JPH0557480A - Composite wire for build up welding to surface of al base material - Google Patents

Abstract

PURPOSE:To provide the composite wire which stably and inexpensively yields a wear resistant and heat resistant alloyed layer having a high joining property to an Al-based material without generating weld defects, such as pits and blow holes on this base material. CONSTITUTION:The composite structure wire formed by coating a metallic core material with a metallic sheath in its longitudinal direction contains Al at >=15% of the total weight of the composite wire and has the m. p. of the core material lower than the m. p. of the metallic sheath. The wear resistant and heat resistant layer is stably and economically obtd. on the surface of the Al-based material and the build-up metal contg. the decreased weld defects, such as pits and blowholes, is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a gas shield in which a wear-resistant and heat-resistant layer is stably and economically obtained on the surface of an Al (aluminum) base material, and further, welding defects such as pits and blow holes are less likely to occur. The present invention relates to composite wires for arc and plasma arc overlay welding.

[0002]

2. Description of the Related Art Al or Al alloys are used in a wide range of fields including automobile parts because they are lighter in weight and have better thermal conductivity and corrosion resistance than steel materials.
However, Al alloys are generally inferior in strength, wear resistance, and heat resistance to iron and steel materials, and the parts and parts that can be applied as substitute materials for iron and steel materials are limited as they are. Further, even when Al or Al alloy is already used, in recent years, further improvement in durability is required as the use environment becomes severe. As a measure, A
In addition to the improvement of the l alloy itself, a method of forming a wear resistant and heat resistant layer on the surface as described below is performed.

(1) There are a method of forming a thin hard coating layer by PVD and CVD, and a method of forming a relatively thick hard coating layer by thermal spraying. However, the film formed by these methods is very hard, but the adhesion to the base material is weak, and there is a risk of peeling or falling off during use, resulting in poor reliability. Furthermore, PV
D and CVD have a slow film formation rate, and it is difficult to form a thick film. In the case of thermal spraying, there are problems in terms of environment such as generation of noise and light rays, and there is a problem that the adhesion to the base material is low and peeling occurs during use.

(2) A method of forming a hard alloy layer by melting an alloying metal together with the surface of a substrate using a high-density energy source such as an electron beam or a laser is disclosed. For example, in Japanese Patent Laid-Open No. 55-27587, V, Cr, Mn, Fe, Co on an Al alloy piston by an electron beam is used.
An alloying treatment technique of Ni is disclosed. 62-
No. 72456, Japanese Utility Model Laid-Open No. 62-72458 discloses a Cu alloying treatment technique using an electron beam. However, if an electron beam of a density energy source is used, alloyed metal having a high melting point can be easily melted to obtain a uniform alloy layer. However, since the alloying treatment by the electron beam is performed in a vacuum container, When the Al alloy is overheated, blowholes and pits are easily generated and the productivity is low. Lasers, like electron beams, have a high energy density,
It is not suitable for Al and Al alloys because of its low absorption rate. Moreover, since the electron beam and laser devices are both expensive, the cost of the applicable parts is high.

