A ductile cast iron hydraulic motor shell blank casting process

Abstract

The application discloses a nodular cast iron hydraulic motor shell blank casting process, which comprises the following steps: step one, placing a mold core into a half mold box above a base and in contact with a mold cavity block, and then closing two mold boxes; step two, melting raw material iron, and adding a spheroidizing agent into the molten iron and mixing it evenly when the iron block is converted into the molten iron. By adding the spheroidizing agent into the molten iron during casting, the spheroidizing degree of the nodular cast iron in the casting can be improved through the spheroidizing agent, and during the casting process, an electromagnetic heating pipe can be additionally arranged outside the casting pipe to perform secondary heating on the molten iron during the casting, so that the problem that the ductility and toughness of the hydraulic motor shell are reduced due to the increase of the proportion of lamellar cementite in the casting caused by the decrease of the temperature of the molten iron during the casting can be effectively avoided.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic motor housing casting technology, specifically a casting process for ductile iron hydraulic motor housing blanks. Background Technology

[0002] A hydraulic motor is an actuator in a hydraulic system that converts the pressure energy of the liquid provided by a hydraulic pump into the mechanical energy (torque and speed) of its output shaft. Liquid is the medium for transmitting force and motion. High-speed gear motors have advantages such as small size, light weight, simple structure, good manufacturability, insensitivity to oil contamination, shock resistance, and low inertia. Disadvantages include larger torque pulsation, lower efficiency, lower starting torque (only 60%-70% of the rated torque), and poor low-speed stability. The housing of a hydraulic motor is manufactured through casting.

[0003] However, current casting processes have some problems: 1. During the casting process, the molten iron flows inside the casting pipe, causing the temperature of the molten iron to drop, affecting the initial casting temperature and leading to an increase in lamellar permeable bodies inside the casting, affecting the toughness and ductility of the casting; 2. After the casting has cooled, it is not easy to demold the casting, affecting processing efficiency. Therefore, it is necessary to design a casting process for ductile iron hydraulic motor housing blanks. Summary of the Invention

[0004] The purpose of this invention is to provide a casting process for ductile iron hydraulic motor housing blanks to solve the above-mentioned problems, thereby resolving the issues mentioned in the background art.

[0005] To address the above problems, this invention provides a casting process for ductile iron hydraulic motor housing blanks:

[0006] A casting process for a ductile iron hydraulic motor housing blank includes the following steps:

[0007] Step 1: Place the mold core into the half mold box located above the base and make it contact the cavity block, then close the two mold boxes together;

[0008] Step 2: Melt the raw material iron. Once the iron block has been converted into molten iron, add a spheroidizing agent to the molten iron and mix it evenly.

[0009] Step 3: After removing impurities from the surface of the molten iron, pour the molten iron into the inside of the casting pipe. After entering the inside of the casting pipe, the molten iron enters the mold cavity composed of two half mold boxes through the conveying pipe. During the casting process, the casting pipe is heated to ensure the stability of the casting temperature.

[0010] Step 4: After pouring a certain amount of molten iron in Step 3, connect the air pump to the casting pipe, and then blow inert gas into the casting pipe and the conveying pipe. When the liquid level of the molten iron rises to half of the inclined surface on the discharge hood, the gas supply can be stopped and the current pressure maintained.

[0011] Step 5: After the molten iron in Step 4 has cooled and solidified, the hydraulic motor housing casting can be removed from the inside of the half mold box and allowed to cool to its natural temperature.

[0012] Step 6: Perform spheroidizing annealing on the casting from Step 5. During the annealing and cooling process, the lamellar cementite in a portion of the pearlite inside the casting can be spheroidized, which can further improve the spheroidization rate of the casting.

[0013] Step 7: Surface harden the casting processed in Step 6 to improve its surface mechanical properties, and the hydraulic motor housing casting can be obtained.

[0014] A casting process and equipment for ductile iron hydraulic motor housing blanks, employing the aforementioned casting process, includes two symmetrically distributed mold boxes slidably connected to the upper end of a base. Multiple evenly distributed connecting plates are fixedly connected inside each mold box. A half-mold box is fixedly connected to each of the connecting plates, and the two half-mold boxes are in contact with each other. A discharge hood is slidably connected inside each mold box, and the discharge hood contacts the half-mold box. A constant-temperature casting mechanism is provided on the base. An auxiliary demolding mechanism is provided on the mold boxes. A mold-separating mechanism is provided on the base. Cavity blocks are fixedly connected inside each of the two half-mold boxes, and the half-mold boxes contact the base and are fixedly connected to the mold boxes.

