JPH0970615A - Flow guide for extrusion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow guide capable of easily determining the shape of an opening part, and optimizing the flow speed of the metallic material inside die holes by the opening part. SOLUTION: The shape of a flow guide opening part 53 is determined in the following procedure. The minimum wall thickness a1, and the coefficient of delay Yi are determined by the material of the metal, the extrusion temperature, and the extrusion speed, and can be experimentally obtained in advance. The equivalent wall thickness wi at reference points P1-P10 of the die hole 51 is respectively calculated. The dimensions of the parts indicated by an arrow on each end can be determined by appropriately selecting the reference wall thickness w0 of the die holes and the reference opening width C0 of the flow guide opening part in accordance with the formula Ci =C0 ×(w0 -a1)/(wi -a1)/Yi . The flow speed of the metallic material inside the die hole can be optimized by the flow guide opening part of such a shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion flow guide for controlling the flow rate of a metal material extruded from a die hole by adjusting the inflow ratio of the metal material into each portion of the die hole.

[0002]

2. Description of the Related Art When a metal material is extruded, appropriate measures must be taken because the flowability of the metal material in the die hole varies depending on the thickness of each part of the die hole (distance between the walls of the die hole). Otherwise, the metallic material that is finally extruded will be deformed.

Therefore, in general, as shown in FIGS. 12 (a) to 12 (c), in forming the die hole 3 in the die 1, the length of the bearing portion 5 in the extrusion direction (hereinafter referred to as the bearing). The length is referred to as "length", where the flow velocity in the die hole tends to be fast, and the flow velocity in the die hole tends to be slow. For example, in the case of the die hole 3 shown in the figure, since the flow velocity at the outermost end portion 3a becomes relatively slow, the bearing length is shorter than that at other portions. Further, since the flow velocity of the central portion 3b is faster than that on both sides thereof, the bearing length is increased.

Recently, a puller has been installed in order to save manpower in the extrusion operation, and along with this, a billet (a lump of metal material)
In order to continuously extrude the extruded material by piecing, the flow guide 9 having the opening 7 whose shape is determined according to the shape of the die hole 3 is provided on the front side of the die 1.
When such a flow guide 9 is installed, the flow velocity difference in each part of the die hole tends to become larger, so that the switching of the bearing length as described above needs to be made larger.

[0005]

However, according to the prior art, when the metal material is extruded by the die 1 having the bearing portion 5 as described above, the portion where the bearing length is switched (FIG. 12 (b), FIG. Points Q1 exemplified in (c)
Q7) has a problem that streak defects are likely to occur on the surface of the extruded material.

In addition, if the bearing portion 5 in which the bearing length changes in a complicated manner is to be formed in the die 1, there is a problem in that it takes time and labor to process the die hole 3 and the manufacturing cost of the die 1 increases. In particular, these issues are:
When the flow guide 9 as described above is installed, it becomes noticeable, which has been a big problem in performing continuous extrusion.

By the way, Japanese Patent Publication No. 31-4920 discloses that the flow rate of the extruded material in each portion of the die hole can be adjusted by adjusting the shape of the opening of the flow guide. If the flow velocity of the extruded material can be adjusted by the shape of the flow guide opening in this way, the switching of the bearing length as described above will be unnecessary or minimized, and the line defect on the extruded material surface can be prevented. In addition to being able to do it, it was expected that die hole processing would not be troublesome.

However, according to the publication, the shape of the flow guide opening is not necessarily an object of easy arithmetic treatment, but requires a die designer's appropriate judgment (the right column on page 3 of the publication). Actually, there is no choice but to adjust the shape of the flow guide opening by trial and error, and if the die designer does not have considerable knowledge and experience, carry out extrusion experiments using a flow guide with an appropriate opening. However, from the result of the extrusion, it was not possible to easily judge how much the opening should be widened and how much the opening should be narrowed. Moreover, even if the die designer is an expert,
There is also a problem that it takes a lot of trouble if the experiment is repeated by repeatedly forming openings having a complicated shape in the flow guide.

