JPH0790293B2 - Warm deep drawing method for aluminum plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a warm deep drawing method and apparatus for an aluminum plate.

[Conventional technology]

Aluminum sheets and aluminum alloy sheets that have strength equivalent to mild steel sheets are inferior in deep drawability due to poor ductility and low r value compared to mild steel sheets, which is sometimes remarkable when the cross-sectional shape is irregular. Is. However,
If these aluminum alloy sheet materials can be used in place of mild steel sheets, the weight can be significantly reduced. Therefore, various methods have been studied so far for warm deep drawing of aluminum sheet materials.

As is well known, warm deep drawing is performed by heating the work piece to room temperature or higher to perform deep drawing, but at that time, how deep drawability is improved and seizure and galling due to it are prevented. The issue is whether it can be done. In order to solve such problems, conventionally, studies have been made particularly on heating methods, lubricants, and mold materials.

The heating method includes i) heating only the material, ii) heating the material and separately heating the mold, and iii) heating the mold and heating the material with this heat. Especially when directed to continuous machining, the method of iii) is generally applied.

As the lubricant, soybean oil, a sheet made of tetrafluoroethylene (commonly called Teflon: trade name), a polymer mixed with graphite, or grease or a lubricant mixed with graphite, molybdenum disulfide or mica There are things, etc.

There have been few studies on die materials, and as a die for drawing stainless steel, one made of steel aluminum alloy is considered to be effective in preventing seizure and is used.

Also in the warm deep drawing of aluminum sheet material, the above-mentioned items are being studied.

[Problems to be Solved by the Invention]

However, warm deep drawing of aluminum sheet has not yet been satisfactory in terms of drawing depth and seizure, and it is reported that the temperature effect of warm deep drawing cannot be expected for aluminum materials ( Pressing technology: Volume 25,
There is also No. 9, P68).

The present invention has been made in view of the above circumstances, and it is extremely useful as described above by further studying the above-mentioned processing conditions and the like and carrying out a multifaceted examination of the processing conditions and the like. The purpose is to establish, realize and provide an effective warm deep drawing method for aluminum sheets.

[Means for Solving the Problems]

The warm deep drawing method of an aluminum plate material according to the present invention uses a mold in which at least a surface of a die for deep drawing and a surface of a blank holder that come into contact with a workpiece and a corner portion are made of a copper aluminum alloy. At the same time, before processing, an industrial lubricant (any one of grease, soap, wax, emulsion, animal and vegetable fats and oils, synthetic ester) in which mica powder is mixed and dispersed in a range of 5% to 20% by weight is a processed material. What is characterized by being applied to the surface, and, at least with the die of the deep-drawing die and the die and the surface of the blank holder in contact with the workpiece in the blank holder, and a die made of a copper aluminum alloy, The surface temperature of the die and the blank holder is in the range of 180 ° C or higher and 300 ° C or lower, and the surface temperature of the punch is set to the die and The surface temperature of the rank holder to is characterized in that the set 20 ° C. to 250 DEG ° C. lower.

Further, when the above two methods are combined and carried out, a remarkable effect can be obtained.

[Action]

The copper-aluminum alloy exhibits a good performance especially as a deep drawing mold because of its small friction coefficient and good slipperiness.
Also, by mixing an appropriate amount of mica in the lubricant base, seizure prevention effect can be obtained, and by using this together with a mold made of a copper aluminum alloy, an excellent seizure / galling prevention effect can be obtained due to the synergistic effect of both. To be demonstrated. Further, by setting the surface temperature of the die and the punch at the time of processing within the above range, excellent deep drawability of the aluminum plate material can be obtained.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of an apparatus used for carrying out the warm deep drawing method for an aluminum plate material according to the present invention. Reference numeral 1 is a warm deep drawing apparatus as a whole, and B is to be processed. A blank (workpiece), 2 is a die, 3 is a blank holder, 4 is a punch, 5 is an operating mechanism for pressing the blank holder 3, and 6 is a heat insulating material. The blank B according to the present invention is an aluminum plate material. The operation mechanism of the punch 4 is omitted. Further, in this case, the warm deep drawing apparatus 1 has a different shape as shown in FIG.
It is intended to form a narrowed portion.

