Magnesium alloy molded article and method of manufacture thereof

Abstract

A magnesium alloy shaped article and a method for manufacturing the same are provided, the method including a first step of extruding a magnesium alloy billet to form a pipe having a predetermined strength, a second step of heat treating the extruded magnesium alloy in an extrusion molding, a third step of forming the heat treated magnesium alloy to a predetermined temperature by a magnesium alloy forming device, a fourth step of coating the formed magnesium alloy shaped article, and a fifth step of painting the coated magnesium alloy shaped article.

Description

[Technical Field]

[0001] The present disclosure relates to magnesium alloy shaped articles and methods of making the same. [Background technology]

[0002] Magnesium alloys are lightweight metals with low density among available structural materials, and have attracted attention for their excellent characteristics such as high specific strength, machinability, and vibration absorption. Magnesium alloys can also be used for special purposes by adjusting the alloy ratio according to each application field, and active research is being conducted to utilize magnesium alloys in various fields.

[0003] However, magnesium alloys have relatively poor mechanical properties, and therefore many efforts have been made to improve the strength and ductility of magnesium alloy workpieces through various methods. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Korean Patent Publication No. 2002-0040562 (Published May 30, 2002) Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide magnesium alloy shaped articles and methods for making same. [Means for solving the problem]

[0006] According to one embodiment of the present disclosure, there is provided a method for manufacturing a magnesium alloy shaped article, the method including: extruding a magnesium alloy billet to form a pipe having a predetermined strength; heat treating the extruded magnesium alloy in the extrusion; forming the heat treated magnesium alloy at a predetermined temperature using a magnesium alloy forming device; coating the formed magnesium alloy shaped article; and painting the coated magnesium alloy shaped article.

[0007] The predetermined strength may be 350 megapascals (MPa).

[0008] The predetermined temperature may be between 200°C and 450°C.

[0009] The magnesium alloy forming device may include a fixed unit that rotatably supports the workpiece, at least one heater module that is removably arranged on the outer peripheral surface of the workpiece and heats the workpiece, a rotating unit that faces the fixed unit and rotates the workpiece supported by the fixed unit, and at least one roller unit that applies pressure to the workpiece while being moved in the axial direction of the workpiece and rotated along the outer peripheral surface of the workpiece.

[0010] The rotating unit can be rotated at 300 to 1200 revolutions per minute (RPM).

[0011] The movement speed of the roller unit can be set to 2 mm / s to 14 mm / s in the axial direction of the workpiece.

[0012] The amount of molding of the roller unit can be from 0.05mm to 1.5mm.

[0013] The roller unit can be rotated at a predetermined inclination toward the workpiece.

[0014] The magnesium alloy shaped article can be manufactured by shaping a magnesium alloy material, wherein the magnesium alloy material is heated to 200°C to 450°C by a magnesium alloy shaping device, and the shaping amount is 0.05mm to 1.5mm.

[0015] According to one embodiment of the present disclosure, there is provided a magnesium alloy shaped article manufactured by the above-described method for manufacturing a magnesium alloy shaped article. [Effects of the Invention]

[0016] As described above, according to the method for producing a magnesium alloy material in the present disclosure, a high-strength magnesium formed article can be produced.

[0017] According to one embodiment of the present disclosure, a highly reliable magnesium alloy article can be manufactured that has mechanical properties that enable it to replace aluminum materials. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic flow diagram of a method for manufacturing a magnesium alloy shaped article according to one embodiment of the present disclosure. [Figure 2] 1 shows a cross section of a magnesium alloy shaped article after extrusion and before any additional heat treatment. [Figure 3] 1 shows a cross section of a magnesium alloy formed article after a cold forming process. [Figure 4] 2 shows a cross section of a magnesium alloy formed article after hot forming. [Figure 5] 1 is a schematic diagram of a magnesium alloy molding device according to an embodiment of the present disclosure. FIG. [Figure 6] 1 is a schematic cross-sectional view of a magnesium alloy forming device according to an embodiment of the present disclosure. FIG. [Figure 7] 1 is a perspective view of a magnesium alloy formed article produced by a method for producing a magnesium alloy formed article according to an embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, magnesium alloy shaped articles and methods for manufacturing the same according to embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0020] It should be noted that when referring to components in the accompanying drawings, the same components are designated by the same reference numerals even if the components are shown in different drawings, and detailed descriptions of well-known features or functions are omitted to avoid unnecessarily obscuring the gist of the present disclosure.

[0021] Terms such as "first," "second," A, B, (a), and (b) may be used to describe components in the embodiments of the present disclosure. These terms are used only to distinguish one component from another, and do not limit the characteristics, order, etc. of corresponding components. Furthermore, unless otherwise specified, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those skilled in the art to which the present disclosure pertains. Terms defined in commonly used dictionaries should be interpreted as having the same meaning as their meaning within the context of the relevant art, and these terms should not be interpreted idealistically or overly formally unless the context clearly dictates otherwise.

