KR20210001054A - Method of manufacturing magnesium alloy sheet - Google Patents

Abstract

The present disclosure relates to a high-strength and highly-formed magnesium alloy sheet and a manufacturing method thereof. According to an embodiment of the present invention, a magnesium alloy sheet manufactured by the method contains 0.5 to 2.1 wt% of Al, 0.5 to 1.5 wt% of Zn, 0.1 to 1.0 wt% of Ca, the balance Mg, and unavoidable impurities with respect to 100 wt% of the total. The magnesium alloy sheet satisfies the room temperature Ericsson value of 6 mm or more and the yield strength of 160 MPa to 300 MPa at the same time.

Description

Method of manufacturing magnesium alloy sheet {METHOD OF MANUFACTURING MAGNESIUM ALLOY SHEET}

An embodiment of the present invention relates to a magnesium alloy plate and a method for manufacturing the same, and more particularly, to a high strength, high-form magnesium alloy plate and a method for manufacturing the same.

Recently, magnesium alloy plate is spreading at a rapid rate in lightening automobiles and lightening mobile devices. This is due to the excellent specific strength, low specific gravity, and electromagnetic shielding ability of the magnesium alloy. In particular, under the rapid growth of the electric vehicle market, interest in lightweight materials is deepening. Along with aluminum plates, magnesium plates are also one of the strong candidates for lightweight materials, and the recent research and development of magnesium plates is rapidly taking place. However, the lack of workability due to the low formability of the magnesium alloy is a major obstacle.

To solve this problem, many research institutes and schools have been conducting research until now. In particular, according to a paper recently published by NIMS in Japan and Kyoto University, it was reported that the formability is improved when rolling after securing the AZ31 alloy sheet, which is a commercial sheet, to the process temperature (Scripta Materialia Vol. 60, Issue 6, P447-450), however, such a process is not suitable for actual mass production processes, and may be impractical due to its low yield strength.

In addition, there are research results showing high formability when an alloy is prepared by adding a rare earth element such as cerium to magnesium. However, when rare earth elements are added, there may be limitations in lowering cost competitiveness compared to aluminum alloys.

In addition, according to Patent Publication No. 2012-0049686, there is a report that when silver is added, high strength and high molding are exhibited. However, since there is a problem that a large amount of silver element must be added, it is not suitable for mass production of actual products using silver.

In addition, when manufacturing a magnesium alloy plate, a large amount of zinc element may be added. However, as the amount of zinc element added increases, solidification is difficult. For this reason, when molten metal comes out between the twin rolls during twin roll casting, a phenomenon in which a part that is not completely solidified adheres to the roll occurs, which makes it difficult to secure the quality of the alloy plate.

In addition, with a prior patent (Korean Patent No. 10-1626820), Al: 2.7 to 3.1% by weight, Zn: 0.75 to 1% by weight, Ca: 0.6 to 0.8% by weight, Mn: 0.3 to 0.35% by weight of magnesium plate. There is a patent that expresses high plasticity, but there is no information on low aluminum and low calcium concentration. Accordingly, recently, a patent (Korean Patent Registration No. 10-1937928) having lowered the Al concentration to 0.5% by weight has been registered, but there is no mention of strength. As described above, a lot of technologies related to high molding have been introduced, but there is a lack of introduction to technologies that simultaneously satisfy high strength high molding.

An embodiment of the present invention is to provide a high-strength, high-form magnesium alloy plate and a method of manufacturing the same.

The method of manufacturing a magnesium alloy plate according to an embodiment of the present invention is based on the total 100% by weight, Al: 0.5 to 2.0% by weight, Zn: 0.5 to 1.5% by weight, Ca: 0.1 to 0.8% by weight, Mn: 0.05 Preparing a master alloy including to 0.5% by weight, the balance Mg, and inevitable impurities; Casting the master alloy to produce a slab; Homogenizing heat treatment of the slab; Rolling the heat-treated slab; And final annealing the rolled slab; including, in the rolling of the heat-treated slab, an intermediate annealing step having an intermediate annealing frequency (intermediate annealing number/total rolling number) of 1/2 to 1/8 It may be included.