A surface (contact surface) 2a and a corner portion 2b of the die 2 which come into contact with the blank B, and the blank holder 3
The contact surface 3a and the corner portion 3b in are made of a copper aluminum alloy (Cu-Al alloy). Further, in this embodiment, the surface of the punch 4 that contacts the blank B, that is, the punch head 4a is also made of a copper aluminum alloy. In this case, the copper-aluminum alloy contains 15% to 15% of A, and also contains one or more of Pb, Fe, Zn, Mn, Ni, Co, etc. at less than 10% (all by weight). Cu alloys are preferred.

The die 2 and the blank holder 3 have heaters 7 (for heating the die) and 8 (for heating the blank holder) for heating them, and the punch 4 has a heater 9 (for punching). A cooling water pipe 9 '(for punch cooling) for cooling and a cooling water pipe 9'for cooling are respectively incorporated. These heaters 7, 8 and 9 may be any of electric ring heaters, pipe heaters, band heaters and the like, and are directly inserted inside the die 2 or the like. These heaters 7, 8, 9 and the cooling water pipe 9'are controlled so that the heating temperature and the cooling water flow rate are respectively controlled by controllers (temperature control means) 10, 11, 12 as shown in FIG. It has become. These controllers 10 (for dice), 11 (for blank holder), 12
Of the die (for punches), the die controller 10 and the blank holder controller 11 detect the temperatures of the die 2 and the blank holder 3 to control the heaters 7 and 8, and input the die 2 and the blank holder 3 in advance. It has the function of maintaining the constant temperature. The punch controller 12 detects the temperature of the punch 4 and controls the punch heating heater 9 and / or the amount of cooling water flowing in the cooling water pipe 9'on the basis of a signal from the arithmetic output device 13. The calculation output device 13 sends a control signal to the punch controller 12 based on the temperature information from the die controller 10 and the blank holder controller 11.

Next, the operation of the warm deep drawing apparatus 1 having the above-mentioned configuration and the warm deep drawing method according to the present invention will be described.

On the surface (screen) of blank B in FIG.
%, The lubricant mixed and dispersed in the range of not more than% is applied in advance.
These lubricants may be industrial lubricants such as grease, soap, wax, emulsion, animal and vegetable oils and fats, synthetic esters, but do not deteriorate up to 300 ° C. and have lubricity at room temperature. It should be excellent.

Here, the amount of the mica powder mixed and dispersed is not less than 5% by weight, the effect (anti-seizure preventing effect) is not exhibited at 5% or less, and 20% is not more than 20% by weight.
This is because the effect is constant and the drawing depth does not change even if the value exceeds, and the cost increases.

The blank B coated with the lubricant as described above is set between the die 2 and the blank holder 3 as shown in FIG. 1 by a feeding mechanism (not shown). During this time, the heaters 7, 8 and 9 for heating the die, for heating the blank holder, and for heating the punch are energized (or cooling water is made to flow in the cooling water pipe 9 '), and the surface temperature of the die 2 and the blank holder 3 is increased. Is 180 ° C to 300 ° C, and the surface temperature of the punch 4 is such that the die 2 and the blank holder 3
The temperature is adjusted to be a low temperature in the range of 20 ° C to 250 ° C. The surface temperature of these dice 2, blank holder 3 and punch 4 is the die controller.
By a command from the controller 10 for blank holder 11, and the controller 12 for punch, it is held at a constant value within the above range even during processing.

Here, the surface temperature of the die 2 and the blank holder 3 is set to 180 ° C. or higher because the elongation of the blank B is slightly increased below 180 ° C. and the r value is a low value which is the same as room temperature. This is because there is no processing temperature effect (see FIG. 3), while the reason why the temperature is 300 ° C. or lower is that the lubricating oil deteriorates at a temperature above this temperature and cleaning becomes impossible. The set surface temperatures of the die 2 and the blank holder 3 differ depending on the material (alloy type) of the blank B to be processed and the processing content.
In addition, the processing resistance is large (for example, irregular shape, large drawing depth,
Etc.) is set to a higher temperature in the above range.

