is 1300Kp, and the extrusion pressure is 11Kp / cm 2 The pouring temperature is 1450±20℃, the pouring time is 11 seconds, and the casting is unpacked after natural cooling in the cavity.

[0074] In the obtained castings, the average graphite size is 5; the pearlite is 78% and the cementite is <3%.

[0075] The tensile strength Rm (N / mm 2 ) is 260MPa, (sample rod diameter 30mm), hardness (cross section): 215-232HBW.

[0076] The yield rate of round grey iron compression parts manufactured by the above process can reach more than 75%, meeting the national standard performance of FC-250.

[0077] Example 4

[0078] A universal casting process for a round grey iron compressor press edge, using the casting system of Example 1 for casting, comprises the following steps:

[0079] a) Smelting: heat and melt 500kg of pig iron, 2000kg of scrap steel and 1500kg of recycled materials at a smelting temperature of 1550±30℃ for 0.5h to obtain molten iron.

[0080] The molten iron in front of the furnace enters a pit-type treatment bag, and is added with a spheroidizer for spheroidization. The spheroidizer adopts an alloy spheroidizer with a Mg content of less than 15%, and is spheroidized by a pit-type flushing method, so that the composition of the molten iron after the furnace is C 3.2%, Si 1.7%, Mn 0.4%, Sb 0.2%, P 0.10%, S 0.08%, Cu 0.2%, Cr 0.15%, Sn 0.03%, Al 0.01%, Zn 0.01%, and the rest is Fe and unavoidable impurities.

[0081] Creeping and inoculation are carried out at the wire feeding station. The inoculant is a silicon-iron-aluminum composite inoculant, whose components include Si 75%, Ca 0.8%, Al 1.1%, and the rest is iron and inevitable impurities. After the wire feeding is completed, molten iron is poured.

[0082] b) The pouring liquid is injected into the cavity through the pouring cup, the closing force is 1450Kp, and the extrusion force is 12Kp / cm 2 The pouring temperature is 1440±20℃, the pouring time is 11 seconds, and the casting is unpacked after natural cooling in the cavity.

[0083] In the obtained castings, the average graphite size is 5; the pearlite is 76%, and the cementite is less than 3%.

[0084] The tensile strength Rm (N / mm 2 ) is 265MPa, (sample rod diameter 30mm), hardness (cross section): 218-227HBW.

[0085] The yield rate of round grey iron compression parts manufactured by the above process can reach more than 75%, meeting the national standard performance of FC-250.

[0086] Comparative Example 1

[0087] Comparative Example 1 adopts a vertical pouring process, and the shell mold and the inner cavity sand core are assembled and then poured. The pouring temperature is 1400±20°C, the pouring time is controlled at 12±0.5 seconds, and the casting is unpacked after naturally cooling in the cavity for 1-1.5 hours.

[0088] The flow channel area of ​​comparative example 1 does not satisfy the formula of the present application. The flow rate of the upper flow channel of the casting is calculated to be too large, which is easy to wash out the sand, while the flow rate of the lower layer is too small, which leads to slow filling and more defects.

[0089] In the obtained castings, the average graphite size is 4; the pearlite is 45%, and the cementite is >3%.

[0090] The tensile strength Rm (N / mm 2 ) is 210MPa, (sample rod diameter 30mm), hardness (cross section): 187HBW.

[0091] The yield rate of round gray iron compression parts manufactured by this process is 60%, which does not meet the national standard performance of FC-250.

[0092] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope involved in the present application is not limited to the technical solution formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the inventive concept, such as a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

[0093] Except for the technical features described in the specification, the remaining technical features are known technologies to those skilled in the art. In order to highlight the innovative features of the present invention, the remaining technical features will not be described here in detail.

Claims

1. A universal casting system for round grey iron compressor press edge, comprising: Pouring cup (1): located at the top of the casting system; Horizontal runner (2): located below the pouring cup (1), the pouring liquid flows from the pouring cup (1) to the horizontal runner (2); Vertical runner (3): connected below the horizontal runner (2), including one or more vertical runners (3), receiving the pouring liquid from the horizontal runner (2), and the vertical runners (3) are connected by overlaps (6); and a mold cavity (7) connected to the vertical pouring channel (3) and distributed on both sides of the vertical pouring channel (3); a feeding riser (4) is provided between the mold cavity (7) and the vertical pouring channel (3); and the mold cavity (7) and the vertical pouring channel (3) are connected via a water inlet (5); The characteristic is that the flow channel area satisfies: Where S is the cross-sectional area of ​​the flow channel (mm) 2 ; μ is the influencing factor coefficient; G is the total weight of metal flowing through the section S during the entire pouring process; T is the filling time, unit s, and H is the static pressure head height.

2. The universal casting system according to claim 1, characterized in that: The overlap (6) is provided with a pressing edge, the pressing edge thickness is 1.0-2.0 mm, and the pressing edge length is 20-50 mm.

3. The universal casting system according to claim 2, characterized in that: The pouring cup (1) has a height of 55-65 mm, and a cup mouth size of 100 mm in length and 100 mm in width.

4. The universal casting system according to claim 3, characterized in that: The height of the feeding riser (4) is 10-30 mm.

5. The universal casting system according to claim 1, characterized in that: A filter residue sheet with a thickness of 3-4 mm is provided between the horizontal runner (2) and the vertical runner (3).

6. A universal casting process for round grey iron compressor press edge, using the casting system according to any one of claims 1 to 5 for casting, characterized in that: Includes steps: The pouring liquid is injected into the cavity through the pouring cup, the clamping force is 1300-1500Kp, and the extrusion pressure is 10-12Kp / cm 2 The pouring temperature is 1400-1470°C, the pouring time is 8-10 seconds, and the casting is unpacked after naturally cooling in the mold cavity (7).

7. The universal casting process according to claim 6, characterized in that: The composition of the casting liquid includes C 2.0%-4.0%, Si 1.5%-2.8%, Mn0.3%-0.8%, Sb<0.2%, P<0.15%, S<0.15%, Cu<0.8%, Cr<0.3%, Sn<0.08%, Al<0.02%, Zn<0.02%, and the rest is Fe and unavoidable impurities.

8. A casting obtained by the casting process according to any one of claims 6-7, characterized in that: The casting yield is ≥75%, and the internal casting defect standard meets ASTM-E446: metallographic and tensile sampling areas are free of defects.

9. The casting according to claim 8, characterized in that Tensile strength of casting Rm (N / mm 2 )≥250MPa, hardness is 200-238HBW.

10. The casting according to claim 9, characterized in that In the casting, the graphite size is 3-6; the pearlite content is ≤85%, and the cementite content is <3%.

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