The intermediate annealing step; may be carried out in a temperature range of 250 to 500 °C.

The intermediate annealing step; may be carried out for 0.5 to 10 hours.

The method of manufacturing the magnesium alloy plate includes the steps of final annealing the rolled slab; Subsequently, the step of performing a skin pass may be further included.

The skin pass implementation step; The temperature range and reduction rate of 100 to 300 °C may be carried out in one rolling at 3 to 25%.

Casting the master alloy to produce a slab; It may be casting under a temperature condition of 600 to 750 °C.

The step of homogenizing heat treatment of the slab; A first heat treatment step in a temperature range of 300 to 400 °C; And a secondary heat treatment step in a temperature range of 400 to 500 °C.

The first heat treatment step in the 300 to 400 °C temperature range; may be carried out for 1 to 30 hours.

The second heat treatment step in the 400 to 500 °C temperature range; may be carried out for 1 hour to 10 hours.

Rolling the heat-treated slab; may be rolling the heat-treated slab to a thickness range of 0.2 mm to 3.0 mm.

Rolling the heat-treated slab; may be rolling the heat-treated slab 3 to 14 times.

Rolling the heat-treated slab; may be carried out in a temperature range of 200 to 350 °C.

Rolling the heat-treated slab; may be performed at a reduction ratio of 10 to 50%.

Final annealing the rolled slab; may be carried out in a temperature range of 300 to 500 °C.

Final annealing the rolled slab; may be carried out for 0.5 to 20 hours.

Magnesium alloy sheet according to an embodiment of the present invention, based on the total 100% by weight, Al: 0.5 to 2.0% by weight, Zn: 0.5 to 1.5% by weight, Ca: 0.1 to 0.8% by weight, Mn: 0.05 to 0.5% by weight %, the balance Mg and unavoidable impurities, an Ericsson value of 6 mm or more at room temperature, a yield strength of 160 to 300 MPa, and a twin fraction of 5 to 30 area%.

The magnesium alloy plate may have a tensile strength of 253 to 350 MPa.

The magnesium alloy plate may have an elongation of 10 to 25%.

According to an embodiment of the present invention, it is possible to provide a high-strength, high-form magnesium alloy plate.

In addition, according to an embodiment of the present invention, the manufactured magnesium alloy plate may have an Ericsson value of 6 mm or more at room temperature.

In addition, according to an embodiment of the present invention, the manufactured magnesium alloy plate may have a yield strength of 160 to 300 MPa.

FIG. 1 shows a photograph of a shape of a high-strength high-forming magnesium plate according to an exemplary embodiment of the present invention and an Al alloy Al5052 plate after a room temperature Ericsson test.
2 is a photograph of the optical microstructure after the final heat treatment of a comparative example of the present invention, and is a photograph of the microstructure inside the material measured at 500 times using an optical microscope.
3 is an optical microstructure picture for each reduction ratio when the skin pass is performed at 250 °C after the final heat treatment in an embodiment of the present invention, and is a picture obtained by measuring the microstructure inside the material at a magnification of 500 using an optical microscope.
4 is an optical microstructure picture for each reduction ratio when the skin pass is performed at 150°C after the final heat treatment in an embodiment of the present invention, and is a picture obtained by measuring the microstructure inside the material at a magnification of 500 using an optical microscope.
5 is a comparative picture of an IPF map between a magnesium alloy plate according to a comparative example of the present invention and an example.
6 is an XRD pole figure comparison picture between a comparative example of the present invention and a magnesium alloy plate according to an example.
Figure 7 shows the Ericsson test method carried out in the present invention.