[0015] Preferably, the constant temperature casting mechanism includes a conveying pipe, a casting pipe, an electromagnetic heating tube, and an induction cooker. The conveying pipe is fixedly connected to the inside of the base, the casting pipe is fixedly connected to the upper end of the conveying pipe, the electromagnetic heating tube is provided on the outside of the casting pipe, the induction cooker is fixedly connected to the upper end of the base, and the output end of the induction cooker is fixedly connected to the electromagnetic heating tube. The electromagnetic heating tube can perform secondary heating of molten iron through electromagnetic fields.

[0016] Preferably, the auxiliary demolding mechanism includes a fixed plate, a connecting pin, a limiting post, and a spring. The fixed plate is fixedly connected to the inside of one of the mold boxes, and the connecting pin is slidably connected to the inside of the fixed plate. One end of the connecting pin is fixedly connected to the limiting post, which is slidably connected to the mold box. The fixed plate is slidably connected to the other mold box. A spring is provided on the outside of the connecting pin, and the limiting post is slidably connected to the discharge cover. The limiting post can limit the discharge cover.

[0017] Preferably, one end of the spring is fixedly connected to the limiting post, and the other end of the spring is fixedly connected to the fixing plate. The spring can automatically reset the limiting post through its elastic force.

[0018] Preferably, the mold parting mechanism includes a hinge frame, a hinge seat, a sliding plate, a guide pin, a second spring, a limiting frame, and a limiting sleeve. The hinge frame is fixedly connected to the mold box, the hinge seat is hinged to the hinge frame, the sliding plate is fixedly connected to the hinge seat, the guide pin is fixedly connected inside the base, the second spring is provided on the outside of the guide pin, the limiting frame is fixedly connected to the upper end of the base, the limiting sleeve is fixedly connected inside the mold box, the sliding plate is slidably connected to the guide pin, and the guide pin can guide the movement direction of the sliding plate.

[0019] Preferably, the sliding plate is slidably connected to the base, the hinge seat is slidably connected to the base, and the limiting sleeve is slidably connected to the limiting frame. The limiting frame can limit the mold box through the limiting sleeve.

[0020] Preferably, one end of the second spring is fixedly connected to the base, and the other end of the second spring is fixedly connected to the sliding plate. The second spring can automatically reset the sliding plate through its elastic force.

[0021] The beneficial effects of this invention are:

[0022] Firstly, by heating the spheroidizing agent in the molten iron during casting, the spheroidization degree of the ductile iron in the casting can be improved. Furthermore, during the casting process, an electromagnetic heating tube can be added to the outside of the casting pipe to reheat the molten iron. This effectively avoids the problem of the molten iron temperature dropping during casting, which would lead to an increase in the proportion of lamellar cementite inside the casting and reduce the ductility and toughness of the hydraulic motor housing.

[0023] Secondly, an auxiliary demolding mechanism and a mold-separating mechanism are added to the base. After the casting cools, the limiting post can be removed from the discharge cover, and the mold box can be moved. After the two mold boxes are removed from the base, the mold boxes can be flipped over, which makes it easier to demold the casting. Attached Figure Description

[0024] For ease of explanation, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0025] Figure 1 This is a perspective view of the overall structure of the present invention;

[0026] Figure 2 For the present invention Figure 1 Stereoscopic section Figure 1 ;

[0027] Figure 3 For the present invention Figure 1 Stereoscopic section Figure 2 ;

[0028] Figure 4 For the present invention Figure 1 Top view;

[0029] Figure 5 For the present invention Figure 1 Right sectional view;

[0030] Figure 6 For the present invention Figure 2 Enlarged view of the A-section structure;

[0031] Figure 7 For the present invention Figure 5 Enlarged view of the structure of part B.

