JP2002249860A - Method for controlling structure of aluminum or aluminum alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling the structure of aluminum or aluminum alloy. SOLUTION: A tool rotating at high speed is brought into contact with the surface of am aluminum or aluminum-alloy member to combine the heat treatment effect of the frictional heat between the tool and the member surface on the tool with the mechanical stirring effect of the tool on the member, by which the structure of the aluminum or aluminum alloy can be controlled. In this method for controlling the structure of the aluminum or aluminum alloy, the number of revolutions of the tool is changed and/or the area of the part where the tool and the member come into contact with each other is arbitrarily changed, by which the amount of the generated frictional heat can be controlled and the heat treatment temperature of the member can be changed into an arbitrary value and, as the result, the grain size and structure of the member can be controlled to arbitrary size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for controlling the structure of aluminum and aluminum alloys,
More specifically, a new aluminum and aluminum alloy structure capable of flexibly adapting to product shapes, high productivity, not requiring large equipment, saving energy, and controlling the grain size of aluminum and aluminum alloy over a wide range. It relates to a control method. INDUSTRIAL APPLICABILITY The present invention is useful as a method that enables very easy and low-cost control of strength and hardness by controlling the structure of aluminum and aluminum alloys.

[0002]

2. Description of the Related Art Conventionally, aluminum and aluminum alloys have high specific strength, and therefore, their application to various structural members has been studied and implemented in various fields.

[0003] Aluminum and aluminum alloy machines
Properties are strongly influenced by the crystal structure.
Have been. In particular, the strength and hardness are affected by the crystal grain size of the structure.
In general, the smaller the crystal grain size, the lower the room temperature
Research shows that it is high strength and high hardness
[Hall-Petch equation, σ = σ₀ +
kd^-1/2, Where σ is the deformation stress, σ₀ And k are materials
And d is the crystal grain size].

As a method of controlling the crystal grain size, it is known that the diameter can be controlled from several tens μm to several mm depending on the cooling rate during casting. But,
In order to improve mechanical properties such as strength, several μm or less,
There is a need for a method of controlling the grain size structure in a finer range.

In order to control the crystal grain size on the order of several μm, it has been conventionally performed to add a trace amount of an additional element to an aluminum alloy as a base material. However, the use of other elements easily does not only reduce costs but also complicates the process of recycling and reusing components.
It is not good.

[0006] For these reasons, in recent years, a method of giving a strong plastic strain to a material to cause a dynamic structural change in the material, and utilizing this to refine a crystal grain has been studied. For example, according to the ECAP method in which a material is repeatedly extruded to give a strong strain, the crystal grain size is about 1 μm.
It has been clarified that the material can be miniaturized, and it is known that the material strength is also dramatically improved.

However, the extrusion method such as the ECAP method has a limitation in the extrusion shape, so that it cannot flexibly cope with the shape of the product. That it becomes necessary, in general, an electric furnace is required for heating, and in general, one product is repeatedly extruded several to several tens of times, so that productivity is poor and a large amount of energy is required,
Is mentioned as a problem.

[0008] In view of the above, there is a strong need in the art to develop a new method for controlling the structure of aluminum or aluminum alloy that can flexibly respond to product shapes, has good productivity, does not require large equipment, and is energy-saving. It has been sought.

[0009]

