Cage type chill for casting a cast steel piece of a crushing shaft set and a casting method thereof

Abstract

A cage type chill for casting a broken shaft group cast steel piece comprises at least two horizontally arranged annular chills, a plurality of vertically arranged long rod chills and a plurality of horizontally arranged short rod chills, the annular chills are arranged in parallel, the long rod chills are connected with the annular chills perpendicularly, the short rod chills are arranged on the annular chills or the long rod chills, the total mass of the annular chills, the long rod chills and the short rod chills accounts for 0.5% to 1% of the mass of the broken shaft group, and the diameter of the annular chills, the long rod chills and the short rod chills is 10 to 15 mm. The application further provides a casting method of the broken shaft group cast steel piece. The casting method of the broken shaft group cast steel piece can improve the yield rate from 45% to more than 75%, improve the production efficiency of the molding process by 60% and reduce the production cost by 35%. The cleaning workshop only needs to supplement a small amount of external defects by welding and polishing, the polishing workload is obviously reduced, and the internal quality and appearance quality of the castings are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and in particular to a cage-type chill for casting steel parts of a crusher shaft assembly and its casting method. Background Technology

[0002] During casting, castings undergo thermal expansion and contraction. Normally, as the casting cools and contracts, it is replenished by molten metal. However, when the casting cools unevenly, some molten metal solidifies first, further enveloping the unsolidified metal and forming a closed cavity. When the unsolidified metal cools and contracts, it cannot receive external replenishment, resulting in shrinkage cavities or porosity. The crusher shaft assembly of a crusher has a large wall thickness. Uneven heat dissipation during casting leads to insufficient solidification in the center after the parts near the inner or outer wall solidify, resulting in uneven feeding and shrinkage cavities or porosity in the casting. To prevent shrinkage cavities or porosity in castings, please refer to... Figure 1 Generally, chills, risers, or a combination of both are used. Chills are divided into two main categories: internal chills and external chills, and are generally in the form of blocks or strips. Internal chills are metal blocks placed inside the mold cavity that fuse with the casting. External chills are metal blocks placed on the surface of the pattern (core box) during molding. External chills can be placed during sand pounding; internal chills can be embedded or glued inside the pattern during mold making, or external chills can be extended outside the mold and fixed within the sand mold.

[0003] For crusher shaft assemblies with a wall thickness of less than 40 cm, 12 to 24 conformal chills are generally required, distributed on the outer and inner walls of the crusher shaft assembly. For crusher shaft assemblies with a thicker wall, even more chills are needed; otherwise, castings with dense internal structure and excellent mechanical properties cannot be obtained. The problem of internal shrinkage cavities in castings has not been completely solved, resulting in a low process yield of only about 45%. At the same time, the labor intensity for workers is high, especially in the difficult-to-operate molding and cleaning workshops. Vibration in the molding workshop can cause chills to be misplaced, leading to casting failure or, during the cooling process after casting, the inconsistent solidification rates inside and outside the crystals result in fatal defects such as shrinkage cavities and voids, leading to scrap. Furthermore, the grinding workload is large, resulting in poor internal and surface quality of the castings, and production costs remain high. Summary of the Invention

[0004] In view of this, it is necessary to provide a cage-type chill for casting steel parts of crusher shaft assembly, so as to reduce the use of internal chills, improve working efficiency, reduce production costs and improve product quality.

[0005] It is also necessary to provide a casting method for the steel components of the crusher shaft assembly to reduce the number of pre-embedded chills, improve work efficiency, reduce production costs, and improve product quality.

[0006] A cage-type chill for casting steel components of a crusher shaft assembly includes at least two horizontally arranged annular chills, several vertically arranged long rod chills, and several horizontally arranged short rod chills. The annular chills are arranged in parallel, the long rod chills are vertically connected to the annular chills, and the short rod chills are arranged on the annular chills or long rod chills. The total mass of the annular chills, long rod chills, and short rod chills accounts for 0.5% to 1% of the mass of the crusher shaft assembly, and the diameter of the annular chills, long rod chills, and short rod chills is 10 to 15 mm.

