JP3301825B2 - Overlay welding method of dissimilar materials to aluminum base material - 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 overlay welding of different materials to an aluminum base material to improve the wear resistance of the aluminum base material.

[0002]

2. Description of the Related Art As part of measures against global warming and CO ₂ , technologies for reducing the weight of vehicles and improving fuel efficiency of engines are required. With respect to vehicle weight reduction, the use of lightweight countermeasures such as aluminum and titanium has been studied. One of the technical bottlenecks in using these lightweight countermeasure materials is that they are inferior in wear resistance compared to conventional iron-based materials. For this reason, research and development is being carried out to improve the wear resistance of aluminum, a lightweight material.
As one of the methods, there is a method of modifying the local surface of aluminum or an aluminum alloy material (including a casting material) with another material.

As this method, several surface modifications by alloyed MIG welding using two wires, a main electrode wire (for example, an aluminum electrode wire) and a filler wire having abrasion resistance, have been proposed (Japanese Patent Laid-Open No. Hei. -117777 publication).

In this double wire welding method, for example, a filler wire is arranged, for example, after the main electrode wire in addition to the main electrode wire, and the filler wire is inserted into a molten pool formed by an arc of the main electrode wire to perform melting. In order to dissolve by inserting filler wire into the molten pool,
There is an advantage that the amount of welding at the time of welding is increased and the build-up welding speed is improved as compared with the single wire method.

[0005]

However, in the above-described double wire welding method, since the filler wire is inserted into the molten pool and melted, the melting point is lower than the temperature of the molten pool formed by the main electrode wire. The filler wire is limited to the material, and the amount of insertion may be naturally limited by the heat capacity of the molten pool.

[0006] For example, when MIG welding of aluminum is performed using only one main wire, an example of temperature measurement of the molten pool (aluminum alloy, thermocouple) is as shown in FIG. The temperature of the molten pool 11 at the site (position A in the illustrated example) is about 900 ° C., and it is not possible to build up a filler material having a melting point exceeding 900 ° C.

Therefore, the melting temperature of aluminum is 660 ° C.
(Pure Al) and the temperature at the filler insertion site of this molten pool is about 9
As a material that can be increased in hardness when melted between 00 ° C. and alloyed with aluminum, it has a higher melting point than aluminum. As a filler material meeting these conditions, strontium ((Sr) melting point 769)
° C) and cerium ((Ce) melting point 795 ° C).

Accordingly, the present invention has been made in view of such circumstances, and has as its object to dissimilar materials to an aluminum base material to which various kinds of wear-resistant materials can be added by overlay welding. The present invention is to provide an overlay welding method.

[0009]

In order to achieve the above object, the present invention provides a method for overlay welding of different materials to an aluminum base material, the method comprising: Place the filler wire of the characteristic material first,
A part of the surface of the aluminum-based base material is melted by an arc of MIG welding using the main wire as an electrode to form a molten pool, and then the filler wire is inserted into the molten pool and melted. The material is added by overlay welding.

Preferably, the main wire is made of an aluminum-based material, and the filler wire is made of a copper-based or titanium-based wear-resistant material. Further, it is preferable that the main wire is made of a copper-based or nickel-based material, and the filler wire is made of a titanium-based wear resistant material.

[0011]

When the molten pool is formed by the arc of MIG welding using the main wire as the electrode, the temperature of the molten pool in front of the main wire in the welding direction is higher. For example, according to the example of the temperature measurement of the molten pool at the time of MIG welding of aluminum, as shown in FIG. 4, the temperature of the molten pool 11 in front of the main wire 10 exceeds about 1600 ° C. almost similarly to the center of the wire 10. ,
It becomes lower as it goes backward from the wire 10.

Therefore, the filler wire is melted at a high temperature by disposing the filler wire in the molten pool by arranging the filler wire in the leading position and the filler wire in the succeeding position. In addition to strontium and cerium, a high melting point wear-resistant material such as copper or titanium can be used for the filler wire, and various kinds of wear-resistant materials can be added by overlay welding.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a nozzle of a torch of a double-wire welding machine, in which a main wire 2 and a filler wire 3 are provided.

The main wire 2 is supported by an electric conductor 4 through which a welding current flows, and is disposed downstream of the welding direction.
It slides in the conductor 4 and is sent out at a constant speed. A wire feeder (not shown) is configured so that the feed speed of the main wire 2 can be set arbitrarily.
Further, when a welding current flows through the conductor 4 of the main wire 2, an arc 6 is generated between the tip of the wire 2 and an aluminum-based base material (for example, an aluminum alloy) 5, and the heat causes the wire 2 to be welded. At the same time, a part of the surface of the base material 5 is melted and a molten pool 7 is formed.