Further, the surface temperature difference of the punch 4 with respect to the surface temperature of the die 2 and the blank holder 3 is determined according to the material of the aluminum plate material forming the blank B and the set heating temperature of the die 2 and the blank holder 3 at that time. Details will be described later. The temperature difference above 20 ℃ is because
In order to reduce the deformation resistance of the flange portion of the blank B sandwiched between the die 2 and the blank holder 3 while increasing the strength of the portion with respect to the corner portion (bent portion) of the punch 4, the strength difference is obtained at both places. The reason why the temperature difference is 250 ° C. or less is that when a temperature difference more than this is applied, the elongation of the corner portion of the blank is excessively reduced, and there is a risk of breakage in the case of an irregular cross section.

Now, in actual processing, the blank B is sandwiched between the heated die 2 and the blank holder 3 and held in that state for several tens of seconds, then the temperature distribution is confirmed and the blank B held under that condition is held. Is deeply drawn by the punch 4.

During deep drawing, aluminum alloy sheets generally have a smaller elastic coefficient than mild steel sheets and are therefore prone to seizure. However, the portion of the die portion that comes into contact with the blank, that is, the contact surface 2a of the die 2 and Corner part 2b
And the contact surface 3a and the corner portion 3b of the blank holder 3
Since the punch head 4a is made of a copper-aluminum alloy as described above, the friction coefficient is small and the slipperiness is good, and the seizure phenomenon is reduced compared to those made of cast iron or alloy tool steel. It will be done. This tendency can be seen even at room temperature, and its effect becomes remarkable in the warm working as in the present invention. As a result, the aperture depth can be increased.

Two examples according to the present invention and the results are shown below in Table-1 and Table-2, respectively.

<Example 1> With reference to a change in warm deep drawability when a mica powder and another substance (graphite) were mixed with a soap base lubricant as a lubricant base and due to a difference in the mixing amount of the mica powder. I experimented. The mold used was that shown in FIG.

Experimental conditions △ Lubricant base: Soap-based lubricant △ Blank material and plate thickness: Aluminum alloy plate A5
182P-O-1mmt. △ Surface temperature of die 2 and blank holder 3: 250 ° C. △ Punch 4 surface temperature: 200 ° C. As is clear from Table 1, when the content ratio of the mixed mica powder is less than 5% by weight, the drawing depth is low and seizure and galling occur. Moreover, no change was observed in the drawing depth even when the amount of mixture exceeded 20%. When graphite was used as the admixture, the drawing depth did not change even when the processing temperature was high as in this example, and additionally seizure and galling occurred.

In any case, an appropriate amount of mica powder (weight ratio 5% to 20%
%) In the case of using the circulating agent mixed and dispersed, the drawing depth becomes larger than that of graphite as the temperature becomes higher, and a good high temperature deep drawing property is exhibited.

Further, when the blank size is larger than that in FIG. 1 and is a size that protrudes from the part made of the copper aluminum alloy in the die 2 and the blank holder 3, a soap-based mixture containing 10% by weight of mica powder is used. Even with a lubricant, strong seizure and galling occurred on the part of the tool steel (the part other than the copper-aluminum alloy) that was in contact with the blank at 150 ° C or higher.

Therefore, in order to prevent the occurrence of seizure or galling, the material of the die 2 and the blank holder 3 and the mica powder should be 5% to 5%.
It can be understood that there is a synergistic effect of the soap-based lubricant in which 20% (weight ratio) is mixed and dispersed.

<Example 2> 10% by weight of mica powder in a soap-based lubricant base as a lubricant
An experiment was carried out on the change in the warm deep drawing property when the surface temperature of the die 2 and the blank holder 3 and the surface temperature of the punch 4 when the mixed material was used were changed. The mold used was the one shown in FIG.