[0032] In the diagram: 1. Base; 2. Mold box; 3. Connecting plate; 4. Half mold box; 5. Discharge cover; 6. Constant temperature casting mechanism; 7. Auxiliary demolding mechanism; 8. Mold splitting mechanism; 9. Cavity block; 61. Conveying pipe; 62. Casting pipe; 63. Electromagnetic heating pipe; 64. Induction cooker; 71. Fixing plate; 72. Connecting pin; 73. Limiting post; 74. Spring 1; 81. Hinge frame; 82. Hinge seat; 83. Sliding plate; 84. Guide pin; 85. Spring 2; 86. Limiting frame; 87. Limiting sleeve. Detailed Implementation

[0033] like Figure 1-7 As shown, the specific implementation adopts the following technical solution: Example

[0034] A casting process for a ductile iron hydraulic motor housing blank includes the following steps:

[0035] Step 1: Place the mold core into the interior of the half mold box 4 located above the base 1 and make it contact the cavity block 9. Then close the two mold boxes 2 together.

[0036] Step 2: Melt the raw material iron. When the iron block is converted into molten iron, add a spheroidizing agent to the molten iron and mix it evenly. The proportion of the spheroidizing agent is 2.5%. The spheroidizing agent is composed of magnesium (34.5%) and rare earth (65.5%).

[0037] Step 3: After removing impurities from the surface of the molten iron, pour the molten iron into the interior of the casting pipe 62. After entering the interior of the casting pipe 62, the molten iron enters the mold cavity composed of two half mold boxes 4 through the conveying pipe 61. During the casting process, the casting pipe 62 is heated to ensure the stability of the casting temperature, which is 1320-1330℃.

[0038] Step 4: After a certain amount of molten iron is poured in Step 3, connect the air pump to the casting pipe 62, and then blow inert gas into the casting pipe 62 and the conveying pipe 61. When the liquid level of the molten iron rises to half of the inclined surface on the discharge hood 5, the gas supply can be stopped and the current pressure is maintained. The inert gas is nitrogen.

[0039] Step 5: After the molten iron in Step 4 has cooled and solidified, the hydraulic motor housing casting can be removed from the inside of the half mold box 4 and allowed to cool to its natural temperature.

[0040] Step 6: Perform spheroidizing annealing on the casting from Step 5. During the annealing and cooling process, some of the lamellar cementite in the pearlite inside the casting can be spheroidized, which can further improve the spheroidization rate of the casting. The annealing temperature is 810℃, then cooled to 695-705℃ and held for 5 hours. After holding, it is cooled at a cooling rate of 45-55℃ / h until it reaches 550℃, after which it can be taken out of the furnace.

[0041] Step 7: Surface harden the casting processed in Step 6 to improve its surface mechanical properties, and the hydraulic motor housing casting can be obtained. After heating the surface temperature of the casting to between 350-400℃, oil quenching is performed.

[0042] In this embodiment, a casting equipment for ductile iron hydraulic motor housing blanks is provided, employing the casting process for ductile iron hydraulic motor housing blanks described in the above embodiment. The equipment includes two symmetrically distributed mold boxes 2 slidably connected to the upper end of the base 1. Multiple evenly distributed connecting plates 3 are fixedly connected inside each mold box 2. Half-mold boxes 4 are fixedly connected to the multiple connecting plates 3, and the two half-mold boxes 4 are in contact with each other. A discharge cover 5 is slidably connected inside the mold box 2, and the discharge cover 5 is in contact with the half-mold box 4. A constant temperature casting mechanism 6 is provided on the base 1. An auxiliary demolding mechanism 7 is provided on the mold box 2. A mold separating mechanism 8 is provided on the base 1. Cavity blocks 9 are fixedly connected inside each of the two half-mold boxes 4, and the half-mold boxes 4 are in contact with the base 1 and fixedly connected to the mold box 2.

[0043] The constant temperature casting mechanism 6 includes a conveying pipe 61, a casting pipe 62, an electromagnetic heating tube 63, and an induction cooker 64. The conveying pipe 61 is fixedly connected inside the base 1. The casting pipe 62 is fixedly connected to the upper end of the conveying pipe 61. The electromagnetic heating tube 63 is arranged on the outer side of the casting pipe 62. The induction cooker 64 is fixedly connected to the upper end of the base 1. The output end of the induction cooker 64 is fixedly connected to the electromagnetic heating tube 63. The electromagnetic heating tube 63 can perform secondary heating of molten iron through electromagnetic fields.