Therefore, an object of the present invention is to provide a flow guide in which the shape of the opening can be easily determined and the flow velocity of the metal material inside the die hole can be optimized by the opening.

[0010]

In order to achieve the above-mentioned object, the present invention has an opening portion whose shape is determined according to the shape of a die hole formed in a die, and is installed on the front side of the die. In the flow guide for extrusion that adjusts the inflow ratio of the metal material to each part of the die hole by the width of the opening, the opening of the opening corresponding to the thickness w _i of the die hole. The width C _i is determined according to the following Equation 2.

[0011]

[Equation 2]

Where w ₀ is the reference thickness of the die hole, w _i is the equivalent thickness at a predetermined position of the die hole, C ₀ is the reference opening width of the flow guide opening, a 1 is the minimum thickness of the die hole,
Y _i is a delay coefficient depending on the distance from the die center.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the wall thickness of the die hole is the distance between the wall surfaces forming the die hole at the place where the die hole is flat. Among them, the reference wall thickness w ₀ is
It is a value that can be set arbitrarily within a range that can be actually extruded, and is usually the thickness of the die hole near the center of the die, but it may be an average value of the thickness of each portion of the die hole or the like. On the other hand, the above-mentioned equivalent wall thickness w _i is a value calculated based on the actual measurement value, and is the distance between the wall surfaces forming the die hole as described above at the flat portion of the die hole, but In the portions, bent portions, intersecting portions, etc., the wall thickness of each portion is converted into the wall thickness corresponding to the flat plate portion according to the flowability of the extruded material.

To give a concrete example, as shown in FIG. 1, the die hole 10 is formed into a flat plate portion 11, 12, 13, and 14, end portions 15, 16, and 17, a bent portion 18, and an intersecting portion 19. Split into and. The dividing position is the end 1 as shown by the alternate long and short dash line in the figure.
It is determined according to the wall thicknesses of 5, 16, 17, the bent portion 18, and the intersecting portion 19. Then, the equivalent thickness w _i of each portion is obtained by the following equation.

[0015]

(Equation 3)

For example, if the end portion 15 is as follows,
It is converted to be equivalent to 2/3 of the wall thickness of the flat plate portion 11.

[0017]

(Equation 4)

For the end portions 16, 17, the bent portion 18, and the intersecting portion 19, the equivalent wall thickness w _i is calculated in the same manner by the above-mentioned mathematical expression 3. The equivalent thickness w _i of the flat plate portions 11 to 14 can be calculated by the above mathematical expression 3, but in the case of the flat plate portion, the equivalent thickness w _i is the so-called thickness itself.

In the present invention, the opening width of the flow guide opening is the distance between the contour line of the die hole and the contour line of the flow guide opening surrounding the die hole. It is not the distance between the wall surfaces. Among them,
The reference opening width C ₀ is an opening width of the flow guide opening corresponding to the position of the reference thickness w ₀ , and is a value which may be arbitrarily set within a range in which the extrusion can be actually performed. Since the reference opening width C ₀ serves as a reference for adjusting the increase or decrease of the opening width C _i at other locations, a relatively small value may be used if the location having the reference wall thickness w _{0 is} a location where the flow velocity is relatively high. However, it is desirable to set a comparatively large value in the place where it becomes late.

The minimum wall thickness a1 is a value calculated based on an actual measurement value. As the thickness of the die hole decreases, the extrusion speed on the outflow side tends to decrease as the thickness decreases.However, the relationship between the two can be measured in advance, and the minimum thickness that can be theoretically extruded should be determined from this relationship. Can be. A method for obtaining the minimum wall thickness a1 will be described later in detail with reference to specific examples.

The delay coefficient Y _i is a value calculated based on the actual measurement value. Flow rate of metal material (extrusion speed)
Tends to be faster at the die center (the center of the die), and this tendency can be measured in advance as the ratio of the extrusion speed to the extrusion speed at the die center. Let Y _i . The method of obtaining the delay coefficient Y _i will also be described later in detail with reference to specific examples.

