Iron mold sand-coated casting ball production process

Abstract

The invention relates to the technical field of cast ball preparation, and discloses a swage sand-coated cast ball production process, which adopts a large swage sand-coated mold with the size of 1000mm * 1000mm, obviously improves the number of cast balls produced in a single production range of phi 50mm to phi 120mm, greatly improves the production efficiency, simultaneously reduces the energy consumption of unit products, and realizes the optimized utilization of productivity. Secondly, a large number of large-diameter exhaust holes and auxiliary exhaust channels are designed in the mold, so that efficient exhaust of gas in the pouring process is effectively ensured, air holes or shrinkage cavities in a casting are avoided, and the quality of cast balls is improved; furthermore, the introduced hydraulic pressing device ensures tight closing of the die by accurately controlling pressure, the dimensional accuracy and the surface quality of the cast ball are further improved, and finally, through a series of heat treatment and electrochemical polishing processes, the mechanical property and the wear resistance of the cast ball are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of casting ball preparation, in particular to a production process of iron mold covered sand casting balls. Background Art

[0002] Wear-resistant cast balls are widely used as consumable grinding media in powder projects such as construction cement, mining metallurgy, energy and thermal power. They are metal balls. Common cast ball sizes are Φ20mm, Φ25mm, Φ30mm, Φ40mm, Φ50mm, etc. They are generally prepared through iron mold sand coating process during production. A single mold can produce multiple cast balls at one time.

[0003] The existing casting ball forming process with a size of Φ50mm to Φ120mm is limited by the small size of the mold, so the number of casting balls formed at one time is small, the overall output is low, and the production capacity is wasted. Therefore, a production process for casting balls with iron mold covered sand is proposed. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a production process for an iron mold covered sand casting ball to solve the background technical problems.

[0005] To achieve the above object, the present invention provides the following technical solution: a production process of iron mold covered sand casting ball, the production process comprising the following steps:

[0006] A large iron-moulded sand-covered mould with a size of 1000mm×1000mm is used. The mould is designed with multiple evenly distributed cavities inside, and each cavity is used to form a casting ball ranging from Φ50mm to Φ120mm;

[0007] In the upper mold of the iron mold covered with sand, multiple exhaust holes with diameters ranging from 5mm to 8mm and auxiliary exhaust channels are designed and arranged to ensure that the gas can be efficiently discharged during the pouring process to avoid the formation of pores or shrinkage cavities inside the casting;

[0008] A hydraulic clamping device is introduced, which consists of at least one pair of hydraulic cylinders. The working pressure of the hydraulic cylinders is controlled between 20MPa and 30MPa. By accurately controlling the pressure, the upper and lower molds of the iron mold covered with sand are ensured to be tightly closed, the phenomenon of molten iron swelling is reduced, and the size accuracy and surface quality of the cast ball are guaranteed;

[0009] Prepare molten iron and cast it. When pouring the molten iron, control the temperature of the molten iron to be between 1300°C and 1500°C, and control the pouring speed to be between 0.1 kg and 0.3 kg per second to ensure that the molten iron can evenly and fully fill the mold cavity;

[0010] After casting is completed, demoulding is then carried out, and the cast ball is quickly cooled by forced air cooling or water cooling, and the cooling time is controlled between 10 minutes and 30 minutes;

[0011] The cooled cast ball is heat treated, including heating to 800°C to 1000°C for heat preservation, the heat preservation time is controlled between 2 hours and 4 hours, and then quenching and tempering are performed to improve the mechanical properties and wear resistance of the cast ball;

[0012] The surface of the cast ball after heat treatment is electrochemically polished to remove the surface oxide scale and improve its smoothness and wear resistance. After polishing, the quality of the cast ball is tested, including size measurement and surface quality inspection, to ensure that the cast ball meets industry standards, and then it is packaged and stored.

[0013] Preferably, the diameter of the exhaust holes on the iron-mold-coated-sand mold is preferably 8 mm, and the number of the exhaust holes is not less than six.

