Efficient die casting method for automobile AT gearbox shell

Abstract

The invention relates to an efficient die-casting method for an automobile AT gearbox shell. The efficient die-casting method comprises the following steps that S1, raw materials are prepared; s2, smelting; s3, die casting; s4, demolding is conducted; according to the efficient die-casting method, a high-copper-zinc-manganese alloy formula is adopted, good die-casting performance and heat treatment response capacity are achieved, a three-section type mold filling mode of pushing a pouring gate at a low speed, filling 80% of a mold cavity at a high speed and filling 20% of the remaining mold cavity at a low speed is adopted during die-casting, air in a pouring gate is effectively exhausted, gas is prevented from being involved in the pouring gate in advance, and the service life of the pouring gate is prolonged. Then, the gas is pushed forwards in an atomized state, so that original gas in a cavity can be pushed to an overflow groove and exhausted conveniently instead of being wrapped to form isolated gas holes, meanwhile, good mold filling capacity is ensured, the speed is reduced at the last stage of mold filling, gas entrapment caused by the water hammer effect is reduced, and after mold filling is completed, die-casting pressure is applied immediately for powerful feeding; ningdu shrinkage is effectively compensated, shrinkage porosity is reduced, and therefore the density and mechanical performance of the die casting are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of AT gearbox manufacturing, in particular to a high-efficiency die casting method of an automobile AT gearbox shell. BACKGROUND

[0002] In the fierce competition of the world automobile market, countries are developing towards high quality, high reliability, light weight, energy saving and low cost. In terms of materials, lightweight is used to replace part of the steel (iron) with aluminum alloy to meet the requirements of high quality and low cost of the automobile; in terms of process, scientificity is used to replace traditional process to improve the precision of the blank, reduce the machining allowance, reduce the consumption of raw materials and reduce the cost. To further expand the use of aluminum alloy materials in automobile structure and powertrain system, the existing preparation method and manufacturing process of aluminum alloy castings have been difficult to meet this requirement. At present, the production and manufacturing methods of aluminum alloy gearbox shell for automobiles in China present the following forms: sand casting, gravity casting, low pressure casting and pressure casting; the automobile aluminum alloy gearbox shell manufactured by these traditional processes presents different degrees of quality problems such as cold separation, depression, cracks and other defects, which seriously affects the performance of the product. At the same time, due to the low yield, low resource and energy utilization rate, low aluminum waste recycling rate and serious environmental pollution, the development of high-speed automobile is hindered.

[0003] Therefore, the present application provides a high-efficiency die casting method of an automobile AT gearbox shell to solve the above problems. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a high-efficiency die casting method of an automobile AT gearbox shell to improve the manufacturing efficiency and manufacturing quality of the AT gearbox shell.

[0005] To solve the above technical problems, the technical scheme of the present application is as follows: a high-efficiency die casting method of an automobile AT gearbox shell, the innovation point of which is as follows: S1, raw material preparation: the raw material components and their mass ratio are as follows: Si 8.2~10.3%, Mg 0.3~0.6%, Cu 0.15~0.25%, Zn 0.6~1.1%, Mn 0.2~0.5%, and the balance is aluminum; the raw material components are mixed uniformly and preheated; S2, smelting: the preheated raw materials are put into a smelting furnace, heated and stirred continuously until the raw materials are completely melted to obtain a molten body; S3, die casting: the die casting mold is preheated in advance, the molten body is pushed into the die casting mold gate at low speed by the injection head, the molten body flows smoothly through the gate at a first slow flow rate, air is discharged, when the molten body reaches the inner gate of the die casting mold, it is switched to a high-speed flow rate to fill the mold cavity at 80% in a mist state, and then switched to a second slow flow rate to slowly fill the remaining space in the mold cavity, and after the mold cavity is filled, the die casting pressure is immediately applied to perform strong post-shrinkage; S4, demolding: after the molten body hardens into a die casting, the die casting mold is opened to take out the die casting, the surface of the die casting is cleaned, and then the die casting after cleaning is deburred and trimmed to obtain an AT gearbox housing.

[0006] Further, in step S2, the temperature is heated to 630-690 DEG C.

[0007] Further, in step S3, the die casting mold is preheated to 150-180 DEG C.

[0008] Further, in step S3, the first slow flow rate is 0.2-0.3 m / s, the high-speed flow rate is 1.1-1.5 m / s, and the second slow flow rate is 0.5-0.8 m / s.

[0009] Further, in step S3, the die casting pressure is 80-120 MPa.