Experimental conditions △ Blank material and plate thickness: Aluminum alloy plate A5
182P-O-1mmt. △ Lubricant: Soap-based lubricant + Mica powder 10% (weight ratio) From Table 2 above, it is understood that the drawing depth is shallow when the surface temperature of the die 2 and the blank holder 3 is less than 180 ° C. 3
At temperatures above 00 ° C, the lubricant deteriorated and turned yellow, making cleaning difficult. Further, when the difference between the punch 4 and the surface temperature of the die 2 and the blank holder 3 is 20 ° C. or less, the deep drawing depth is shallow, and when the temperature difference exceeds 250 ° C., the deep drawing depth is also shallow. Further, as a result of investigating some points not shown in Table-2, the result shown in FIG. 4 was obtained. In the figure, a straight line e that is rising to the right with a chain line indicates that T ₁ (the temperature of the die 2 and the blank holder 3) and T ₂ (the temperature of the punch 4) are the same. The present invention, in the figure, the area surrounded by points a, b, c, d, a is the area for performing warm deep drawing of aluminum sheet material, but this figure is practically indicated by diagonal lines in the figure. It is shown that it is preferable to perform processing within the area indicated by. That is, for example, when T ₁ is 200 ° C., T ₂ is about 120.
℃, and if T ₁ is 250 ℃, T ₂ is about 50-190 ℃, T ₁ is
In the case of 300 ° C, the best result can be obtained by setting T ₂ near 55 ° C. In general, when T ₁ is low temperature (low temperature in the above range), T ₂ is relatively high temperature side, and when T ₂ is high temperature (high temperature in the above range)
T ₂ are relatively to the cold side, and T ₁ is the case where the intermediate temperature within the range T ₂ are capable of managing a wide range, there is a tendency such.

In general, it is well known that not only an aluminum plate but also a deep drawing process, a strength difference is given by causing a temperature difference between the central part and the peripheral part of the blank as described above, thereby increasing the limiting drawing ratio. Especially, in the case of an aluminum plate, by setting the surface temperature of the die 2 (and the blank holder 3) and the punch 4 in the above range, a very remarkable effect can be obtained.

As described above, at least the die 2 of the deep-drawing die and the surface of the blank holder 3 in contact with the workpiece (contact surfaces 2a, 3a) and the corners 2b, 3b are made of copper-aluminum alloy. In addition, before processing, if a warm deep drawing of the aluminum plate is performed by applying a lubricant in which the mica powder is mixed and dispersed in the range of 5% to 20% by weight to the surface of the workpiece, It is possible to reliably prevent the sticking and the galling that accompanies it, thereby increasing the drawing depth and enabling continuous deep drawing of the aluminum plate material. Similarly, using the above mold, the surface temperature of the die 2 and the blank holder 3 is set in the range of 180 ° C to 300 ° C,
Moreover, by setting the surface temperature of the punch 4 to be lower than the surface temperature of the die 2 and the blank holder 3 by 20 ° C. to 250 ° C., the deep drawing depth can be surely increased, and the drawing shape becomes an axial target. This is particularly advantageous when processing irregular shapes that do not result.

When these methods are simultaneously carried out, the deep drawing depth can be made sufficiently large, and seizure and galling do not occur, and continuous deep drawing of aluminum plate material becomes possible.

Further, by configuring the warm deep drawing apparatus 1 for aluminum plate material as described above, it becomes possible to reliably and automatically perform temperature control of the die 2, the blank holder 3, and the punch 4 in the above-mentioned set range. In particular, since the punch 4 is provided with the heater 9 for heating the punch and the cooling water pipe 9 ', even when the set temperatures of the die 2 and the blank holder 3 are changed (especially when set to a high temperature), the punch 4 is surely secured. In addition, the surface temperature of the punch 4 can be set within the above range, and good deep drawing can be performed as described above. Although not shown, the temperature adjustment method of the punch 4 may be a method of causing the oil whose temperature is adjusted by a heater and a cooler arranged outside to flow into the punch 4 to control the temperature.