[0022] Figure 1 is a schematic flow diagram of a method for manufacturing a magnesium alloy molded article according to one embodiment of the present disclosure, Figure 2 shows a cross-section of a magnesium alloy molded article before a separate heat treatment after extrusion molding, Figure 3 shows a cross-section of a magnesium alloy molded article after a cold forming process, Figure 4 shows a cross-section of a magnesium alloy molded article after a hot forming process, Figure 5 is a schematic configuration diagram of a magnesium alloy molding device according to one embodiment of the present disclosure, Figure 6 is a schematic cross-sectional view of a magnesium alloy molding device according to one embodiment of the present disclosure, and Figure 7 is a perspective view of a magnesium alloy molded article manufactured by a method for manufacturing a magnesium alloy molded article according to one embodiment of the present disclosure.

[0023] Referring to Figures 1 to 6, a method for manufacturing a magnesium alloy shaped article includes extruding a magnesium alloy billet to form a pipe having a predetermined strength (S100), heat treating the extruded magnesium alloy (S200), forming the heat-treated magnesium alloy at a predetermined temperature using a magnesium alloy forming device (S300), coating the formed magnesium alloy shaped article (S400), and painting the coated magnesium alloy shaped article (S500).

[0024] Extrusion molding The method for manufacturing a magnesium alloy shaped article can include extruding a magnesium alloy billet (S100). The magnesium alloy billet can be extruded into a pipe shape having a predetermined strength, and the extruded magnesium alloy pipe can preferably have a strength of 350 megapascals (MPa). Extrusion is a process used to provide an object with a constant cross-sectional profile, and the extrusion process can also increase material strength. The extruded magnesium alloy article can be a pipe-shaped tube, and the magnesium alloy pipe can preferably have a length of 800 mm and a diameter of 9.5 mm.

[0025] If extrusion is performed without preheating the die, clogging may occur. Even if the die is preheated before extrusion, it may be preferable to adjust the ram speed or perform the extrusion without delay to prevent the die from cooling excessively during extrusion. If it is difficult to preheat the die or the ram speed is too low, the billet temperature may continue to drop, increasing the extrusion load and causing clogging. As the extrusion ratio increases, the microstructure becomes finer, which ensures improved strength but can be inversely proportional to the elongation of the material. If the extrusion ratio is too low, the material may have excessively low strength or may be produced unevenly due to differences in the microstructure of the magnesium alloy extrusion in each section and many coarse particles.

[0026] Magnesium alloys may include, but are not limited to, aluminum-zinc (AZ) based alloys having Al and Zn as the main additive elements, aluminum-manganese (AM) based alloys having Al and Mn as the main additive elements, zirconium-zinc (ZK) based alloys having Zr and Zn as the main additive elements, aluminum-rare earth (AE) based alloys having Al and rare earth as the main additive elements, yttrium-rare earth (WE) based alloys having Y and rare earth as the main additive elements, or alloys having Li (lithium) as the main additive element.

[0027] For example, a magnesium alloy may contain 4.8 wt% to 6.2 wt% Zn, 0.45 wt% to 0.1 wt% Zr, the balance being magnesium and unavoidable impurities.

[0028] Heat Treatment The extruded magnesium alloy pipe can be heat treated (S200). In the extrusion (S100), the extruded magnesium alloy pipe can be heat treated, which can increase the tensile strength of the magnesium alloy pipe. The increase in tensile strength may be preferably about 10%.

[0029] molding The method may include forming the heat-treated magnesium alloy (S300). To form a magnesium alloy pipe, the magnesium alloy may be formed only within a predetermined temperature range. The predetermined temperature may preferably be 150°C to 300°C. A suitable forming process for the magnesium alloy formed article of the present disclosure may be achieved by a predetermined revolutions per minute (RPM), a predetermined feed rate, and a predetermined forming amount. The feed rate refers to the movement speed of the roller unit in the axial direction of the workpiece, and the forming amount refers to the forming amount based on the diameter of the workpiece. Preferably, the predetermined RPM may be 300 RPM to 1200 RPM, the predetermined feed rate may be 2 mm / s to 14 mm / s, and the predetermined forming amount may be 0.05 mm to 1.5 mm, but is not limited thereto.