Terms such as first, second and third are used to describe various parts, components, regions, layers, and/or sections, but are not limited thereto. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, a first part, component, region, layer or section described below may be referred to as a second part, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for referring only to specific embodiments and is not intended to limit the present invention. Singular forms as used herein also include plural forms unless the phrases clearly indicate the opposite. The meaning of “comprising” as used in the specification specifies a specific characteristic, region, integer, step, action, element and/or component, and the presence of another characteristic, region, integer, step, action, element and/or component, or It does not exclude additions.

When a part is referred to as being "on" or "on" another part, it may be directly on or on another part, or other parts may be involved in between. In contrast, when a part is referred to as being “directly above” another part, no other part is intervened.

In addition, unless otherwise specified,% means% by weight, and 1 ppm is 0.0001% by weight.

Although not defined differently, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms defined in a commonly used dictionary are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal meaning unless defined.

However, the intermediate frequency referred to in the present disclosure refers to the intermediate annealing frequency per total rolling number (ie, intermediate annealing frequency/total rolling frequency).

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art may easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

The master alloy used in the method for manufacturing a magnesium alloy plate according to an embodiment of the present invention is not limited as long as it can be used in the method for manufacturing a magnesium alloy plate, for example, based on 100% by weight of the total, Al: 0.5 to 2.0 A master alloy including weight%, Zn: 0.5 to 1.5% by weight, Ca: 0.1 to 0.8% by weight, Mn: 0.05 to 0.5% by weight, the balance Mg and unavoidable impurities may be used.

Next, the step of manufacturing a slab by casting the master alloy may be performed.

The method of casting the master alloy is not limited as long as it is a method of manufacturing an alloy slab, but, for example, a twin roll casting method, a billet casting method, and a gravity casting method may be applied.

More specifically, the master alloy is heated to prepare a molten metal of 600 to 750 °C, and the molten metal is solidified to obtain a slab.

In one embodiment of the present invention, a slab having a thickness of 3.5mm to 9mm may be manufactured by casting under a temperature condition of 600 to 750 °C, more specifically 600 to 720 °C.

Thereafter, a step of homogenizing heat treatment of the cast slab may be performed.

Specifically, the step of homogenizing heat treatment of the slab may include a first heat treatment step in a temperature range of 300 to 400 °C; And a secondary heat treatment step in a temperature range of 400 to 500 °C. In addition, the first heat treatment step in the 300 to 400 °C temperature range may be performed for 1 hour to 30 hours, specifically 1 to 24 hours, and more specifically 1 to 22 hours. In addition, the secondary heat treatment step in the 400 to 500 °C temperature range may be performed for 1 to 10 hours, specifically 1 to 8 hours, and more specifically 1 to 6 hours.

Thereafter, the step of rolling the heat-treated slab may be performed.

In the step of rolling the heat-treated slab, the slab may be rolled 3 to 14 times, specifically 4 to 12 times, and more specifically 6 to 9 times, depending on the target thickness.

In addition, the rolling may be carried out in a temperature range of 200 to 350 °C, specifically 250 to 350 °C, more specifically 275 to 325 °C.If the temperature is less than 200 °C, excessive edge cracking occurs during rolling. As a result, there is a problem that sheet breakage occurs easily during rolling, and when the temperature exceeds 350°C, tension control of the coil sheet during rolling is impossible, and there is a problem in mass production application due to difficulty in applying rolling oil.

In addition, the rolling may be performed at a reduction ratio of 10 to 50%, specifically 10 to 35%, and more specifically 10 to 25%. If the reduction ratio is less than 10%, the total number of rolling increases, which may lead to a problem of lack of productivity, and it may be difficult to secure a driving force required for securing a high mold by the final heat treatment.

The heat-treated slab may be rolled to a thickness of 0.2 mm to 3.0 mm, specifically 0.3 to 2.5 mm, and more specifically 0.4 to 2.0 mm.

