Refractory material core shaft type hard alloy die

Abstract

The utility model discloses a refractory material core shaft type hard alloy die which comprises a cylindrical locking nut, hard alloy rings and a core shaft base body, the upper end of the core shaft base body is fixedly connected with the cylindrical locking nut through threads, and the outer wall of the core shaft base body is fixedly provided with the hard alloy rings in a sleeved mode. The mandrel base body is divided into an upper section, a middle section and a lower section which are cylinders with different diameters, the diameters of the upper section, the middle section and the lower section are sequentially increased from top to bottom, a first matching step is arranged at the joint of the upper section and the middle section, and a second matching step is arranged at the joint of the middle section and the lower section. The hard alloy rings with high hardness and high wear resistance are embedded in the wall of the mandrel base body, and the mandrel base body adopts a heat treatment process of carburizing and quenching low-carbon alloy steel, so that the outer layer of the mandrel base body is ensured to have higher hardness and strength, and the interior of the mandrel base body is ensured to have better toughness; and it is ensured that when the mandrel base body is subjected to unbalanced lateral force, the mandrel base body cannot be broken due to insufficient toughness.

Description

Technical Field

[0001] The utility model relates to the technical field of refractory product molding, in particular to a refractory mandrel-type hard alloy mold. Background Art

[0002] The sliding nozzle is a control device for molten steel during the casting process of the continuous casting machine. It can accurately adjust the water flow from the ladle to the continuous casting tundish to balance the inflow and outflow of molten steel, making the continuous casting operation easier to control. The sliding nozzle generally consists of a drive device, a mechanical part and a refractory part, among which the refractory part includes a slide plate and a sliding nozzle.

[0003] The skateboard is usually pressed by a friction press. During the skateboard brick blank forming process, the casting hole in the skateboard brick blank needs to use a core mold. The traditional core mold is an integrated structure, which is formed by ordinary carbon steel material and then used after being processed by carburizing and quenching process. This core mold is easy to wear, and the maximum number of core blanks is 240. The service life is short. Moreover, after the core is worn, the resistance to brick discharge is large, and the size of the brick blank casting hole is difficult to guarantee.

[0004] Announcement No. CN213412374U discloses a core-inserted mold for refractory material pressing skateboards. The technical solution is: the core is a wear-resistant tube, the outer diameter of the wear-resistant tube is the same as the casting hole in the skateboard, one end of the positioning shaft is provided with an external thread, and the middle of the positioning shaft is provided with a positioning shoulder matching the inner diameter of the core; the guide shaft is a stepped shaft, and the end face of the guide shaft with a smaller diameter is provided with a threaded hole matching the external thread of the positioning shaft, the core is sleeved on the end of the guide shaft with a smaller diameter, and the external thread of the positioning shaft is threadedly connected to the threaded hole on the end face of the guide shaft with a smaller diameter. The utility model can be reused many times, has good wear resistance, prolongs the service life of the core mold, ensures the quality of the brick casting hole, and is suitable for all skateboard core molds.

[0005] The above technical solution may encounter the following problems during use:

[0006] 1. During repeated pressing, errors will occur, causing the positioning shaft and the guide shaft to be subjected to unbalanced lateral forces, which in turn leads to insufficient toughness of the positioning shaft and the guide shaft and causes them to break.

[0007] 2. When the core mold is worn, the corresponding entirety needs to be replaced, and it is not possible to replace the specific worn parts separately, which increases the cost of replacing the mold. Utility Model Content

[0008] The utility model aims to provide a refractory mandrel-type carbide die, which solves the above-mentioned problems in the prior art.

[0009] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a refractory mandrel-type cemented carbide mold, comprising a cylindrical locking nut, a cemented carbide ring and a mandrel base, the upper end of the mandrel base being connected and fixed to the cylindrical locking nut by a thread, a plurality of cemented carbide rings being fixed on the outer wall of the mandrel base by a sleeve, the upper end of the mandrel base being provided with a 3×45° chamfer, the lower end of the mandrel base being provided with a 3×45° chamfer, the mandrel base being divided into three sections of cylinders with different diameters, namely, an upper section, a middle section and a lower section, the diameters of the three sections of the cylinders increasing from top to bottom, a first matching step being provided at the connection between the upper section and the middle section, the height of the first matching step being 3 mm, and the first matching step being provided with a chamfered arc angle with a radius of 0.8 mm, a second matching step being provided at the connection between the middle section and the lower section, the height of the second matching step being 2 mm, and the second matching step being provided with a chamfered arc angle with a radius of 0.6 mm.