[0044] The auxiliary demolding mechanism 7 includes a fixed plate 71, a connecting pin 72, a limiting post 73, and a spring 74. A fixed plate 71 is fixedly connected inside one of the mold boxes 2, and a connecting pin 72 is slidably connected inside the fixed plate 71. One end of the connecting pin 72 is fixedly connected to the limiting post 73, which is slidably connected to the mold box 2. The fixed plate 71 is slidably connected to the other mold box 2. A spring 74 is provided on the outside of the connecting pin 72. The limiting post 73 is slidably connected to the discharge cover 5, and the limiting post 73 can limit the discharge cover 5. One end of the spring 74 is fixedly connected to the limiting post 73, and the other end of the spring 74 is fixedly connected to the fixed plate 71. The spring 74 can automatically reset the limiting post 73 through its elastic force.

[0045] The mold-separating mechanism 8 includes a hinge frame 81, a hinge seat 82, a sliding plate 83, a guide pin 84, a second spring 85, a limiting frame 86, and a limiting sleeve 87. The hinge frame 81 is fixedly connected to the mold box 2, and the hinge seat 82 is hinged to the hinge frame 81. The sliding plate 83 is fixedly connected to the hinge seat 82. The guide pin 84 is fixedly connected inside the base 1, and a second spring 85 is provided on the outer side of the guide pin 84. The limiting frame 86 is fixedly connected to the upper end of the base 1, and the limiting sleeve 87 is fixedly connected inside the mold box 2. The movable plate 83 is slidably connected to the guide pin 84, which can guide the movement direction of the sliding plate 83. The sliding plate 83 is slidably connected to the base 1, the hinge seat 82 is slidably connected to the base 1, the limiting sleeve 87 is slidably connected to the limiting frame 86, and the limiting frame 86 can limit the mold box 2 through the limiting sleeve 87. One end of the second spring 85 is fixedly connected to the base 1, and the other end of the second spring 85 is fixedly connected to the sliding plate 83. The second spring 85 can drive the sliding plate 83 to automatically reset through elastic force.

[0046] The usage state of the present invention is as follows: when in use, molten iron is poured into the inside of the casting tube 62. During the pouring process, the induction cooker 64 is started. The induction cooker 64 can heat the casting tube 62 and the molten iron flowing inside the casting tube 62 through the electromagnetic heating tube 63. During the heating process, the temperature of the molten iron can be effectively prevented from dropping too much, and the degree of spheroidization after the casting is formed can be guaranteed.

[0047] After casting is completed and the casting has cooled, push the limiting post 73. The limiting post 73 moves the connecting pin 72 and compresses the spring 74. When the limiting post 73 disengages from the discharge cover 5, the two mold boxes 2 move through the gap between them. During the movement, the mold box 2 moves the limiting sleeve 87 and compresses the spring 85 through the sliding plate 83. When the limiting sleeve 87 disengages from the limiting frame 86, the mold box 2 can be flipped over, thereby demolding the casting inside the half mold box 4, making it easier to demold the casting.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. A casting equipment for ductile iron hydraulic motor housing blanks, characterized in that: The system includes a base (1), with two symmetrically distributed mold boxes (2) slidably connected to the upper end of the base (1). Multiple evenly distributed connecting plates (3) are fixedly connected inside each of the two mold boxes (2). Half-mold boxes (4) are fixedly connected to the multiple connecting plates (3). The two half-mold boxes (4) are in contact with each other. A discharge cover (5) is slidably connected inside the mold box (2), and the discharge cover (5) is in contact with the half-mold box (4). A constant temperature casting mechanism (6) is provided on the base (1). An auxiliary demolding mechanism (7) is provided on the mold box (2). A mold separating mechanism (8) is provided on the base (1). The two half-mold boxes (4) have internal... Each part is fixedly connected to a cavity block (9), the half mold box (4) is in contact with the base (1), and the half mold box (4) is fixedly connected to the mold box (2); the constant temperature casting mechanism (6) includes a conveying pipe (61), a casting pipe (62), an electromagnetic heating pipe (63), and an induction cooker (64). The conveying pipe (61) is fixedly connected inside the base (1), the casting pipe (62) is fixedly connected to the upper end of the conveying pipe (61), the electromagnetic heating pipe (63) is provided on the outside of the casting pipe (62), the induction cooker (64) is fixedly connected to the upper end of the base (1), and the output end of the induction cooker (64) is fixedly connected to the electromagnetic heating pipe (63).