[0007] A casting method for a steel crusher shaft assembly includes the following steps: Step S1: Fabricate a cage-shaped chill according to the inner diameter and wall thickness of the crusher shaft assembly; Step S2: Use molding sand to make the casting cavity for casting the crusher shaft assembly; Step S3: Depending on the wall thickness of the crusher shaft assembly, place 1 to 3 cage-shaped chills in the casting cavity. When 2 or 3 cage-shaped chills are placed in the casting cavity, the short rod chills of two adjacent cage-shaped chills are in contact. At the same time, 2 to 6 external chills are embedded in the hammer part of the crusher shaft assembly in the molding sand; 6 to 12 external chills are embedded in the outer circle of the crusher shaft assembly in the molding sand. Step S4: Pour molten steel into the mold cavity at a casting temperature of 1580~1620 degrees Celsius; Step S5: When the molten steel cools to less than or equal to 200 degrees Celsius, the casting is removed from the sand. Step S6: After the sand removal is completed, wait for the casting to cool to room temperature, then weld and grind the surface of the crushing shaft assembly to obtain the crushing shaft assembly.

[0008] Beneficial effects: Compared with the prior art, the casting method of the crusher shaft assembly cast steel parts of the present invention increases the yield from 45% to over 75%, improves the production efficiency of the molding process by 60%, and reduces production costs by 35%. The cleaning workshop only needs to repair and grind a few external defects, significantly reducing the amount of grinding work, and the internal and external quality of the castings are significantly improved. Attached Figure Description

[0009] Figure 1 This diagram shows the positional relationship between the chill and the cast steel components of the crushing shaft assembly in the conventional process of existing technology.

[0010] Figure 2 This diagram shows the positional relationship between the cage-type chill used for casting the steel components of the crusher shaft assembly and the steel components of the crusher shaft assembly according to the present invention.

[0011] Figure 3 This is a schematic diagram of the structure of the cage-type chill used for casting the cast steel parts of the crusher shaft assembly according to the present invention.

[0012] Figure 4 This is an illustration of the effect of a crusher shaft assembly prepared using traditional processes in existing technologies.

[0013] Figure 5 An effect diagram of the crushing shaft assembly prepared by the casting method of the crushing shaft assembly cast steel part of the present invention.

[0014] Figure 6 This is a schematic diagram of the contact tension between an existing block chill and a molten metal surface.

[0015] In the figure: 10 cage-type chills, 20 ring-shaped chills, 30 long rod chills, 40 short rod chills, 50 inner chills, 60 outer chills, and 70 hammer for casting steel components of the crusher shaft assembly. Detailed Implementation

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Please refer to Figure 2 and Figure 3 A cage-type chill 10 for casting steel components of a crusher shaft assembly includes at least two horizontally arranged annular chills 20, several vertically arranged long rod chills 30, and several horizontally arranged short rod chills 40. The annular chills 20 are arranged in parallel, the long rod chills 30 are vertically connected to the annular chills 20, and the short rod chills 40 are arranged on the annular chills 20 or the long rod chills 30. The total mass of the annular chills 20, the long rod chills 30, and the short rod chills 40 accounts for 0.5% to 1% of the mass of the crusher shaft assembly, and the diameter of the annular chills 20, the long rod chills 30, and the short rod chills 40 is 10 to 15 mm.

[0018] This design uses small-diameter, thin metal rods to form a cage-like chill. The annular chill 20, long chill 30, and short chill 40 are all arranged in a prescribed, neat direction. Because the metal rods have small inner diameters and are very thin, they occupy little space during casting, resulting in a fast melting speed. Their neat arrangement guides and promotes the directional flow of the molten metal, ensuring liquid stability and preventing turbulence. This also prevents the accumulation of impurities or slag within the molten metal. More importantly, due to their small inner diameters and thin diameters, and because they are all cylindrical with smooth, rounded surfaces, as the liquid rises from bottom to top during melting, gases also rise and are expelled. Figure 6The original solution using block chills, as long as it is a block structure, cannot be made very small according to the requirements of manual fixing of chills during construction. It must be a block with a side length of at least 5cm. This results in a large flat surface. During the liquid rise process, according to the principle of liquid tension, the liquid surface will contact the edges and corners of the block chill, forming a closed space. The center of the flat surface is the last to contact the liquid. Gas can easily form in the middle position and cannot be discharged. These gases are trapped in the liquid and cannot be discharged. After cooling, they can easily form pore defects inside the alloy.

