TWI614071B - Semi-liquid forging method of magnesium alloy rim - Google Patents

Description

Semi-liquid forging method of magnesium alloy rim

This creation is about a semi-liquid forging method for a magnesium alloy rim.

Magnesium alloys have been widely used in transportation, electronic products and other fields, especially in the automotive industry, due to their low density, good thermal conductivity, high specific strength, high specific stiffness, excellent damping capacity and easy recovery. Manufacturing of the circle. Since the car rim is of unsprung mass, the weight of the unsprung mass is reduced by 1 kg, and the weight of the whole car is about 10 kg. The 16-inch magnesium alloy forged rim replaces the 16-inch aluminum forged rim. Each rim can lose about 5 kilograms, so when you change the four 16-inch aluminum forged wheels of a car to 16-inch magnesium forged rims, wait for the whole car. The weight loss is about 200 kg, which is quite conducive to energy saving and carbon reduction. At the same time, the damping performance of magnesium alloy is about 30 times higher than that of aluminum alloy. Compared with aluminum forged rim, magnesium alloy forged rim has better elastic recovery and shock absorption capability, which can effectively reduce the contact between wheel and road surface. The resulting vibration is transmitted to the vehicle to provide a more comfortable ride.

The prior art method for manufacturing a magnesium alloy forged rim is to first form a magnesium alloy cast rod by a direct water-cooled semi-continuous casting method, and then slice the magnesium alloy cast rod subjected to heat homogenization treatment into a forged billet, and then send the forged billet. The magnesium alloy forged rim is produced in a high pressure forging machine.

However, since the content of non-metallic impurities in the magnesium alloy cast rod is difficult to reduce, the quality of the magnesium alloy cast rod is difficult to ensure, and the magnesium alloy forged rim has the problem of easily generating irregular cracks, which affects the safety of use. In addition, the prior art method for manufacturing a magnesium alloy forged rim requires first performing thermal homogenization treatment on the magnesium alloy cast rod, and requires the use of a large forging device, resulting in a lengthy process and a large amount of energy consumption and cost. Furthermore, the magnesium alloy cast rod produced by the direct water-cooling semi-continuous casting method tends to have dendrites, columnar crystals or coarse equiaxed crystals, so that the obtained magnesium alloy forged rim has internal defects, thereby lowering the magnesium alloy. Mechanical properties of forged rims.

In view of the above-mentioned shortcomings of the prior art, the purpose of this creation is to reduce the cost of the magnesium alloy forged rim and to ensure the quality of the magnesium alloy forged rim.

In order to achieve the aforementioned creative purposes, the technical means adopted by the present invention is to provide a semi-liquid forging method for a magnesium alloy rim, the steps comprising: providing a magnesium alloy processing system, wherein the magnesium alloy processing system comprises a slurry output a flow passage, a feeding tube, a screw and a heater, one end of the feeding tube is connected to the slurry output flow passage, and the screw is reciprocally movable along the axial direction of the receiving tube and is rotatable Passing through the receiving tube, the heater is connected to the receiving tube; the heater is heated to a magnesium alloy raw material in the holding tube and the screw is rotated to stir the magnesium alloy raw material, Thereby obtaining a snail a semi-liquid magnesium alloy slurry between the rod and the slurry output flow passage, wherein the semi-liquid magnesium alloy slurry comprises spherical magnesium alloy crystal grains and a liquid magnesium alloy; and the screw is axially of the material Moving to fill the semi-liquid magnesium alloy slurry between the screw and the slurry output flow passage into the forging die through the slurry output flow passage; at a pressure of 25 MPa to 35 MPa and 560 ° C to 570 ° C The temperature is applied to the semi-liquid magnesium alloy slurry filled in the forging die; and the semi-liquid magnesium alloy slurry filled in the forging die is cured to obtain the magnesium alloy rim.

Preferably, the semi-liquid forging method of the magnesium alloy rim further comprises the steps of preheating the material tube, the slurry output flow path and the forging mold.

