JP2002146435A - Method for manufacturing sheet metal product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a sheet metal product by which strain after heat treatment can be easily removed and also manufacturing cost as well as the manufacturing man-hour can be reduced. SOLUTION: The method for manufacturing the sheet metal product has a stress-relieving step for removing strain resultant from a heat treatment step where an unfinished product is subjected to temperature-raise and cooling. In the stress relieving step, the strain is removed by subjecting the unfinished product 5 to temperature-raise up to tempering temperature and pressing the product 5 using a press die 10 having a cavity 10a conforming to the shape of a finished product 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a strain removing step for removing a strain (heat treatment deformation / heat treatment strain) caused by a heat treatment step of heating / cooling a product before completion.
The present invention relates to a method for manufacturing a thin metal product made of a light alloy such as aluminum, steel, or the like to be provided and manufactured.

[0002]

2. Description of the Related Art Conventionally, a metal unfinished product which has been subjected to a heat treatment such as quenching is distorted by rapid cooling, and it is difficult to secure the product dimensions and shape such as warpage. And the like, hit the product before completion,
A predetermined size and shape were secured.

However, when a product has a thin wall and has complicated irregularities, the distortion of each part is a deformation on the + side,
Since the dimensional error becomes complicated due to the deformation on the negative side, it takes a long time to correct the punching out even for a skilled person.

The present invention has been made to solve the above-mentioned problems, and can easily remove strain after heat treatment.
An object of the present invention is to provide a method for manufacturing a sheet metal product that can reduce the number of manufacturing steps and manufacturing costs.

[0005]

SUMMARY OF THE INVENTION A manufacturing method according to the present invention comprises a sheet metal product manufactured by providing a strain removing step for removing a strain generated by a heat treatment step of heating and cooling a product before completion. Wherein the strain removing step comprises: elevating the temperature of the unfinished product to a tempering temperature, and pressing the product by a press mold having a cavity corresponding to the shape of the finished product to remove the strain. It is characterized by doing.

The heat treatment step can be exemplified by a quenching step of raising and rapidly cooling the unfinished product, and preferably further includes a tempering step after quenching. And it is preferable to perform the said distortion removal process during a tempering process. Of course, the strain relief step may be performed after the heat treatment step.

[0007]

In the method for manufacturing a sheet metal product according to the present invention, in the strain relief step, the unfinished product at the tempering temperature is pressed by a press die having a cavity corresponding to the shape of the finished product. , Heat treatment strain is removed.

Therefore, as in the case of pressing a product before completion, the distortion of each part can be removed at the same time, and in a short time,
Easy to secure product dimensions. Furthermore, in a mode in which the product before completion is pressed at a tempering temperature, unlike cold working performed at normal temperature or hot pressing performed at a high temperature, a mode in which warm pressing is performed, Stress can be removed, proof stress can be improved, and moreover, distortion can be removed neatly without adhesion of scale or the like.

Therefore, in the method for manufacturing a sheet metal product according to the present invention, strain after heat treatment can be easily removed, the number of manufacturing steps and manufacturing cost can be reduced, and complicated unevenness is provided. This is suitable when mass-producing a thin metal product by heat treatment.

[0010] If the heat treatment step includes a quenching step, even if the heat treatment distortion generated in the quenching step is large, the distortion can be easily removed by applying the present invention.
It is possible to suitably reduce the number of manufacturing steps and manufacturing cost of a sheet metal product.

Further, the heat treatment step includes a quenching step,
May include a tempering step after the quenching step, in which case, if the strain relief step is performed during the tempering step, compared to the case where the strain relief step is performed, after the completion of the heat treatment step Further, since it is not necessary to raise the temperature of the unfinished product to the tempering temperature, the number of manufacturing steps and manufacturing costs can be further reduced. Of course, if you do not consider this point,
After the heat treatment step, the temperature of the product before completion may be raised to perform a strain relief step.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

A product 1 manufactured in the embodiment is made of an aluminum alloy (AC4W.ADC1) as shown in FIGS.
2. ADC 10) is a pillar used for the body of an automobile, and has a total length X of about 900 mm and a width Y of 60
The unevenness 3 is formed in multiple stages with 0 mm and a thickness Z of about 2.5 mm.