The main wire 2 is made of an aluminum-based material (aluminum or an aluminum alloy (including an aluminum casting)), a copper-based material, a nickel-based material, or the like.

The filler wire 3 is supported by the conductor 8 and is disposed at the front of the welding direction. The filler wire 3 slides in the conductor 8 and is sent out at a constant speed, and is inserted in front of the molten pool 7. It has become. A wire feeder (not shown) is configured such that the feed speed of the filler wire 3 can be set arbitrarily. The filler wire 3 is a material different from the main wire 2 and has a wear-resistant property, for example, a copper-based material (copper or copper alloy), a titanium-based material, or the like.

Inside the nozzle 1, these wires 2, 3
, An inert gas such as Ar is supplied to the outside.

Now, in order to modify the surface of the aluminum base material, for example, the aluminum alloy 5, the main wire 2 is fed from the nozzle 1 of the torch at a constant speed and a predetermined welding is performed on the conductor 4 of the main wire 2. An electric current is applied to generate an arc 6 between the tip of the wire 2 and the surface of the aluminum alloy 5. Thereby, the wire 2 is welded to the aluminum alloy 5 by the heat of the arc 6 and a part of the aluminum alloy 5 is melted to form a molten pool 7. At this time, it is preferable to position the nozzle 1 so that the arc 6 has an advancing angle that is desirable as a shield for the molten pool 7.

Then, the filler wire 3 is fed from the nozzle 1 of the torch at a constant speed and inserted into the molten pool 7 in the front in the welding direction. As a result, the filler wire 3 is melted, and the high melting point wear-resistant material (filler wire 3) is added to the aluminum alloy (base material) 5 by overlay welding.

As described above, by disposing the filler wire 3 in the molten pool 7 by disposing the filler wire 3 in the molten pool 7 by disposing the filler wire 3 in the lead, the filler wire 3 is melted at a high temperature. For example, a wear-resistant material that is a different material having a high melting point such as copper (melting point of pure copper is 1085 ° C.) or titanium (melting point of pure titanium is 1725 ° C.) can be used for the filler wire 3. That is, the main wire 2
Since the weld pool 7 is formed by the MIG welding arc 6 having the electrode as an electrode, the temperature of the weld pool 7 in front of the main wire 2 in the welding direction increases. The temperature of the molten pool 7 is determined by the welding conditions of the main wire 2. For example, when MIG welding of aluminum is performed only with the main wire, an example of temperature measurement of the molten pool (aluminum alloy, thermocouple) is shown in FIG. As a result, the temperature of the molten pool 11 in front of the main wire 10 exceeds about 1600 ° C. in almost the same manner as the central portion of the wire.
Therefore, as shown in FIG. 1, by inserting the filler wire 3 in front of the molten pool 7, even a material having a melting temperature exceeding 900 ° C. can be used as a material of the filler wire 3. Thereby, a high melting point wear-resistant material such as copper or titanium can be used as the material of the filler wire 3, and various kinds of wear-resistant materials can be added by overlay welding. Thereby, the filler wire 3
Alloying with the composition of the main wire 2 and the wear resistance of the surface of the aluminum alloy (base material) 5 can be improved.

Further, since the temperature of the molten pool 7 into which the filler wire 3 is inserted is as high as about 1600 ° C. or more, the melting amount of the wire 3 can be increased. This is because the amount of the wire 3 that can be inserted as the filler wire 3 must take into account the decrease in the temperature of the molten pool 7 due to the filler wire 3 and the temperature of the molten pool 7 is high. This allows the build-up welding of the wear resistant material at a concentration of about 1/3 or more.

Furthermore, since the filler wire 3 is inserted into the molten pool 7 to dissolve it, the temperature of the molten pool 7 is reduced as compared with the case where the wire 3 is not inserted. Risk is reduced.

Next, a specific example of the present invention will be described.

Using the above-described double-wire welding machine, the state of the build-up of the Al-Cu alloy on the aluminum alloy was examined.

