JP3088162B2 - Friction welding method between aluminum alloy and carbon steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for friction welding a dissimilar material joint of an aluminum alloy and carbon steel used as various strength members.

[0002]

2. Description of the Related Art When an aluminum alloy and carbon steel are joined by a so-called fusion joining method such as arc welding or electron beam welding, a brittle intermetallic compound of aluminum and iron is formed, so that joining is not possible. It is possible.

[0003] In this regard, the friction welding method is not a fusion welding method but basically belongs to a solid-phase welding method. Therefore, the friction welding method is a welding method in which an intermetallic compound is hardly generated as compared with the fusion welding method.

However, in the friction welding method,
At present, only a brittle joint is obtained with a combination of an aluminum alloy and carbon steel, and a joint strength equivalent to the aluminum alloy base material strength is not obtained at present.

[0005] The present invention has been made under such circumstances, and provides a joining method capable of obtaining a joint strength close to that of an aluminum alloy base material when producing a joint between an aluminum alloy and carbon steel. The purpose is to do so.

[0006]

Means for Solving the Problems In order to solve the above problems, the present inventor focused on a friction welding method which is considered to be relatively advantageous for preventing the formation of a compound at a bonding interface, and as a result of intensive studies, The present invention has been completed by finding out that it is possible by regulating the material of the joining member and the specific pressure welding conditions in an organically related manner.

That is, the present invention relates to a method of friction welding an aluminum alloy and carbon steel by combining an aluminum alloy having a Mg content of 3.5% or less with a carbon steel having a C content of 0.6% or less. The actual friction time T ₁ (sec) from the contact of these two members to the stop of the relative rotation is expressed by the following equation: 0.1 ≦ T ₁ ≦ − (4/5) X + 1.2 (X: carbon And a method of friction welding between an aluminum alloy and carbon steel characterized by satisfying the C content of steel (%)) and joining at an upset pressure of 12 to 30 kgf / mm ² under friction welding conditions. Is what you do.

Hereinafter, the present invention will be described in more detail.

[0009]

[Action]

Important matters in friction welding an aluminum alloy and carbon steel are prevention of compound formation at a joining interface, elimination of oxides and the like, and application of heat and pressure necessary for joining.

If the Mg content in the aluminum alloy exceeds 3.5%, oxide formation at the joint interface during welding becomes excessive and cannot be eliminated only by controlling the welding conditions, and a high-strength joint can be obtained. difficult. Therefore, aluminum alloys whose Mg content is 3.5% or less are targeted.

Further, the C content in carbon steel is 0.6%.
If it exceeds, the friction torque generated at the time of upset becomes too small, and it becomes difficult to remove the compound and to make a strong metal bond. As a result, a high-strength joint cannot be obtained, so that the C content is 0.6% or less. For carbon steel.

However, the higher the C content in the carbon steel, the lower the friction torque generated during upset, so that it is difficult to remove the compound formed at the interface under the condition of a long friction time (> T ₁ ). Therefore, the appropriate friction time (T ₁ ) according to the C content in the above range in the carbon steel
Must be selected.

That is, it has been found that it is necessary to control the actual friction time (T ₁ ) within a range satisfying the following equation. T ₁ ≦ − (4/5) X + 1.2 (where X: C content (%) of carbon steel)

However, if the actual friction time (T ₁ ) is shorter than 0.1 sec, the heating required for friction becomes insufficient.
0.1 sec or more is required. Therefore, in the present invention, welding is performed with a substantial friction time (T ₁ ) satisfying the following equation. 0.1 ≦ T ₁ ≦ − (4/5) X + 1.2

Further, the upset pressure (P ₂ ) needs to be a certain value or more in order to secure metal bonding at the interface and to eliminate compounds due to friction torque and pressure generated during upset. It has been found that a pressure of at least 12 kgf / mm ² or more is required for the combination of an aluminum alloy and carbon steel targeted by the present invention. On the other hand, when the pressure exceeds 30 kgf / mm ² , it has been found that the aluminum alloy material buckles or opens in the radial direction, particularly when the pipe material is pressed, so that a good pressed portion cannot be obtained. Therefore, the appropriate upset pressure (P ₂ ) is set to 12 kgf / mm ² or more and 30 kgf / mm ² or less.

The factors of the pressing conditions include friction pressure (P ₁ ), upset time (T ₂ ), rotation speed (N) and brake timing, but these are not particularly limited. However, it is recommended to control within the following range.

First, if the friction pressure (P ₁ ) is too small, the heating of the interface becomes insufficient, and if it is too large, the heating becomes too large, which promotes the formation of a compound at the interface. Therefore, the appropriate range of the friction pressure (P ₁ ) is 2 kgf / mm ² or more and 102 kgf / mm ^2.
mm ² or less is desirable.

The upset time (T ₂ ) is the retention time after upset and does not directly affect the performance of the joint, but 3 seconds for joining with an aluminum alloy having high thermal conductivity.
There is no problem if the above is maintained.

There is no problem with the rotational speed (N) as long as it is within the range of a general friction welding machine (1000 to 4000 rpm).

Regarding the brake timing, it is necessary that the rotation component still remains at the time when the upset pressure is applied (see FIG. 2). However, when the upset pressure is applied after the rotation is completely stopped, It should be noted that the torque at the time of upset becomes 0, and the exclusion of the compound at the interface becomes insufficient.

It is needless to say that the aluminum alloy and the carbon steel to be used in the present invention can appropriately contain other components as needed as long as the above components satisfy the predetermined contents.

Next, an embodiment of the present invention will be described.

