JP2006336053A - Intermediate of magnesium or magnesium based alloy and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate of magnesium or a magnesium based alloy capable of excellently treated with a stable quality. <P>SOLUTION: In the intermediate of magnesium or the magnesium based alloy electrolyzed by bringing an electrode into contact with an electrode contact part 21 provided around a formed part 16, a plurality of the electrode contact parts 21 are formed around the vicinity of the formed part 16. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an intermediate of magnesium or a magnesium-based alloy (hereinafter collectively referred to as a magnesium material) and a method for producing the same.

Magnesium material is the lightest of all practical metals, and its thin-walled products are excellent in specific strength, electromagnetic shielding properties, heat dissipation, vibration damping, etc. It has the advantage of being finished. Therefore, in recent years, it has been widely used in various fields such as communication equipment, computer equipment, optical equipment, automobile parts, and sports equipment. +-
Magnesium materials have the above-mentioned features, but are easily corroded, and therefore surface treatment is necessary to improve the corrosion resistance (corrosion resistance) of the product. For this surface treatment, for example, various methods such as anodizing treatment, plating treatment, painting treatment, and chromate treatment are performed.

  As is well known, an anodizing treatment is performed by connecting a molded product made of a magnesium material to an anode in an electrolytic bath using an external power source, and performing electrolysis, and coating the surface of the molded product with an oxide or a metal salt. It is a process to form. In addition to improving corrosion resistance (corrosion resistance), this anodizing treatment is performed for various purposes such as, for example, improvement of wear resistance, and imparting lubricity as a coating base treatment.

  Conventionally, a molded product obtained by pressing (plastic), extruding, casting, or molding a magnesium material generally has irregularities such as protrusions, dents, or steps, and the molded product having such irregularities is an anode. When set in an electrolytic bath for oxidation, the distance between the molded product and the opposing electrode (cathode) is partially different due to surface irregularities.

  For this reason, the resistance value of the molded product (anode) and the electrode (cathode) facing it are partially different, and as a result, the state of the film formed on the surface of the molded product (eg thickness, density, etc.) becomes uneven. It is difficult to form a certain film, for example, color unevenness or burning occurs, and the quality deteriorates.

  In order to eliminate such an adverse effect, a chemical conversion treatment with an acid or the like is performed before the anodic oxidation treatment to form a resistance film such as a hydroxide film or an oxide film on the entire surface of the molded product. By forming the resistance film on the entire surface of the molded product in this way, the influence of the unevenness of the molded product at the time of the above-described anodizing treatment is mitigated, and a relatively uniform anodizing treatment is possible.

  In addition, regarding the surface treatment of a magnesium material, the following patent documents can be mentioned, for example.

JP 2001-192872 A Japanese Patent Laid-Open No. 9-241897 JP 2002-30456 A

  When a molded product with a resistance film formed on the entire surface as described above is set in an electrolytic bath for anodization treatment and anodization is performed by bringing a part of the molded product into contact with the electrode, the resistance film is molded. Since it is between a product and an electrode, the electrical resistance value between them becomes high, and therefore a good anodizing treatment is not performed.

  The case of the anodizing treatment has been described above, but the same problem occurs in other electrolytic treatments such as electroplating.

  An object of the present invention is to provide an intermediate of magnesium or a magnesium-based alloy that eliminates the drawbacks of the prior art and can perform good electrolytic treatment with stable quality, and a method for producing the same.

In order to achieve the above object, the first means of the present invention is to provide an intermediate of magnesium or a magnesium-based alloy having an electrode contact portion in the periphery of a molded portion and performing an electrolytic treatment by contacting the electrode with the electrode contact portion. ,
A plurality of electrode contact portions are formed around the molded portion.

  According to a second means of the present invention, in the first means, the plurality of electrode contact portions are formed so as to surround the molding portion.

  According to a third means of the present invention, in the first means, an electric resistance film is formed on the surface of the molded part.

  According to a fourth means of the present invention, in the third means, the electric resistance film contains magnesium hydroxide.

  According to a fifth means of the present invention, in the first means, a plurality of the molding parts are repeatedly formed at a predetermined interval, and the electrode contact part is formed at an intermediate position between the molding part and an adjacent molding part. It is characterized by being.