Rolling the heat-treated slab may further include an intermediate annealing step.

The intermediate annealing step may be carried out at a medium annealing frequency of 1/2 to 1/8, specifically 1/3 to 1/8, and more specifically 1/4 to 1/8 (intermediate annealing number/total rolling number). have. For example, if the intermediate annealing frequency is 1/8, the intermediate annealing was performed once per eight rolling cycles.

In addition, the intermediate annealing may be carried out at a temperature range of 250 to 500 °C, specifically 300 to 500 °C, more specifically 350 to 500 °C or 400 to 450 °C. If the temperature is less than 200 °C, there may be a problem that recrystallization is slow at a low temperature due to insufficient driving force for recrystallization, and when the temperature is higher than 500 °C, there may be a problem that local melting occurs in the plate.

In addition, the intermediate annealing may be performed for 0.5 to 10 hours, specifically 0.5 to 9 hours, more specifically 0.5 to 5 hours or 0.5 to 3 hours. When the intermediate annealing is performed for less than 0.5 hours, there may be a problem in that it is difficult to form uniform recrystallization in the plate material, and when it exceeds 10 hours, there may be a problem that abnormal crystals grow.

Thereafter, a step of final annealing the rolled slab may be performed.

The final annealing step may be carried out in a temperature range of 300 to 500 °C, specifically 350 to 500 °C, more specifically 350 to 450 °C or 350 to 400 °C, 0.5 to 20 hours, specifically 0.5 To 15 hours, more specifically 0.5 to 10 hours, or 0.5 to 5 hours, or 0.5 to 3 hours.

After the final annealing of the rolled slab, it may further include performing a skin pass.

The step of performing the skin pass may be performed at a temperature range of 100 to 300 °C, specifically 100 to 250 °C, and more specifically 100 to 200 °C. If the skin pass is carried out at a temperature of less than 100°C, the temperature is too low to cause cracks in the magnesium alloy plate.If the skin pass is carried out at a temperature above 300°C, there is a problem that it is difficult to secure strength due to low yield strength improvement. I can.

In addition, the skin pass may be performed in one rolling with a reduction ratio of 3 to 25%, specifically 8 to 24%, more specifically 10 to 22%, or 20%. If the reduction ratio is more than 25%, there may be a problem that cracks occur during rolling.

The magnesium alloy sheet prepared according to an embodiment of the present invention includes: Al: 0.5 to 2.0 wt%, Zn: 0.5 to 1.5 wt%, Ca: 0.1 to 0.8 wt%, Mn: 0.05 to 0.5 wt%, the balance Mg and It may contain inevitable impurities, but is not limited thereto.

The prepared magnesium alloy plate may have an Ericsson value of 6 mm or more at room temperature, specifically 6.5 mm to 11 mm, more specifically 7.0 mm to 10 mm, and more specifically 7.0 mm to 9 mm. In addition, the yield strength may be 160 to 300 MPa, specifically 210 to 290 MPa, and more specifically 260 to 280 MPa. In addition, the twin fraction may be 5 to 30 area%, specifically 12 to 35 area%, and more specifically 20 to 40 area%. In addition, the tensile strength may be 253 to 350 MPa, specifically 265 to 325 MPa, and more specifically 280 to 300 MPa. In addition, the elongation may be 10 to 25%.

The Ericsson value is an index for evaluating the formability of a plate, especially the pressability, and it measures the formability by measuring the height at which the specimen is deformed.

More specifically, the Ericsson value according to an embodiment of the present invention is a speed of 5 mm/min at room temperature using a spherical punch having a diameter of 20 mm after fixing the outer periphery of the test piece of 60 mm x 60 mm with a force of 10 KN. It is to measure the distance the punch travels until the disk-shaped specimen breaks, that is, the height at which the specimen is deformed.