(3) As a method of using MIG arc and TIG arc, Japanese Patent Laid-Open No. 179569/1983 uses a mixed powder of Al or Al alloy powder and NbC powder, TiC powder, and VC powder as a filler material. , A method of surface hardening an Al-based material by a TiG arc is disclosed. Furthermore, JP-A-3-169495 and JP-A-3-169
Japanese Patent No. 496 discloses an Al surface hardening method using a composite filler material in which a metal wire rod or a ceramic wire rod other than Al is housed in an Al sheath. However, when powder is used as the filler, there are problems such as stable feeding of the filler and segregation of the composition, and it is difficult to obtain an alloy layer having a uniform composition. For example, N
In the mixed powder of ceramics such as bC and TiC powders and Al alloy powder, ceramics such as carbides are generally crushed powders and thus are irregularly shaped powders, stable feeding is difficult, and mixed powders having different specific gravities are Uniform feeding is difficult. Therefore, since the amount of dilution of the added metal varies, the composition of the obtained alloy layer becomes non-uniform, which causes variations in characteristics such as wear resistance and heat resistance. Further, in the welding of Al and Al alloys, since H ₂ , N ₂ , O _{2 and the} like are easily absorbed in a molten state, welding defects such as pits and blowholes are easily generated, and the gas component brought from the filler metal is , Is a major factor in its occurrence. Metal powder such as Al alloy powder is generally manufactured by a gas atomizing method or a water atomizing method,
It contains a lot of gas. Therefore, when a metal powder such as an Al alloy powder is used as the filler material, there is a problem that welding defects such as blow holes and pits are likely to occur due to the gas contained in the powder. Further, when a composite wire is used as the filler material, welding defects such as blowholes and pits are less than that of powder, but if the melting point of the core material enclosed inside the jacket metal is higher than the melting point of the jacket metal, the jacket metal will be Melt first,
Then, the encapsulated core material melts.
When such a phenomenon occurs, segregation of the components is likely to occur in the alloy layer, such as where the alloy layer has a large amount of skin metal component and where the alloy layer has a large amount of core component, and it is difficult to obtain an alloy layer having a uniform composition.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of alloying treatment, and its purpose is to provide pits, blowholes, etc. on the surface of an Al-based material. The present invention is to provide a composite wire which does not cause welding defects and which has a high bondability with a base material, a stable wear-resistant and heat-resistant alloying layer, and which can be obtained at low cost.

[0007]

The composite wire for overlay welding of the present invention has the following structure. That is,
A composite structure wire in which a metal core material is longitudinally covered with a metal skin, characterized by containing 15% or more of Al with respect to the total weight of the composite wire, and the melting point of the core material is lower than the melting point of the metal skin. It is a composite wire for overlay welding on the surface of an Al-based material. The overlay welding means used for the composite wire of the present invention is a gas shield arc (TI) which is a simple welding method.
G, MIG welding) and plasma welding methods.

[0008]

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a view showing a cross-sectional shape of the composite wire of the present invention. (A) is coated with a metal having an opening,
(B) is coated with a metal having no opening.
Here, 1 is a core material, and 2 is an outer skin. The cross-sectional shape of the core material 1 is composed of one type of core material as shown in FIG. 2 (a), 2
Those made of different kinds of core materials (b) and (c), those made of three kinds of core materials (d) and the like can be applied. The manufacturing method of the composite wire of FIG. 1 (a) is obtained by using a strip steel for the metal outer skin, inserting the core material 1 while forming the strip steel into a curve, and then performing wire drawing to a predetermined diameter. You can In the method of manufacturing a composite wire of (b), a steel strip is used as a metal outer sheath, the core material 1 is inserted while the strip steel is formed into a curved shape, both ends of the strip steel are closed by laser or resistance welding, and thereafter, A wire is drawn to a predetermined diameter, or a pipe is used as a metal outer shell.
As disclosed in Japanese Patent No. 244519, it can be obtained by a method in which the core material 1 is inserted from the end of the pipe while vibrating the pipe and then wire drawing is performed to a predetermined diameter.

2B can be obtained by the manufacturing method of FIG. 1B, FIG. 2C can be obtained by the manufacturing method of FIG. 1A, and FIG. It can be obtained by repeating the manufacturing method of (b). As described above, the structure of the composite wire of the present invention is one in which one or more core materials are covered with a metal outer shell having an opening in the longitudinal direction or a metal outer shell having no opening. It has been found that the combination of the composition and the metal skin composition has a great influence on the performance of the overlay metal on the surface of the Al-based material. That is, the inventors of the present invention have found that Cu having no opening in the longitudinal direction as shown in FIG.
For the pipe and the Al pipe, the cross-sectional shape C shown in FIG.
U wire and Al wire are used as core materials.
Using the technique disclosed in Japanese Patent Publication No.
A Cu wire was inserted into an l wire and an Al pipe, and wire drawing was performed up to a diameter of 1.2 mm to fabricate two types of composite wires as prototypes.
In addition, the composite wire in which the Al wire is inserted into the Cu pipe is
The composite wire in which the Cu wire was inserted in the Al pipe was designated as B. The ratio of Cu to Al was 50% Cu and 50% Al based on the total weight of the composite wire.