The sixth means of the present invention is a step of processing a material made of magnesium or a magnesium-based alloy to produce an intermediate body having a molded part and an electrode contact part,
Masking the electrode contact portion of the intermediate with a masking member such as a tape;
Forming an electric resistance film on the surface of the masked intermediate;
A step of electrolytically treating the intermediate on which the electric resistance film is formed;
And a step of removing the masking member from the electrolytically processed intermediate.

The seventh means of the present invention is a step of processing a material made of magnesium or a magnesium-based alloy to produce an intermediate having a molded part,
Forming an electric resistance film on the surface of the intermediate;
Removing the electrical resistance film at a location corresponding to the electrode contact portion of the intermediate body on which the electrical resistance film is formed;
And an electrode contact portion from which the electrical resistance film has been removed is brought into contact with an electrode for electrolytic treatment.

  According to an eighth means of the present invention, in the sixth or seventh means, the electric resistance film contains magnesium hydroxide.

  A ninth means of the present invention is characterized in that, in the eighth means, the electrical resistance film corresponding to the electrode contact portion is removed with an acid such as an organic carboxylic acid.

  According to a tenth means of the present invention, in the sixth or seventh means, the molding part is repeatedly formed at a predetermined interval, and the electrode contact is provided at an intermediate position between the molding part and an adjacent molding part. A part is formed.

  The eleventh means of the present invention is characterized in that, in the sixth or seventh means, the electrolytic treatment is an anodic oxidation treatment.

  In the present invention, as described above, since the plurality of electrode contact portions are formed around the molded portion, the electrolytic treatment on the molded portion is performed without unevenness, and good electrolytic treatment with stable quality can be performed.

  Further, as described above, since the present invention forms an electric resistance film on the surface of the intermediate body after masking the electrode contact portion of the intermediate body, no electric resistance film is formed on the electrode contact section. The electrode is in good electrical contact with the electrode and can be subjected to good electrolytic treatment with stable quality.

  Furthermore, as described above, the present invention removes the electrical resistance film corresponding to the electrode contact portion of the intermediate body on which the electrical resistance film is formed, and then performs the electrolytic treatment by contacting the electrode with the electrode contact portion. The electrical contact between the intermediate and the electrode is good, and good electrolytic treatment with stable quality can be performed.

  The following embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a flowchart for explaining a warm plastic working method according to the first embodiment, and FIG. 2 is a schematic configuration diagram of a continuous press type warm plastic working device according to the embodiment.

  First, the warm plastic working method according to the present invention will be described with reference to FIG. As shown in the figure, in step (hereinafter abbreviated as S) 1, the magnesium material is hot-rolled. This hot rolling includes a heated roll method for heating a roll and a cold roll method for not heating a roll. In the rolled plate material, a processed texture in which hexagonal bottom surfaces are arranged parallel to the plate surface is formed.

  Pure magnesium or a magnesium alloy having a purity of 99% is used as the magnesium material. Examples of the magnesium alloy include an Mg—Al—Zn alloy, an Mg—Zn—Zr alloy, an Mg—Al alloy, and an Mg—rare earth element alloy.

  Specific examples of the Mg—Al—Zn alloy include AZ31A, AZ31B, AZ31C, AZ61A, AZ80A, and AZ91. Specific examples of the Mg—Zn—Zr alloy include ZK51A, ZK61A, ZK60, M6, M5, and M4. Specific examples of the Mg—Al alloy include AM100A.

Specific examples of the Mg-rare earth alloy include EZ33A, ZE41A, and QE22A. By adding rare earth elements (RE: mainly Ce or / and Nd as misch metal or didymium), Mg is added to the grain boundaries. ₁₂ RE crystallizes in a network, and the creep resistance is particularly improved. In addition, the addition of Ag or Y significantly improves the yield strength.

  As the magnesium material, one whose average crystal grain size is controlled within the range of 0.1 μm to 80 μm, preferably within the range of 0.5 μm to 50 μm, more preferably within the range of 1 μm to 30 μm is used. . Those having an average crystal grain size of less than 0.1 μm are prone to cracking, and the workability is lowered at that point. On the other hand, if the average crystal grain size exceeds 80 μm, the workability (formability), particularly the elongation, is lowered. Cannot be precisely processed (molded). Therefore, it is necessary to control the average crystal grain size within the range of 0.1 μm to 80 μm in order to maintain good characteristics, for example, acoustic characteristics and to provide good workability (formability).