More preferably, the step of preheating the raw material tube, the slurry output flow path and the forging mold comprises: preheating the raw material tube to a preheating temperature of 560 ° C to 600 ° C, preheating the slurry The flow path is fed to a preheat temperature of 550 ° C to 580 ° C and the forging die is preheated to a preheat temperature of 500 ° C to 550 ° C.

Preferably, the semi-liquid forging method of the magnesium alloy rim further comprises the step of spraying a release agent inside the forging die. Wherein, the release agent comprises graphite or boron nitride (BN). The obtained magnesium alloy rim is taken out from the forging die by the use of a release agent.

Preferably, the temperature of the semi-liquid magnesium alloy slurry between the screw and the slurry output flow channel is 560 ° C to 600 ° C, and the screw is located between the screw and the slurry output flow path. Semi-liquid magnesium alloy slurry The solid phase ratio is 15% to 55%.

Preferably, the magnesium alloy raw material is in the form of particles, and the magnesium alloy raw material has a length of 1.0 mm to 1.5 mm, the magnesium alloy raw material has a width of 1.0 mm to 1.5 mm, and the magnesium alloy raw material has a height of 4.0 mm to 5.0mm.

Preferably, the inner tube has an inner diameter of from 90 mm to 130 mm.

Preferably, the heater heats the magnesium alloy raw material in the charging tube and rotates the screw to stir the magnesium alloy raw material, thereby obtaining the screw and the slurry output flow path. The step of separating the semi-liquid magnesium alloy slurry comprises: causing the heater to pass a protective gas to the magnesium alloy raw material in the holding pipe, and to rotate the screw The magnesium alloy raw material is stirred to obtain the semi-liquid magnesium alloy slurry between the screw and the slurry output flow path. Wherein the shielding gas comprises argon.

By using the shielding gas, the magnesium alloy raw material can be effectively prevented from being oxidized upon heating.

Preferably, the heater heats the magnesium alloy raw material in the charging tube and rotates the screw to stir the magnesium alloy raw material, thereby obtaining the screw and the slurry output flow path. The step of between the semi-liquid magnesium alloy slurry comprises: heating the magnesium alloy raw material in the holding tube at a heating temperature of 560 ° C to 600 ° C and bringing the screw at 250 rpm to The rotation speed of 1000 rpm is rotated to agitate the magnesium alloy raw material, thereby obtaining the step of the semi-liquid magnesium alloy slurry between the screw and the slurry output flow path.

Preferably, the step of forging and solidifying the semi-liquid magnesium alloy slurry filled in the forging die, thereby obtaining the magnesium alloy rim comprises: pressing at a pressure of 25 MPa to 35 MPa And a step of forging the semi-liquid magnesium alloy slurry filled in the forging die at a temperature of 560 ° C to 570 ° C; and curing the semi-liquid magnesium alloy slurry filled into the forging die to obtain the magnesium The steps of the alloy rim.

The semi-liquid forging method of the magnesium alloy rim of the present invention, the magnesium alloy raw material is made into a semi-liquid magnesium alloy slurry by the magnesium alloy processing system, and the semi-liquid magnesium alloy slurry is filled into the forging mold The steps of forging and solidifying can achieve the following advantages:

First, improve the dimensional accuracy of the obtained magnesium alloy rim and achieve Near Net-shape Forming, thereby improving material utilization and saving materials and energy.

2. The structure of the obtained magnesium alloy rim is fine and has a spherical crystal body, which does not have dendritic crystals existing in the conventional forged part, and thus has good structural strength and good applicability.

3. When the magnesium alloy slurry is filled into the forging die, the thermal impact on the forging die is small, thereby prolonging the service life of the forging die.

4. The applicable forging equipment has a low tonnage.

Accordingly, the semi-liquid forging method of the magnesium alloy rim not only has the advantages of low manufacturing cost and the ability to produce a magnesium alloy rim having good quality, but also has the advantage of being environmentally friendly.