In order to investigate the characteristics of the overlay metal of these trial-produced composite wires, an aluminum plate (JIS A
A bead-on-plate test was performed by the MIG welding method using 1050P: 10t × 50W × 100 l). The welding conditions are shown below. Welding conditions Power source polarity DC (+) Welding current 180A Arc voltage 24V Welding speed 30cm / min Wire protrusion length 20mm Shielding gas Ar: 25 l / min

The arc phenomenon of two kinds of composite wires,
In order to investigate the droplet transfer phenomenon, a high-speed camera (1/1
The photograph was taken at 000 f / p / s). As the characteristic value of the overlay metal, the hardness distribution of the weld bead in the welding direction and in the direction perpendicular to the welding direction was measured. A detailed view is shown in FIG.
FIG. 3A shows a procedure for measuring the hardness in the welding direction. The hardness was measured at a pitch of 0.5 mm between the center portions AB of the beads (10 mm). FIG. 3B shows a hardness measurement procedure in the vertical direction. The hardness was measured at a pitch of 0.5 mm between AB (A: 0.5 mm from the surface, B: bond portion). The hardness measurement load was 300 gr.

FIG. 4 shows the result of investigation of hardness distribution in the welding direction.
The hardness distribution in the vertical direction is shown in FIG. As shown in FIGS. 4 and 5, the composite wire A had a stable hardness, and a built-up metal of about Hv200 was obtained. On the other hand, the composite wire B had a large variation in hardness, and varied from the maximum Hv250 to the minimum Hv160. The cause was compared with the droplet transfer phenomenon measured by a high-speed camera. As a result, the composite wire A showed the globuler transfer in which the droplets migrate regularly, whereas the composite wire B showed the transfer form in which the globuler transfer and the spray transfer were mixed. By this,
In the composite wire A, droplets formed by alloying Cu of the outer skin and Al of the core material are transferred, so that the composition of the overlay metal is made uniform,
It is considered that the hardness was stable. Further, in the composite wire B, droplets formed by alloying Al of the outer shell and Cu of the core material are transferred during the globular transition, but Al of the outer coating metal (melting point: 660 ° C.) having a low melting point is transferred by arc heat or joules during the spray transfer. Cu of the core material that was melted earlier by heat and left unmelted
It is considered that since only the (melting point: 1083 ° C.) was spray-transferred thereafter, the composition of the overlay metal became non-uniform and the hardness varied. Although the structure of the overlay metal obtained with the composite wire A was uniformly dispersed with the eutectic structure of Al and Cu, the structure of the overlay metal obtained with the composite wire B was Al and C.
The hypereutectic structure and the hypoeutectic structure of u were mixed.

As is clear from the above experiment, when the outer metal has a higher melting point than the core metal, the alloyed droplets migrate to obtain a good overlay metal. If the melting point is lower than that of the core metal, the outer metal will be melted first by arc heat or Joule heat, and the core material will remain unmelted, so alloying will not proceed well, and the overlay metal It turned out that the quality is not stable. still,
This phenomenon similarly occurred when TIG arc or plasma arc was used. Further, in the present invention, even in the composite wire coated with two or more kinds of core materials, the melting point of the outer cover metal must be higher than the melting point of the core material metal. When the cross-sectional shape of the core material is as shown in FIG. 2B, the core portions are combined so that the melting point of the outer portion 4 is higher than that of the central portion 3. Figure 2 (d)
Also in the case of, the combination is performed so that the melting point of the central portion 5 becomes the lowest. For example, when the outer skin of FIG. 1 (a) has a core material of FIG. 2 (b), the metal outer skin 1 is Ni, and the central portion 3 is A for the core metal.
l, the outer part 4 is made of Cu, or the outer skin of FIG. 1 (b) is made of the core material of FIG. 2 (d), the metal outer skin 1 is Ti, the central portion 5 is Mg, and the intermediate portion 6 is Al. The outer portion 7 may be made of Ni or the like.