  The average crystal grain size of the magnesium material is controlled to a desired value by adjusting the rolling conditions of the material (peripheral speed and heating temperature of the rolling roll), annealing conditions (annealing temperature, annealing time and annealing atmosphere), etc. it can. The plate thickness of the work is suitably in the range of 30 μm to 150 μm.

  Next, in S2, the black skin portion on the surface of the rolled material is CG (silicon carbide) polished to mechanically remove the black skin, and in S3, finish rolling is performed again to obtain a workpiece to be processed. Carbide, oil and fat, other dirt, etc. are attached to the surface of the workpiece by rolling process, etc., and the workpiece is cleaned using an organic solvent such as thinner or a surfactant to remove them. Is performed (S4).

  Next, in S5, a magnesium hydroxide layer is formed on the entire surface of the workpiece. Formation of this magnesium hydroxide layer maintains the temperature of the process solution in the range of 120 to 140 ° C. by adding an appropriate amount of sodium hydroxide to the aqueous sodium nitrite solution and stirring. The concentration of the sodium nitrite aqueous solution is suitably 50 g / L to 100 g / L, and the amount of sodium hydroxide added is suitably 395 g / L to 405 g / L.

  The workpiece is immersed in this heated treatment solution for 0.5 to 5 minutes. In addition, in order to determine immersion time according to the stain | pollution | contamination degree of a workpiece | work, the immersion time is given the width | variety as mentioned above.

  After immersion, the workpiece is taken out of the treatment solution and washed with water, and the above-described pretreatment is performed until the surface of the workpiece becomes milky white and is not glossy, thereby forming a dense magnesium hydroxide layer on the entire surface of the workpiece. By immersion in the above-mentioned sodium nitrite aqueous solution, deposits such as lubricant carbonized during rolling that could not be removed with the organic solvent in S4 can be reliably removed, and the surface of the workpiece is cleaned cleanly. A magnesium hydroxide layer is formed. By forming the magnesium hydroxide layer on the entire surface in this way, a rolled material having a stable surface property over a long period of time can be obtained.

  Next, in S6, the pretreated workpiece is immersed in a lubricant solution for a predetermined time to form a magnesium soap layer on the surface. Examples of the lubricant include an aliphatic carboxylate having no substituent or a substituent having 6 to 24 carbon atoms and a substituent having no substituent or a substituent. And at least one organic compound selected from the group of aromatic carboxylates having 7 to 20 carbon atoms.

  In the aliphatic carboxylate, the aliphatic chain may be a straight chain or a branched chain. Moreover, it may be saturated or unsaturated. The number of carbon atoms in the molecule is preferably 10-24, more preferably 8-22.

  Examples of the aliphatic carboxylic acid of the aliphatic carboxylate include hexanoic acid, 4-methylvaleric acid, 2-ethylbutyric acid, 2,2-dimethylbutyric acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, Examples include lauric acid, myristic acid, palmitic acid, heptadecanoic acid, stearic acid, icosanoic acid, behenic acid, and isostearic acid.

  Examples of the salt of the aliphatic carboxylate include alkali metal salts, alkaline earth metal salts, amine salts, and ammonium salts, and alkali metal salts and alkaline earth metal salts are particularly preferable.

  Furthermore, examples of the substituent of the aliphatic carboxylate include a hydroxyl group, a carboxy group, an amino group, an alkoxy group, an acetyl group, and a halogen atom. The degree of substitution is 5 or less, preferably 3 or less, more preferably 0 or 1.

  Preferred organic compounds of the aliphatic carboxylate include, for example, sodium oleate, sodium laurate, sodium myristate, sodium stearate, sodium behenate, sodium 1,2-hydroxyoctadecanoate, sodium isostearate, 2-dodecanoic acid There is sodium.

  The number of carbon atoms in the aromatic carboxylate is preferably 7-20, more preferably 7-14.

  Examples of the aromatic carboxylic acid of the aromatic carboxylate include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, diphthalic acid, benzenetricarboxylic acid, benzenetetracarboxylic acid, and naphthoic acid.

  Examples of the salt of the aromatic carboxylate include alkali metal salts, alkaline earth metal salts, amine salts, and ammonium salts, and alkali metal salts and alkaline earth metal salts are particularly preferable.

