JPH08257629A - Production of clad material by extruding method - Google Patents

Abstract

PURPOSE: To provide a producing method, by which the thickness of surface shell can easily be changed and the high quality can be kept. CONSTITUTION: A first billet 7 for surface shell and a second billet 8 for core part are charged into a container 2 in order in the extending direction, and a clad material composed of the surface shell and the core part is produced by extending the second billet 8 with a stem 5. At this time, the thickness of the surface shell is changed by changing the compressive force acted in the second billet 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for producing a clad material by an extrusion method.

[0002]

2. Description of the Related Art A clad material is a laminate of materials having different properties and is manufactured for the purpose of improving the functional characteristics of the member by laminating a bonding material, a corrosion resistant material, a vibration resistant material, etc. on the surface. . Various production methods have been put into practical use, and one of them is an extrusion method.

As a technique for producing a clad material by an extrusion method, for example, Japanese Patent Laid-Open No. 138017/1993 "Method for producing a solid clad material" has been disclosed. This technique uses a cylindrical core forming billet in which a protruding fitting protrusion is integrally formed at the center of the front end face, and a ring-shaped skin forming billet fitted in the fitting protrusion. In this method, extrusion is performed with a solid die whose rear end surface is formed into a concave conical surface, and the constituent metal is quantitatively moved to the forming hole by utilizing the inclination of the conical surface at the rear end of the die. Is a technique whereby the thickness of the epidermis can be made uniform in the longitudinal direction.

[0004]

However, since the above technique utilizes the inclination of the dice cone angle, it is easy to entangle the epidermis, and if the epidermis has a defect such as a flaw, a streak (streak) Defects will occur. Also,
In order to prevent this, it is necessary to remove the skin from the surface by a certain amount such as cutting. Therefore, the quality of the clad material is deteriorated or the cost is increased.
Further, in the above technique, the shape of the billet is complicated, and the degree of freedom of the shape is limited.

Further, the above technique is a technique for making the thickness of the epidermis uniform, and does not refer to a technique for changing the thickness of the epidermis. However, in recent years, it is necessary to change the clad ratio, which indicates the thickness ratio of the skin, if necessary, and this research needs to proceed. Therefore, an object of the present invention is to provide a technique capable of simplifying the shape of the billet and changing the cladding ratio.

[0006]

In order to solve the above problems, the present invention provides a method for manufacturing a clad material in which a compressive force is applied to two types of billets arranged in a container via a stem to extrude from a bearing. The first billet serving as the skin of the clad material is disposed on the die side in the container, and the second billet serving as the core portion is disposed so as to be connected to the first billet, and the clad is changed by changing the compressive force. It is characterized by changing the ratio.

The compressive force is the length of the bearing corresponding to the die hole, the choke angle corresponding to the inclination angle when the bearing has a tapered shape, the extrusion ratio calculated by the billet cross-sectional area / product cross-sectional area, and the extrusion speed. It is characterized by being set by at least one selected from

[0008]

1 (a) and 1 (b) are principle views of a method for producing a clad material by an extrusion method according to the present invention. An extrusion apparatus 1 for carrying out the method of the present invention comprises a container 2 and a bearing 3. And a plunger or stem 5. In (a), the container 2 is provided with a first skin
The billet 7 and the core second billet 8 are loaded in this order. In (b), the loaded billets 7 and 8 are pressed by the stem 5.

2 (a) to 2 (d) are manufacturing process diagrams of the clad material according to the present invention. As shown in (a), the first billet 7 is partially pushed by the stem 5 so that the bearing 3
It swells out from the front, and the front center of the second billet 8 gradually bulges forward by that amount. In (b), a part of the second billet 8 largely enters the center of the first billet 7. In the figure,
Arrows conceptually indicate the flow of metal.
(C) shows a steady state, in which the clad material 9 where the core of the second billet 8 is covered by the skin of the first billet 7 is extruded from the bearing 3. (D) shows a state in which the work further progresses and the remaining amounts of the first billet 7 and the second billet 8 have decreased. That is, the work can be continued until one of the billets 7 and 8 is exhausted.