[0019] Compared to the original design that used a block chill, this design uses a thinner cylindrical rod with a diameter of 10-15 mm. It has no large flat surfaces and all edges are rounded. This means that when it comes into contact with the molten metal, there is no problem of gas being trapped in the middle of the flat surface. Therefore, after cooling, the internal structure of this design is dense and free of defects such as pores.

[0020] In a preferred embodiment, the material of the cage-type chill 10 for casting the steel components of the crusher shaft assembly of the present invention is a silicon-manganese alloy.

[0021] In a preferred embodiment, when the wall thickness of the crushing shaft assembly is less than 250 mm, the total mass of the annular chill 20, the long rod chill 30, and the short rod chill 40 accounts for 0.5% of the mass of the crushing shaft assembly.

[0022] In a preferred embodiment, when the wall thickness of the crushing shaft assembly is 250-400 mm, the total mass of the annular chill 20, the long rod chill 30, and the short rod chill 40 accounts for 0.6%-0.8% of the mass of the crushing shaft assembly.

[0023] In a preferred embodiment, when the wall thickness of the crusher shaft assembly is greater than 400 mm, the total mass of the annular chill 20, the long rod chill 30, and the short rod chill 40 accounts for 0.8% to 1% of the mass of the crusher shaft assembly.

[0024] In a preferred embodiment, the annular chill 20, the long rod chill 30, and the short rod chill 40 are connected by welding.

[0025] The annular chill 20 of the present invention has a larger cooling range and a more uniform cooling effect compared with the prior art of setting an inner chill 50 with gaps in the horizontal annular area of ​​the crushing shaft assembly.

[0026] The long-rod chill 30 of this invention serves two purposes: firstly, it connects to the annular chill 20; secondly, compared to the prior art with intermittently spaced inner chills 50, it provides a larger cooling range and more uniform cooling effect within the vertical region. Furthermore, the annular area formed by multiple long-rod chills 30 is evenly distributed within the casting, resulting in more consistent cooling rates across different parts.

[0027] The short chills 40 of the present invention further cool the inner wall of the casting in the longitudinal direction. The number of short chills 40 is large, and the cooling range is larger.

[0028] Compared to the internal chill 50 in the prior art, the three-dimensional mesh structure formed by the annular chill 20, the long rod chill 30, and the short rod chill 40 of the present invention has a larger cooling coverage of the molten steel in the cavity, and the cooling speed and solidification speed of the molten steel in the cavity are more consistent, thus making it less likely to form shrinkage cavities inside the casting.

[0029] If the diameters of the annular chill 20, long chill 30, and short chill 40 are too large, it will affect the melting inside the chill and also cause the cooling rate to be too fast, resulting in uneven cooling rates between the internal and external areas of the casting, thus producing shrinkage cavities. If the diameters of the annular chill 20, long chill 30, and short chill 40 are too small, it will cause the chill to melt prematurely. When molten steel is poured into the mold cavity, the liquid level gradually rises. If the chill melts prematurely, the chill above the molten steel surface will not be supported and will collapse, thus affecting the cooling effect of the chill.

[0030] The material of the cage-type chill of this invention is the same as or similar to that of the casting, as long as the prepared crushing shaft assembly meets the requirements in terms of mechanical properties. After the molten steel is poured into the mold cavity, the cage-type chill of this invention can gradually melt at the high temperature of the molten steel. During the melting process, it can also have a rapid cooling effect on the molten steel. In conjunction with the external chill 60, it can achieve synchronous cooling inside and outside of the casting, improve the problem of internal shrinkage of the product, and obtain a casting with dense internal structure and excellent mechanical properties.

[0031] A casting method for a steel crusher shaft assembly includes the following steps: Step S1: Fabricate a cage-shaped chill according to the inner diameter and wall thickness of the crusher shaft assembly; The cage-shaped chill, namely the cage-shaped chill 10 for casting the steel parts of the crusher shaft assembly of the present invention, has its diameter determined according to the inner diameter of the crusher shaft assembly, its quantity determined according to the wall thickness of the crusher shaft assembly, and its height determined according to the height of the crusher shaft assembly. The material used to make the cage-shaped chill is similar to the material used to cast the molten steel.