  Examples of the substituent of the aromatic carboxylate include a hydroxyl group, a carboxy group, an amino group, an alkoxy group, an acetyl group, a halogen atom, and an alkyl group having 1 to 6 carbon atoms. The degree of substitution is 5 or less, preferably 3 or less, more preferably 0 or 1.

  Preferred organic compounds of the aromatic carboxylate include, for example, sodium benzoate, potassium benzoate, sodium isophthalate, sodium terephthalate, sodium diphthalate and the like.

  If necessary, for example, a rust preventive agent, a viscosity modifier, an antioxidant, an antifoaming agent, and a pH adjuster can be added to the lubricant.

  In this embodiment, sodium stearate and sodium hydroxide are added and dissolved in water, and this lubricant solution is heated and maintained so as to be in a temperature range of 80 ° C to 100 ° C. The amount of sodium stearate added is 8 g / L to 12 g / L.

  By immersing the aforementioned workpiece in this lubricant solution, the magnesium hydroxide layer on the workpiece surface causes a chemical reaction to form a magnesium soap layer made of magnesium carboxylate. The immersion time for the workpiece is suitably 1 minute to 5 minutes.

  Thus, the workpiece | work which formed the magnesium soap layer in the surface is set to the below-mentioned warm plastic working apparatus, and predetermined | prescribed warm plastic working is performed (S7).

  FIG. 2 is a schematic configuration diagram of a continuous press type warm plastic working apparatus according to the embodiment. As shown in the figure, this warm plastic working apparatus is provided with an intermittent feed mechanism 4, a forming mechanism 5 and a cutting mechanism 6 along the flow direction X of the machining step.

  In the intermittent feed mechanism 4, a strip-shaped workpiece 2 wound in a roll shape is set. A magnesium soap layer 3 is formed on the surface of the work 2 in S4 of FIG. The strip-shaped workpiece 2 is intermittently sent out to the forming mechanism 5 side at a predetermined feed pitch P1 while being sandwiched between chucking mechanisms 7a and 7b that reciprocally move back and forth.

  In the case of this embodiment, the molding mechanism 5 has a first molding part 8a, a second molding part 8b, a third molding part 8c, and a fourth molding part 8d, and these molding parts 8a to 8d are in the flow direction of the machining process. It is provided along X.

  The first molding portion 8a is composed of a first fixed-side press die 8a-1 and a first movable-side press die 8a-2, and the second molding portion 8b is composed of the second fixed-side press die 8b-1 and the second fixed-side press die 8b-1. 2 movable side press mold 8b-2, and the third molding part 8c is composed of a third fixed side press mold 8c-1 and a third movable side press mold 8c-2, and a fourth molding part. 8d is composed of a fourth fixed press die 8d-1 and a fourth movable press die 8d-2.

  Each fixed-side press die 8a-1 to 8d-1 is attached to the fixed platen 9, and each movable-side press die 8a-2 to 8d-2 is attached to the movable platen 10. Each fixed-side press die 8a-1 to 8d-1 and each movable-side press die 8a-2 to 8d-2 incorporate an electric heater 11 and a temperature sensor (not shown), for example, 200 ° C. The temperature is individually controlled in the range of ˜250 ° C.

  A presser member 12 is slidably disposed around each fixed-side press die 8a-1 to 8d-1, and each presser member 12 is always moved upward by a spring 13 to each movable-side press die 8a-2 to 8d. -2 side is elastically biased.

  The distance P2 between the first molded part 8a and the second molded part 8b, the distance P3 between the second molded part 8b and the third molded part 8c, and the distance P4 between the third molded part 8c and the fourth molded part 8d are both workpieces. Each molded part 8 is positioned so as to be equal to the feed pitch P1 of 2.

  The movable platen 10 to which the movable side press dies 8a-2 to 8d-2 are attached is supported by a plurality of rods so as to be movable up and down, and a hydraulic cylinder is fixed to a top plate attached to the heads of the plurality of rods. (Both not shown).

  With this hydraulic cylinder, the movable platen 10 moves up and down with a predetermined stroke, and each movable side press die 8a-2 to 8d-2 is in contact with or close to the workpiece 2 when lowered, and the workpiece 2 is fixed to each other. Positioning is performed in two stages, that is, a press molding mode position for pressing the side press dies 8a-1 to 8d-1. The movable platen 10 (movable side press dies 8a-2 to 8d-2) shown in FIG. 2 shows the state of the standby position.