[0014] Preferably, the hydraulic clamping device also includes a pressure sensor and a control system. The pressure sensor monitors the working pressure of the hydraulic cylinder in real time and feeds back the data to the control system. The control system automatically adjusts the working pressure of the hydraulic cylinder according to a preset pressure range to ensure the stability and accuracy of the mold clamping force.

[0015] Preferably, the preset pressure range of the hydraulic cylinder is between 1.2 times and 1.5 times the minimum pressure required for mold closing.

[0016] Preferably, before pouring the molten iron, the molten iron is also degassed to further reduce the gas content in the molten iron and improve the internal quality of the cast ball.

[0017] Preferably, the working pressure of the hydraulic cylinder is maintained for a period of time after the mold is closed, and the pressure holding time is controlled between 1 minute and 5 minutes to ensure that the mold always remains tightly closed during the pouring of molten iron, further reducing the occurrence of molten iron expansion.

[0018] Preferably, before pouring molten iron, the mold is preheated, and the preheating temperature is controlled between 200° C. and 300° C. to reduce the temperature difference between the mold and the molten iron and avoid deformation or cracking of the mold caused by thermal stress.

[0019] Preferably, after the casting is completed, the cast balls are sampled and tested, including hardness test, impact toughness test and magnetic particle flaw detection, to ensure that the cast balls meet industry standards.

[0020] Preferably, after demoulding and cooling, the method further includes a step of preliminary sorting of the cast balls, wherein the cast balls are classified into qualified products, defective products and waste products according to the size and appearance quality parameters of the cast balls, so as to be subsequently processed in different ways.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention adopts a large iron-mold sand-coated mold with a size of 1000mm×1000mm, which significantly increases the number of cast balls in the range of Φ50mm to Φ120mm produced in a single production, greatly improves production efficiency, reduces energy consumption per unit product, and realizes optimal utilization of production capacity; secondly, the large diameter and large number of exhaust holes designed on the mold, as well as the auxiliary exhaust channels, effectively ensure the efficient discharge of gas during the pouring process, avoid the generation of pores or shrinkage holes inside the casting, and improve the quality of the cast ball; further, the introduced hydraulic clamping device ensures the tight closure of the mold by precisely controlling the pressure, further improving the dimensional accuracy and surface quality of the cast ball; finally, after a series of heat treatments and electrochemical polishing processes, the mechanical properties and wear resistance of the cast ball are significantly improved.

[0023] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this technical field without creative work are within the scope of protection of the present invention.

[0026] See also Figure 1 The present invention provides a production process of an iron mold-coated sand cast ball. The present invention adopts a large iron mold-coated sand mold of 1000mm×1000mm to realize the mass production of cast balls of Φ50mm to Φ120mm.

[0027] Embodiment 1:

[0028] The casting ball production process includes:

[0029] Step 1: Select a large iron mold covered with sand with a size of 1000mm×1000mm. The mold is designed with multiple evenly distributed cavities, each of which is used to form a casting ball within the range of 80mm.

[0030] Six exhaust holes with a diameter within the range of 8 mm are designed and arranged on the upper mold of the iron mold covered with sand.

[0031] Step 2:

[0032] A hydraulic cylinder is used to tightly close the upper mold and the lower mold of the sand-coated mold, and a pressure sensor and a control system are used to control the working pressure between 20MPa and 30MPa. After closing, the pressure is maintained for 1 minute to 5 minutes.

[0033] Step 3:

[0034] Prepare molten iron, degas the molten iron, and pour it into a closed sand-covered mold. When pouring the molten iron, control the molten iron temperature to be between 1300°C and 1500°C, and control the pouring speed to be between 0.1 kg and 0.3 kg per second to ensure that the molten iron can evenly and fully fill the mold cavity.

[0035] Step 4:

[0036] After casting is completed, demoulding is carried out and the cast ball is quickly cooled by forced air cooling or water cooling;

[0037] Step 5:

[0038] After demolding and cooling, the cast balls are initially sorted into qualified products, defective products and waste products according to parameters such as the size and appearance quality of the cast balls, so as to be processed differently later.

