JP4611052B2 - Rolling method and processing method of magnesium alloy sheet for forming process - Google Patents

Description

  The present invention relates to a rolling method and a processing method of a magnesium alloy plate for forming excellent in various formability such as drawing.

  In the processing of metal products, except for some special materials, it is possible to apply a method such as press forming to a metal plate that has been thinned by rolling, from the viewpoint of overall quality such as manufacturing cost and shape stability. It is generally considered advantageous. For this reason, in the process of thinning a metal plate, a well-known rolling process using a rolling roll or the like is frequently used. Since a metal material may be work-hardened with plastic working, annealing is generally performed for the purpose of improving workability after plastic working to some extent. Since the deformation resistance of metal materials tends to decrease as the processing temperature increases, in order to perform rolling on metal materials that are inferior in workability, the temperature of the material during rolling can be increased using a heating device such as a heating furnace. Hot rolling and warm rolling are performed. However, since magnesium material has excellent thermal conductivity and low specific gravity, even if it is pre-heated before rolling, the temperature will drop in a short time, making it impossible to stably roll long coil materials. was there. For this reason, it is difficult to obtain a large reduction ratio in difficult-to-work materials such as alloys mainly composed of magnesium, and therefore, the present state is that a sheet thickness size of a required thickness is obtained by increasing the number of rolling passes. In order to improve rolling properties, oil-based lubricants are generally used during rolling, but during warm rolling, the lubricant is vaporized and white smoke is generated, resulting in a poor working environment. There were problems such as lack of stability due to the oil film being cut.

  A magnesium alloy, which is a lightweight metal, has been suitably used as an outer case of a mobile electronic device such as a mobile communication device or a notebook computer that is strongly required to be lighter. However, various methods have been proposed because magnesium alloys are poor in moldability. For example, the temperature of the processing part such as a die, punch, or wrinkle pressing member of the forming apparatus is heated to about 150 to 400 ° C., and a forming process or a lubricant is used. Patent Document 1 discloses an embodiment of a magnesium rolling method.

JP 2003-328063 A

  An object of this invention is to provide the rolling method and shaping | molding method of the magnesium alloy plate for shaping | molding excellent in various formability, such as drawing. In particular, an object of the present invention is to provide a method for efficiently rolling and reducing the rolling reduction while preventing or suppressing edge cracks at the edge of the plate material and a method for improving the formability after rolling.

In order to achieve the object of the present invention, the method for rolling a magnesium alloy sheet for forming according to the present invention is a water-soluble urethane resin, a water-soluble polyester resin, a water-soluble acrylic resin, a water-soluble epoxy resin, or Do two or more Ri, and a method characterized by rolling an organic resin containing a heat-resistance imparting agent is coated on the magnesium alloy sheet surface,
Preferably, the organic resin contains one or more of silane coupling agent, colloidal silica, and lubricant . Furthermore, the heat resistance imparting agent is a siloxane compound, or the sheet temperature is rolled in a temperature range of room temperature to 350 ° C.

  Further, the processing method of the magnesium alloy plate of the present invention is a method characterized by forming a forming magnesium alloy plate rolled by any of the rolling methods described above, and the plate temperature is room temperature. It is a processing method characterized by forming in a temperature range of ˜350 ° C.

  The rolling method of the magnesium alloy sheet for forming according to the present invention is not a method of rolling by rolling a lubricant or solid lubricant on the surface of the magnesium alloy sheet at the time of rolling so far. Since it is a method of rolling a coated magnesium alloy plate, it is possible to prevent or suppress problems during rolling such as ear cracks. The method of processing a magnesium alloy plate is a method of rolling a magnesium alloy plate for forming This is a method of forming a magnesium alloy sheet for forming using a material, while being covered with an organic resin. Especially when the organic resin contains a heat-resistance imparting agent such as a siloxane compound, the room temperature is 350 ° C. or higher. An excellent rolling effect or processing effect can be exhibited in the following temperature range.

