Treatment method for improving elongation of magnesium alloy sheet

Abstract

The invention provides a treatment method for improving the ductility of a magnesium alloy sheet, and aims to further improve the ductility of the magnesium alloy sheet to meet the sheet metal stamping requirements of luggage products, and the treatment method is characterized by comprising the following steps: injecting No.30 engine oil into a container and heating to a first preset temperature; the magnesium alloy sheet is immersed in engine oil and heated at the constant temperature for a first duration; cooling is conducted after constant-temperature heating for the first duration, the oil temperature is kept at the second preset temperature, and then heating is conducted for the second duration; and finally, the magnesium alloy sheet is taken out and cooled.

Description

Technical Field

[0001] The present invention relates to the technical field of magnesium alloy sheet processing, and in particular to a processing method for improving the elongation of a magnesium alloy sheet. Background Art

[0002] Magnesium alloys can be used in the forming of bags and other products due to their good strength and ductility. However, due to the inherent ductility of magnesium alloys, when using magnesium alloy sheets for sheet metal stamping to form the body, exceeding the ductility limit of ordinary magnesium alloy sheets can easily cause damage to the oxide protective layer on the surface of the magnesium alloy sheet, thereby impairing its performance. In this regard, the existing technology is to heat the magnesium alloy sheet before stamping, and then perform a coating process after the magnesium alloy sheet is stamped to spray a protective film layer on the surface of the product. This not only increases the production cost, but also limits production efficiency because the magnesium alloy sheet needs a certain amount of time to cool down after stamping before the coating process can be performed. Summary of the Invention

[0003] The present invention proposes a treatment method for improving the elongation of magnesium alloy sheets, the purpose of which is to further improve the ductility of magnesium alloy sheets to meet the sheet metal stamping requirements of luggage products. This is achieved through the following technical means:

[0004] A treatment method for improving the elongation of a magnesium alloy sheet according to the present invention comprises the following operations:

[0005] Injecting synthetic No. 30 motor oil into the container and heating it to a first preset temperature;

[0006] Immersing the magnesium alloy sheet in engine oil and heating it at a constant temperature for a first time; cooling the oil after the first time, maintaining the oil temperature at a second preset temperature and heating it for a second time;

[0007] Finally, the magnesium alloy sheet is taken out and cooled.

[0008] In one or more embodiments of the present invention, the first preset temperature is between 180-220 degrees Celsius, the second preset temperature is between 140-160 degrees Celsius, the first duration is 20-30 minutes, and the second duration is 30-60 minutes.

[0009] Another method for improving the elongation of a magnesium alloy sheet according to the present invention comprises the following operations:

[0010] Filling the container with synthetic No. 30 motor oil and heating it to a third preset temperature;

[0011] immersing the magnesium alloy sheet in engine oil and heating it at a constant temperature for a third period;

[0012] Finally, the magnesium alloy sheet is taken out and cooled.

[0013] In one or more embodiments of the present invention, the third preset temperature is between 140-160 degrees Celsius, and the third time length is 30-60 minutes.

[0014] Compared with the prior art, the advantages of the present invention include at least:

[0015] 1) After the process of the present invention, the ductility of the magnesium alloy sheet is greatly improved from the original 20-30δ / % at room temperature to 65-75δ / %, so that many sheet metal stamping processes can be carried out smoothly, which has greatly promoted the application of the material.

[0016] 2) The present invention adopts the oil heating process on the one hand to consider increasing the ductility of the material after short-term high-temperature heating, and on the other hand, it can also avoid adding additional oil during the stamping process after the subsequent material is cooled, eliminating the cleaning process in the subsequent processing steps. Therefore, the present invention is the best pre-process for sheet metal stamping.

[0017] 3) The magnesium alloy sheet does not need to be heated again after being cooled during stamping, which avoids the trouble and hassle of the original magnesium alloy material needing to be formed in a heated state, improves production efficiency and reduces the corresponding processing costs. DETAILED DESCRIPTION

[0018] The application scheme is further described as follows:

[0019] Example 1

[0020] A method for improving the elongation of magnesium alloy sheets includes the following operations:

[0021] No. 30 engine oil is injected into the container and heated to a first preset temperature, which is generally between 180-220 degrees Celsius;

[0022] Immersing the magnesium alloy sheet in engine oil and heating it at a constant temperature for a first time period, typically between 20 and 30 minutes; cooling the oil after the first time period, maintaining the oil temperature at a second preset temperature and heating it for a second time period, typically between 140 and 160 degrees Celsius, typically between 30 and 60 minutes;

[0023] Finally, the magnesium alloy sheet is taken out and cooled, and sheet metal stamping can be performed after it is completely cooled.