[0039] Step 6:

[0040] The cooled cast ball is heat treated by heating to 800°C to 1000°C for 2 to 4 hours of heat preservation, followed by quenching and tempering.

[0041] Step 7: Electrochemically polish the surface of the heat-treated cast ball to remove the oxide scale on the surface and improve its smoothness and wear resistance.

[0042] Step 8: After polishing, the quality of the cast balls is inspected, including the size measurement and surface quality inspection of all cast balls, as well as sampling inspection of the cast balls, including hardness test, impact toughness test and magnetic particle inspection, and then packaged and stored.

[0043] Embodiment 2:

[0044] The casting ball production process includes:

[0045] Step 1: Select a large iron mold covered with sand with a size of 1000mm×1000mm. The mold is designed with multiple evenly distributed cavities, each of which is used to form a casting ball within the range of 80mm.

[0046] On the upper mold of the iron mold covered with sand, two exhaust holes with a diameter within the range of 5mm are designed and arranged.

[0047] Step 2:

[0048] A hydraulic cylinder is used to tightly close the upper mold and the lower mold of the sand-coated mold, and a pressure sensor and a control system are used to control the working pressure between 20MPa and 30MPa. After closing, the pressure is maintained for 1 minute to 5 minutes.

[0049] Step 3:

[0050] Prepare molten iron, degas the molten iron, and pour it into a closed sand-covered mold. When pouring the molten iron, control the molten iron temperature to be between 1300°C and 1500°C, and control the pouring speed to be between 0.1 kg and 0.3 kg per second to ensure that the molten iron can evenly and fully fill the mold cavity.

[0051] Step 4:

[0052] After casting is completed, demoulding is carried out and the cast ball is quickly cooled by forced air cooling or water cooling;

[0053] Step 5:

[0054] After demolding and cooling, the cast balls are initially sorted into qualified products, defective products and waste products according to parameters such as the size and appearance quality of the cast balls, so as to be processed differently later.

[0055] Step 6:

[0056] The cooled cast ball is heat treated by heating to 800°C to 1000°C for 2 to 4 hours of heat preservation, followed by quenching and tempering.

[0057] Step 7: Electrochemically polish the surface of the heat-treated cast ball to remove the oxide scale on the surface and improve its smoothness and wear resistance.

[0058] Step 8: After polishing, the quality of the cast balls is inspected, including the size measurement and surface quality inspection of all cast balls, as well as sampling inspection of the cast balls, including hardness test, impact toughness test and magnetic particle inspection, and then packaged and stored.

[0059] Embodiment three:

[0060] The casting ball production process includes:

[0061] Step 1: Select a large iron mold covered with sand with a size of 1000mm×1000mm. The mold is designed with multiple evenly distributed cavities, each of which is used to form a casting ball within the range of 80mm.

[0062] Six exhaust holes with a diameter within the range of 8 mm are designed and arranged on the upper mold of the iron mold covered with sand.

[0063] Step 2:

[0064] Prepare molten iron, degas the molten iron, and pour it into a closed sand-covered mold. When pouring the molten iron, control the molten iron temperature to be between 1300°C and 1500°C, and control the pouring speed to be between 0.1 kg and 0.3 kg per second to ensure that the molten iron can evenly and fully fill the mold cavity.

[0065] Step 3:

[0066] After casting is completed, demoulding is carried out and the cast ball is quickly cooled by forced air cooling or water cooling;

[0067] Step 4:

[0068] After demolding and cooling, the cast balls are initially sorted into qualified products, defective products and waste products according to parameters such as the size and appearance quality of the cast balls, so as to be processed differently later.

[0069] Step 5:

[0070] The cooled cast ball is heat treated by heating to 800°C to 1000°C for 2 to 4 hours of heat preservation, followed by quenching and tempering.

[0071] Step 6: Electrochemically polish the surface of the heat-treated cast ball to remove the oxide scale on the surface and improve its smoothness and wear resistance.