[0010] The advantages of the present application are: The high-efficiency die casting method of the present application uses an alloy formula with high copper, zinc and manganese, has good die casting properties and heat treatment response ability, and adopts a three-stage filling method of low-speed pushing the gate, high-speed filling the cavity at 80%, and slow-speed filling the remaining 20% of the cavity, effectively discharging air in the gate, preventing air from being prematurely entrapped, then pushing forward in a mist state, which is beneficial to pushing the original gas in the cavity to the overflow groove and the exhaust, instead of being wrapped to form isolated pores, while ensuring good filling ability, reducing air entrapment due to water hammer effect by reducing the speed at the end of the filling, and immediately applying the die casting pressure for strong post-shrinkage after the filling is completed, effectively compensating for Ningdu shrinkage, reducing shrinkage, thereby improving the density and mechanical properties of the die casting. DETAILED DESCRIPTION

[0011] To further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purposes, the specific embodiments, structures, features and effects according to the present application are described in detail as follows.

[0012] EMBODIMENT The present embodiment provides a high-efficiency die casting method for an automobile AT gearbox housing, comprising the following steps: S1, raw material preparation: the raw material components and their mass ratio are: Si 8.2~10.3%, Mg 0.3~0.6%, Cu 0.15~0.25%, Zn 0.6~1.1%, Mn 0.2~0.5%, and the balance is aluminum; the raw material components are mixed uniformly and then preheated; S2, smelting: the preheated raw materials are put into a smelting furnace, heated to 660 DEG C and continuously stirred until the raw materials are completely melted to obtain a molten body; S3, die casting: the die casting mold is preheated to 170 DEG C in advance, the molten body is pushed into the die casting mold gate at a low speed by using a pressure head, the molten body flows smoothly through the gate at a first slow speed of 0.25 m / s, air is excluded, when the molten body reaches the inner gate of the die casting mold, it is switched to a high speed of 1.3 m / s to rapidly fill 80% of the mold cavity in an atomized state, and then switched to a second slow speed of 0.6 m / s to slowly fill the remaining space of the mold cavity, after the mold cavity is filled, a die casting pressure of 100 MPa is immediately applied for strong post-shrinkage; S4, demolding: after the molten body hardens into a die casting, the die casting mold is opened to take out the die casting, the surface of the die casting is cleaned, then the die casting after cleaning is deburred and trimmed to obtain an AT gearbox shell.

[0013] The high-efficiency die casting method of the application adopts an alloy formula with high copper, zinc and manganese, has good die casting property and heat treatment response capability, and adopts a three-stage filling mode of low-speed pushing the gate, high-speed filling 80% of the cavity and slow-speed filling the remaining 20% of the cavity during die casting, effectively excludes air in the gate, prevents air from being prematurely entrapped, then pushes forward in an atomized state, which is beneficial to pushing the original air in the cavity to the overflow groove and the exhaust, instead of being wrapped to form isolated pores, while ensuring good filling capacity, reducing air entrapment caused by water hammer effect by reducing the speed at the end of filling, and immediately applying die casting pressure for strong post-shrinkage after filling is completed, effectively compensating for Ningdu shrinkage, reducing shrinkage, thereby improving the density and mechanical properties of the die casting.

[0014] The above is only a preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed as above, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the technical solution of the application. Any modification, change and modification of the above embodiments based on the technical essence of the application are still within the scope of the technical solution of the application.

Claims

1. A highly efficient die-casting method for an automotive AT transmission housing, characterized in that: Includes the following steps: S1. Raw material preparation: The raw material components and their mass ratios are as follows: Si 8.2~10.3%, Mg 0.3~0.6%, Cu 0.15~0.25%, Zn 0.6~1.1%, Mn 0.2~0.5%, with the balance being aluminum; after mixing all the raw material components evenly, preheat the mixture. S2. Melting: The preheated raw materials are put into the melting furnace, heated and stirred continuously until all the raw materials are melted to obtain a molten body; S3. Die casting: Preheat the die casting mold in advance, use the injection head to push the molten material into the gate of the die casting mold at a low speed, so that the molten material flows smoothly through the gate at the first slow flow rate to remove air. When the molten material reaches the inner gate of the die casting mold, switch to a high flow rate to quickly fill 80% of the mold cavity in an atomized state. Then switch to a second slow flow rate to slowly fill the remaining space of the mold cavity. After the cavity is filled, immediately apply die casting pressure for strong feeding. S4. Demolding: After the molten material hardens into a die casting, the die casting mold is opened to remove the die casting. The surface of the die casting is cleaned, and then burrs and flash are removed from the cleaned die casting to obtain the AT gearbox housing.

2. The high-efficiency die-casting method for automotive AT transmission housing according to claim 1, characterized in that: In step S2, the temperature is raised to 630~690℃.

3. The high-efficiency die-casting method for automotive AT transmission housing according to claim 1, characterized in that: In step S3, the die-casting mold is preheated to 150~180℃.

4. The high-efficiency die-casting method for automotive AT transmission housing according to claim 1, characterized in that: In step S3, the first slow flow velocity is 0.2~0.3 m / s, the high flow velocity is 1.1~1.5 m / s, and the second slow flow velocity is 0.5~0.8 m / s.

5. The high-efficiency die-casting method for automotive AT transmission housing according to claim 1, characterized in that: In step S3, the die-casting pressure is 80~120MPa.