Hereinafter, the present invention will be described in detail.
As a magnesium alloy plate used as a substrate for rolling and processing a magnesium alloy plate for forming according to the present invention, a pure magnesium plate, 1.0 to 9.0% by weight of aluminum as an alloy component, and 0.5 to 0.5% of zinc are used. 6.0% by weight, containing 0.05 to 2.0% by weight of manganese, the balance being made of a magnesium alloy composed of magnesium and inevitable impurities, and a crystal grain size of 2 to 50 μm, more preferably 2 to 10 μm It is preferable that the thickness is 0.05 to 2.0 mm. The surface of these magnesium alloy plates is coated with an organic resin to form a magnesium alloy plate used for rolling and forming.

  The organic resin coated on the surface of the magnesium alloy plate is preferably a water-soluble or water-dispersible resin, and is any one of a water-soluble urethane resin, a water-soluble polyester resin, a water-soluble acrylic resin, and a water-soluble epoxy resin. It is preferable. These organic resins may be used alone or in combination of two or more. Depending on the application, a solvent-based resin may be used.

  These organic resins may be used by coating and drying the above magnesium alloy plate alone to form a film, but in order to improve rolling processability and corrosion resistance, the organic resin may contain the following substances. It may be used. For example, by including a silane coupling agent or the like, the adhesion of the organic resin film to the magnesium alloy plate, particularly the adhesion during rolling, is significantly improved. The silane coupling agent is preferably contained in the organic resin film at 5% by weight or less, more preferably 1% by weight or less. Even if the content exceeds 5% by weight, the effect of improving the adhesion is saturated, which is disadvantageous economically.

  Moreover, by including colloidal silica etc., the hardness of the organic resin film is improved, the scratch resistance is improved, and the corrosion resistance is also improved. For example, colloidal silica is preferably contained in the organic resin film at 50% by weight or less. When the content exceeds 50% by weight, the organic resin film becomes too hard, the workability of the organic resin film deteriorates, and the organic resin film easily cracks during processing.

  Furthermore, by including a lubricant, rolling workability and formability of a magnesium alloy sheet for forming work in which an organic resin film is formed on the magnesium alloy sheet are improved. Lubricants include higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, calcium salts of these higher fatty acids, aluminum salts, zinc salts, barium salts, magnesium salts, higher fatty acid esters thereof, polyethylene wax, Polyolefin wax such as polypropylene wax, fluorine-based wax such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride, inorganic powder such as graphite, molybdenum disulfide, and boron nitride can be used. . These lubricants are preferably contained in the organic resin film at 20% by weight or less. When the content exceeds 20% by weight, the adhesion deteriorates even when the organic resin film is processed on the magnesium plate. Said silane coupling agent, colloidal silica, and lubricant may be contained individually by 1 type in the organic resin film, respectively, but 2 or more types may contain them.

  The organic resin obtained as described above is applied to and dried on at least one side of the pure magnesium plate or magnesium alloy plate, depending on the case, to form an organic resin film. The thickness of the organic resin film is preferably 0.1 to 30 μm, more preferably 1 to 10 μm after drying. Thus, a magnesium alloy sheet for forming used in the rolling method and processing method of the present invention is obtained.

  The magnesium alloy sheet for forming used in the rolling method and processing method of the present invention obtained as described above is excellent in rolling processability and formability, and can be suitably formed into a container by drawing, When the magnesium alloy sheet for forming is heated to a temperature range of room temperature (for example, 10 ° C.) to 350 ° C., preferably 200 to 350 ° C., and rolled or drawn, the workability is improved. In the drawing process, it is possible to form a container having a longer side wall length than the bottom diameter. However, when rolling or forming in a temperature range exceeding 200 ° C, the organic resin film decomposes and discolors or cracks occur in the film, which deteriorates the appearance and makes it difficult to improve the rolling processability and drawing processability. become. Therefore, by adding a heat resistance imparting agent to the organic resin film, the organic resin film can be stably molded without causing discoloration or cracking in the high temperature processing temperature range of 200 to 350 ° C. or less. It is possible to improve the rolling workability and drawing workability. As a result, in the rolling process and drawing process, it is possible to lower the processing temperature at which the same processability as that obtained when using a conventional lubricating oil is used in the temperature range of 350 ° C. or lower. The merit that the above heat treatment becomes unnecessary is acquired.