The present inventors have confirmed by experiments that there is a marked difference between the conventional method and the method of the present invention, as will be described later. We decided to explain this difference theoretically based on the following hypothesis. 3 (a) and 3 (b) are views for theoretically explaining the method of the present invention, and the first billet 4 has a triangular cross section in the steady state of FIG. 2 (c). This cross section is called dead metal, and its shape is determined by the properties of the material.
Therefore, in FIG. 3A, the slope 4 a of the first billet 4 is
Is θ, the pushing force along the slope 4a is N, and the stem pushing force is P, the following relational expression holds. The inclination angle θ is a slippery angle determined by the material. N = P · cos θ

In FIG. 3B, it is assumed that a part of the first billet 7 is peeled off by the shearing force of the second billet 8, and the critical shear stress at that time is τ, and the force N causes the peeling along the slope 4a. When the cross-sectional area of the part to be filled is A, the following formula is established. The critical shear stress τ is a value determined by the composition of the material, temperature and the like. N = τ · A ... In the above equations and expressions, cos θ and τ are constant under the conditions. Further, the following formula is established from the formula and the formula. P · cos θ = τ · A ... A = (cos θ / τ) · P In the equation, (cos θ / τ) is constant, so P
By changing A, it is possible to change A, and by changing A, the thickness of the epidermis can be changed.
The above explanation is a hypothesis, and the experimental value described later is positive.

Based on the above hypothesis, a specific method of changing P was examined. FIGS. 4A to 4D are views showing a specific example of the method of the present invention and a comparative example, and FIG.
The bearing 3A at this time is a straight bearing, and its diameter is d and its length is l. (B) shows the first embodiment, in which the length of the bearing 3B is L which is sufficiently larger than that of the comparative example. If the extrusion speed is not changed because the resistance increases, the extrusion force P increases and, as a result, the skin thickness increases. (C) shows the second embodiment, in which the diameter of the bearing 3C is smaller than that of the comparative example by D
It is what If the extrusion speed is not changed because the resistance increases, the extrusion force P increases and, as a result, the skin thickness increases. Bearing 3 with constant container diameter
Since the diameter of C is changed, the extrusion ratio is changed in this case.

(D) shows a third embodiment, in which the bearing 3
D is a tapered tapered bearing, and the inclination angle thereof is called a choke angle, and the choke angle α is appropriately given. Although the choke angle of the comparative example is 0, when the choke angle α is given as shown in the figure, the bearing 3D has a tapered shape, so that the resistance increases, so if the extrusion speed is not changed, the extrusion force P increases, As a result, the epidermal thickness increases. In addition, in the structure of (a) as the fourth embodiment, the resistance increases as the moving speed of the stem increases, so that the pushing force P increases, and as a result, the thickness of the skin increases. In this case, the extrusion speed is changed.

[0014]

EXAMPLES Examples of the present invention will be described below. The bearing refers to a portion of the hole formed in the die where the material is actually formed. Further, as described above, the extrusion ratio is a value obtained by dividing the billet cross-sectional area by the product cross-sectional area. Figure 5
Is a graph according to the first embodiment of the present invention, in which the horizontal axis represents the bearing length and the vertical axis represents the cladding ratio (%). The clad ratio (%) is (skin thickness (mm) ÷ clad material radius (m
m)) × 100. First Example: As described in FIG. 4B, the bearing length was changed stepwise, and the clad ratio (%) at that time was examined. The test conditions are as shown in the table in the lower half of the figure. The first billet aluminum material for skin 6063 The second billet aluminum material for core 4032 Billet temperature 450 ° C Choke angle 0 ° Extrusion ratio 24 Extrusion speed 30m / min ( Stem speed) As is clear from the graph, the skin depth can be changed by changing the bearing length. However, the bearing length directly affects the molding of the material and increases the skin depth linearly. However, if the bearing length becomes too long, the contact friction becomes excessive, and this friction force may break the skin. Therefore, the bearing length is 15m
The upper limit is about m.

FIG. 6 is a graph according to the second embodiment of the present invention, in which the horizontal axis represents the extrusion ratio and the vertical axis represents the cladding ratio (%). Second Example: As described in FIG. 4C, the extrusion ratio was changed stepwise, and the cladding ratio (%) at that time was examined. The test conditions are as shown in the table in the lower half of the figure. First billet aluminum material for skin 6063 Second billet aluminum material for core 4032 Billet temperature 450 ° C Bearing length 5 mm Choke angle 0 ° Extrusion speed 400 mm / min (Clad material speed) As is clear from the graph, the skin depth can be changed by changing the extrusion ratio. However, when the extrusion ratio is increased, the bending of the mold, especially the die, is increased, which affects the dimensional accuracy of the product. Therefore, the upper limit of the extrusion ratio is 50 for large billets and 100 for small billets.

