JPH0751850A - Method for build-up welding of different material to aluminum base metal - Google Patents

Abstract

PURPOSE:To add many kinds of wear resistant materials to the surface of an aluminum base metal by build-up welding. CONSTITUTION:A main wire 2 is arranged succeedingly and a filler wire 3 consisting of a wear resistant characteristic material having the m.p. higher than the m.p. of them, main wire 2 is arranged precedently. The surface of the aluminum base metal 5 is partly melted by arcs 6 of MIG welding having the main wire 2 as its electrode to form a molten pool 7 and thereafter, the filler wire 3 is inserted into the molten pool 7 and is melted to add the high melting wear resistant material by build-up welding.

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 different kinds of materials to an aluminum base material for improving the wear resistance of the aluminum base material.

[0002]

2. Description of the Related Art As a part of measures against global warming and CO ₂ , there are demands for technologies such as weight reduction of vehicles and improvement of fuel efficiency of engines. Regarding the weight reduction of vehicles, the adoption of lightweight countermeasure materials such as aluminum and titanium is being considered. The technical bottleneck in using these lightweight materials is that they are inferior in wear resistance to conventional iron-based materials. For this reason, research and development has been conducted to improve the wear resistance of aluminum, which is a lightweight material.
As part of this, there is a method of modifying the local surface of aluminum or an aluminum alloy material (including cast material) with another material.

As this method, some surface modifications have been proposed by alloying MIG welding using two wires, a main electrode wire (for example, an aluminum electrode wire) and a filler wire having wear resistance. -117777 publication).

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

[0005]

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

For example, when MIG welding of aluminum is performed with only one main wire, an example of measuring the temperature of the molten pool (aluminum alloy, thermocouple) is as shown in FIG. 4, and filler insertion (following) is performed. The temperature of the molten pool 11 at the portion (position A in the illustrated example) becomes about 900 ° C., and it becomes impossible to build-up alloy the filler material having a melting point exceeding 900 ° C.

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

Therefore, the present invention has been made in view of such circumstances, and an object thereof is to dissimilar materials to an aluminum base material to which various kinds of wear resistant materials can be added by overlay welding. It is to provide a build-up welding method of.

[0009]

In order to achieve the above-mentioned object, a method for depositing different kinds of materials on an aluminum base material of the present invention is such that a main wire follows and a wear resistance having a melting point higher than that of the main wire. Place the filler wire of the characteristic material in advance,
A part of the surface of the aluminum 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 to melt the molten metal to obtain high melting point wear resistance. The material is added by build-up welding.

It is preferable that the main wire is made of an aluminum material and the filler wire is made of a copper or titanium 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 an electrode, the temperature of the molten pool at the front of the main wire in the welding direction is higher. For example, according to an example of measuring the temperature of the molten pool during 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., which is almost the same as the central portion of the wire 10. ,
It becomes lower as it goes backward from the wire 10.

Therefore, by arranging the main wire at the rear and the filler wire at the front and inserting the filler wire into the molten pool, the filler wire is melted at a high temperature, so that, for example, during MIG welding of aluminum. In addition to strontium and cerium, copper-based and titanium-based high melting point wear resistant materials can be used for the filler wire, and various 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. Inside the nozzle 1, 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 arranged in a backward direction of the welding direction.
It slides in the conductor 4 and is sent out at a constant speed. A wire feeding device (not shown) is configured so that the feeding speed of the main wire 2 can be arbitrarily set.
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 the aluminum-based base material (for example, aluminum alloy) 5, and the heat is applied to weld the wire 2. At the same time, a part of the surface of the base material 5 is melted to form a molten pool 7.

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

The filler wire 3 is supported by the conductor 8 and arranged in front of the welding direction. The filler wire 3 slides in the conductor 8 and is fed out at a constant speed so that it can be inserted in front of the molten pool 7. It has become. A wire feeding device (not shown) is configured so that the feeding speed of the filler wire 3 can be arbitrarily set. The filler wire 3 is made of a material different from that of the main wire 2 and having wear resistance characteristics, and is made of, for example, a copper-based material (copper or copper alloy) or a titanium-based material.

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

Now, in order to modify the surface of the aluminum base material, for example, the aluminum alloy 5, the main wire 2 is fed at a constant speed from the nozzle 1 of the torch, and the conductor 4 of the main wire 2 is welded in a predetermined manner. 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. As a result, 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 the 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 at a constant speed from the nozzle 1 of the torch and inserted into the front of the molten pool 7 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.