10‧‧‧Magnesium alloy processing system

11‧‧‧Slurry output runner

12‧‧‧Into the hopper

13‧‧‧Feed tube

14‧‧‧Protective gas input

15‧‧‧heater

16‧‧‧ screw

17‧‧‧ Screw drive unit

18‧‧‧ check valve

20‧‧‧Magnesium alloy raw materials

S1, S2, S3, S4, S5‧‧ steps

Figure 1 is a step of the semi-liquid forging method of the magnesium alloy rim of the present invention. Flowchart; and Figure 2 is a schematic view of a magnesium alloy processing system used in the semi-liquid forging method of the magnesium alloy rim.

In the following, embodiments of the present invention will be described in detail by the following specific embodiments, and those skilled in the art can readily understand the advantages and functions of the present invention, and without departing from the invention. Various modifications and changes are made in the spirit of the invention to practice or apply the invention.

Example

Referring to FIGS. 1 and 2, in the present embodiment, the semi-liquid forging method of the magnesium alloy rim of the present invention comprises: providing a magnesium alloy processing system 10 step S1, preheating the magnesium alloy processing system 10, and preparing a step S2 of forging a mold, the step S3 of heating and stirring a magnesium alloy raw material 20 to obtain a half liquid magnesium alloy slurry, and the magnesium alloy processing system 10 filling the semi-liquid magnesium alloy slurry to Step S4 in the forging die and step S5 of forging and solidifying the semi-liquid magnesium alloy slurry to obtain the magnesium alloy rim, and each step S1, S2, S3, S4, S5 is described in detail as follows: As shown, in the step S1 of providing the magnesium alloy processing system 10, the magnesium alloy processing system 10 includes a slurry output flow path 11, a feed hopper 12, a feed tube 13, and a shielding gas input port 14. a heater 15 and a screw 16, the hopper 12 is disposed on one side of the slurry output flow path 11, and the two ends of the material supply tube 13 are respectively connected with the hopper 12 and the slurry output flow path 11. Connected, the protector body input port 14 is set Between the hopper 12 and the sump 13 , the heater 15 is mounted on the sump 13 , the screw 16 is axially disposed in the sump 13 , the screw 16 can be along the swell The axial direction of the tube 13 reciprocates, and the screw 16 can rotate in the receiving tube 13; further, one end of the screw 16 is provided with a screw driving device 17, and the screw driving device 17 drives the screw 16 along the The axial direction of the receiving tube 13 is opposite to the direction of the slurry output flow path 11 or the reverse direction of the slurry tube 13, and the screw driving device 17 can drive the screw 16 to rotate, and the other end of the screw 16 is provided with a backstop. The valve 18 is located between the screw 16 and the slurry output flow passage 11. In the present embodiment, the inner diameter of the receiving tube 13 is 130 millimeters (mm), and the material of the receiving tube 13 is alloy steel.

In the step S2 of preheating the magnesium alloy processing system 10 and preparing the forging die, the receiving tube 13 is heated by the heater 15 for 90 minutes to 120 minutes to reach a preheating temperature of 580 ° C and preheating the Slurry output flow path 11 to 550 ° C preheating temperature, and preheat the forging die to 530 ° C preheating temperature and spray release agent inside the forging die; in this embodiment, the release agent It is boron nitride.