More specifically, the tensile strength according to an embodiment of the present invention means a value obtained by dividing the maximum tensile load until fracture of the test piece by the cross-sectional area of the test piece before the test. Specifically, it was measured using a uniaxial tensile tester at room temperature, and the strain rate was 10 ^-3 /s.

More specifically, the elongation according to an embodiment of the present invention is a rate at which a material is stretched during a tensile test, and refers to a value expressed as a percentage of the length of the changed test piece compared to the length of the test piece before testing. Specifically, it was the same as the tensile strength measurement conditions, and the length increased compared to the initial length of the gauge portion was measured.

More specifically, the yield strength according to one embodiment of the present invention refers to a value obtained by dividing the load when permanent deformation of 0.2% is caused from the elastic section by the far end area.

Hereinafter, it will be described in detail through examples. However, the following examples are for illustrative purposes only, and the contents of the present invention are not limited by the following examples.

Experimental example

Experimental Example 1: Intermediate annealing frequency control

Examples 1 to 6

An alloy containing Al: 2.0% by weight, Zn: 0.8% by weight, Ca: 0.6% by weight, the balance Mg and inevitable impurities based on the total 100% by weight was prepared as a master alloy.

The master alloy was heated at a temperature of 700°C to prepare a molten metal, and cast by a strip casting method to prepare a slab having a thickness of 5 mm.

The slab was subjected to a first homogenization heat treatment at 400 °C for 22 hours, and then a second homogenization heat treatment at 450 °C for 2 hours.

The homogenized heat-treated slab was rolled at a temperature of 300 °C. The rolled slab was annealed at 450 °C for 2 hours. At this time, the intermediate annealing frequency was changed to 1/3 to 1/8. Thereafter, the final annealing was performed at 400 °C for 2 hours, and then a skin pass was performed in which the rolling reduction was performed once at a temperature of 150 °C with a reduction ratio of 20% to prepare magnesium alloy sheets of Examples 1 to 6.

Comparative Example 1

Unlike the example, the eight-rolled slab was not subjected to intermediate annealing, but was finally annealed at 400 °C for 2 hours, and then the magnesium alloy plate of Comparative Example 1 was prepared without a skin pass.

Comparative Example 2

Unlike the example, the eight-rolled slab was not subjected to intermediate annealing, but was finally annealed at 400 °C for 2 hours, followed by a skin pass in which the slab rolled once at a temperature of 150 °C with a reduction ratio of 20% was performed. The magnesium alloy plate of 2 was prepared.

Comparative Examples 3 to 5

A magnesium alloy plate was manufactured in the same manner as in Example 1, except that the number of rolling was changed to 3, 9 and 10 times.

Table 1 below shows the manufacturing conditions of each of the Examples and Comparative Examples, and Table 2 shows the measured physical property values of the magnesium alloy plates of the prepared Examples and Comparative Examples.

division Number of rolling Intermediate annealing Intermediate annealing frequency ^* Skin Pass Example 1 3 O 1/3 O Example 2 4 O 1/4 O Example 3 5 O 1/5 O Example 4 6 O 1/6 O Example 5 7 O 1/7 O Example 6 8 O 1/8 O Comparative Example 1 8 X - X Comparative Example 2 8 X - O Comparative Example 3 9 O 1/9 O Comparative Example 4 10 O 1/10 O

*Intermediate annealing frequency = Intermediate annealing number/Total rolling number

division Ericsson value (mm) Yield strength (MPa) Tensile strength (MPa) Elongation (%) Example 1 7.2 266 285 10.5 Example 2 7.2 268 281 10.9 Example 3 7.1 270 285 10.5 Example 4 7.2 269 288 10.6 Example 5 7.0 268 289 10.7 Example 6 7.05 272 300 10.5 Comparative Example 1 6.0 154 255 24.1 Comparative Example 2 4.3 271 297 9.2 Comparative Example 3 4.7 272 300 8.7 Comparative Example 4 4.6 271 301 8.5

Looking at Comparative Example 1 in which the skin pass was not performed, it can be seen that the intensity is very low compared to the Example. In addition, looking at Comparative Examples 3 and 4 in which the intermediate annealing frequency exceeded 1/8, it can be seen that the moldability is inferior to the Example.