[0030] The forming process can be performed by a magnesium alloy forming device 100. The magnesium alloy forming device 100 can include a fixed unit 110 that rotatably supports the workpiece 10, a rotating unit 120 that faces the fixed unit and rotates the workpiece 10 supported by the fixed unit, at least one heater module 140 that is removably disposed on the outer circumferential surface of the workpiece 10 and heats the workpiece 10, and at least one roller unit 130 that applies pressure to the workpiece 10 while moving in the axial direction of the workpiece 10 and rotating along the outer circumferential surface of the workpiece 10, and the roller unit 130 rotates at a predetermined inclination relative to the workpiece 10. The roller unit 130 can have a forming length of 600 mm. The workpiece 10 can preferably be a magnesium pipe formed by extruding a magnesium billet.

[0031] The workpiece 10 may be supported by the support unit 110 and rotated by the rotation unit 120. One side of the workpiece 10 may be coupled to the rotation unit 120 and the other side may be supported by the support unit 110, and the workpiece 10 coupled to the rotation unit 120 may be rotated by the rotation unit 120. The support unit 110 may be configured to provide pressure to resist vertical expansion of the workpiece 10 while the processing region of the workpiece 10 is processed by the roller unit 130. The workpiece 10 may undergo plastic deformation during processing, thereby elongating its length, and the support unit 110 may provide pressure to resist vertical expansion of the workpiece 10. Each workpiece 10 may have different physical properties, such as elongation or hardness, and therefore may elongate by different amounts during processing. Here, the support unit 110 provides pressure to resist vertical expansion of the workpiece 10 during processing, thereby ensuring that the workpiece 10 maintains a constant length during processing and that this length does not change after forming.

[0032] The roller unit 130 can shape the workpiece 10 by applying pressure to the workpiece 10 while rotating along the outer circumferential surface of the workpiece 10. The roller unit 130 can apply pressure to the workpiece 10 by moving in the axial direction of the workpiece 10 while rotating along the outer circumferential surface of the workpiece 10 and changing the forming amount, which determines the cross-sectional area of ​​the workpiece 10, based on a user's selection. The roller unit 130 can form magnesium alloy molded articles with various shapes, such as tapered and wavy shapes, by moving in the axial direction of the workpiece 10. The diameter of the roller unit 130 can have a predetermined length, and can preferably be 50 mm to 80 mm.

[0033] The roller unit 130 can be tilted at a predetermined angle, and the workpiece 10 can have various shapes depending on the tilt. The tilt angle can be determined based on the selection of a person skilled in the art.

[0034] The rotation unit 120 may include a rotary drive shaft for rotating the rotation unit, and the rotary drive shaft may be rotated by a drive motor, for example, but not limited to, a stepping motor.

[0035] The roller unit 130 is an element that applies pressure to a processing region of the workpiece 10 for processing, and can be fixed to, for example, a tool holder (not shown). The roller unit 130 can be rotatable in the magnesium alloy forming device 100, and can therefore be rotated by frictional force when pressure is applied to the workpiece 10 for processing the workpiece. The magnesium alloy forming device 100 can be configured to be moved in the axial direction (horizontal direction in FIG. 5 ) and radial direction (vertical direction in FIG. 5 ) of the workpiece 10 for processing.

[0036] The roller unit 130 may be a roller that is in direct contact with the workpiece 10 to deform the workpiece 10. A plurality of roller units 130 may be provided, each positioned above and below the workpiece 10 based on its height. The roller movement unit may be moved forward or backward relative to the support unit 110 in the horizontal direction H. An adjustment link (not shown) may be linked to the movement of the roller movement unit so that the roller unit 130 moves toward or away from the central axis of the workpiece 10, thereby adjusting the position of the roller unit 130. The roller movement unit may be configured to move the roller unit forward in the horizontal direction of the workpiece 10, or conversely, to move the roller unit backward. For this purpose, the roller movement unit may be, but is not limited to, a horizontally disposed cylinder or servo motor.

[0037] The roller unit 130 may further include a roller rotation unit (not shown) that rotates the roller unit along the outer circumferential surface of the workpiece 10 .

[0038] When the rotation unit 120 is rotated, the workpiece 10 can be rotated around its vertical axis, and the roller unit 130 presses the outer surface of the rotating workpiece 10, thus processing the workpiece 10 into the desired tapered shape.

[0039] The fixing unit 110 or the rotation unit 120 may further include a compensation unit (not shown) that compensates for vibrations of the workpiece 10 that occur when the workpiece 10 is rotated or processed. The compensation unit may preferably be a mandrel. The compensation unit is inserted into the workpiece 10 to compensate for vibrations that occur when the workpiece 10 is rotated or processed, thereby reducing forming errors caused by the vibrations and thereby improving forming reliability.