  FIG. 3 is a cross-sectional view at the heating mode position showing the heating state of the workpiece 2 in the first molding portion 8a. A dome-shaped protrusion 14a is provided at the head of the first fixed-side press mold 8a-1, while a dome-shaped protrusion corresponding to the protrusion 14a is formed on the lower surface of the first movable-side press mold 8a-2. A recess 15a is formed.

  As shown in FIG. 2, when the movable platen 10 (movable side press die 8a-2) is in the standby position, the workpiece 2 is sandwiched between chucking mechanisms 7a and 7b and placed on the fixed side press die 8a-1. Sent. After the work 2 is fed out for a predetermined length, the chucking mechanisms 7a and 7b are retracted from the dotted line position to the solid line standby position in an open state.

  Next, the movable side press die 8a-2 is lowered to the heating mode position, the lower surface of the flat work 2 is in contact with the head of the fixed side press die 8a-1 and the pressing member 12, and the upper surface of the work 2 is The periphery of the portion of the workpiece 2 which is in contact with the lower surface of the movable press die 8a-2 and is about to be molded is elastically sandwiched between the lower surface of the movable press die 8a-2 and the pressing member 12.

  As described above, the fixed-side press die 8a-1 and the movable-side press die 8a-2 have the electric heater 11 built therein and are heated to a predetermined temperature, and the presser member 12 is fixed to the fixed-side press die 8a. Since the workpiece 2 is in a high temperature state due to heat conduction in contact with -1, the workpiece 2 will be formed by contact or proximity of the fixed-side press die 8a-1, the movable-side press die 8a-2, and the pressing member 12. The part and its surroundings are heated.

  By maintaining the heating mode state of FIG. 3 for a predetermined time (for example, about 5 to 10 seconds), the thin plate-like workpiece 2 has a temperature suitable for warm plastic working, for example, the fixed-side press die 8a-1 and movable. It is heated to about 200 ° C. to 250 ° C., which is substantially the same temperature as the side press die 8a-2. The time of the heating mode can be appropriately adjusted depending on the thickness, material, thermal characteristics, shape and size of the workpiece 2, and the like.

  Since the heating mode is short as described above and the heating temperature is relatively low, there is no fear that the crystal grains grow and the workability is not lowered.

  Thereafter, by pressing the movable side press die 8a-2 toward the fixed side press die 8a-1, the holding member 12 is lowered downward against the elasticity of the spring 13, and the protrusion 14a and the concave portion are opposed to each other. A part of the workpiece 2 is press-formed into the same shape as 15a. At the time of this press molding, since the periphery of the part to be processed is firmly clamped by the movable-side press die 8a-2 and the pressing member 12, the generation of wrinkles in the peripheral part can be prevented.

  When the first stage processing is completed, the movable platen 10 is lifted to the position shown in FIG. 2 by the hydraulic cylinder, and the part of the work 2 formed by the first forming portion 8a is moved to the next by the feeding operation of the chucking mechanisms 7a and 7b. To the second molding portion 8b.

  In the second molding portion 8b to the fourth molding portion 8d, the workpiece 2 is repeatedly heated and plastically processed by intermittently feeding it forward, and finally the dome portion 16 is formed on the workpiece 2 as shown in FIG. Can be formed in succession.

  Returning to FIG. 2 again, the workpiece 2 that has passed through the forming mechanism 5 as described above is sent to the cutting mechanism 6. The cutting mechanism 6 includes a receiving portion 17 attached to the fixed platen 9, a blade portion 18 attached to the movable platen 10, and a counter 19 connected to a control unit (not shown).

  The counter 19 measures the number of times the workpiece 2 is fed by the intermittent feeding mechanism 4 or the number of presses by the molding mechanism 5 to detect the number of molding portions (dome portion 16 in the present embodiment) formed on the workpiece 2. can do. When a predetermined number of formed parts are formed on the work 2 and pass under the blade part 18, the blade part 18 is taken out and the work 2 is cut to obtain a strip-shaped formed sheet 20 as shown in FIG.

  The molded sheet 20 is transferred to the next masking process, resistance film forming process, anodizing process, and electrodeposition coating finishing process, and then the molded part (the dome part 16 in the present embodiment) is separated from the work 2.