Experimental Example 2: When the reduction ratio of the skin pass process was different

An alloy containing Al: 2.0% by weight, Zn: 0.5% by weight, Ca: 0.6% by weight, the balance Mg and inevitable impurities based on the total 100% by weight was prepared as a master alloy.

The master alloy was heated at a temperature of 700 °C to prepare a molten metal, and cast by a strip casting method to produce a slab having a thickness of about 5 mm.

The slab was first heat treated at 400 °C for 22 hours, and then secondary heat treated at 450 °C for 2 hours.

The heat-treated slab was rolled 8 times at a temperature of 300 °C.

The rolled slab was annealed at 450°C for 2 hours, and finally annealed at 400°C for 2 hours, and then the skin pass was rolled once by varying the temperature and reduction ratio as shown in Table 3 below. Then, a magnesium alloy plate was manufactured.

Table 3 below shows the measurement of the physical property values of the magnesium alloy sheet manufactured by varying the reduction ratio.

Skin Pass Conditions Ericsson Value
(mm) Yield strength
(MPa) The tensile strength
(MPa) Elongation (%) division No skin pass process 9.12 154 252 25.1 Comparative Example 5 Rolling temperature (℃) Reduction rate (%) 300 20 7.4 245 276 24.2 Example 7 250 4 7.31 209 262 23.1 Example 8 9 7.65 239 267 20.1 Example 9 15 7.67 263 276 17.0 Example 10 20 7.39 268 282 17.8 Example 11 150 3 8.63 212 260 24.5 Example 12 8 8.37 237 265 20.8 Example 13 11 8.16 247 267 18.8 Example 14 20 7.90 273 288 14.7 Example 15 100 3 8.25 202 258 22.0 Example 16 6 8.24 237 268 21.2 Example 17 9 8.02 261 274 17.9 Example 18 13 7.77 259 274 17.4 Example 19 20 7.66 269 289 12.1 Example 20 25 7.28 273 299 10.2 Example 21 50 20 5.8 276 298 6.9 Comparative Example 6

Fig. 3 shows the microstructure observed when the reduction ratio is changed at 250°C, and Fig. 4 shows the microstructure observed when the reduction ratio is changed at 150°C. As can be seen from FIGS. 3 and 4, it was found that as the reduction ratio increased, a severely deformed structure was shown.

On the other hand, for a clear structure analysis, the structures of the magnesium alloy plate of Comparative Example 5 and the magnesium alloy plate of Example 15 were analyzed by installing EBSD (Electron Backscatter Diffaraction) in SEM (Scanning Electron Microscopy), and IPF (Inverse Pole Figure) It is shown in Figure 5 by analyzing the map. Referring to FIG. 5, Comparative Example 5 shows a structure in which crystal grains of various orientations are distributed, there is almost no deformed structure, and is completely annealed. However, looking at Example 15, it was confirmed that the amount of black portions deformed by the skin path increased a lot. Most of this black part is composed of twin crystals, and the twin fraction at this time was approximately 30 area% as an area fraction.

In addition, the entire tissues of Comparative Example 5 and Example 15 were analyzed by XRD and shown in FIG. 6. FIG. 6 shows a pole figure by XRD for the texture analysis. According to the XRD analysis of Example 15, a low pole value of 5 or less is shown even after the skin pass, and it can be seen that the pole is widely distributed in the TD direction. Therefore, it can be seen through the texture analysis that the high formability is maintained even after the skin pass.

The present invention is not limited to the embodiments, but may be manufactured in a variety of different forms, and those of ordinary skill in the art to which the present invention pertains to other specific forms without changing the technical spirit or essential features of the present invention. It will be appreciated that it can be implemented. Therefore, the embodiments described above are illustrative in all respects and should be understood as non-limiting.