[0010] Preferably, the outer wall of the upper section of the mandrel base is provided with a standard M42 threaded interface, the height of the upper section of the mandrel base is 69 mm, the height of the middle section of the mandrel base is 81 mm, and the height of the lower section of the mandrel base is 50 mm.

[0011] Preferably, the material of the mandrel base is low-carbon alloy steel that has undergone a carburizing and quenching process, and the outer surface roughness accuracy of the middle section and the lower section of the mandrel base is Ra0.8.

[0012] Preferably, the upper end of the cylindrical locking nut is provided with a 5×45° chamfer, the diameter of the cylindrical locking nut is 55.48mm, the height of the cylindrical locking nut is 75mm, the inner wall of the cylindrical locking nut is provided with a standard M42 threaded interface, the lower end of the cylindrical locking nut is provided with a through hole coaxial with the M42 standard threaded interface, the diameter of the through hole is 48.4mm, and the depth of the through hole is 8mm.

[0013] Preferably, the outer wall diameter of the cemented carbide ring is 56 mm, the inner wall diameter of the cemented carbide ring is 48 mm, the outer wall roughness and the inner wall roughness of the cemented carbide ring are both Ra0.8, and the material of the cemented carbide ring is YG10.

[0014] Preferably, the cylindrical locking nut is made of 42CrMo that has been quenched and blackened.

[0015] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0016] 1. By embedding a high-hardness, high-wear-resistant cemented carbide ring on the wall of the mandrel base, the advantage of high wear resistance of cemented carbide is fully utilized. At the same time, the mandrel base adopts a heat treatment process of carburizing and quenching of low-carbon alloy steel, which not only ensures that the outer layer of the mandrel base has high hardness and strength, and has sufficient supporting strength for the cemented carbide ring, but also ensures that the inside of the mandrel base has good toughness, ensuring that the mandrel base does not break due to insufficient toughness when subjected to unbalanced lateral force.

[0017] 2. By inlaying multiple carbide rings on the outer wall of the mandrel base, when the carbide rings are worn, only the worn carbide rings need to be replaced, which reduces the cost of brick molds to 12.5% ​​of the original, and at the same time improves the uniformity of the product aperture size. Due to the high density of cemented carbide and high roughness accuracy, the demoulding force is reduced, which can effectively prevent cracks in the hole, improve the product's qualified rate and safety factor, reduce the time for changing and repairing molds, reduce the labor intensity of employees, and at the same time increase the effective working time of brick pressing equipment, improve molding efficiency and product appearance quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an overall cross-sectional schematic diagram of the utility model;

[0019] Figure 2 It is a schematic cross-sectional view of the mandrel base of the utility model;

[0020] Figure 3 It is a schematic diagram of fixing the cylindrical locking nut of the utility model.

[0021] Notes in the figure: 1. Cylindrical locking nut; 2. Carbide ring; 3. Mandrel base; 301. First matching step; 302. Second matching step. DETAILED DESCRIPTION

[0022] The following is a further detailed description of the implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0023] See also Figure 1 , Figure 2 and Figure 3A refractory mandrel carbide mold comprises a cylindrical locking nut 1, a carbide ring 2 and a mandrel base 3, wherein the upper end of the mandrel base 3 is connected and fixed to the cylindrical locking nut 1 through a thread, the upper end of the cylindrical locking nut 1 is provided with a 5×45° chamfer, the diameter of the cylindrical locking nut 1 is: 55.48mm, the height of the cylindrical locking nut 1 is: 75mm, the inner wall of the cylindrical locking nut 1 is provided with an M42 standard threaded interface, and an M42 standard threaded interface is opened on the inner wall of the cylindrical locking nut 1 to facilitate the quick connection and fixation between the cylindrical locking nut 1 and the mandrel base 3 The lower end of the cylindrical locking nut 1 is provided with a through hole coaxial with the M42 standard threaded interface, and a through hole is opened at the lower end of the cylindrical locking nut 1 to ensure that the cylindrical locking nut 1 is quickly plugged into the core shaft base 3 for threaded connection. The diameter of the through hole is 48.4 mm, and the depth of the through hole is 8 mm. The material of the cylindrical locking nut 1 is 42CrMo that has been quenched and blackened. The cylindrical locking nut 1 is made of 42CrMo and is quenched and blackened to ensure sufficient locking force, as well as sufficient hardness, strength and wear resistance to prevent deformation during use.