According to the flow guide for extrusion according to claim 1, the reference wall thickness w of the die hole in the equation (2) is used.
₀ , the reference opening width C ₀ of the flow guide opening, the minimum wall thickness a1 of the die hole, and the delay coefficient Y _i are selected after arbitrarily selecting the metal material, the extrusion temperature, and the extrusion speed on the outflow side as processing conditions. Then, since it can be determined by performing a simple preliminary experiment, after that, according to the above mathematical formula 2, the setting is made for the location of the wall thickness w _i of the die hole according to the equivalent wall thickness w _i at the predetermined position of the die hole The opening width C _i of the flow guide opening to be formed can be calculated.

Therefore, the shape of the desired opening portion of the flow guide can be easily determined based on the above formula 2 regardless of the shape of the die hole by performing a simple preliminary experiment in advance. be able to. Therefore, the shape of the opening of the flow guide does not need to be adjusted by trial and error, which is labor-free, and even an unskilled person can design the flow guide opening.

In particular, the calculated opening width C _i is an optimum value calculated by the above-mentioned formula 2, and is larger than the reference opening width C ₀ at a portion where the equivalent wall thickness w _i is smaller than the reference wall thickness w _0. On the other hand, at a location where the equivalent wall thickness w _i is larger than the reference wall thickness w _0, it is smaller than the reference opening width C ₀ . As a result, the inflow of the metal material is suppressed where the flow velocity inside the die hole tends to increase, and the inflow of the metal material is promoted where the flow velocity inside the die hole tends to decrease.

Therefore, the switching of the bearing length of the die hole can be eliminated or minimized, the line defect on the surface of the extruded material can be prevented, and the die hole processing is not troublesome. Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention.

[0026]

EXAMPLE An example of a flow guide to which the present invention is applied will be described below with reference to the drawings in order to further clarify the embodiment of the present invention. Note that the embodiments described below are merely examples of the embodiments of the present invention, and the embodiments of the present invention are not limited to the specific materials and shapes illustrated below.

As shown in FIG. 2, the extrusion device 20 includes a container 21, a stem 22, a flow guide 23, a die 24,
Container 21 equipped with backer 25, bolster 26, etc.
The billet 31 housed inside is pressed by the stem 22 and the long extruded material 32 is extruded from the die 24.

Next, the procedure for setting the shape of the flow guide opening will be described. First, in order to investigate the influence of the wall thickness of the die hole and the opening width of the flow guide opening on the extrusion flow rate, as shown in FIG. 3, a two-hole flat plate die and a flow guide matching it were prepared.

The size of each part of the die hole is the die hole width M1 =
15 mm, die hole spacing M2 = 25 mm, reference die hole wall thickness w ₀ = 2 mm, experimental die hole wall thickness w _i =
Four pieces of 1.9 mm, 2.4 mm, 3 mm, and 3.7 mm were prepared. In each case, the bearing length of the die hole is 2 mm.

The size of the flow guide openings is a standard opening width C ₀ = 7 mm, and 16 pieces of experimental opening widths C _i = 3 mm, 5 mm, 7 mm, and 9 mm are prepared for the above four dies. did. A flow guide was combined with these four dies to perform extrusion a total of 16 times, and the extrusion speed V ₀ from the reference die hole and the extrusion speed V _i from the experimental die hole were measured on the outflow side. Other extrusion conditions are: container diameter: 100 mm, billet material: 6
063, extrusion temperature: 450 ° C., extrusion speed on outflow side 10 m
/ Min.