In the step S2 of heating and stirring the magnesium alloy processing unit 10 to obtain the semi-liquid magnesium alloy slurry, the magnesium alloy raw material 20 is put into the hopper 12 to enter the receiving tube 13 while being The shielding gas inlet port 14 is supplied with argon gas into the receiving tube 13 and rotates the screw rod 16 to heat and stir the magnesium alloy raw material 20 in the filling tube 13 by the heater 15 and the screw 16 respectively. The semi-liquid magnesium alloy slurry is further obtained. Wherein, while heating, the shearing force is generated by the rotation of the screw 16, the magnesium alloy raw material 20 is stirred by the screw 16, and the backing is stopped. The semi-liquid magnesium alloy slurry is formed between the valve 18 and the slurry output flow channel 11, and the semi-liquid magnesium alloy slurry comprises spherical magnesium alloy crystal grains and a liquid magnesium alloy; that is, the semi-liquid magnesium The alloy slurry is a mixture of a solid magnesium alloy and a liquid magnesium alloy, and the semi-liquid refers to the coexistence of solid and liquid. In the present embodiment, the magnesium alloy raw material 20 is in the form of particles, and the length, width and height thereof are 1.5 mm, 1.5 mm and 5 mm, and the magnesium alloy raw material 20 is a magnesium aluminum zinc alloy (AZ80). The heater 15 heats the magnesium alloy raw material 20 at a heating temperature of 580 ° C, and the screw 16 is rotated at a maximum rotation speed of 600 rpm to stir the magnesium alloy raw material 20, and the temperature of the semi-liquid magnesium alloy slurry is 580 ° C, and The semi-liquid magnesium alloy slurry has a solid phase ratio of about 50%.

In step S4 of filling the semi-liquid magnesium alloy slurry into the forging die, the screw 16 is caused to output the slurry 16 along the axial direction of the receiving pipe 13 toward the slurry tube 13 toward the slurry. The direction of the flow path 11 is moved to fill the semi-liquid magnesium alloy slurry formed between the check valve 18 and the slurry output flow path 11 into the forging die via the slurry output flow path 11.

In the step S5 of forging and solidifying the semi-liquid magnesium alloy slurry to obtain the magnesium alloy rim, a hydraulic forging machine forging and cooling solidifying the semi-liquid magnesium alloy slurry filled into the forging die, Thereby, the magnesium alloy rim is obtained in the forging die; thereafter, demolding is performed to take the magnesium alloy rim out of the forging die. In this embodiment, the temperature of the semi-liquid magnesium alloy slurry filled into the forging die is 560 ° C to 570 ° C, and the hydraulic forging machine is a semi-liquid magnesium alloy filled into the forging die at a pressure of 30 MPa. The slurry is forged, that is, the semi-liquid magnesium alloy slurry filled into the forging die is tied at 30 MPa. The pressure and the temperature of 560 ° C to 570 ° C are forged; and after forging, the semi-liquid magnesium alloy slurry filled into the forging die is cooled to below 500 ° C to solidify to form the magnesium alloy rim.

The semi-liquid magnesium alloy slurry filled in the forging die has a small volume shrinkage after forging curing into the magnesium alloy rim, thereby advantageously improving the dimensional accuracy of the magnesium alloy rim and achieving near net shape forming, and further Improve material utilization and save materials and energy.

The semi-liquid magnesium alloy slurry filled into the forging die does not undergo long-term interdendritic liquid flow during forging and solidification, and thus does not form macrosegregation, and the semi-liquid magnesium alloy slurry will flow during the flow process. Laminar flow occurs, which reduces gas inclusions and reduces the porosity of the resulting magnesium alloy rim. Accordingly, the magnesium alloy rim obtained from the semi-liquid magnesium alloy slurry has a fine structure and a spherical crystal body, and does not have dendritic crystals existing in ordinary forged parts, so that it can have good structural strength. Reduce the formation of internal defects and improve the overall mechanical properties.

In addition, the temperature at which the semi-liquid magnesium alloy slurry is filled into the forging die is lower than that of the liquid metal, and the thermal shock to the forging die is small, thereby contributing to an increase in the service life of the forging die.

In addition, the semi-liquid magnesium alloy slurry has a significantly lower deformation resistance than the solid magnesium alloy, so the forged wheel is made of a semi-liquid magnesium alloy slurry compared to the forged rim made of a solid magnesium alloy. The tonnage of the forging equipment required for the ring is also significantly lower.

In summary, the semi-liquid forging method of the magnesium alloy rim has the advantages of low cost, environmental friendliness and the ability to produce a magnesium alloy rim having good quality.