DISCLOSURE OF THE INVENTION In view of the above prior art, the present invention has been made as a result of intensive studies with the aim of developing a new method for controlling the structure of aluminum and aluminum alloys. The object of the present invention is to provide a large facility capable of flexibly responding to product shapes for aluminum and aluminum alloys, for which a great demand is expected as a structural material, with good productivity. It is an object of the present invention to provide a new organization control method which does not require a computer and is aimed at energy saving. That is, an object of the present invention is to provide a new method for controlling the structure of aluminum and aluminum alloy, which can control the crystal grain size structure of aluminum and aluminum alloy over a wide range.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of contacting a tool rotating at a high speed with the surface of an aluminum or aluminum alloy member, and performing a heat treatment of the member by frictional heat between the tool and the member surface; A method for controlling the structure of aluminum or an aluminum alloy in combination with the mechanical stirring effect of a member by a tool, wherein the number of rotations of the tool is changed, and / or the area of a portion where the tool and the member come into contact is arbitrarily set. By changing the amount of frictional heat generated to change the heat treatment temperature of the member to an arbitrary value, thereby controlling the grain size structure of the member to an arbitrary size. A method for controlling the structure of an aluminum alloy. Further, the present invention, in the above method, by changing the diameter of the portion of the rotary tool, which generates frictional heat in contact with the member, by arbitrarily changing the area of the portion where the tool and the member contact,
By setting the rotation axis of the rotating tool at an angle in advance with respect to the normal direction of the surface of the member to be brought into contact in advance, the angle between the part contacting the member of the rotating tool and the surface of the member is set to 0 degree or more and 10 degrees or less, Further, it is a preferred embodiment that the area of the portion where the tool and the member come into contact is arbitrarily changed by changing the distance between the rotating tool and the surface of the member.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, in order to clarify the present invention more specifically, a specific configuration of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a process of controlling the structure of an aluminum plate 4 of an aluminum member using a rotary tool. The rotary tool 1 generates frictional heat by rubbing the surface of the aluminum member with the tool bottom surface 1a that rubs the aluminum plate. Simultaneously, the pin 1b at the tip is inserted into the inside of the member and mechanical agitation is applied to give a dynamic structural change to the member. Reference numeral 2 denotes a stirring section, and 3 denotes a friction mark. By moving the rotary tool 1 along the member surface,
The processing can be performed over a wide range to control the structure of the member.

The present invention reduces the amount of frictional heat generated by changing the number of revolutions of the rotary tool 1 and changing the contact area between the tool bottom surface portion 1a that rubs the aluminum plate and the member. The heat treatment temperature of the aluminum plate of the aluminum member is controlled by changing the temperature.

In particular, in the present invention, the tool bottom portion 1a
The contact area between the bottom surface of the tool and the member is changed by changing the diameter of the tool and the positional relationship between the bottom surface of the tool and the member. Preferably, the diameter of the part of the tool that generates frictional heat by contacting the member is 7 mm.
２０20 mm, but is not limited to these.

FIG. 2 shows a step of changing the contact area between the tool bottom surface (shoulder portion) and the aluminum member by changing the distance between the tool bottom surface 1a and the aluminum member surface. The optimal distance between the tool bottom and the aluminum plate surface is determined by the diameter of the tool bottom,
A range of approximately 0 to 0.3 mm is desirable. If it is larger than that, the contact area becomes small, so that frictional heat sufficient to sufficiently soften the aluminum plate cannot be obtained. Defects that adversely affect mechanical properties, such as vacancies, can increase.
The rotation axis of the rotary tool 1 is installed to be inclined backward with respect to the traveling direction of the tool. The inclination angle is 0 degree or more and 10 degrees or less,
Most preferably, 3 to 5 degrees is desirable, and if less than 3 degrees, it may be difficult to finely control the increase or decrease in the contact area between the bottom surface of the tool and the surface of the aluminum member,
Conversely, if it is larger than that, the tool must be inserted deeper into the aluminum member when increasing the contact area, and as a result, there is a possibility that a problem arises in that the depression formed on the surface of the aluminum member increases. In FIG. 2, 3
Is the surface position of the aluminum plate when the bottom surface of the tool and the surface of the aluminum plate are most in contact with each other (contact area; large; the positional relationship between the tool and aluminum at this time is defined as position A);
4 is the aluminum plate surface position when the tool bottom surface is slightly separated from the aluminum plate surface (contact area; medium, this case is defined as position B). 5 is aluminum when the tool bottom surface and the aluminum plate surface are separated most. Plate surface position (contact area;
Small, this case is defined as position C).