  As shown in FIG. 5, a plurality of penetrating holes 21 are formed in an array around the forming portion (the dome portion 16 in the present embodiment) of the forming sheet 20. That is, as shown in the figure, a plurality of molding portions (in this embodiment, the dome portion 16) are repeatedly formed at predetermined intervals, and both left and right sides of the middle position between the molding portion and the adjacent molding portion. Each of the molded portions is surrounded by a plurality of holes 21 (four holes 21 in this embodiment). This hole 21 can be formed, for example, at the fourth forming portion 8d which is the final stage of the forming mechanism 5.

  Returning to FIG. 1 again, after the warm plastic working (S7), the masking tape 22 is formed above the hole 21 except for the forming portion (the dome portion 16 in this embodiment) of the forming sheet 20 in S8 as shown in FIG. Mask with. In the case of the present embodiment, since the holes 21 are formed at both ends of the molded sheet 20 at equal intervals, the masking tape 22 is adhered along the both ends of the molded sheet 20. Note that masking with the masking tape 22 is applied to the front and back surfaces of the molded sheet 20.

  In this embodiment, the masking tape is used as the masking member. However, instead of the masking tape, a pressing member can be used, and the portion where the hole 21 of the molded sheet 20 is formed can be sandwiched and masked from both sides by the pressing member. . If it is a pressing member, it can be used for masking any number of times, and the manufacturing cost can be reduced.

  Next, in S9, the electric resistance film 23 is formed on the masked molded sheet 20 surface. In the case of this embodiment, by immersing the masked molded sheet 20 in a solution in which an appropriate amount of sodium hydroxide is dissolved in an aqueous sodium nitrite solution and the liquid temperature is maintained in the range of 120 ° C to 140 ° C, An electric resistance film 23 is formed on the entire surface of the molded sheet 20.

  The concentration of the sodium nitrite aqueous solution is 50 g / L to 100 g / L, and the amount of sodium hydroxide added is suitably 395 g / L to 405 g / L.

  Although sodium nitrite is used in this embodiment, the electric resistance film 23 can also be formed using a chromic acid system, a manganese phosphate system, a stannic acid system, a zirconium salt system, or the like. Since the sodium nitrite does not contain metal, it is preferable from the viewpoint of film quality stability and waste liquid treatment.

  After forming the electric resistance film 23, the masking tape 22 is peeled off from the molded sheet 20 (S10). The state of the peeled molded sheet 20 is shown in FIG. 7, and the row-shaped conductive portions 24 that expose the surface of the magnesium material on which the electric resistance film 23 is not formed are formed around the holes 21. When the pressing member is used as the masking member as described above, removing the pressing member from the molded sheet 20 is masking removal (S10).

  After this masking removal (S10), the molded sheet 20 is anodized (S11). This anodizing treatment includes three steps of pretreatment, oxidation treatment, and posttreatment. The pretreatment is a treatment for removing the lubricant and the like adhering to the molded sheet 20, and specifically, alkali cleaning. Since magnesium is resistant to alkali, it can be washed effectively at high temperature using a highly alkaline detergent.

  The pre-formed molded sheet 20 is made of, for example, a mixed aqueous solution of sodium hydroxide, ethylene glycol, and sodium oxalate, immersed in an electrolytic bath maintained at 75 ° C. to 80 ° C., and subjected to predetermined energization. As shown in FIG. 8 at the time of this energization, the electrode pin group 25 is inserted in each hole 21 of the molding sheet 20, and the electrode pin group 25 is connected to the anode of the electrolytic bath. As described above, since the electric resistance film 23 is not formed in the hole 21 and in the vicinity of the hole 21, the electrical connection between the molded sheet 20 and the electrode pin group 25 is good. In addition, since the electric resistance film 23 is formed on the surface of the molded portion (the dome portion 16 in the present embodiment), even if the molded portion has irregularities, the irregularities are less affected and the anodic oxidation is performed almost uniformly. Is called.

  A direct current having an arbitrary waveform is supplied to the electrolysis, and in particular, a pulse wave, a sawtooth wave, and a high-speed inverted superposition wave are suitable. For the electrode pin group 25 and the anode and cathode (both not shown) of the electrolytic bath, insoluble materials such as steel, stainless steel, nickel and carbon are used.