  For example, as the heat resistance imparting agent, it is preferable to use a heat resistant resin such as polyimide or a siloxane compound. Examples of siloxane compounds include polymers and monomers of organosiloxanes such as dimethylsiloxane, diethylsiloxane, methylethylsiloxane, diphenylsiloxane, and methylphenylsiloxane, or polyalkylene oxide groups, hydroxyl groups, amide groups, and carboxyl groups in these organosiloxane molecules. , One having at least one substituent of at least one of a sulfone group and an amino group is preferably used. These heat resistance imparting agents are preferably contained in the organic resin film in an amount of 5 to 80% by weight, and more preferably 10 to 60% by weight. Thus, by including a heat resistance imparting agent in the organic resin film, the magnesium alloy plate for forming is heated to a warm working temperature range of 200 to 350 ° C. and rolled at a higher reduction ratio. It becomes possible. In the forming process in the temperature range from room temperature to 350 ° C. after rolling, the magnesium alloy plate of the present invention can be drawn into a magnesium alloy container. The heat resistance imparting agent may be contained alone in the organic resin, but may be contained in combination with any one or two or more of the above silane coupling agents, colloidal silica, and lubricants. .

  The magnesium alloy container thus obtained can be coated on the organic resin film. Or it is good also as a magnesium alloy container by carrying out the shaping | molding process of the coating board which gave the coating beforehand on the organic resin film of said magnesium alloy board for shaping | molding process. It is also possible to remove the organic resin film using an alkaline solution after molding into a container, or remove it using a shot blasting method in which abrasive particles are sprayed on the surface, and perform surface treatment such as anodizing or plating. It is.

Hereinafter, the present invention will be described in detail with reference to examples.
(Rolling magnesium alloy sheet for forming)
On both surfaces of a magnesium alloy plate having a thickness of 1.0 mm having the following alloy components, the resin solution shown in Table 1 or the resin shown in Table 1 and the silane coupling agent, colloidal silica, lubricant, and heat resistance shown in Table 1 are used. In the resin solution containing the property-imparting agent, the thickness of the resin film after drying becomes the thickness shown in Table 1 so that each additive has the content shown in Table 1 in the state after drying. As described above, the magnesium alloy plate for forming process coated and dried using a bar coater: Sample numbers 1 to 5, plate temperature: 190 ° C., roll temperature: 90 ° C., rolling speed: 4 m / min, rolling rate: 25% Rolled under the conditions of Regarding sample numbers 6 to 13, rolling was performed under the conditions of plate temperature: 230 ° C., roll temperature: 90 ° C., rolling speed: 4 m / min, rolling rate: 32.5%.
<Alloy components>
Al: 3.2 wt%, Zn: 1.1 wt%, Mn: 0.31 wt%, balance: Mg and inevitable impurity elements <average crystal grain size>
10 μm