Further, the thin metal product 1 is manufactured by manufacturing a pre-finished product 5 by die casting, heat-treating the pre-finished product 5, and performing a strain relief treatment on the heat-treated pre-finished product 1. The heat treatment process of the embodiment includes a quenching process (solution treatment) and a tempering process (artificial aging process).
And T6 processing.

The strain removing step is performed by using a press die 10 as shown in FIG. This press die 10
Is the cavity 10 of the external shape of the finished product 1 at the time of mold clamping.
It is configured to include two split dies 11 and 12 forming a. In the case of the embodiment, the strain relief process is performed after the completion of the heat treatment process.

That is, in the case of the embodiment, as shown in FIG. 4, a forming step I of the unfinished product 5 by die casting, a quenching step IIa of a heat treatment step II, and a tempering step II.
b, a strain removing step III. In the quenching step IIa, a temperature raising step IIaa (the required time is about 70 minutes) for raising and maintaining the product 5 before completion at about 490 ° C.
Quenching step IIab (required time: about 5 minutes) immersed in a water bath at ℃. In the tempering step IIb, the pre-finished product 5 after quenching is heated to the tempering temperature of about 225 ° C. and gradually cooled to the ambient temperature (the required time is about 110 minutes).

The aluminum alloy (AC4
The quenching temperature of W / ADC12 / ADC10) is 48
0 to 500 ° C., and the tempering temperature is 215 to 235.
° C.

In the strain removing step III, the pre-completion product 5 is heated to about 225 ° C., and as shown in FIG. The pre-completion product 5 is pressed, the press die 10 is opened, and the completed product 1 is taken out (required time 30 to 30).
About 60 minutes).

The mold clamping force is increased from about 50 t in increments of 50 to 100 t while maintaining the mold clamping force in the range of about 300 to 500 t, and is maintained for several seconds (for example, 2 seconds).

Further, in the case of the embodiment, the strain removing step II
In I, the unfinished product 5 is put into a heating furnace for raising the temperature, and the temperature is raised to the tempering temperature. Then, the unfinished product 5 is taken out from the heating furnace and pressed in an air atmosphere. Pressed using the mold 10, and the product 5 before completion was heated to about 225 ° C. at the time of press working.
Is cooled to about 50 ° C. in 1-2 minutes.

FIG. 5 is a graph showing the measured strain (unit: mm) with respect to the set dimensions at points A to U (see FIG. 1) in the product 5 before completion and the product 1 before completion. Also,
FIG. 6 is a graph showing, as a comparative example, a strain measurement of a product that has been subjected to press working using the press die 10 by simply raising the temperature of the unfinished product 5 to about 185 ° C. in the strain removing step III. showed that. Further, FIG. 7 is a graph showing, as another comparative example, a strain measurement of a product that was subjected to press working using a press die 10 at a normal temperature of a product 5 before completion in a strain removal step III. .

As can be seen from the graphs of FIGS.
Before the quenching step IIa, the strain at each point A to U was ± 0.5 mm or less, but after the heat treatment step II,
B ・ E ・ F ・ G ・ H ・ I ・ J ・ K ・ L ・ T (particularly I
(Point) has a large strain. However, after passing through the strain removing step III, in the comparative example shown in FIGS. 6 and 7, the I, N, and T points have a large strain, whereas in the case of the embodiment shown in FIG. In each point A ~
It can be seen that the strain at U is less than ± 1 mm, and the dimensional accuracy of the product is sufficiently ensured.

In the case where the strain is removed by tapping, it takes about 5 hours. In the case of the embodiment, the strain can be removed in a short time of only about 30 to 60 minutes. The number of manufacturing steps and manufacturing cost of the metal product 1 can be significantly reduced.

Therefore, according to the manufacturing method of the embodiment, the strain after the heat treatment can be easily removed, the number of manufacturing steps and the manufacturing cost can be reduced, and a thin metal product having complicated unevenness can be obtained. 1 is suitable when mass-produced by heat treatment.