[0072] Step 7: After polishing, the quality of the cast balls is inspected, including the size measurement and surface quality inspection of all cast balls, as well as sampling inspection of the cast balls, including hardness test, impact toughness test and magnetic particle inspection, and then packaged and stored.

[0073] Comparative Example 1:

[0074] Step 1: Select an iron mold covered with sand with a size of 600 mm × 600 mm. The mold is designed with multiple evenly distributed cavities, each of which is used to form a casting ball within a range of 80 mm.

[0075] Six exhaust holes with a diameter within the range of 8 mm are designed and arranged on the upper mold of the iron mold covered with sand.

[0076] Step 2:

[0077] A hydraulic cylinder is used to tightly close the upper mold and the lower mold of the sand-coated mold, and a pressure sensor and a control system are used to control the working pressure between 20MPa and 30MPa. After closing, the pressure is maintained for 1 minute to 5 minutes.

[0078] Step 3:

[0079] Prepare molten iron, degas the molten iron, and pour it into a closed sand-covered mold. When pouring the molten iron, control the molten iron temperature to be between 1300°C and 1500°C, and control the pouring speed to be between 0.1 kg and 0.3 kg per second to ensure that the molten iron can evenly and fully fill the mold cavity.

[0080] Step 4:

[0081] After casting is completed, demoulding is carried out and the cast ball is quickly cooled by forced air cooling or water cooling;

[0082] Step 5:

[0083] After demolding and cooling, the cast balls are initially sorted into qualified products, defective products and waste products according to parameters such as the size and appearance quality of the cast balls, so as to be processed differently later.

[0084] Step 6:

[0085] The cooled cast ball is heat treated by heating to 800°C to 1000°C for 2 to 4 hours of heat preservation, followed by quenching and tempering.

[0086] Step 7: Electrochemically polish the surface of the heat-treated cast ball to remove the oxide scale on the surface and improve its smoothness and wear resistance.

[0087] Step 8: After polishing, the quality of the cast balls is inspected, including the size measurement and surface quality inspection of all cast balls, as well as sampling inspection of the cast balls, including hardness test, impact toughness test and magnetic particle inspection, and then packaged and stored.

[0088] Comparative Example 2:

[0089] Step 1: Select an iron mold covered with sand with a size of 800 mm × 800 mm. The mold is designed with multiple evenly distributed cavities, each of which is used to form a casting ball within a range of 80 mm.

[0090] On the upper mold of the iron mold covered with sand, two exhaust holes with a diameter within the range of 5mm are designed and arranged.

[0091] Step 2:

[0092] A hydraulic cylinder is used to tightly close the upper mold and the lower mold of the sand-coated mold, and a pressure sensor and a control system are used to control the working pressure between 20MPa and 30MPa. After closing, the pressure is maintained for 1 minute to 5 minutes.

[0093] Step 3:

[0094] Prepare molten iron, degas the molten iron, and pour it into a closed sand-covered mold. When pouring the molten iron, control the molten iron temperature to be between 1300°C and 1500°C, and control the pouring speed to be between 0.1 kg and 0.3 kg per second to ensure that the molten iron can evenly and fully fill the mold cavity.

[0095] Step 4:

[0096] After casting is completed, demoulding is carried out and the cast ball is quickly cooled by forced air cooling or water cooling;

[0097] Step 5:

[0098] After demolding and cooling, the cast balls are initially sorted into qualified products, defective products and waste products according to parameters such as the size and appearance quality of the cast balls, so as to be processed differently later.

[0099] Step 6:

[0100] The cooled cast ball is heat treated by heating to 800°C to 1000°C for 2 to 4 hours of heat preservation, followed by quenching and tempering.

[0101] Step 7: Electrochemically polish the surface of the heat-treated cast ball to remove the oxide scale on the surface and improve its smoothness and wear resistance.

