Manufacturing method of sleeve for die cast

Abstract

The present invention relates to a method for manufacturing a sleeve for die casting with improved service life, manufacturing efficiency, and material recovery rate. A method for manufacturing a sleeve for die casting according to the present invention comprises: a first step of melting an alloy material; a second step of applying a release agent to the inner diameter of a centrifugal casting mold; a third step of loading the molten alloy material into a movable ladle; a fourth step of centrifugal casting; a fifth step of cooling the centrifugal casting mold after forming is complete; a sixth step of withdrawing a product from the centrifugal casting mold; a seventh step of turning the withdrawn product; an eighth step of stress relief softening heat treatment on the turned product; a ninth step of milling the stress relief softening heat-treated product; a tenth step of homogenizing heat treatment on the milled product; an eleventh step of grinding the homogenized heat-treated product; a twelfth step of honing the ground product; and a thirtied heat treatment on the honed product.

Description

Technology Field

[0001] The present invention relates to a sleeve used in a die-casting mold, and more specifically, to a method for manufacturing a die-casting sleeve that has an improved service life and improved manufacturing efficiency and material recovery rate. Background Technology

[0003] Die casting refers to a process of manufacturing metal objects or products by injecting molten metal into a mold under pressure exceeding atmospheric pressure and maintaining pressure until solidification is complete. It is widely used in production sites because it allows for high precision in castings, reduces machining costs, and is highly advantageous for mass production.

[0005] A die-casting sleeve is a cylinder-shaped component used to press the aforementioned molten metal into a mold at a pressure greater than atmospheric pressure. It is typically configured to be inserted inside the mold body and is designed so that a piston moves inside, operating in such a way that the piston pressurizes the molten metal introduced into the sleeve.

[0007] Since a piston moves and high pressure acts inside the sleeve, the metal fatigue and wear of the sleeve are severe; therefore, it is common practice to replace the sleeve with a new one after a certain number of uses.

[0009] We will examine the general manufacturing method of the aforementioned sleeve through the manufacturing method of a sleeve for an automobile transmission. Registered Patent Publication No. 10-2041482 describes a hot forging process comprising: a step of manufacturing an initial billet by cutting a round bar of chrome-molybdenum steel (SCM420H) while maintaining a diameter (40.0 mm), height (51.7 mm), and weight (0.51 kg) and applying heat at 1050°C thereto; a finisher step for forming a molded body from the initial billet so that an outer diameter of 78.3 mm and a height of 20.6 mm are maintained and circular grooves are formed on the upper and lower parts of the central region; a piercing step for manufacturing a ring rolling preform by cutting the circular grooves of the molded body with a punching machine to maintain an outer diameter of 78.3 mm and an inner diameter of 55.2 mm and a height of 20.6 mm, while maintaining a temperature of 900°C; and a step of supplying the ring rolling preform formed in the piercing step of the hot forging process to a primary conveyor device to form a ring rolling preform An ultra-precision shape ring rolling process comprising: a step of moving the shape downward to make contact with a detection sensor and waiting while caught on a waiting latch installed at the bottom of a primary conveyor device; a step in which a rotating means operates in response to a signal from the detection sensor to pass through the waiting latch and be placed in a lower mounting gap for the ring rolling preform waiting on the waiting latch; a step of extracting the mounted ring rolling preform by a robot operated by a control device and placing it on a ring rolling die device; a step of manufacturing the ring rolling preform placed on the ring rolling die device into a ring-shaped molded product maintaining an outer diameter of 94 mm, an inner diameter of 73.8 mm, and a height of 20.6 mm using the ring rolling die device; a step for automatically removing the manufactured ring-shaped molded product downward into an input hopper; and a step of supplying the ring-shaped molded product removed through the input hopper to a secondary conveyor device and transporting it externally for stacking; and the outer diameter and inner diameter of the ring-shaped molded product It is characterized by comprising a molded part cutting process for manufacturing a transmission sleeve by cutting a groove and an involute spline gear using a cutting machine, and a process for heat treating the transmission sleeve manufactured in the molded part cutting process.

[0011] The aforementioned conventional technology is a method for manufacturing sleeves for automobile transmissions, but since the sleeves for die casting are also manufactured by cutting and boring a round bar made of STD61 steel or a similar material coated with tungsten, there is a disadvantage that manufacturing costs increase significantly due to material loss and increased processing labor.