In the embodiment, the strain relief step III
In the above, the press die 10 is kept at the normal temperature, but may be raised in advance to the tempering temperature of the product 5 before completion. When the temperature of the press die 10 is raised to the tempering temperature, it is desirable to simultaneously perform the strain relief step III during the tempering step IIb as shown in the process diagram of FIG.

That is, in the heating furnace in which the tempering step IIb is performed, the unfinished product 5 having undergone the quenching step IIa is heated to the tempering temperature (heating step), and the tempering temperature is set in the heating furnace. Pressing is performed using the press die 10 that has been heated to a temperature (strain removing step). Then, as the temperature of the heating furnace is lowered, the temperature is gradually cooled (slow cooling step) to complete the tempering step IIb. In this case, as in the embodiment, separately from the tempering step IIb, the strain removing step III
Since the heat treatment is not performed, the time required for raising the temperature and the energy used in the strain relief process itself can be omitted, and the number of manufacturing steps and cost can be further reduced.

Further, when the strain relief step III is performed simultaneously during the tempering step IIb, the press die 10 is set in a heating furnace maintained at the tempering temperature, and the quenching step II is performed.
The pre-completion products 5 after a) are sequentially put into a furnace, heated to a tempering temperature, and then pressed using a press die 10 that has been heated to the tempering temperature. Alternatively, the tempering step IIb may be completed by taking out from the heating furnace and gradually cooling. In this case, the number of manufacturing steps and costs can be further reduced as compared with the above case, since the temperature of the heating furnace and the press mold 10 are not lowered.

In the embodiment, the sheet metal product 1 is made of an aluminum alloy. However, the thin metal product 1 may be made of a non-ferrous metal material containing an alloy of nickel, zinc, magnesium, or the like, or a metal material such as a steel material of stainless steel. The present invention can be applied to products formed from materials.

Further, in the embodiment, the case where the product 5 before the completion of the heat treatment step II is formed by die casting is shown. The pre-completion product 5 may be manufactured from forging such as press working or cutting.

Furthermore, in the case of the embodiment, the case where the sheet metal product 1 is manufactured by the heat treatment step including the quenching step and the tempering step has been described. Then, the present invention may be applied.

[Brief description of the drawings]

FIG. 1 is a plan view of a sheet metal product manufactured according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a cross-sectional view showing a use state of a press die used in a strain relief step of the embodiment.

FIG. 4 is a diagram showing a manufacturing process of the embodiment.

FIG. 5 is a graph showing a measurement result of strain at each point of the product manufactured in the same embodiment.

FIG. 6 is a graph showing a measurement result of strain at each point of a product manufactured in a comparative example.

FIG. 7 is a graph showing a measurement result of strain at each point of a product manufactured in another comparative example.

FIG. 8 is a diagram illustrating a manufacturing process according to a modification of the embodiment.

[Explanation of symbols]

 1 ... (Sheet metal product / finished product) product 5 ... Unfinished product 10 ... Press mold 10a ... Cavity

Claims (5)

[Claims] 1. A method for producing a sheet metal product, comprising: a strain removing step for removing a strain caused by a heat treatment step of raising and cooling the temperature of a product before completion, wherein the strain removing step is performed. Raising the temperature of the unfinished product to a tempering temperature, and pressing by a press mold having a cavity corresponding to the shape of the finished product, thereby removing the strain. . 2. The method for manufacturing a sheet metal product according to claim 1, wherein the heat treatment step includes a quenching step of heating and rapidly cooling the unfinished product. 3. The heat treatment step includes a quenching step of heating and quenching the unfinished product, and a tempering step of heating and gradual cooling of the unfinished product after the quenching step. The method for manufacturing a sheet metal product according to claim 1, wherein: 4. The method for producing a sheet metal product according to claim 3, wherein the strain removing step is performed during the tempering step. 5. The method for manufacturing a sheet metal product according to claim 1, wherein the strain removing step is performed after the heat treatment step.