FIG. 7 is a graph according to the third embodiment of the present invention, where the horizontal axis is the choke angle and the vertical axis is the cladding ratio (%). Third Example: As described in FIG. 4D, the choke angle was changed stepwise, and the cladding ratio (%) at that time was examined. The conditions of the test are as shown in the table in the lower half of the figure, as follows: 1st billet aluminum material for skin 6063 2nd billet aluminum material for core 4032 Billet temperature 450 ° C Bearing length 3mm Extrusion ratio 24 Extrusion speed 30m / min ( Stem velocity) As is apparent from the graph, the skin depth can be changed by changing the choke angle. However, when the choke angle exceeds 0.5 °, the skin thickness does not become so thick. On the contrary, if it is less than 0.5 °, it is difficult to obtain machining accuracy, so if the bearing length is 10 to 15 °, the bearing length is 2-3 mm.
It is preferable that

FIG. 8 is a graph according to the fourth embodiment of the present invention, in which the horizontal axis represents the extrusion speed and the vertical axis represents the cladding ratio (%). Fourth Example: The extrusion rate was changed stepwise, and the clad ratio (%) at that time was investigated. The extrusion speed can be changed only by changing the moving speed of the stem. The test conditions are as shown in the table in the lower half of the figure. First billet aluminum material for skin 6063 Second billet aluminum material for core 4032 Choke angle 0 ° Billet temperature 450 ° Bearing length 5mm Extrusion ratio 24 From the graph As can be seen, varying the extrusion rate can change the skin depth. However, even if the extrusion speed is increased, the skin thickness is not so much increased. On the contrary, there is a possibility that the heat generated by the friction in the bearing becomes remarkable and the shape of the skin becomes bad. Therefore, the upper limit of the aluminum material 6063 is 60 m / min.

The skin depth may be changed by combining one or more of the above embodiments. Among them, the method of changing the bearing length of the first embodiment is more effective because both the productivity and the finishing accuracy can be controlled independently.
Desirably, alone or in combination with Example 1, other examples. Also, when the billet temperature is changed, the resistance force in the bearing changes, and the compression force changes accordingly.
Therefore, it is possible to change the billet ratio alone or in combination with the above factors.

[0019]

The present invention has the following effects due to the above configuration. According to a first aspect of the present invention, in a method for manufacturing a clad material in which a compressive force is applied to two types of billets arranged in a container via a stem to extrude the clad material from a bearing, the clad material has a skin on the die side in the container. Arrange billets,
The second billet, which is connected to the first billet and serves as the core, is arranged, and the clad ratio is changed by changing the compressive force. Therefore, the billet is specially processed. There is no need to apply it, and the production cost can be reduced. In addition, since the thickness of the epidermis is changed by changing the compressive force acting on the second billet, it is possible to easily meet various demands for the epidermis thickness.

According to a second aspect of the present invention, the compression force is calculated by the length of the bearing corresponding to the die hole, the choke angle corresponding to the inclination angle when the bearing has a tapered shape, and the billet cross-sectional area / product cross-sectional area. Since it is set by at least one selected from the ratio and the extrusion speed, the thickness of the skin can be easily changed, and the manufacturing can be performed extremely efficiently, which simplifies the manufacturing work and burdens the operator. Becomes lighter.

[Brief description of drawings]

FIG. 1 is a principle diagram of a method for manufacturing a clad material by an extrusion method according to the present invention.

FIG. 2 is a manufacturing process diagram of a clad material according to the present invention.

FIG. 3 is a diagram for theoretically explaining the method of the present invention.

FIG. 4 is a diagram showing a specific example of the method of the present invention and a comparative example.

FIG. 5 is a graph according to the first embodiment of the present invention.

FIG. 6 is a graph according to the second embodiment of the present invention.

FIG. 7 is a graph according to the third embodiment of the present invention.

FIG. 8 is a graph according to a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Clad material extrusion device, 2 ... Container, 3 ... Bearing, 4 ... Die, 5 ... Stem, 7 ... 1st billet for skin, 8 ... 2nd billet for core, 9 ... Clad material, P ... Compressive force .

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tadashi Kobayashi 1-10-1 Shin-Sayama, Sayama-shi, Saitama Prefecture Honda Engineering Co., Ltd. (72) Takeshi Akutsu 1-10-1 Shin-Sayama, Sayama-shi, Saitama Prefecture Within Da Engineering Co., Ltd.

Claims (2)

[Claims] 1. A method for manufacturing a clad material in which a compressive force is applied to two types of billets arranged in a container via a stem to extrude the clad material from a bearing. A billet is arranged, a second billet that is connected to the first billet and serves as a core is arranged, and the clad ratio is changed by changing the compression force. Production method. 2. The compression force is a length of a bearing corresponding to a die hole, a choke angle corresponding to an inclination angle when the bearing has a tapered shape, an extrusion ratio calculated by a billet cross-sectional area / product cross-sectional area, The method for producing a clad material by the extrusion method according to claim 1, characterized in that it is set by at least one selected from the extrusion rate.