[0013] Registered Patent Publication No. 10-1693645 was disclosed, which aims to replace only a part of the die-cast sleeve in order to compensate for the disadvantage of material loss according to the manufacturing method by cutting and boring the round bar described above. The aforementioned prior art relates to an inserter-type die-casting sleeve inserted into a mold to guide a piston and inject molten metal into the mold, comprising: a cylinder portion including an inner diameter portion formed internally in a cylinder shape; a flange portion inserted into the outer surface of the cylinder portion; and a classifier coupled to one side of the cylinder portion and a part of the inner diameter portion; wherein molten metal is guided into a space formed by a gate portion formed in the cylinder portion and a guide portion formed in the classifier and discharged at a 90-degree angle to the longitudinal direction of the cylinder portion; wherein a step is formed on one side of the outer surface of the cylinder portion, and one side of the step contacts the flange portion; wherein the flange portion includes an outer surface forming the outside, a right side formed to the right of the outer surface, a left side formed to the left of the outer surface, an inner surface forming the inside, a first stage formed with a diameter larger than the inner surface, and a first stage side formed on the first stage side; wherein the first stage and the first stage side contact the step of the cylinder, and the inner surface contacts the outer surface of the cylinder; and wherein the flange portion has a diameter larger than the first stage. It is characterized by further including a second stage and a second stage side forming a side of the second stage.

[0015] However, since the aforementioned separable sleeves are also produced through processing involving boring and cutting after cutting, increased material loss is inevitable, and there is a problem where manufacturing efficiency is significantly reduced as the number of processing steps for product production increases further due to the separable configuration. Prior art literature

[0017] Korean Registered Patent Publication No. 10-2041482 Korean Registered Patent Publication No. 10-1693645 The problem to be solved

[0018] The present invention, taking into account the aforementioned problems, aims to provide a method for manufacturing a die-cast sleeve that can significantly improve the economic efficiency of product manufacturing by greatly reducing the amount of material removed during the conventional die-cast sleeve manufacturing process.

[0020] In addition, the present invention aims to provide a method for manufacturing a die-cast sleeve in which the manufacturing process is reduced and the manufacturing efficiency of the product is significantly improved by melting an alloy steel with excellent wear resistance and fatigue resistance and then manufacturing the die-cast sleeve using a centrifugal casting method. means of solving the problem

[0022] A method for manufacturing a sleeve for die casting according to the present invention comprises: a first step of melting an alloy material; a second step of applying a release agent to the inner diameter of a centrifugal casting mold; a third step of loading the molten alloy material into a movable ladle; a fourth step of centrifugal casting; a fifth step of cooling the centrifugal casting mold after forming is complete; a sixth step of withdrawing a product from the centrifugal casting mold; a seventh step of turning the withdrawn product; an eighth step of stress relief softening heat treatment on the turned product; a ninth step of milling the stress relief softening heat-treated product; a tenth step of homogenizing heat treatment on the milled product; an eleventh step of grinding the homogenized heat-treated product; a twelfth step of honing the ground product; and a thirtied heat treatment on the honed product. Effects of the invention

[0024] The present invention manufactures a die-casting sleeve by melting an alloy material and forming it via centrifugal casting, rather than by cutting a round bar, thereby significantly reducing the amount of material wasted due to cutting and greatly improving the economic efficiency of product manufacturing.

[0026] In addition, the present invention has the effect of reducing the manufacturing process and significantly improving product manufacturing efficiency by melting an alloy material with excellent wear resistance and fatigue resistance and manufacturing a die-casting sleeve using a centrifugal casting method. Brief explanation of the drawing

[0028] FIG. 1 is a block diagram showing a method for manufacturing a sleeve for die casting according to the present invention. Specific details for implementing the invention

[0029] The specific details for solving the problem according to the present invention are described in detail below, together with the attached drawings. However, the attached drawings may be exaggerated, omitted, or schematically illustrated for the convenience of explaining the essential parts, and terms and names used in the description may be implicitly determined by the shape, function, or role of the components rather than their dictionary meanings. Descriptions regarding direction are determined based on the direction first presented in the first drawing, and descriptions regarding position are determined as inside or outside based on the center of each component or the center of a circle. Furthermore, specific descriptions regarding prior art and ordinary technology are omitted or replaced with simple symbols or names, as they may obscure the essence.