[0024] See also Figure 1 The outer wall of the mandrel base 3 is fixed with a plurality of carbide rings 2 by means of a sleeve. The outer wall diameter of the carbide ring 2 is 56 mm, the inner wall diameter of the carbide ring 2 is 48 mm, the outer wall roughness and the inner wall roughness of the carbide ring 2 are both Ra0.8, and the inner wall of the carbide ring 2 is finely processed on a grinder to ensure that the required roughness accuracy and reasonable assembly properties are met. The material of the carbide ring 2 is YG10, and the upper and lower end faces of the carbide ring 2 need to be ground before being assembled with the mandrel base 3. The bed is used for fine machining to ensure that the roughness accuracy and parallelism of the upper and lower end faces of the cemented carbide ring 2 and the verticality of the upper and lower end faces and the axis of the cemented carbide ring 2 meet the requirements. By installing multiple cemented carbide rings 2 on the core shaft base 3, it is beneficial to reduce the bending stress of the cemented carbide part. At the same time, it is convenient for maintenance, reducing the number of replacements of the cemented carbide ring 2 and reducing the maintenance cost. The cemented carbide ring 2 is made of cemented carbide with a grade of YG10, so that the cemented carbide ring 2 has the characteristics of high hardness, good wear resistance, and good toughness.

[0025] See also Figure 2The upper end of the mandrel base 3 is provided with a 3×45° chamfer, and the lower end of the mandrel base 3 is provided with a 3×45° chamfer. By providing a 3×45° chamfer at the upper end of the mandrel base 3, it is ensured that the mandrel base 3 can accurately and quickly enter the hole of the mandrel on the cover plate that matches it. The mandrel base 3 is divided into three sections of cylinders with different diameters, namely, an upper section, a middle section and a lower section. The diameters of the three sections of the cylinders increase from top to bottom. A first matching step 301 is provided at the connection between the upper section and the middle section. The first matching step 301 is provided at the connection between the upper section and the middle section. The height of the step 301 is 3 mm, the first matching step 301 is rounded with a radius of 0.8 mm, the second matching step 302 is provided at the connection between the middle section and the lower section, the height of the second matching step 302 is 2 mm, and the second matching step 302 is rounded with a radius of 0.6 mm. By providing the first matching step 301 and the second matching step 302 matching with the cemented carbide ring 2 on the mandrel base 3, and performing the rounding treatment on the first matching step 301 and the second matching step 302, the pressure at this place is reduced. Due to the stress concentration caused by machining and heat treatment, the outer wall of the upper section of the mandrel base 3 is provided with a standard M42 threaded interface, the height of the upper section of the mandrel base 3 is 69mm, the height of the middle section of the mandrel base 3 is 81mm, and the height of the lower section of the mandrel base 3 is 50mm. The material of the mandrel base 3 is low-carbon alloy steel that has undergone carburizing and quenching process. The material of the mandrel base 3 is low-carbon alloy steel suitable for carburizing and quenching, which can ensure the high strength and high wear resistance of the surface of the mandrel base 3. At the same time, the core of the mandrel base 3 The core shaft base 3 has high toughness. The surface hardness of the core shaft base 3 after heat treatment is not less than HRC55. At the same time, the matching part of the core shaft base 3 and the cemented carbide ring 2 needs to be fine-machined with an external cylindrical grinder to ensure that the required roughness accuracy and reasonable assembly properties are met. The outer surface roughness accuracy of the middle and lower sections of the core shaft base 3 is Ra0.8, and the working surface of the core shaft base 3 needs to be fine-machined with an external cylindrical grinder to ensure that the roughness accuracy reaches Ra0.8, which is beneficial to reduce demoulding friction, reduce wear on the core shaft, and extend service life.

[0026] The refractory mandrel carbide mold in the utility model is to clean the surface of the semi-finished mandrel base 3 and the cylindrical locking nut 1 which are processed by lathe and have machining allowance, and prevent the defects of soft spots due to uneven carburization in the heat treatment process of carburizing and quenching. The mandrel base 3 is made of low-carbon alloy steel, and the heat treatment process of carburizing and quenching is used to improve the strength and wear resistance. In order to speed up the carburizing speed, the carburizing and quenching temperature is set to 930°C, the carbon potential in the strong carburizing stage is set to 1.2, and the time is 8 hours; The carbon potential of the diffusion stage is set to 0.85, and the time is 4 hours. After the time is up, the temperature in the furnace is lowered to 870°C, and the furnace is directly quenched in salt water. When the temperature reaches room temperature, it is promptly put into the tempering furnace for 180°C, 2 hours of tempering, and the hardness is tested. If the hardness is above HRC55, it is considered qualified. After the heat treatment is completed, the part on the mandrel base 3 that matches the cemented carbide ring 2 is finely machined by a grinder. The inner hole size of the cemented carbide ring 2 needs to be used as a reference for matching to ensure that the cemented carbide ring 2 and the mandrel base 3 have suitable matching properties;

[0027] The cylindrical locking nut 1 is made of 42CrMo. The processed cylindrical locking nut 1 with grinding margin is heated to 50°C above the phase change temperature and kept warm for more than 1 hour to make the cylindrical locking nut 1 completely austenitized. It is directly taken out of the furnace and quenched in salt water. The hardness is above HRC55 to be qualified.