[0102] Step 8: After polishing, the quality of the cast balls is inspected, including the size measurement and surface quality inspection of all cast balls, as well as sampling inspection of the cast balls, including hardness test, impact toughness test and magnetic particle inspection, and then packaged and stored.

[0103] This test example provides the number of cast balls obtained by one-time casting prepared by Example 1-3 and Comparative Example 1-2, performance test and test results

[0104] The porosity and shrinkage rate of the cast ball are tested by ultrasonic flaw detector;

[0105]

[0106] First, by comparing Example 1 and Example 2, it can be found that the exhaust holes on the iron mold covered with sand are different. Example 1 uses exhaust holes with a diameter of 8 mm and the number of exhaust holes is six, and Example 2 uses exhaust holes with a diameter of 5 mm and the number of exhaust holes is two. The experimental results show that the porosity and shrinkage rate of the cast balls produced by Example 1 are lower than those of the cast balls produced by Example 2, and the yield rate is better and the quality of the cast balls is higher. This is due to the exhaust holes ensuring that the gas can be efficiently discharged during the pouring process. This shows that when casting cast balls with larger diameters, the size and number of exhaust holes can significantly improve the quality of the cast balls.

[0107] Secondly, by comparing Example 1 and Example 3, it can be found that in Example 3, the hydraulic cylinder is not used to tightly close the upper mold and the lower mold of the mold-coated sand mold. The experimental results show that in Example 1, the hydraulic cylinder is used to tightly close the upper mold and the lower mold of the mold-coated sand mold, and the cast ball has higher quality. This is due to the fact that the hydraulic cylinder controls the closing pressure of the mold-coated sand mold, which can reduce the expansion of the molten iron box, thereby reducing the occurrence of pores and shrinkage holes during the casting process.

[0108] Furthermore, by comparing Example 1 with Comparative Example 1 and Comparative Example 2, it can be found that the iron mold covered with sand molds used in Example 1 are different from those used in Comparative Example 1 and Comparative Example 2. Example 1 uses a 1000mm×1000mm iron mold covered with sand mold to prepare 64 80mm cast balls at one time, while Comparative Example 1 and Comparative Example 2 both use an iron mold covered with sand mold with a size less than 1000mm×1000mm to cast 80mm cast balls, and the number of balls that can be prepared at one time is lower than the number of balls that can be prepared at one time by the 1000mm×1000mm iron mold covered with sand mold, so that when the 1000mm×1000mm iron mold covered with sand mold is used to generate cast balls, the production efficiency is greatly improved and the energy consumption is reduced per unit time;

[0109] Comparative Example 1 and Example 1 both use six 8mm exhaust holes, and both use a hydraulic cylinder to control the closing pressure of the mold-covered sand mold. The experimental results show that the quality of the cast balls cast by Comparative Example 1 and Example 1 is relatively high, which further verifies that the use of a hydraulic cylinder to control the closing pressure of the mold-covered sand mold can reduce the phenomenon of molten iron expansion tank, and at the same time verifies that when casting a cast ball with a larger diameter, the size and number of the exhaust holes can significantly improve the quality of the cast ball;

[0110] Comparative Example 2 is the same as Example 3, and neither of them uses a hydraulic cylinder to control the closing pressure of the sand-covered mold. The experimental results show that the quality of the cast balls cast in Comparative Example 2 is poor, which further verifies that the hydraulic cylinder controlling the closing pressure of the sand-covered mold can reduce the phenomenon of molten iron swelling.

[0111] Experiments have shown that the present invention uses a 1000mm×1000mm iron mold covered with sand mold to produce a large number of cast balls of Φ50mm to Φ120mm at one time, which greatly improves the production efficiency and reduces energy consumption per unit time; at the same time, large diameter and large number of exhaust holes are used, and a hydraulic cylinder is used to control the closing pressure of the iron mold covered with sand mold to ensure that the cast balls of Φ50mm to Φ120mm produced meet industry standards.