  Thereafter, oxidation treatment is performed, followed by washing with water, washing with hot water and drying. By this anodizing treatment, a dense oxide film is formed on the surface of the molded sheet 20. This oxide film functions as an anti-corrosion film for the internal metal and also serves as a base film for painting. Therefore, after this anodizing treatment, the electrodeposition coating finish of S12 can be performed. If necessary, a dye can be applied between the anodizing treatment (S11) and the electrodeposition coating finish (S12) by, for example, an immersion method.

  In this way, after the electrodeposition coating finish is performed, the dome portion 16 can be sequentially punched from the molded sheet 20, and the dome portion 16 can be used as an acoustic speaker.

  9 to 11 are for explaining a second embodiment of the present invention. FIG. 9 is a flowchart for explaining a warm plastic working method according to this embodiment. FIGS. 10 and 11 are for explaining this embodiment. It is a perspective view which shows the state in the middle of the shaping | molding sheet which concerns on.

  In FIG. 9, the content from the rolling process of the magnesium material in S21 to the warm plastic working step in S27 is the same as the content from S1 to S7 shown in FIG.

  In this embodiment, masking is not performed, and the electric resistance film 23 is formed on the entire surface of the molded sheet 20 as shown in FIG. 10 (S28). The electrical resistance film 23 is formed by the same method as in the first embodiment. Next, as shown in FIG. 11, the conductive portion 24 is formed by partially removing the electric resistance film 23 adhering to and around the hole 21 of the molded sheet 20 (S29).

  For partial removal of the electric resistance film 23, an organic acid such as an organic carboxylic acid or a mineral acid is used. As the organic carboxylic acid, for example, monocarboxylic acid, dicarboxylic acid, oxy or ketocarboxylic acid, aromatic carboxylic acid and the like are used.

  More specifically, examples of the monocarboxylic acid include formic acid and acetic acid. Examples of the dicarboxylic acid include oxalic acid and malonic acid. Examples of the oxy or ketocarboxylic acid include lactic acid, tartaric acid, and citric acid. Examples of the aromatic carboxylic acid include salicylic acid and sulfosalicylic acid, and one or a mixture of two or more thereof is used.

  As the mineral acid, for example, nitric acid, sulfuric acid, chromic acid, hydrofluoric acid, or a mixed acid thereof is used.

  In this embodiment, an organic acid or a mineral acid is used for partial removal of the electric resistance film, and it is chemically removed. However, it can be removed mechanically using, for example, a brush, buff, belt, barrel, blast, or the like. It is.

  Thereafter, anodization is performed in S30, and electrodeposition coating finish is performed in S31. Since the contents of this anodizing treatment and electrodeposition coating finish are the same as S11 and S12 described with reference to FIG.

  The present embodiment is configured as described above, and a masking step (S8) such as attaching the masking tape as in the first embodiment to a molded sheet or holding the formed sheet with a pressing member to fix it. In addition, complicated steps such as masking removal (S10) for stripping the masking tape from the molded sheet and removing the pressing member from the molded sheet can be omitted, and partial removal (S29) is easy because the resistance film is thin. is there. Therefore, according to the present embodiment, the number of work steps is reduced, and the efficiency can be improved.

  In the above embodiment, a magnesium soap layer is formed as the lubricating layer, but instead of forming the magnesium soap layer, a normal lubricant such as an oil-based lubricant or a silicone-based inorganic lubricant can be applied. When applying a normal lubricant in this way, a lubricant application step is included instead of the magnesium hydroxide layer formation step (S5, S25) and the magnesium soap layer formation (S6, S26) of the above embodiment. become.

  In the above-described embodiment, the case where the magnesium material is subjected to press (plastic) processing has been described. However, the present invention is not limited to this, for example, in the case of a molded product obtained by extrusion, casting, or molding. It is also applicable to.

  In the above-described embodiment, a plurality of molded portions are repeatedly formed as in a molded sheet, and electrode assemblies such as a plurality of holes are provided in the aggregate so as to sandwich each molded portion. It is also possible to provide an electrode contact portion such as a plurality of holes around the lever.

  In the above-described embodiment, the electrode contact portion including a hole is provided. However, the electrode contact portion may not be a hole, but may be another shape such as a flat portion or a cut and raised piece or a rib.