[0032] Step S2: Use molding sand to make the casting cavity for casting the crusher shaft assembly; The crusher shaft assembly of the present invention adopts sand casting process, using molding sand to make casting cavity, and pre-embedded external chill 60 in molding sand to facilitate cooling of molten steel.

[0033] Step S3: Depending on the wall thickness of the crusher shaft assembly, place 1 to 3 cage-shaped chills in the casting cavity. When 2 or 3 cage-shaped chills are placed in the casting cavity, the short rod chills 40 of two adjacent cage-shaped chills are in contact. At the same time, 2 to 6 external chills 60 are embedded in the hammer part 70 of the crusher shaft assembly in the molding sand. 6 to 12 external chills 60 are embedded in the outer circle of the crusher shaft assembly in the molding sand. When the wall thickness of the crushing shaft assembly is less than 250 mm, a cage-shaped chill is placed in the cavity. The mass of the cage-shaped chill accounts for 0.5% of the mass of the crushing shaft assembly, i.e., the casting mass. The diameter of the cage-shaped chill is the inner diameter of the crushing shaft assembly plus half the wall thickness, so that the cage-shaped chill is located in the middle of the cavity. When the wall thickness of the crusher shaft assembly is 250~400 mm, two cage-shaped chills are placed in the cavity. The mass of the two cage-shaped chills accounts for 0.6%~0.8% of the mass of the crusher shaft assembly, i.e., the casting mass. The two cage-shaped chills are arranged in approximately concentric circles. One cage-shaped chill is located at about one-third of the cavity thickness, and the other cage-shaped chill is located at about two-thirds of the cavity thickness. The short rod chills 40 of the two cage-shaped chills are in contact with each other. When the wall thickness of the crusher shaft assembly is greater than 400 mm, three cage-shaped chills are placed in the cavity. The mass of the three cage-shaped chills accounts for 0.8% to 1% of the mass of the crusher shaft assembly, i.e., the casting mass. The first cage-shaped chill is placed at one-quarter of the cavity, the second cage-shaped chill is placed at one-half of the cavity, and the third cage-shaped chill is placed at three-quarters of the cavity. The short rod chills 40 of the two adjacent cage-shaped chills are in contact.

[0034] The method of embedding the external chill 60 in the molding sand is the same as the existing technology. This invention uses a cage-type chill instead of the internal chill 50, making the placement of the cage-type chill more convenient and accurate. Especially for thick-walled crusher shaft assemblies, the internal chill 50 can be placed inside the mold cavity, without needing to be adhered to or embedded in the molding sand surface. This accelerates the cooling rate inside the casting, resulting in more uniform and closer cooling rates for different parts of the casting. Consequently, the casting is less prone to shrinkage cavities and has a denser internal structure.

[0035] Step S4: Pour molten steel into the mold cavity at a casting temperature of 1580~1620 degrees Celsius; Considering that excessively high molten steel temperatures result in high energy consumption, prolonged casting cooling time, and potential sand mold deformation, while excessively low temperatures can easily lead to inclusions, the optimal casting temperature is 1580~1620 degrees Celsius. During the casting process, regardless of casting size, the pouring flow rate remains at a standard pouring flow rate.

[0036] Step S5: When the molten steel cools to less than or equal to 200 degrees Celsius, the casting is removed from the sand. Step S6: After the sand removal is completed, wait for the casting to cool to room temperature, then weld and grind the surface of the crushing shaft assembly to obtain the crushing shaft assembly.

[0037] According to the national standards GB / T 40802-2021 "General Castings of Carbon Steel and Low Alloy Steel" and GB 7233-87 "Ultrasonic Testing and Quality Rating Methods for Cast Steel Parts", as well as relevant enterprise requirements, for products such as crusher shaft assemblies with large wall thickness, requiring dense internal structure and excellent mechanical properties, the traditional process, which involves embedding an external chill 60 in the molding sand and embedding an internal chill 50 in the side wall of the molding sand, produces a crusher shaft assembly with a yield of 45%. However, the yield of the crusher shaft assembly cast steel parts using the casting method of the present invention is 75%, indicating that the yield of the present invention is significantly improved.