S1, S2, S3, S4, S5‧‧ steps

Claims (9)

A semi-liquid forging method for a magnesium alloy rim, the method comprising: providing a magnesium alloy processing system, wherein the magnesium alloy processing system comprises a slurry output flow path, a material supply tube, a screw and a heater, One end of the feeding tube is connected to the slurry output flow passage, and the screw is reciprocally movable in the axial direction of the receiving tube and can be axially rotatably inserted in the receiving tube, the heater and the Sheng The tube is connected; the heater is heated to a magnesium alloy raw material in the holding tube and the screw is rotated to stir the magnesium alloy raw material, thereby obtaining a gap between the screw and the slurry output flow path. a semi-liquid magnesium alloy slurry, wherein the semi-liquid magnesium alloy slurry comprises spherical magnesium alloy grains and a liquid magnesium alloy; and the screw is moved along an axial direction of the material tube to place the screw and the slurry The semi-liquid magnesium alloy slurry between the material output channels is filled into a forging die through the slurry output channel; the half filled into the forging die is pressed at a pressure of 25 MPa to 35 MPa and a temperature of 560 ° C to 570 ° C Liquid magnesium alloy slurry for forging; and curing The semi-liquid magnesium alloy slurry is filled into the forging die to obtain the magnesium alloy rim. The semi-liquid forging method of the magnesium alloy rim according to claim 1, further comprising the steps of preheating the material tube, the slurry output flow path, and the forging mold. The semi-liquid forging method of the magnesium alloy rim according to claim 2, wherein the step of preheating the raw material tube, the slurry output flow path, and the forging mold comprises: Preheating the feed tube to a preheating temperature of 560 ° C to 600 ° C, preheating the slurry output flow path to a preheating temperature of 550 ° C to 580 ° C and preheating the forging die to a preheating of 500 ° C to 550 ° C temperature. The semi-liquid forging method of the magnesium alloy rim according to any one of claims 1 to 3, further comprising the step of spraying a release agent inside the forging die. The semi-liquid forging method of the magnesium alloy rim according to any one of claims 1 to 3, wherein the temperature of the semi-liquid magnesium alloy slurry between the screw and the slurry output flow path is 560. °C to 600 ° C, and the semi-liquid magnesium alloy slurry between the screw and the slurry output flow channel has a solid phase ratio of 15% to 55%. The semi-liquid forging method of the magnesium alloy rim according to any one of claims 1 to 3, wherein the magnesium alloy raw material is in a granular form, and the magnesium alloy raw material has a length of 1.0 mm to 1.5 mm, the magnesium alloy The width of the raw material is from 1.0 mm to 1.5 mm, and the height of the magnesium alloy raw material is from 4.0 mm to 5.0 mm. The semi-liquid forging method of the magnesium alloy rim according to any one of claims 1 to 3, wherein the inner diameter of the material tube is from 90 mm to 130 mm. The semi-liquid forging method of the magnesium alloy rim according to any one of claims 1 to 3, wherein the heater heats the magnesium alloy raw material in the holding pipe and rotates the screw The step of agitating the magnesium alloy raw material to obtain the semi-liquid magnesium alloy slurry between the screw and the slurry output flow path comprises: causing the heater to the magnesium alloy raw material located in the raw material tube Passing a protective gas into the holding tube and rotating the screw to stir the magnesium alloy A gold raw material to obtain the semi-liquid magnesium alloy slurry between the screw and the slurry output flow path. The semi-liquid forging method of the magnesium alloy rim according to any one of claims 1 to 3, wherein the heater heats the magnesium alloy raw material in the holding pipe and rotates the screw The step of agitating the magnesium alloy raw material to obtain the semi-liquid magnesium alloy slurry between the screw and the slurry output flow path comprises: arranging the heater at a heating temperature of 560 ° C to 600 ° C The magnesium alloy raw material in the charging tube is heated and the screw is rotated at a speed of 250 rpm to 1000 rpm to stir the magnesium alloy raw material, thereby obtaining the between the screw and the slurry output flow path. The step of a semi-liquid magnesium alloy slurry.