FIG. 4 is a graph showing the measurement results in which the horizontal axis shows the wall thickness w _i and the vertical axis shows the extrusion speed ratio V _i / V ₀ . The horizontal axis represents the opening width C _i and the vertical axis represents the extrusion speed ratio V.
_A graph of _i / V ₀ is shown in FIG.
As is clear from the graphs of FIGS. 4 and 5, the die hole wall thickness w _i , the flow guide opening portion opening width C _i , and the extrusion speed ratio V
A relationship that can be approximated by the following Expression 5 is recognized between _i / V ₀ .

[0032]

(Equation 5)

In the above mathematical expression 5, the constant a1 indicates the intersection of the straight line drawn in the graph of FIG. 4 and the horizontal axis, but this value is constant regardless of the opening width C _i of the flow guide opening. Yes, in this case a1 = 0.7. This constant a1
= 0.7 is a point at which the extrusion speed V _i = 0 in theory, and means that the extrusion is possible when the wall thickness w _i is larger than this, so it can be considered as the minimum wall thickness a1. it can. Further, since the graph of FIG. 5 passes through the origin, it can be seen that the extrusion speed ratio V _i / V ₀ can also be increased n times by increasing the opening width C _i of the flow guide opening by n times.

By the way, according to the above equation 5, the wall thickness w
_The extrusion speed ratio V _i / V _{0 at} the point of _{0 and} the point of wall thickness w _i
It can be seen that the following formula 6 should be established in order to make the above constant.

[0035]

(Equation 6)

When this is arranged, the following formula 7 is obtained.

[0037]

(Equation 7)

In the above measurement result, the reference opening width C ₀ =
7 mm, reference wall thickness w ₀ = 2 mm, minimum wall thickness a1 = 0.7
Therefore, after that, when the wall thickness w _i of the die hole is determined, the opening width C _{i at} which the extrusion speed is the same as that of the portion having the reference wall thickness w ₀ is calculated.

Now, in the two-hole flat plate die shown in FIG.
The location with the wall thickness w _{0 and} the location with the wall thickness w _i are at the same distance from the die center, but normally, the distances from the die center of each part of the die hole are not uniform, and the distance from this die center is also It is known to affect the extrusion rate. Therefore, next, in order to investigate the influence of the distance from the die center on the extrusion flow rate, as shown in FIG. 6, a perforated round hole die and a flow guide matching it were prepared.

The size of each part of the die hole is 5 mm for each die hole diameter.
mm, distance of each die hole from the die center r ₀ = 0 m
m, r ₁ = 15 mm, r ₂ = 20 mm, r ₃ = 30 m
m, the bearing length of the die hole is 2 mm, and the die radius R = 50 mm. The opening width C _i of the flow guide opening is 3 mm.

Extrusion is carried out by combining this die and a flow guide, and the extrusion speed V ₀ from the die hole of the die center and the extrusion speed V _i from the die hole at a distance r _i from the die center are measured on the outflow side. did. Other extrusion conditions are: container diameter: 100 mm, billet material:
6063, extrusion temperature: 450 ° C., extrusion rate on outflow side 10
m / min.

FIG. 7 is a graph showing the measurement results with the horizontal axis representing the ratio r _i / R of the distance r _i to the die radius R and the vertical axis representing the extrusion speed ratio V _i / V ₀ . As is apparent from this graph, the distance ratio r _i / R and the extrusion speed ratio V
_{Between i} / V ₀ and the distance from the die center, the extrusion speed V _i tends to decrease, and this tendency can be approximated by a curve as shown in the figure, and is represented by the following formula 8, for example. You can

[0043]

(Equation 8)

In the above formula 8, in the case of the curve shown in FIG. 7, b1 = 0.7 and b2 = 2.0. Therefore, the delay coefficient Y _i at the distance r _i from the die center
Can be calculated based on Equation 8 above. In addition,
The graph shown in FIG. 7 does not necessarily have to be mathematical expression. For example, the delay coefficient Y _i can be obtained by directly reading the value from the graph.