  As a comparative example, the above-described magnesium alloy plate spray-coated with lubricating oil was rolled under the same conditions. Sample number 14 is plate temperature: 190 ° C., roll temperature: 90 ° C., rolling speed: 4 m / min, rolling rate: 25%, sample number 15 is plate temperature: 230 ° C., roll temperature: 90 ° C., rolling speed : Rolled under conditions of 4 m / min and rolling rate: 32.5%. The appearance of the magnesium alloy sheet after rolling and the appearance of the organic resin film were observed with the naked eye, and the depth of the ear cracks (cracks) generated at both edges was shown as an average value of 20 arbitrarily selected. The results are shown in Table 2. In the magnesium alloy sheet of the present invention, no discoloration is observed in the organic resin film, and there is no occurrence of ear cracks, or even if they occur, the depth is small and it is confirmed that the rolling processability is excellent. did. On the other hand, in the comparative example using lubricating oil, as shown in Table 2, a deep ear crack was recognized in the magnesium alloy plate, and it was confirmed that rolling workability was inferior. Furthermore, in order to evaluate whether the shaping | molding process of the magnesium alloy rolling plate of this invention is possible, about the sample numbers 1-5, the plate temperature: 190 degreeC, roll temperature: With respect to sample numbers 6 to 13 under the conditions of 90 ° C., rolling speed: 4 m / min, rolling rate: 25%, sheet temperature: 230 ° C., roll temperature: 90 ° C., rolling speed: 4 m / min, rolling rate: 32 After rolling under the condition of 5%, as for sample Nos. 1 to 5, punch shoulder R: 4 mm, punch temperature: normal temperature, die temperature: 190 ° C., blank holder temperature: 190 ° C., drawing speed: 1 mm / second The drawing ratio was 1.8 under the conditions, and for sample numbers 6 to 13, punch shoulder R: 4 mm, punch temperature: normal temperature, die temperature: 250 ° C., blank holder temperature: 250 ° C., drawing speed Ratio squeezed under the conditions of 1 mm / sec: 2.5 performs drawing of cracks was confirmed that there is no occurrence of flaws as a practical problem without generating. Regarding the comparative example, after spraying the lubricating oil again, the sample number 14 was punch shoulder R: 4 mm, punch temperature: normal temperature, die temperature: 190 ° C., blank holder temperature: 190 ° C., drawing speed: 1 mm / sec. Then, the drawing ratio is 1.8, and sample number 15 is punch shoulder R: 4 mm, punch temperature: normal temperature, die temperature: 250 ° C., blank holder temperature: 250 ° C., drawing speed: 1 mm / sec. Drawing was performed with a drawing ratio of 2.5 under the conditions described above, but drawing was not possible due to cracking. ,

  As described above, the method for rolling a magnesium alloy plate for forming formed by coating an organic resin on a magnesium alloy plate has excellent rolling workability. Further, when a heat resistance imparting agent is contained in the organic resin, it can be rolled at a high temperature up to 350 ° C. Also, in the case of forming the magnesium alloy rolled plate of the present invention, it has excellent formability, and when drawn at such a high temperature, the magnesium alloy container can be processed at a higher degree of workability. Drawing can be performed.

In the method for rolling a magnesium alloy plate for forming according to the present invention, which is performed by coating a magnesium plate with an organic resin, it is possible to prevent or suppress the ear cracking, so that rolling at a higher reduction ratio is possible. Moreover, in the shaping | molding processing method of this invention, it is possible to manufacture to a magnesium alloy container with high workability. In particular, when a heat resistance imparting agent such as a siloxane compound is included in the organic resin, an excellent lubrication effect and the like is expressed in a temperature range of room temperature to 350 ° C., particularly in a warm processing temperature range of 200 to 350 ° C., Higher rolling workability can be realized, and the magnesium alloy rolled plate of the present invention can be formed into a magnesium alloy container.

Claims (6)

Water-soluble urethane resins, water-soluble polyester resins, water-soluble acrylic resin, any one of a water-soluble epoxy resin, or Ri Do two or more, and an organic resin magnesium alloy sheet surface containing heat-resistance imparting agent A method for rolling a magnesium alloy sheet for forming, characterized by covering and rolling. The said organic resin contains any 1 type in a silane coupling agent, colloidal silica, and a lubricant, or 2 or more types, The rolling method of the magnesium alloy plate for shaping | molding of Claim 1 characterized by the above-mentioned. The method for rolling a magnesium alloy sheet for forming according to claim 1 or 2 , wherein the heat resistance imparting agent is a siloxane compound. The method for rolling a magnesium alloy sheet for forming according to any one of claims 1 to 3 , wherein the sheet temperature is rolled in a temperature range of room temperature to 350 ° C. A method for processing a magnesium alloy sheet, comprising forming a magnesium alloy sheet for forming that is rolled by the rolling method according to any one of claims 1 to 4 . 6. The method for processing a magnesium alloy plate according to claim 5 , wherein the forming is performed in a temperature range of room temperature to 350 ° C.