Claims (18)

With respect to the total 100% by weight, Al: 0.5 to 2.0% by weight, Zn: 0.5 to 1.5% by weight, Ca: 0.1 to 0.8% by weight, Mn: 0.05 to 0.5% by weight, a master alloy containing the balance Mg and inevitable impurities Preparing;
Casting the master alloy to produce a slab;
Homogenizing heat treatment of the slab;
Rolling the heat-treated slab; And
Including; final annealing the rolled slab,
The step of rolling the heat-treated slab includes an intermediate annealing step in which the intermediate annealing frequency (intermediate annealing number/total rolling number) is 1/2 to 1/8. The method of claim 1,
The intermediate annealing step; The
That is to be carried out in the temperature range of 250 to 500 °C, the method for producing a magnesium alloy plate. The method of claim 1,
The intermediate annealing step; The
That is to be carried out for 0.5 to 10 hours, the method of manufacturing a magnesium alloy plate. The method of claim 1,
The method of manufacturing the magnesium alloy plate,
Final annealing the rolled slab; A method of manufacturing a magnesium alloy plate further comprising the step of performing a skin pass afterwards. The method of claim 4,
Performing the skin pass; the
The temperature range of 100 to 300 °C and the reduction ratio is 3 to 25% to be carried out in a single rolling, the method of manufacturing a magnesium alloy plate. The method of claim 1,
Casting the master alloy to produce a slab;
The method for producing a magnesium alloy plate is cast under a temperature condition of 600 to 750 °C. The method of claim 1,
The step of homogenizing heat treatment of the slab;
A first heat treatment step in a temperature range of 300 to 400 °C; And
The method of manufacturing a magnesium alloy plate comprising a secondary heat treatment step in a temperature range of 400 to 500 °C. The method of claim 7,
The first heat treatment step in the 300 to 400 °C temperature range; the
That is to be carried out for 1 to 30 hours, the method of manufacturing a magnesium alloy plate. The method of claim 7,
The secondary heat treatment step in the 400 to 500 °C temperature range; the
That is to be carried out for 1 to 10 hours, the method of manufacturing a magnesium alloy plate. The method of claim 1,
Rolling the heat-treated slab; the
The method of manufacturing a magnesium alloy plate by rolling the heat-treated slab to a thickness of 0.2 mm to 3.0 mm. The method of claim 1,
Rolling the heat-treated slab; the
The method of manufacturing a magnesium alloy plate by rolling the heated slab 4 to 14 times. The method of claim 1,
Rolling the heat-treated slab; the
That is to be carried out in a temperature range of 200 to 350 °C, the method for producing a magnesium alloy plate. The method of claim 1,
Rolling the heat-treated slab; the
A method of manufacturing a magnesium alloy plate that is performed in a reduction ratio of 10 to 50%. The method of claim 1,
Final annealing the rolled slab; The
That is to be carried out in a temperature range of 300 to 500 °C, the method for producing a magnesium alloy plate. The method of claim 1,
Final annealing the rolled slab; The
That is to be carried out for 0.5 to 20 hours, the method of manufacturing a magnesium alloy plate. With respect to the total 100% by weight, Al: 0.5 to 2.0% by weight, Zn: 0.5 to 1.5% by weight, Ca: 0.1 to 0.8% by weight, Mn: 0.05 to 0.5% by weight, the balance contains Mg and inevitable impurities,
Ericsson value is 6 mm or more at room temperature,
Yield strength is 160 to 300 MPa,
Magnesium alloy plate with a twin fraction of 5 to 30 area%. The method of claim 16,
The magnesium alloy plate has a tensile strength of 253 to 350 MPa, a magnesium alloy plate. The method of claim 16,
The magnesium alloy plate has an elongation of 10 to 25%, a magnesium alloy plate.

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