Such a delay due to the distance from the die center can be eliminated by increasing the opening width C _i of the flow guide opening. As shown in FIG. 5, if the opening width C _i of the flow guide opening is multiplied by n, the extrusion speed V _i is also increased by n times, so that, for example, a portion where the delay coefficient becomes 0.5, that is, the extrusion speed. At the location where the value of H is reduced to half, the opening width C _i of the flow guide opening may be doubled.

That is, if the delay of the extrusion speed due to the distance r _i from the die center is also taken into consideration, the above equation 7 is given by the following equation 9
Can be rewritten in

[0047]

[Equation 9]

Next, based on the above equation 9, FIG.
The flow guide opening was designed for the die hole 51 as shown in FIG. As shown in FIG. 8A, the die hole 51 has a substantially U-shaped cross-sectional shape, and the size of each part is T1.
= 4 mm, T2 = 2.8 mm, T3 = 2 mm, T4 = 1
17 mm and T5 = 55 mm. The reference points P1 to P10 for determining the shape of the flow guide opening are divided into the end portion, the flat plate portion and the bent portion at the points S1 to S4 of the chain double-dashed line in the figure, and then the die center. It is selected appropriately considering the distance from.

The equivalent wall thickness w _{i at} the reference points P1 to P10, the distance r _i from the die center, and the delay coefficient Y _i are
It is as shown in Table 1 below. Further, the reference opening width C ₀ = 7 m
m, the reference wall thickness w ₀ = 2 mm, and the minimum wall thickness a1 = 0.7. By substituting these values into the above mathematical formula 9, the aperture width C _i shown in Table 1 below is calculated.

[0050]

[Table 1]

FIG. 8B shows the flow guide opening 53 determined based on the above calculation result. In the figure, the points indicated by the double-ended arrows in the figure are the reference points P shown in FIG.
The opening width C _i is calculated in correspondence with 1 to P10, and the points where the opening width C _i is largely switched are smoothly connected by curves. In addition, in such a place where the opening width C _i is largely switched, by setting a large number of the reference points,
Although the opening width C _i can be set more strictly, there is no problem in practical use as long as the reference points as illustrated are connected smoothly.

Next, the die having the die hole 51 shown in FIG. 8 and the flow guide having the opening 53 were mounted on the extrusion device 20 shown in FIG. 2 to perform extrusion. Extrusion conditions are: container diameter: 200 mm, billet material: 606
3, extrusion temperature: 480 ° C., extrusion speed on outflow side 25 m / m
in. Although the container diameter is different from that in the preliminary experiment, it is taken into consideration by substituting it in the variable R on the right side of the equation 9 when calculating the delay coefficient Y _i .
The extrusion temperature is 6063 which is a practical extrusion temperature (44
Within the range of 0 to 480 ° C., there is no change that affects the calculation result of the above-mentioned formula 9. Furthermore, regarding the extrusion speed, a practical extrusion speed of 6063 (10 to 30 m
Within the range of / minute), there is no change that affects the calculation result of Equation 9 above.

Then, in order to confirm the dimensions of the obtained extruded material, the length of a portion corresponding to the length T4 shown in FIG. 8A was measured. The result is shown in FIG. As is clear from FIG. 9, the extruded material satisfying the required dimensions could be stably extruded by 20 m or more. No streak defects were observed on the surface of the extruded material.

As described above, according to the flow guide having the opening portion 53 whose shape is determined based on the above-mentioned mathematical expression 9, it is not necessary to switch the bearing length of the die hole, and the line defect on the surface of the extruded material can be prevented. On top of that, it is easy to process the die holes. Further, since the opening width is determined based on the mathematical formula, the shape of the opening can be easily determined only by performing a simple preliminary experiment in advance. Therefore, it is not necessary to adjust the shape of the opening of the flow guide by trial and error, and it is possible to design the flow guide opening without requiring any effort.

Although one embodiment of the present invention has been described above, with respect to the specific configuration of the present invention, other than the above embodiment, various embodiments within the scope not departing from the gist of the present invention can be adopted. You can For example, in the embodiments, the flow guide corresponding to a die hole having a U-shaped cross section is shown, but the present invention is applicable to die holes having various cross sectional shapes.