[0024]

Embodiment 1

[Table 1] A5052, A505 having the chemical components (wt%) shown in
6. A6061 aluminum alloy pipe (40mmφ × 3mmt)
× 100mml) and a combination of carbon steel (S45C) machined to 40mmφ × 3mmt only at the press-contact part, using a brake-type friction press machine,

[Table 2] A friction welding test was performed under the conditions shown in FIG. FIG. 1 shows the shape of the test piece. After the pressure welding, a joint tensile test was performed after removing burrs. The relationship between the joint strength and the pressure welding conditions in each test is shown in FIGS.

As is clear from the figure, A5056 having a high Mg content cannot provide a strength of 20 kgf / mm ² or more, but each of the other combinations has a friction time (T ₁ ) having a certain value (0). .8Sec) below and, in the condition of 12 kgf / mm ² or more upset pressure _{(P 2), 25kgf / mm} 2 or more strength is obtained.

[0026]

Example 2 A60 having the chemical components (wt%) shown in Table 1
61 aluminum alloy pipes,

[Table 3] Carbon steel (S15C, S2
Using a combination of 5C, S45C, S55C, and SUP3), a friction welding test was performed under the conditions shown in Table 2 using a brake-type friction welding machine. The test piece used had the same shape as in Example 1. After the pressure welding, a joint tensile test was performed after removing burrs. 6 to 10 show the relationship between the joint strength and the pressure welding conditions in each test.

As is clear from the figure, S having a high C content is
In UP3, only a strength of about 20 kgf / mm ² was obtained, but in other combinations, the upset pressure of friction time (T ₁ ) was less than a certain value and more than 12 kgf / mm ² , respectively.
Under the condition of (P ₂ ), a strength of 25 kgf / mm ² or more was obtained.

FIG. 11 summarizes the conditions under which a strength of 25 kgf / mm ² or more is obtained in the combination of A6061 and carbon steel in relation to the C content of carbon steel and the actual friction time (T ₁ ). . As shown in the figure, a negative slope solid line (T ₁ = −
It can be seen that the above strength can be obtained in the range of (4/5) X + 1.2) or less.

[0029]

As described in detail above, according to the present invention,
In friction welding between aluminum alloy and carbon steel, the Mg content of the aluminum alloy and the C content of the carbon steel are regulated, and in particular, the real friction time is regulated in relation to the C content of the carbon steel, and the upset pressure is also regulated. As a result, joint strength close to that of the aluminum alloy base material can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing the shape and dimensions of a test piece.

FIG. 2 is a diagram illustrating the relationship among time, rotation speed, pressure, and offset in friction welding.

FIG. 3 shows the relationship between the joint strength (TS) and the actual friction time (T ₁ ) at various upset pressures (P ₂ ) in the joint of the aluminum alloy (A5052) and the carbon steel (S45C) obtained in Example 1. FIG.

FIG. 4 shows the relationship between the joint strength (TS) and the actual friction time (T ₁ ) at various upset pressures (P ₂ ) in the joint of the aluminum alloy (A5056) and carbon steel (S45C) obtained in Example 1. FIG.

FIG. 5 shows the relationship between the joint strength (TS) and the actual friction time (T ₁ ) at various upset pressures (P ₂ ) in the joint of the aluminum alloy (A6061) and the carbon steel (S45C) obtained in Example 1. FIG.

FIG. 6 shows the relationship between the joint strength (TS) and the actual friction time (T ₁ ) at various upset pressures (P ₂ ) in the joint of the aluminum alloy (A6061) and carbon steel (S15C) obtained in Example 2. FIG.

FIG. 7 shows the relationship between the joint strength (TS) and the actual friction time (T ₁ ) at various upset pressures (P ₂ ) in the joint between the aluminum alloy (A6061) and the carbon steel (S25C) obtained in Example 2. FIG.

FIG. 8 shows the relationship between the joint strength (TS) and the actual friction time (T ₁ ) at various upset pressures (P ₂ ) in the joint of the aluminum alloy (A6061) and the carbon steel (S45C) obtained in Example 2. FIG.

FIG. 9 shows the relationship between the joint strength (TS) and the actual friction time (T ₁ ) at various upset pressures (P ₂ ) in the joint between the aluminum alloy (A6061) and the carbon steel (S55C) obtained in Example 2. FIG.

FIG. 10 shows an aluminum alloy (A6061) obtained in Example 2.
Strength (TS) and effective friction time (T ₁ ) at various upset pressures (P ₂ ) for joints of steel and carbon steel (SUP3)
FIG.

FIG. 11 shows the joint obtained in the example, 25 kgf / m
FIG. 4 is a diagram showing conditions for obtaining a joint strength of m ² or more in relation to the C content of carbon steel and the actual friction time (T ₁ ).

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-231183 (JP, A) JP-A-1-215481 (JP, A) JP-A-60-206588 (JP, A) JP-A-63- 104790 (JP, A) JP-A-5-185253 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 20/12

Claims (1)

(57) [Claims] 1. A method of friction welding an aluminum alloy and carbon steel, wherein the Mg content is 3.5% by weight (hereinafter the same).
After combining the following aluminum alloy and carbon steel with a C content of 0.6% or less, the actual friction time T ₁ (sec) from the contact of these two members to the stop of relative rotation is as follows: When the expression 0.1 ≦ T ₁ ≦ − (4/5) X + 1.2 (X: C content (%) of carbon steel) is satisfied and the upset pressure under friction welding conditions is 12 to 30 kgf / mm ² , A friction welding method between aluminum alloy and carbon steel characterized by joining under conditions.