[0024] In this embodiment, AZ32B magnesium alloy sheet (composition includes: magnesium Mg 93%, aluminum Al 3%, zinc Zn 1%, Mn 0.3%, a small amount of copper Cu, silicon Si, calcium Ca) is selected as the implementation material. During the first stage of heating, 200 degrees Celsius is selected as the first preset temperature, and during the second stage of heating, 150 degrees Celsius is selected as the second preset temperature.

[0025] Table 1 Comparison of mechanical properties and temperature of AZ31 B magnesium alloy sheet

[0026]

[0027] AZ31B magnesium alloy sheets are brittle and prone to breaking, especially during molding at the corners of luggage. The present invention significantly improves the ductility of AZ31B magnesium alloy sheets. Using a tensile tester (or extensometer) to measure the ductility of the processed sheets, data shows that the ductility can be increased from 20-30 δ / % at room temperature to 65-75 δ / %. This allows for smooth sheet metal stamping processes, significantly promoting the application of the material and making it suitable for use in a wide range of end products, including magnesium alloy luggage.

[0028] This embodiment uses synthetic No. 30 motor oil, which can withstand higher temperatures (flash point temperature > 240°C). A conventional industrial heating cabinet can be used as the container. The magnesium alloy sheet is placed in a stainless steel carrier frame, immersed in No. 30 motor oil, and then heated. Because the heating cabinet itself is a relatively closed environment and the heating process is not long-term (each batch is heated for an average of 1 hour), no decomposition products or carbonization will occur. After the magnesium alloy sheet cools, it does not need to be heated again for stamping, avoiding the problem of the original magnesium alloy material needing to be heated for forming (troublesome and troublesome).

[0029] The method of this embodiment is suitable for scenarios with large processing volumes. The temperature is first raised to a higher temperature to provide a more adequate reaction environment for the material, and then lowered to the optimal temperature range of about 150 degrees Celsius for oil cooking.

[0030] Example 2

[0031] A method for improving the elongation of magnesium alloy sheets includes the following operations:

[0032] No. 30 engine oil is injected into the container and heated to a third preset temperature, wherein the third preset temperature is between 140 and 160 degrees Celsius, preferably 150 degrees Celsius;

[0033] The magnesium alloy sheet is immersed in engine oil and heated at a constant temperature for a third period of time, which is 30-60 minutes; finally, the magnesium alloy sheet is taken out and cooled.

[0034] Similar to Example 1, a tensile tester (or extensometer) is used to measure the ductility of the processed sheet. The data show that the ductility of the AZ31B magnesium alloy sheet is basically increased by more than 30% after the process of the present invention. The method of this embodiment is suitable for scenarios with less processing volume, and oil boiling is directly performed in the optimal temperature range of about 150 degrees Celsius.

[0035] The above preferred embodiments should be regarded as examples of the implementation methods of the present application scheme. Any technical deductions, replacements, improvements, etc. that are identical or similar to the present application scheme or made based on it should be regarded as within the scope of protection of this patent.

Claims

1. A method for improving the elongation of a magnesium alloy sheet, characterized in that: The following operations are included: Injecting synthetic No. 30 motor oil into the container and heating it to a first preset temperature; Immersing the magnesium alloy sheet in engine oil and heating it at a constant temperature for a first time; cooling the oil after the first time, maintaining the oil temperature at a second preset temperature and heating it for a second time; Finally, the magnesium alloy sheet is taken out and cooled.

2. The method for improving the elongation of a magnesium alloy sheet according to claim 1, characterized in that: The first preset temperature is between 180-220 degrees Celsius.

3. The method for improving the elongation of a magnesium alloy sheet according to claim 1, characterized in that: The second preset temperature is between 140-160 degrees Celsius.

4. The method for improving the elongation of a magnesium alloy sheet according to claim 1, characterized in that: The first duration is 20-30 minutes.

5. The method for improving the elongation of a magnesium alloy sheet according to claim 1, characterized in that: The second duration is 30-60 minutes.

6. A method for improving the elongation of a magnesium alloy sheet, characterized in that: The following operations are included: Filling the container with synthetic No. 30 motor oil and heating it to a third preset temperature; immersing the magnesium alloy sheet in engine oil and heating it at a constant temperature for a third period; Finally, the magnesium alloy sheet is taken out and cooled.

7. The method for improving the elongation of a magnesium alloy sheet according to claim 6, characterized in that: The third preset temperature is between 140-160 degrees Celsius.

8. The method for improving the elongation of a magnesium alloy sheet according to claim 6, characterized in that: The third duration is 30-60 minutes.

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