2. The casting equipment for ductile iron hydraulic motor housing blanks according to claim 1, characterized in that: The auxiliary demolding mechanism (7) includes a fixed plate (71), a connecting pin (72), a limiting post (73), and a spring (74). The fixed plate (71) is fixedly connected inside one of the mold boxes (2). The connecting pin (72) is slidably connected inside the fixed plate (71). One end of the connecting pin (72) is fixedly connected to the limiting post (73). The limiting post (73) is slidably connected to the mold box (2). The fixed plate (71) is slidably connected to the other mold box (2). A spring (74) is provided on the outside of the connecting pin (72). The limiting post (73) is slidably connected to the discharge cover (5).

3. The casting equipment for ductile iron hydraulic motor housing blanks according to claim 2, characterized in that: One end of the spring (74) is fixedly connected to the limiting post (73), and the other end of the spring (74) is fixedly connected to the fixing plate (71).

4. The casting equipment for ductile iron hydraulic motor housing blanks according to claim 1, characterized in that: The mold splitting mechanism (8) includes a hinge frame (81), a hinge seat (82), a sliding plate (83), a guide pin (84), a second spring (85), a limiting frame (86), and a limiting sleeve (87). The hinge frame (81) is fixedly connected to the mold box (2). The hinge seat (82) is hinged to the hinge frame (81). The sliding plate (83) is fixedly connected to the hinge seat (82). The guide pin (84) is fixedly connected inside the base (1). The second spring (85) is provided on the outside of the guide pin (84). The limiting frame (86) is fixedly connected to the upper end of the base (1). The limiting sleeve (87) is fixedly connected inside the mold box (2). The sliding plate (83) is slidably connected to the guide pin (84).

5. The casting equipment for ductile iron hydraulic motor housing blanks according to claim 4, characterized in that: The sliding plate (83) is slidably connected to the base (1), the hinge seat (82) is slidably connected to the base (1), and the limiting sleeve (87) is slidably connected to the limiting frame (86).

6. The casting equipment for ductile iron hydraulic motor housing blanks according to claim 5, characterized in that: One end of the second spring (85) is fixedly connected to the base (1), and the other end of the second spring (85) is fixedly connected to the sliding plate (83).

7. A casting process for ductile iron hydraulic motor housing blanks, applied to the casting equipment for ductile iron hydraulic motor housing blanks as described in claim 1, characterized in that, Includes the following steps: Step 1: Place the mold core into the interior of the half mold box (4) located above the base (1) and make contact with the cavity block (9), and then close the two mold boxes (2); Step 2: Melt the raw material iron. Once the iron block has been converted into molten iron, add a spheroidizing agent to the molten iron and mix it evenly. The spheroidizing agent accounts for 2.5% of the total composition and is composed of 34.5% magnesium and 65.5% rare earth elements. Step 3: After removing impurities from the surface of the molten iron, pour the molten iron into the interior of the casting pipe (62). After entering the interior of the casting pipe (62), the molten iron enters the mold cavity composed of two half mold boxes (4) through the conveying pipe (61). During the casting process, the casting pipe (62) is heated to ensure the stability of the casting temperature. The casting temperature is 1320-1330℃. Step 4: After a certain amount of molten iron is poured in step 3, connect the air pump to the casting pipe (62), and then blow inert gas into the casting pipe (62) and the conveying pipe (61). When the liquid level of the molten iron rises to half of the inclined surface of the discharge hood (5), the gas supply can be stopped and the current pressure is maintained. The inert gas is nitrogen. Step 5: After the molten iron in Step 4 has cooled and solidified, the hydraulic motor housing casting can be removed from the inside of the half mold box (4) and allowed to cool to its natural temperature. Step 6: Perform spheroidizing annealing on the casting from Step 5. The annealing temperature is 810℃, then cooled to 695-705℃ and held for 5 hours. After holding, cool at a rate of 45-55℃ / h until it reaches 550℃, then it can be removed from the furnace. Step 7: Surface harden the casting after step 6 by heating the surface temperature of the casting to between 350-400℃ and then oil quenching to obtain the casting of the hydraulic motor housing.

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