[0028] YG10 is used to make the cemented carbide ring 2. The sintered alloy ring blank with processing allowance is tested for hardness. The hardness ≥ HRA90 is qualified. Then it is ground using a surface grinder and an internal and external cylindrical grinder to achieve the dimensional accuracy required by the drawing.

[0029] During assembly and use: after testing that the sizes of the mandrel base 3, the carbide ring 2 and the cylindrical locking nut 1 are within the tolerance range, the burrs and oil stains have been cleaned up, and the auxiliary assembly tools have been prepared, wrap the lower part of the mandrel base 3 with copper sheet, clamp it with a vise, make the axis of the mandrel base 3 and the upper end face of the vise jaws perpendicular, put the carbide ring 2 into a box-type resistance furnace, heat it to the set temperature, and quickly assemble it on the matching part of the mandrel base 3. When the carbide ring 2 and the mandrel base 3 are both matched without gap, tighten them with the cylindrical locking nut 1 in time, and spot weld them at the joint of the end faces of the mandrel base 3 and the cylindrical locking nut 1 to prevent the cylindrical locking nut 1 from loosening during use, causing axial movement of the carbide ring 2 and generating a gap.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A refractory mandrel-type cemented carbide mold, characterized in that: The invention comprises a cylindrical locking nut (1), a hard alloy ring (2) and a mandrel base (3), wherein the upper end of the mandrel base (3) is connected and fixed to the cylindrical locking nut (1) by means of a thread, a plurality of hard alloy rings (2) are fixed to the outer wall of the mandrel base (3) by means of a sleeve, the upper end of the mandrel base (3) is provided with a 3×45° chamfer, the lower end of the mandrel base (3) is provided with a 3×45° chamfer, the mandrel base (3) is divided into three cylindrical sections of different diameters, namely, an upper section, a middle section and a lower section, The diameters of the three cylindrical sections, namely the upper section, the middle section and the lower section, increase from top to bottom. A first matching step (301) is provided at the connection between the upper section and the middle section. The height of the first matching step (301) is 3 mm. The first matching step (301) is rounded with a radius of 0.8 mm. A second matching step (302) is provided at the connection between the middle section and the lower section. The height of the second matching step (302) is 2 mm. The second matching step (302) is rounded with a radius of 0.6 mm.

2. A refractory mandrel-type carbide mold according to claim 1, characterized in that: The outer wall of the upper section of the mandrel base (3) is provided with an M42 standard threaded interface, the height of the upper section of the mandrel base (3) is 69 mm, the height of the middle section of the mandrel base (3) is 81 mm, and the height of the lower section of the mandrel base (3) is 50 mm.

3. A refractory mandrel-type carbide die according to claim 1, characterized in that: The material of the mandrel base (3) is low-carbon alloy steel that has undergone a carburizing and quenching process, and the outer surface roughness accuracy of the middle section and the lower section of the mandrel base (3) is Ra0.

8.

4. A refractory mandrel-type carbide die according to claim 1, characterized in that: The upper end of the cylindrical locking nut (1) is provided with a 5×45° chamfer, the diameter of the cylindrical locking nut (1) is 55.48 mm, the height of the cylindrical locking nut (1) is 75 mm, the inner wall of the cylindrical locking nut (1) is provided with an M42 standard threaded interface, the lower end of the cylindrical locking nut (1) is provided with a through hole coaxial with the M42 standard threaded interface, the diameter of the through hole is 48.4 mm, and the depth of the through hole is 8 mm.

5. The refractory mandrel cemented carbide mold according to claim 1, characterized in that: The outer wall diameter of the cemented carbide ring (2) is 56 mm, the inner wall diameter of the cemented carbide ring (2) is 48 mm, the outer wall roughness and the inner wall roughness of the cemented carbide ring (2) are both Ra0.8, and the material of the cemented carbide ring (2) is YG10.

6. A refractory mandrel-type cemented carbide mold according to claim 1, characterized in that: The material of the cylindrical locking nut (1) is 42CrMo that has been quenched and blackened.

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