[0040] The magnesium alloy forming device may further include a heater module 140 for heating the workpiece 10 to a predetermined temperature. At least one heater module 140 may have the form of a removable cover and be arranged along the outer circumferential surface of the workpiece 10. A heater module 140 attached to a position requiring heating may be selectively driven based on the forming direction or forming position from among the multiple heater modules 140. The magnesium alloy forming device may overcome limitations on the forming direction by including the heater module 140. The magnesium alloy forming device may move forward, backward, or back and forth depending on the type of forming direction. Furthermore, the magnesium alloy forming device may perform a reciprocating stroke, thereby providing improved performance and productivity compared to a single stroke. The magnesium alloy forming device may include the heater module 140 for heating the workpiece to a predetermined temperature, which may be 100°C to 500°C, preferably 200°C to 450°C. In the following, the heater module 140 can heat the workpiece 10 at 200°C to 450°C, because magnesium alloys have low ductility and therefore their workability and formability decrease at temperatures below 100°C, and the properties of the magnesium alloy itself can change at certain higher temperatures, making it more susceptible to internal defects. Furthermore, the magnesium alloy forming device can use a temperature controller and an actuator to improve its processing-based operation, ease of use of the equipment, and small-lot production of a variety of products.

[0041] Coatings and Paints The magnesium alloy shaped article formed in forming (S300) can be coated in a coating (S400), and the coated magnesium alloy shaped article can be painted in a painting (S500). The magnesium alloy shaped article formed in forming (S300) can be painted after being coated, thus forming a magnesium alloy shaped article. [Example]

[0042] The magnesium alloy material is heat-treated to produce a magnesium alloy formed article. Fig. 2 shows a cross section of the magnesium alloy formed article in Example 1 after extrusion molding of the magnesium alloy and before processing, Fig. 3 shows a cross section of the magnesium alloy formed article in Example 2 after the cold forming step in the magnesium alloy forming process, and Fig. 4 shows a cross section of the magnesium alloy formed article in Example 3 after the hot forming step in the magnesium alloy forming process.

[0043] Example 1 The magnesium alloy casting billet is extruded to produce a magnesium alloy extrusion material, which is then cut and processed to produce a specimen for compression testing, thereby producing the specimen shown in Figure 2.

[0044] Example 2 A magnesium alloy extrusion material is manufactured by extruding a magnesium alloy cast billet similar to that in Example 1. The magnesium alloy extrusion material is shaped and processed by performing a cold forming process on the magnesium alloy extrusion material, and then the magnesium alloy shaped article is cut and processed to prepare a specimen for a compression test, thereby manufacturing the specimen shown in Figure 3.

[0045] Example 3 A magnesium alloy extrusion material is manufactured by extruding a magnesium alloy casting billet similar to that in Example 1. Next, the magnesium alloy extrusion material is shaped and processed. Here, the shaping process is carried out under a temperature condition of 150 to 300 degrees during the shaping process, and then the magnesium alloy shaped article is cut and processed to prepare a specimen for a compression test, thereby producing the specimen shown in FIG.

[0046] The present disclosure is not necessarily limited to the above-described embodiments, and it is apparent to those skilled in the art to which the present disclosure pertains that various modifications and variations of the present disclosure may be made within the scope of equivalents of the present disclosure. Therefore, the true scope of the present disclosure is defined by the following claims.

Claims

1. 1. A method for producing a magnesium alloy shaped article, comprising the steps of: extruding the magnesium alloy billet to form a pipe having a predetermined strength; heat treating the magnesium alloy extruded in the extrusion molding; forming the heat-treated magnesium alloy at a predetermined temperature using a magnesium alloy forming device; coating the formed magnesium alloy shaped article; painting the coated magnesium alloy shaped article; The method includes:

2. The method of claim 1 , wherein the predetermined intensity is 350 megapascals (MPa).

3. The method of claim 1 , wherein the predetermined temperature is between 150° C. and 300° C.

4. The magnesium alloy molding device comprises: A fixing unit that rotatably supports the processing object; At least one heater module removably disposed on an outer peripheral surface of the workpiece and configured to heat the workpiece; a rotation unit facing the fixed unit and rotating the workpiece supported by the fixed unit; at least one roller unit that applies pressure to the workpiece while moving in an axial direction of the workpiece and rotating along the outer circumferential surface of the workpiece; The method of claim 1 , comprising:

5. The method of claim 4 , wherein the rotating unit is rotated at between 300 revolutions per minute (RPM) and 1200 revolutions per minute (RPM).

6. The method according to claim 4 , wherein the speed of movement of the roller unit in the axial direction of the workpiece is between 2 mm / s and 14 mm / s.

7. The method of claim 4, wherein the forming amount of the roller unit is from 0.05 mm to 1.5 mm.

8. The method of claim 4 , wherein the roller unit is rotated at a predetermined inclination toward the workpiece.

9. 1. A magnesium alloy shaped article produced by shaping a magnesium alloy material, wherein the magnesium alloy material is heated to 200°C to 450°C by a magnesium alloy shaping device, and the shaping amount is 0.05mm to 1.5mm.

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