[0031] In addition, specific structures, shapes, forms, arrangements, sizes, etc. of the configurations identifiable through the drawings, and the operation of the configurations and the resulting effects, etc., which can be inferred from the drawings, may obscure the main point and thus may be omitted from detailed descriptions; similarly, bolts, welded parts, holes, etc., applied for joining the configurations may obscure the main point and thus may be omitted from the drawings.

[0033] The method for manufacturing a sleeve for die casting according to the present invention is,

[0034] A first step (S10) of melting the alloy material, and

[0035] A second step (S20) of applying a release agent to the inner diameter of a centrifugal casting mold, and

[0036] A third step (S30) of loading the molten alloy material into a movable ladle, and

[0037] The fourth step (S40) of centrifugal casting molding, and

[0038] A fifth step (S50) of cooling the centrifugal casting mold after molding is complete, and

[0039] Step 6 (S60) of withdrawing the product from the centrifugal casting mold, and

[0040] Step 7 (S70) of turning the withdrawn product, and

[0041] Step 8 (S80) of stress-relieving softening heat treatment on a turned product, and

[0042] Step 9 (S90) of milling a stress-relieving softened heat-treated product, and

[0043] A tenth step (S100) of homogenizing heat treating a milled product, and

[0044] Step 11 (S110) of grinding a homogenized heat-treated product, and

[0045] Step 12 (S120) of honing a ground product, and

[0046] It is characterized by including a 13th step (S130) of nitriding heat treatment on a honed product. Below, the process for each step is examined in detail.

[0048] First step (S10) of melting the alloy material: After preparing the alloy material to be formed by centrifugal casting, it is melted. The alloy material according to the present invention comprises C 0.47 to 0.53 wt%, Si 0.15 to 0.25 wt%, Mn greater than 0.45 and 0.55 wt%, P greater than 0 and 0.03 wt%, S greater than 0 and 0.03 wt%, Cr 4.15 to 4.50 wt%, Mo 1.95 to 2.05 wt%, V 1.00 to 1.30 wt%, W 1.30 to 1.90 wt%, unavoidable impurities greater than 0 and 1 wt%, and the remainder is Fe. The alloy material having the above composition is charged into a high-frequency induction melting furnace and melted at a temperature of 1650°C.

[0050] Step 2 (S20) of applying a release agent to the inner diameter of a centrifugal casting mold: A release agent according to the present invention is applied to the inner diameter of a centrifugal casting mold. The release agent according to the present invention is composed of SiO2 98.29 wt%, Fe2O3 0.06 wt%, Al2O3 1.1 wt%, TiO2 0.02 wt%, CaO 0.04 wt%, MgO 0.03 wt%, Na2O 0.03 wt%, K2O 0.03 wt%, and LOi 0.4 wt%.

[0052] Step 3 (S30) of loading the molten alloy material into a movable ladle: The molten alloy material is loaded into a movable ladle to be poured into a centrifugal casting mold. At this time, the ladle heating temperature is 600℃ and the ladle molten metal temperature is 1550℃.

[0054] Step 4 (S40) of centrifugal casting: The molten alloy material loaded into a movable ladle is poured into a centrifugal casting mold and then centrifugally cast. The time for pouring the molten alloy material into the centrifugal casting mold is 60 seconds, and the rotation speed during centrifugal casting is 12,000 rpm.

[0056] Step 5 (S50) of cooling the centrifugal casting mold after molding is completed: When centrifugal casting is completed, the centrifugal casting mold is cooled. The cooling method of the centrifugal casting mold is air cooling, and the cooling time is within 600 seconds.

[0058] Step 6 (S60) of withdrawing the product from the centrifugal casting mold: After the centrifugal casting molding is completed through Step 5 (S50) and the cooling of the centrifugal casting mold is also completed, the molded product is withdrawn from the centrifugal casting mold.

[0060] Step 7 (S70) of turning the drawn-out product: The product drawn out through Step 6 (S60) is brought into contact with a rotating workpiece using a tool with a tip and transported, and the product is rotated and processed to the desired dimensions and shape. In the method for manufacturing a die-cast sleeve according to the present invention, since the molten alloy material is formed by centrifugal casting and already manufactured into a pipe shape before turning, material loss is minimized during the turning step.

[0062] Step 8 (S80) of stress relief softening heat treatment on a turned product: The product, which has been turned through Step 7 (S70), is subjected to stress relief softening heat treatment. The stress relief softening heat treatment according to the present invention is performed by furnace cooling at a pit furnace temperature of 680°C, and the cooling temperature is 60 minutes per inch of product.