[0016]

EXAMPLES As examples, examples of the structure control according to the present invention for rolled pure aluminum for industrial use are shown below, and the effects of the present invention will be clarified.

FIG. 3 shows that the rotation speed of the tool is 1540 rpm,
When the moving speed is constant at 0.5 mm / sec, the diameter of the tool bottom surface in contact with the aluminum member is changed from 7 to 10 mm, and at the same time, the positional relationship between the tool bottom surface and the aluminum member surface is changed in three stages. The temperature attained by the aluminum member processing section increased by frictional heat is shown.
The tool position A is a state in which the entire bottom surface of the tool is in contact with the aluminum member surface, and the tool position B is a tool position A.
In this state, the tool is raised 0.1 mm from the tool to reduce the contact area between the tool bottom surface and the aluminum member surface.
Is a state in which the tool is raised 0.2 mm from the tool position A and the contact area is most reduced.

FIG. 4 shows that the rotational speed of the tool is constant at 890 rpm, the moving speed is constant at 0.5 mm / sec, the diameter of the tool bottom contacting the aluminum member is changed from 7 to 10 mm, and at the same time, the tool bottom and the aluminum member surface are changed. 5 shows the ultimate temperature of the aluminum member processing section which has increased due to frictional heat when the positional relationship of the above is changed in three stages. The definitions of the tool positions A, B, and C are the same as in FIG.

Up to this point, the rise in temperature of the member due to frictional heat is controlled by changing the number of revolutions of the tool, the diameter of the bottom surface of the tool in contact with the aluminum member, and the distance between the bottom surface of the tool and the surface of the member. From 130 ° C to 470
It was found that the temperature can be arbitrarily changed up to ° C.

Table 1 shows the relationship between the ultimate temperature of industrial pure aluminum during processing and the structure obtained.
When the temperature of the processing section reaches 400 to 470 ° C., the crystal grain size increases to about 100 μm. This greatly exceeds the crystal grain size of the base material. When the temperature is 380-390 ° C., the crystal grain size is 50-80 μm, and the temperature is 270-390 μm.
When the temperature is 320 ° C., the size can be reduced to 20 to 40 μm, and when the temperature is 200 ° C. or less, the size can be reduced to 1 to several μm.

[0021]

[Table 1]

FIG. 5 shows an example of the hardness measurement results of industrial pure aluminum whose crystal grain size has been reduced according to the present invention.
The hardness of the processing section is 52 to 57 HV, and the hardness of the base material is 37 to 4
It can be seen that it is higher than 1 HV.

FIG. 6 shows a step of dynamically changing the contact area between the tool bottom surface and the member surface to produce a member having a different crystal grain size for each location. Thus, according to the present invention, only at the site where the member is needed,
It is possible to locally perform a treatment for increasing the strength and hardness, which is not only efficient but also contributes to cost reduction.

As described above, a typical embodiment of the present invention has been described in detail with respect to an example applied to industrial pure aluminum. However, the present invention should not be construed as being limited to such specific examples. And a known aluminum alloy represented by JIS A5083 and the like.

[0025]

As described above, according to the present invention, it is simpler than conventional extrusion and rolling, the degree of freedom of the shape of the member is large, and the crystal grain size is 1 μm depending on the processing conditions.
Can be arbitrarily controlled within a wide range from 1 to 100 μm.

Also, by dynamically changing the processing conditions,
It is possible to locally control the crystal grain size of the member,
Thus, it is possible to locally increase the strength and hardness of only the necessary parts of the member. In addition, after such a process, if necessary, a portion that has not been subjected to the strengthening and hardening processes can be easily cut,
Plastic working or the like can be performed.

Further, according to the present invention, the additive element is not added to the base aluminum alloy, an electric furnace for heating is not required, and special equipment such as a large press is not required. The strength and hardness of the aluminum and aluminum alloy can be controlled very easily and at low cost by controlling the structure of the aluminum alloy and the aluminum alloy.