To give a specific example, for a die hole D1 as shown in FIG. 10A, for example, the flow guide opening having a shape as shown in FIG. F1 can be determined. Further, for the die hole D2 as shown in FIG.
The flow guide opening F2 having a shape as shown in FIG. 1 (b) can be determined. 10 and 11, the numbers shown in the figures are the dimensions of the die holes D1 and D2 and the flow guide openings F1 and F2.

Although the bearing length of the die hole can be made constant in the embodiment, the bearing length of the die hole is finely adjusted if it is judged by actual extrusion that more strict adjustment is necessary. You may. Even in this case, since the switching of the bearing length of the die hole can be minimized, it is possible to prevent streak defects on the surface of the extruded material as compared with the prior art.

[0058]

As described above, according to the flow guide of the present invention, the shape of the opening can be easily determined, and the flow rate of the metal material inside the die hole can be optimized by the opening. Therefore, it is not necessary to adjust the shape of the opening of the flow guide by trial and error, and it is possible to design the flow guide opening even by an unskilled person in addition to saving the labor. Further, the switching of the bearing length of the die hole becomes unnecessary or minimized, the streak defect on the surface of the extruded material can be prevented, and the dice hole processing is not troublesome.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a method of dividing a die hole.

FIG. 2 is a configuration diagram showing an outline of an extrusion apparatus of an example.

FIG. 3 is a front view of a two-hole flat plate die and a flow guide adapted thereto.

FIG. 4 is a graph showing the relationship between the wall thickness of the die hole and the extrusion speed ratio.

FIG. 5 is a graph showing the relationship between the opening width of the flow guide and the extrusion speed ratio.

FIG. 6 is a front view of a perforated round hole die and a flow guide adapted thereto.

FIG. 7 is a graph showing the relationship between the relative distance from the die center and the extrusion speed ratio with respect to the die radius.

8A and 8B show a die hole and a flow guide opening portion of an example, FIG. 8A is a front view of the die hole, and FIG. 8B is a front view of the die hole and the flow guide opening portion.

FIG. 9 is a graph showing the relationship between the extruded length and the measured dimension of an extruded material extruded using the die of the example.

FIG. 10 shows a die hole and a flow guide opening as another embodiment, (a) is a front view of the die hole, and (b).
FIG. 4 is a front view of a die hole and a flow guide opening.

FIG. 11 shows a die hole and a flow guide opening according to still another embodiment, (a) is a front view of the die hole,
(B) is a front view of a die hole and a flow guide opening.

FIG. 12 shows a conventional die and flow guide,
(A) is the front view, (b) is the sectional view on the AA line, (c)
FIG. 6 is a sectional view taken along line BB.

[Explanation of symbols]

20 ... Extrusion device, 21 ... Container, 22 ...
Stem, 23 ... Flow guide, 24 ... Dice,
25 ... backer, 26 ... bolster, 31 ...
-Billet, 32 ... Extruded material.

Front Page Continuation (72) Inventor Hidenori Ito 5-11-3 Shimbashi, Minato-ku, Tokyo Sumitomo Light Metal Industry Co., Ltd.

Claims (1)

[Claims] 1. A die having an opening whose shape is determined according to the shape of a die hole formed in the die, the opening being installed on the front side of the die, and the width of the opening widening the width of the opening to each portion of the die. In the flow guide for extrusion processing for adjusting the inflow ratio of the metal material, the opening width C _i of the opening corresponding to the location of the wall thickness w _i of the die hole is determined according to the following formula 1. A characteristic flow guide for extrusion processing. [Equation 1] [Where, w ₀ is the reference thickness of the die hole, w _i is the equivalent thickness at a predetermined position of the die hole, C ₀ is the reference opening width of the flow guide opening, a 1 is the minimum thickness of the die hole, and Y _i is Delay coefficient depending on the distance from the die center. ]