The base material is an aluminum alloy casting AC2B (component; Si: 5.0 to 7.0) which is often used for engine parts.
%, Cu: 2.0 to 4.0%, Fe: 1.0% or less, Mn:
0.5m or less, remaining Al) 20m with 5R groove
A test piece having a thickness of m was prepared and used by casting. Welding materials include
Aluminum material A1070 of the same kind as the base material as the main wire
(Components: Si: 0.20%, Cu: 0.04%, Fe: 0.25%,
A wire of φ1.2 prepared with Mn: 0.03%, Al: ≧ 99.70%) is used as a filler wire as a copper alloy / arms bronze alloy component (Mn: 0.93%, Fe: 2.67).
%, Ni: 1.02%, Al: 7.60%, the remaining Cu) were used.

These wires were mounted on the above-mentioned double wire welding machine such that the main wire was followed by the filler wire, and the welding current (main wire), welding speed, and filler supply amount were shown in Table 1. Under the conditions shown, 100 mm bead-on-blade welding was performed on the groove of the test piece.

[0028]

[Table 1]

The test piece thus welded is checked for its appearance such as cracks, and then the hardness (Hv) of the weld metal, the structure observation, and copper (alloy component) are observed at the center section of the weld. The quantitative analysis of Cu) was examined. The quantitative analysis of this copper was measured by an energy dispersive analyzer (manufactured by Horiba, Ltd.) attached to a scanning electron microscope (SEM) at three locations above, inside, and below the welding beat. Calibration was performed.

As a result, FIG. 2 shows the relationship between the filler feed rate and the Cu content, and the relationship between the Cu content and the hardness of the deposited metal.
And FIG. 2 and 3, it can be seen that the dispersion of the Cu component is large both when the amount of the supplied filler is small and when the amount of the supplied filler is large. The cause of this component variation is that when the filler feed rate is small, the molten pool temperature is high and the alloy component sinks to the lower part of the bead due to the difference in specific gravity. It is conceivable that stirring is insufficient because the solidification is fast without rising.

Thus, in order to obtain a weld metal having a uniform composition, there is an appropriate range of the welding current, welding speed, and filler feed rate. According to the test results, welding current: 260 A, welding speed: 300 mm / min Under the conditions of a filler feed rate of 23 to 38 g / min, a bead having a uniform composition having a Cu content of 20 to 36% can be obtained. At the same time, as can be seen from FIG. 3, the hardness is almost proportional to the Cu content, and a hardness of Hv 150 to 250 can be obtained in the above condition range.

Therefore, it has been confirmed that by disposing the filler wire in front of the main wire and inserting the filler wire into the molten pool, it is possible to perform alloying welding using aluminum and copper having different melting points. Further, it was found that by setting appropriate conditions, the components of the deposited metal can be freely set in a wide range of the Cu content of 20 to 36%.
Further, since the hardness of the deposited metal increases in proportion to the Cu content, it is possible to freely set a modified layer according to the required hardness by arbitrarily changing the filler supply amount.

[0033]

In summary, according to the present invention, there is an excellent effect that various kinds of wear-resistant materials can be added to the surface of the aluminum base material by overlay welding.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a nozzle of a torch of a double wire welding machine for carrying out a method of the present invention.

FIG. 2 is a diagram showing a relationship between a filler supply amount and a Cu content.

FIG. 3 is a diagram showing the relationship between the Cu content and the hardness of the deposited metal.

4A is a diagram showing a relationship between a distance and a temperature when MIG welding is performed using only one main wire, and FIG. 4B is a cross-sectional view thereof.

[Explanation of symbols]

 2 Main wire 3 Filler wire 5 Base metal 6 Arc 7 Weld pool

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yuji Nakahara 4-7-17 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Within Kyodo Oxygen Co., Ltd. (72) Inventor Hideki Miyauchi 1850 Minato, Wakayama City, Wakayama Prefecture Kyodo Oxygen Co., Ltd. Examiner Masato Kato (56) References JP-A-64-62279 (JP, A) JP-A-54-50443 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 9/04

Claims (3)

(57) [Claims] 1. A main wire is disposed downstream, and a filler wire of a wear-resistant material having a higher melting point than the main wire is disposed in advance, and the surface of the aluminum base material is formed by MIG welding arc using the main wire as an electrode. To form a molten pool by melting a part of the aluminum base material, wherein the filler wire is inserted into the molten pool and melted, and a high melting point wear-resistant material is added by overlay welding to an aluminum base material. Overlay welding method of different materials. 2. The method according to claim 1, wherein the main wire is made of an aluminum-based material, and the filler wire is made of a copper-based or titanium-based wear-resistant material. . 3. The method according to claim 1, wherein the main wire is made of a copper-based or nickel-based material, and the filler wire is made of a titanium-based wear-resistant material. .