In this way, by disposing the main wire 2 behind and the filler wire 3 ahead and inserting the filler wire 3 into the molten pool 7, the filler wire 3 is melted at a high temperature, For example, a wear resistant material having a high melting point such as a copper-based material (melting point of pure copper: 1085 ° C.) or a titanium-based material (melting point of pure titanium: 1725 ° C.) can be used for the filler wire 3. That is, the main wire 2
Since the molten pool 7 is formed by the arc 6 of the MIG welding using the electrode as the electrode, the temperature of the molten pool 7 in front of the main wire 2 in the welding direction becomes higher. The temperature of the molten pool 7 depends on 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. almost in the same manner as in 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 of more than 900 ° C. can be used as the material of the filler wire 3. As a result, a high melting point wear-resistant material such as a copper-based or titanium-based material can be used as the material of the filler wire 3, and various wear-resistant materials can be added by overlay welding. This allows the filler wire 3
It is possible to achieve alloying of the wear resistant material and the composition of the main wire 2 and improve the wear resistant property of the surface of the aluminum alloy (base material) 5.

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 higher, the melting amount of the wire 3 can be increased. This is because the amount that can be inserted as the filler wire 3 must take into consideration the temperature decrease of the molten pool 7 due to the filler wire 3, and the temperature of the molten pool 7 is high, so increase the melting amount of the wire 3. This enables build-up welding of the wear resistant material at a concentration of about 1/3 or more.

Further, since the filler wire 3 is inserted into the molten pool 7 and melted, the temperature of the molten pool 7 is lowered as compared with the case where the wire 3 is not inserted, so that the cooling rate until solidification is slowed and welding cracks occur. The risk is reduced.

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

Using the above-mentioned double wire welding machine, the state of 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:
20m with groove of 5R using 0.5% or less, remaining Al)
A m-thick test piece was prepared and used by casting. For welding material,
Aluminum material A1070 of the same type as the base material as the main wire
(Components: Si: 0.20%, Cu: 0.04%, Fe: 0.25%,
A wire of φ1.2 made with Mn: 0.03%, Al: ≧ 99.70%) is used as a filler wire for the copper alloy arm bronze (component: Mn: 0.93%, Fe: 2.67).
%, Ni: 1.02%, Al: 7.60%, the remaining Cu) was used for each wire of φ1.6.

These wires were mounted on the above-mentioned double wire welding machine so that the main wire would be the trailing wire and the filler wire would be the leading wire. The welding current (main wire), welding speed and filler feed rate are 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 welded test piece was checked for appearance such as cracking, and then the hardness (Hv) of the weld metal, microstructure observation, and copper (alloy component) were observed at the central cross section of the welded portion. The quantitative analysis of Cu) was investigated. In addition, this copper quantitative analysis is performed at an energy dispersive analyzer (manufactured by HORIBA, Ltd.) attached to a scanning electron microscope (SEM) at three places, above, in the middle, and below the welding beat, and is a standard sample of known Cu content. Was calibrated by.

As a result, the relationship between the feed amount of filler and the Cu content and the relationship between the Cu content and the hardness of the deposited metal are shown in FIG.
And shown in FIG. It can be seen from FIGS. 2 and 3 that there is a large variation in the Cu component both when the feed amount of the filler is small and when it is large. As a cause of this component variation, when the filler feed amount is low, the molten pool temperature is high and the alloy component sinks to the bottom of the bead due to the difference in specific gravity, and when the filler feed amount is large, conversely the molten pool temperature is It does not rise and solidification is fast, so stirring may be insufficient.

Therefore, in order to obtain a weld metal having a uniform composition, there are appropriate ranges of welding current, welding speed, and filler feeding amount. In this test result, welding current: 260 A, welding speed: 300 mm / min. In the condition that the filler feed amount is 23 to 38 g / min, beads having a uniform composition with 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 is obtained within the above condition range.

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

[0033]

In summary, according to the present invention, it is possible to add various wear-resistant materials to the surface of the aluminum base material by overlay welding.

[Brief description of 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 the method of the present invention.

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

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 with only one main wire, and FIG. 4B is a sectional view thereof.

[Explanation of symbols]

 2 Main wire 3 Filler wire 5 Base material 6 Arc 7 Molten pool

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Nakahara 4-7-19 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Joint oxygen corporation (72) Hideki Miyauchi, 1850 Minato, Wakayama, Wakayama Joint oxygen stock formula In the company

Claims (3)

[Claims] 1. A surface of an aluminum-based base material is arranged by arranging a main wire as a trailing wire, a filler wire having a higher melting point than that of the main wire as a wear-resistant material in front of the main wire, and an arc of MIG welding using the main wire as an electrode. After forming a molten pool by melting a part of the above, the filler wire is inserted into the molten pool and melted, and the high melting point wear-resistant material is added by overlay welding to the aluminum base material. Overlay welding method for dissimilar materials. 2. The overlay welding method for dissimilar materials to an aluminum base material according to claim 1, wherein the main wire is made of an aluminum-based material, and the filler wire is made of a wear-resistant material such as a copper-based or titanium-based material. . 3. The overlay welding method for dissimilar materials to an aluminum base material 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. .