As a result, it is expected that the application of aluminum and aluminum alloys to mechanical structures and the like will be promoted, and the industrial use thereof will be greatly expanded.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an apparatus capable of implementing a method for controlling the structure of aluminum and an aluminum alloy according to the present invention.

FIG. 2 is an explanatory diagram showing a positional relationship between a rotary tool according to the present invention and surfaces of aluminum and an aluminum alloy member on which structure control is performed.

FIG. 3 is a graph showing the relationship between the diameter of the tool bottom surface and the positional relationship between the tool and the surface of the industrial pure aluminum material when the number of rotations of the tool is 1540 rpm when the structure control is performed according to the present invention.
It is explanatory drawing which shows the influence which it has on the attainment temperature of the industrial pure aluminum material during a process.

FIG. 4 is a graph showing the relationship between the diameter of the tool bottom surface and the positional relationship between the tool and the surface of the industrial pure aluminum material when the rotational speed of the tool is 890 rpm when the structure control is performed according to the present invention. It is explanatory drawing which shows the influence which it has on the attainment temperature of an aluminum material.

FIG. 5 is an explanatory diagram showing an example of hardness distribution measurement of industrial pure aluminum having a refined crystal grain size according to the present invention.

FIG. 6 shows a method for controlling the structure of aluminum and an aluminum alloy according to the present invention, in which the height or the number of rotations of the rotating tool is dynamically changed, so that the crystal grain size at an arbitrary position of the aluminum member is changed to an arbitrary size. It is a schematic diagram which shows that control is possible.

[Explanation of symbols]

(Description of reference numerals in FIG. 1) 1 Rotary tool 1a Tool bottom portion for friction with aluminum plate 1b Pin 2 Stirrer 3 Friction mark 4 Aluminum plate (Description of reference symbols in FIG. 2) 1 Rotary tool 1a Tool bottom surface 1b Pin 2 Rotation axis 3 Aluminum plate surface position when tool bottom and aluminum plate surface are most in contact (contact area; large, position A) 4 Aluminum plate surface position when tool bottom and aluminum plate surface are slightly separated (contact area; Medium, position B) 5 Aluminum plate surface position when tool bottom and aluminum plate surface are farthest apart (contact area; small, position C) (Explanation of reference numerals in FIGS. 3 and 4) A Tool bottom and aluminum plate surface Aluminum plate surface position when contacted most (contact area; large) B Aluminum plate surface position when tool bottom and aluminum plate surface are slightly separated (contact area Aluminum plate surface position when the most away medium) C tool bottom and the surface of the aluminum plate (contact area; small)

Claims (3)

[Claims] An aluminum or aluminum alloy member is brought into contact with a tool which rotates at a high speed, and a heat treatment effect of the member due to frictional heat between the tool and the member surface and a mechanical stirring effect of the member by the tool are used in combination with the aluminum or aluminum alloy. A method for controlling the structure of an alloy, comprising controlling the amount of frictional heat generated by changing the number of revolutions of a tool and / or arbitrarily changing the area of a portion where the tool comes into contact with the member. A method of controlling the structure of aluminum or an aluminum alloy, wherein the heat treatment temperature is changed to an arbitrary value to control the crystal grain size structure of the member to an arbitrary size. 2. The method according to claim 1, wherein the area of the portion of the rotary tool that contacts the member and generates frictional heat is changed by changing the diameter of the portion of the rotary tool. 3. The method for controlling the structure of aluminum or an aluminum alloy according to item 1. 3. An angle between a portion of the rotating tool contacting the member and the surface of the member is set to 0 ° or more by installing the rotating shaft of the rotating tool at an angle with respect to the normal direction of the surface of the member to be contacted in advance. 2. The aluminum or aluminum alloy according to claim 1, wherein an area of a portion where the tool and the member come into contact is arbitrarily changed by making the angle equal to or less than 10 degrees and further changing a distance between the rotating tool and the member surface. 3. Organization control method.