[0064] Step 9 (S90) of milling the stress-relieving softening heat-treated product: After the stress-relieving softening heat-treated product is fixed to a clamp after passing through Step 8 (S80), it is machined to the desired dimensions and shape using a rotating tool.

[0066] Step 10 (S100) of homogenizing heat treatment of a milled product: A homogenizing heat treatment is performed on a product that has been milled through Step 9 (S90). The homogenizing heat treatment according to the present invention is performed at 860°C for 60 minutes per inch of product.

[0068] Step 11 (S110) of grinding the homogenized heat-treated product: The outer surface of the product, which has undergone homogenized heat treatment through Step 10 (S100), is ground. Since the grinding process described above is a known technique, a detailed description is omitted.

[0070] Step 12 (S120) of honing a ground product: The inner surface of the product, which has been ground through Step 11 (S110), is honed. After honing, the surface roughness standard is RZ 3.5.

[0072] Step 13 (S130) of nitriding heat treatment of a honed product: The honed product, which has been completed through Step 12 (S120), is nitrided heat treated. The nitriding heat treatment according to the present invention is 120 minutes at a nitriding temperature of 560℃.

[0074] The present invention is described above by illustrating the configuration of the invention and the specific components included therein to facilitate understanding of the principles of the configuration sought by the invention, and by providing an explanation based on such drawings. The structure, form, shape, arrangement, direction, and quantity of the configuration and specific components included in the invention are determined in consideration of the principles sought, and these may be modified in various ways as necessary. The configuration and specific components presented in the present invention serve as examples for those skilled in the art to understand the effects sought in the invention and the principles that are most desirable to apply to obtain better effects. Accordingly, while it is most desirable to complete the present invention by including all the configurations described above, the invention may be completed by selecting or excluding some of the configurations described above for cost reduction, ease of manufacturing, environmental conditions, or as necessary, or by separating one or more configurations and merging them with other configurations. Furthermore, each configuration described above may be independently applied to technical fields other than this technical field, taking into account principles, uses, functions, roles, operations, and effects. Based on this, the scope of rights of the present invention may be specified as follows to encompass as much as possible the claims of the present invention, and claims may be made in order of broadest scope. Explanation of the symbols

[0076] S10: Stage 1 S20: Stage 2 S30: Stage 3 S40: Stage 4 S50: Stage 5 S60: Stage 6 S70: Stage 7 S80: Stage 8 S90: Stage 9 S100: Stage 10 S110: Step 11 S120: Step 12 S130: Stage 13

Claims

Claim 1 A first step (S10) of melting the alloy material, a second step (S20) of applying a release agent to the inner diameter of the centrifugal casting mold, a third step (S30) of loading the molten alloy material into a movable ladle, a fourth step (S40) of centrifugal casting, a fifth step (S50) of cooling the centrifugal casting mold after forming is complete, a sixth step (S60) of withdrawing the product from the centrifugal casting mold, a seventh step (S70) of turning the withdrawn product, an eighth step (S80) of furnace cooling the turned product at a pit furnace temperature of 680°C and performing stress relief softening heat treatment at a cooling temperature of 60 minutes per inch of product, a ninth step (S90) of milling the stress relief softening heat-treated product, and homogenizing the milled product at 860°C for 60 minutes per inch of product. The method comprises a 10th step (S100) of heat treatment, an 11th step (S110) of grinding the homogenized heat-treated product, a 12th step (S120) of honing the ground product, and a 13th step (S130) of nitriding heat treatment the honed product, wherein the alloy material of the 1st step (S10) comprises C 0.47 to 0.53 wt%, Si 0.15 to 0.25 wt%, Mn 0.45 to 0.55 wt%, P greater than 0 and less than or equal to 0.03 wt%, S greater than 0 and less than or equal to 0.03 wt%, Cr 4.15 to 4.50 wt%, Mo 1.95 to 2.05 wt%, V 1.00 to 1.30 wt%, W 1.30 to 1.90 wt%, unavoidable impurities greater than 0 and less than or equal to 1 wt%, and the remainder A method for manufacturing a sleeve for die casting, characterized by being composed of Fe, wherein the 8th step aims to remove residual stress generated by turning and soften the material to improve subsequent milling machinability, and the 10th step aims to homogenize the microstructure after milling to ensure consistency of the internal microstructure and improve mechanical properties. Claim 2 delete

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