In the above embodiment, the head 4a of the punch 4 was also made of a copper aluminum alloy, but the blank B
From the viewpoint of preventing seizure between the die 2 and the blank holder 3, the contact surface 2a and the corner portion 2b of the die 2 and the contact surface 3a and the corner portion 3b of the blank holder 3 are made of a copper aluminum alloy. Anything will do. However, if the punch head 4a is also made of a copper-aluminum alloy as described above, even when the punch 4 is also heated as in this embodiment, it is possible to prevent galling between the punch 4 and the blank B, which is extremely effective. is there. Further, although it is of course possible to use a copper-aluminum alloy for the entire die (die 2 and blank holder 3), it is difficult in terms of cost and the above-mentioned effects do not change.

In the embodiment, the controllers 10 and 11 are provided for the die heating heater 7 and the blank holder heating heater 8, respectively. However, in this embodiment, relative to the die 2 and the blank holder 3. Since the temperature difference is not provided, the heater 7 for heating the die and the heater 8 for heating the blank holder may be controlled by one controller.

Further, as the aluminum plate according to the present invention, not only industrial pure aluminum (JIS1000 series) but also JIS2000,3
000, 4000, 5000, 6000, 7000, 8000 series are also included, and the above effects can be obtained in any alloy.

〔The invention's effect〕

As described above, according to the invention of claim 1, it is possible to surely prevent seizure and galling associated therewith during warm deep drawing of an aluminum plate material, thereby increasing the deep drawing depth and continuous deep drawing. Processing is possible.

Further, according to the invention of claim 2, it is possible to increase the deep drawing depth, which is particularly advantageous for deformed deep drawing in which the drawing shape is not an axial object.

According to the invention of claim 3, the deep drawing depth can be made sufficiently large without causing seizure or galling, and continuous processing of deformed deep drawing is also possible.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of an aluminum plate warm working apparatus used in the present invention, and FIG. 2 is a schematic configuration diagram showing heating means and control means in the apparatus.
FIG. 3 is a graph showing the temperature characteristics of the aluminum plate material, and FIG. 4 is a graph showing the optimum processing area with respect to the die / blank holder temperature and the punch temperature. B: Blank (workpiece), 1 ... Warm deep drawing machine, 2 ... Die, 2a ... Contact surface, 2b ... Corner part, 3 ... Blank holder, 3a ... Contact surface, 3b ...... Corner part, 4 …… Punch, 7 …… Die heating heater, 8 …… Blank holder heating heater, 9 …… Punch heating heater, (the above-mentioned symbols 7, 8 and 9 are heating means) 9 ′ ... … Cooling water piping (cooling means) 10 …… Die controller, 11 …… Blank holder controller, 12 …… Punch controller. (The above symbols 10, 11, 12 are temperature control means)

Claims (3)

[Claims] 1. A die having at least a surface of a die for deep-drawing die and a blank holder which comes into contact with a workpiece and a corner portion are made of a copper aluminum alloy, and the mica powder is weighed before processing. Aluminum characterized by applying an industrial lubricant (any one of grease, soap, wax, emulsion, animal and vegetable oils and fats, synthetic ester) mixed and dispersed in a ratio of 5% or more and 20% or less to the surface of the work material. A warm deep drawing method for sheet materials. 2. A die having at least a deep die die and a blank holder, the die contacting surface of which is in contact with a workpiece and a corner portion are made of a copper aluminum alloy, and the surface temperature of the die and the blank holder is used. To 180 ° C. or higher and 300 ° C. or lower, and the surface temperature of the punch is set to be 20 ° C. to 250 ° C. lower than the surface temperature of the die and the blank holder. 3. The warm deep drawing method for an aluminum plate material according to claim 1, wherein the surface temperature of the die and the blank holder is in the range of 180 ° C. to 300 ° C., and the surface temperature of the punch is the die and the blank. A warm deep-drawing method for aluminum sheet material, characterized by setting the surface temperature of the holder 20 to 250 ° C lower.