[0038] Also, please see Figure 4 and Figure 5 Since the present invention does not require the installation of internal chill 50, but only the placement of cage chill, the operation time is significantly reduced. At the same time, the internal and external defects of the produced castings are significantly reduced, requiring only welding and minor grinding of external defects, thus significantly reducing the workload and operation time. Furthermore, due to the increased yield, the production efficiency of the molding process is increased by 60% compared to the traditional process, and the production cost of the castings is reduced by 35%.

[0039] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A casting method for a steel crusher shaft assembly, characterized in that: Includes the following steps: Step S1: Fabricate a cage-shaped chill according to the inner diameter and wall thickness of the crusher shaft assembly; Step S2: Use molding sand to make the casting cavity for casting the crusher shaft assembly; Step S3: Depending on the wall thickness of the crusher shaft assembly, place 1 to 3 cage-shaped chills in the casting cavity. When 2 or 3 cage-shaped chills are placed in the casting cavity, the short rod chills of two adjacent cage-shaped chills are in contact. At the same time, 2 to 6 external chills are embedded in the hammer part of the crusher shaft assembly in the molding sand; 6 to 12 external chills are embedded in the outer circle of the crusher shaft assembly in the molding sand. Step S4: Pour molten steel into the mold cavity at a casting temperature of 1580~1620 degrees Celsius; Step S5: When the molten steel cools to less than or equal to 200 degrees Celsius, the casting is removed from the sand. Step S6: After the sand removal is completed, wait for the casting to cool to room temperature, then weld and grind the surface of the crushing shaft assembly to obtain the crushing shaft assembly. The cage-type chill is a cage-type chill used for casting cast steel parts of the crusher shaft assembly. It includes at least two horizontally arranged annular chills, several vertically arranged long rod chills, and several horizontally arranged short rod chills. The annular chills are arranged in parallel, the long rod chills are vertically connected to the annular chills, and the short rod chills are arranged on the annular chills or long rod chills. The total mass of the annular chills, long rod chills, and short rod chills accounts for 0.5% to 1% of the mass of the crusher shaft assembly. The diameter of the annular chills, long rod chills, and short rod chills is 10 to 15 mm. In step S3, when the wall thickness of the crushing shaft assembly is less than 250 mm, one cage-shaped chill is placed in the cavity. The mass of the cage-shaped chill accounts for 0.5% of the mass of the crushing shaft assembly, and the diameter of the cage-shaped chill is the inner diameter of the crushing shaft assembly plus half the wall thickness. When the wall thickness of the crushing shaft assembly is 250~400 mm, two cage-shaped chills are placed in the cavity. The mass of the two cage-shaped chills accounts for 0.6%~0.8% of the mass of the crushing shaft assembly. One cage-shaped chill is located at one-third of the cavity, and the other cage-shaped chill is located at two-thirds of the cavity. The short rod chills of the two cage-shaped chills are in contact with each other. When the wall thickness of the crusher shaft assembly is greater than 400 mm, three cage-type chills are placed in the cavity. The mass of the three cage-type chills accounts for 0.8% to 1% of the mass of the crusher shaft assembly. The first cage-type chill is placed at one-quarter of the cavity, the second cage-type chill is placed at one-half of the cavity, and the third cage-type chill is placed at three-quarters of the cavity. The short rod chills of two adjacent cage-type chills are in contact.

2. The casting method for the steel components of the crusher shaft assembly as described in claim 1, characterized in that: When the wall thickness of the crusher shaft assembly is less than 250 mm, the total mass of the annular chill, long chill, and short chill accounts for 0.5% of the mass of the crusher shaft assembly.

3. The casting method for the steel components of the crusher shaft assembly as described in claim 1, characterized in that: When the wall thickness of the crusher shaft assembly is 250~400 mm, the total mass of the annular chill, long rod chill, and short rod chill accounts for 0.6%~0.8% of the mass of the crusher shaft assembly.

4. The casting method for the steel components of the crusher shaft assembly as described in claim 1, characterized in that: When the wall thickness of the crusher shaft assembly is greater than 400 mm, the total mass of the annular chill, long rod chill, and short rod chill accounts for 0.8% to 1% of the mass of the crusher shaft assembly.

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