It is a flowchart for demonstrating the warm plastic working method which concerns on 1st Embodiment of this invention. It is a schematic block diagram of the warm plastic working apparatus which concerns on embodiment of this invention. FIG. 5 is a cross-sectional view at a workpiece heating mode position in a first forming part of the warm plastic working device. It is sectional drawing of the workpiece | work processed by the warm plastic processing apparatus. It is a perspective view of the forming sheet obtained by the warm plastic working apparatus. It is a perspective view which shows the masked state of the molding sheet. It is a perspective view which shows the state before the anodizing process of the molding sheet. FIG. 7 is a cross-sectional view taken along line XX. It is a flowchart for demonstrating the warm plastic working method which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the state which formed the resistance film in the shaping | molding sheet which concerns on the embodiment. It is a perspective view which shows the state before the anodizing process of the molding sheet.

Explanation of symbols

  1: Magnesium hydroxide layer, 2: Workpiece, 3: Magnesium soap layer, 4: Intermittent feed mechanism, 5: Molding mechanism, 6: Cutting mechanism, 7a, 7b: Chucking mechanism, 8a: First molding part, 8a -1: 1st fixed side press mold, 8a-2: 1st movable side press mold, 8b: 2nd molding part, 8b-1: 2nd fixed side press mold, 8b-2: 2nd movable side Press mold, 8c: third molding part, 8c-1: third fixed side press mold, 8c-2: third movable side press mold, 8d: fourth molding part, 8d-1: fourth fixed side Press die, 8d-2: Fourth movable side press die, 9: Fixed platen, 10: Movable platen, 11: Electric heater, 12: Presser member, 13: Spring, 14a-14d: Projection, 15a-15d : Recessed part, 16: dome part, 17: receiving part, 18: blade part, 19: counter, 20: molded sheet 21: hole, 22: masking tape, 23: electrical resistance film, 24: conductive portion, 25: electrode pin group.

Claims (11)

In an intermediate of magnesium or a magnesium-based alloy that has an electrode contact part around the molded part and performs an electrolytic treatment by contacting the electrode with the electrode contact part,
A magnesium or magnesium-based alloy intermediate characterized in that a plurality of electrode contact portions are formed around the molded portion. 2. The magnesium or magnesium-based alloy intermediate according to claim 1, wherein the plurality of electrode contact portions are formed so as to surround the molded portion. 2. The magnesium or magnesium-based alloy intermediate according to claim 1, wherein an electric resistance film is formed on a surface of the molded part. 4. The magnesium or magnesium-based alloy intermediate according to claim 3, wherein the electric resistance film includes magnesium hydroxide. 2. The intermediate body of magnesium or magnesium-based alloy according to claim 1, wherein a plurality of the formed portions are repeatedly formed at a predetermined interval, and the electrode contact portion is formed at an intermediate position between the formed portion and the adjacent formed portion. An intermediate of magnesium or a magnesium-based alloy. A step of processing a material made of magnesium or a magnesium-based alloy to form an intermediate body having a molded portion and an electrode contact portion;
Masking the electrode contact portion of the intermediate with a masking member;
Forming an electric resistance film on the surface of the masked intermediate;
A step of electrolytically treating the intermediate on which the electric resistance film is formed;
And a step of removing the masking member from the electrolytically treated intermediate. A method for producing an intermediate of magnesium or a magnesium-based alloy. A step of processing a material made of magnesium or a magnesium-based alloy to produce an intermediate having a molded part;
Forming an electric resistance film on the surface of the intermediate;
Removing the electrical resistance film at a location corresponding to the electrode contact portion of the intermediate body on which the electrical resistance film is formed;
A process for producing an intermediate of magnesium or a magnesium-based alloy, comprising: an electrode contact portion from which the electric resistance film has been removed; 8. The method for producing an intermediate of magnesium or a magnesium-based alloy according to claim 6 or 7, wherein the electric resistance film includes magnesium hydroxide. 9. The method for producing an intermediate of magnesium or a magnesium-based alloy according to claim 8, wherein an electrical resistance film corresponding to the electrode contact portion is removed with an acid. Production method. The method of manufacturing an intermediate of magnesium or a magnesium-based alloy according to claim 6 or 7, wherein a plurality of the formed parts are repeatedly formed at a predetermined interval, and the intermediate part between the formed part and the adjacent formed part is formed. An electrode contact part is formed, The manufacturing method of the intermediate body of magnesium or a magnesium base alloy characterized by the above-mentioned. 8. The method for producing an intermediate of magnesium or a magnesium-based alloy according to claim 6 or 7, wherein the electrolytic treatment is an anodizing treatment.

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