[0112] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A production process for iron mold covered sand casting balls, characterized in that: The production process includes: A large iron-moulded sand-covered mould with a size of 1000mm×1000mm is used. The mould is designed with multiple evenly distributed cavities inside, and each cavity is used to form a casting ball ranging from Φ50mm to Φ120mm; In the upper mold of the iron mold covered with sand, multiple exhaust holes with diameters ranging from 5mm to 8mm and auxiliary exhaust channels are designed and arranged to ensure that the gas can be efficiently discharged during the pouring process to avoid the formation of pores or shrinkage cavities inside the casting; A hydraulic clamping device is introduced, which consists of at least one pair of hydraulic cylinders. The working pressure of the hydraulic cylinders is controlled between 20MPa and 30MPa. By accurately controlling the pressure, the upper and lower molds of the iron mold covered with sand are ensured to be tightly closed, the phenomenon of molten iron swelling is reduced, and the size accuracy and surface quality of the cast ball are guaranteed; Prepare molten iron and cast it. When pouring the molten iron, control the temperature of the molten iron to be between 1300°C and 1500°C, and control the pouring speed to be between 0.1 kg and 0.3 kg per second to ensure that the molten iron can evenly and fully fill the mold cavity; After casting is completed, demoulding is then carried out, and the cast ball is quickly cooled by forced air cooling or water cooling, and the cooling time is controlled between 10 minutes and 30 minutes; The cooled cast ball is heat treated, including heating to 800°C to 1000°C for heat preservation, the heat preservation time is controlled between 2 hours and 4 hours, and then quenching and tempering are performed to improve the mechanical properties and wear resistance of the cast ball; The surface of the cast ball after heat treatment is electrochemically polished to remove the surface oxide scale and improve its smoothness and wear resistance. After polishing, the quality of the cast ball is tested, including size measurement and surface quality inspection, to ensure that the cast ball meets industry standards, and then it is packaged and stored.

2. The process for producing iron mold covered sand casting balls according to claim 1, characterized in that: The diameter of the exhaust holes on the iron-mold-coated-sand mold is preferably 8 mm, and the number of the exhaust holes is not less than six.

3. The process for producing iron mold covered sand casting balls according to claim 1, characterized in that: The hydraulic clamping device also includes a pressure sensor and a control system. The pressure sensor monitors the working pressure of the hydraulic cylinder in real time and feeds the data back to the control system. The control system automatically adjusts the working pressure of the hydraulic cylinder according to the preset pressure range to ensure the stability and accuracy of the mold clamping force.

4. The process for producing an iron mold covered sand casting ball according to claim 3, characterized in that: The preset pressure range of the hydraulic cylinder is between 1.2 times and 1.5 times the minimum pressure required for mold closing.

5. The process for producing iron mold covered sand casting balls according to claim 1, characterized in that: Before pouring the molten iron, the molten iron is also degassed to further reduce the gas content in the molten iron and improve the internal quality of the cast ball.

6. The process for producing iron mold covered sand casting balls according to claim 3, characterized in that: The working pressure of the hydraulic cylinder is maintained for a period of time after the mold is closed, and the pressure holding time is controlled between 1 minute and 5 minutes to ensure that the mold always remains tightly closed during the pouring of molten iron, further reducing the occurrence of molten iron expansion.

7. The process for producing iron mold covered sand casting balls according to claim 1, characterized in that: Before pouring molten iron, the mold is preheated and the preheating temperature is controlled between 200℃ and 300℃ to reduce the temperature difference between the mold and the molten iron and avoid deformation or cracking of the mold caused by thermal stress.

8. The process for producing iron mold covered sand casting balls according to claim 1, characterized in that: After casting is completed, the cast balls are sampled and tested, including hardness test, impact toughness test and magnetic particle inspection, to ensure that the cast balls meet industry standards.

9. The process for producing iron mold covered sand casting balls according to claim 1, characterized in that: After demolding and cooling, the process also includes a preliminary sorting step for the cast balls. According to the size and appearance quality parameters of the cast balls, the cast balls are divided into qualified products, defective products and waste products for subsequent different treatments.

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