Further, in the present invention, Al is contained in the skin material,
It is desirable that one or both of the core materials contain 15 wt% or more of the total weight of the composite wire. 1 for Al
By containing 5 wt% or more, the wettability with the Al-based material becomes good. If it is less than 15 wt%, the wettability with the Al-based material is poor, the bonding strength between the overlay metal and the base material is reduced, and the bead may be peeled or cracked. In addition, FIG. 6 shows the cross-sectional shape of the composite wire according to the present invention (a),
It shows with (b), (c), (d), (e), (f). Furthermore, the cross-sectional shape of the composite wire of the present invention is not limited to a perfect circle, and can be formed into various shapes such as an elliptical shape, a square shape, and a flat shape. In any case, the melting point of the metal outer shell is the melting point of the core material. Must be higher than.

[0015]

EXAMPLES The effects of the composite wire according to the present invention will be described more specifically by way of examples. Table 1 shows the trial-fabricated composite wire having a diameter of 1.6 mm, and Table 2 shows the results of the characteristic investigation of the overlay metal. An aluminum plate (JIS A 1050P: 10t × 50W × 100) was used to investigate the characteristics of the overlay metal.
The bead-on-plate test by the TIG arc welding method was carried out using
We investigated cracks and peeling of beads and blow holes. The hardness of the overlay metal was measured in the manner shown in FIG. 3 (b), and Table 2 shows the minimum and maximum values of hardness and the range (R). For the cracking and peeling of the bead, the cross section of the welded part is examined with an optical microscope (× 100), and the blow hole is based on JIS Z 3105 (radiation transmission test method of aluminum welded part and classification method of transmission photograph). went. The welding conditions are as follows. Welding conditions Power source polarity DC (-) Welding current 160A Arc voltage 15V Welding speed 10cm / min Shielding gas He: 25 l / min

In Table 2, No. 1-No. No. 7 is an example of the present invention that satisfies all the requirements of the present invention. 1, No.
2, No. No. 7 uses one kind of core material, No. 7 Three
No. No. 4 uses two kinds of core materials, No. 4 5, N
o. No. 6 used three types of core materials, and the hardness of the overlay metal was stable, there was no bead peeling or cracking, and good results were obtained for blowholes. On the other hand, No. 8, No. Although No. 9 uses one kind of core material, it is an example in which the melting point of the outer cover is lower than the melting point of the core material, and the hardness of the overlay metal largely varies. No. 1
No. 0 uses two kinds of core materials, but since the melting point of the outer cover is lower than the melting point of the core material, the hardness of the overlay metal largely varies. Furthermore, No. No. 11 uses one kind of core material, and since the melting point of the outer cover is higher than the melting point of the core material, the hardness of the overlay metal is stable, but the amount of Al is small relative to the total weight of the composite wire and the beads are It was peeling off.
As for blowholes, the present invention example and the comparative example were good. This is because the composite wire was used as the filler material.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

As described above, according to the composite wire of the present invention, the wear resistance and heat resistant layer can be stably and economically obtained on the surface of the Al base material, and the occurrence of welding defects such as pits and blow holes. It is possible to obtain a built-up metal with a small amount.

[Brief description of drawings]

FIG. 1 is a diagram showing a cross-sectional shape of a composite wire,

FIG. 2 is a diagram showing a cross-sectional shape of a core material,

FIG. 3 is a diagram showing a hardness measurement procedure,

FIG. 4 is a diagram showing a hardness distribution of a welding bead in a welding direction,

FIG. 5 is a diagram showing hardness distribution in a direction perpendicular to the welding direction,

FIG. 6 is a view showing a cross-sectional shape of the composite wire of the example.

[Explanation of symbols]

 1 Outer skin 2,3,4,5,6,7 Core material 8 Al plate 9 Weld bead

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Koike 3-5-4 Tsukiji, Chuo-ku, Tokyo Inside Nittetsu Welding Industry Co., Ltd. (72) Inventor Yoshio Kobe 3-5 Tsukiji, Chuo-ku, Tokyo No. 4 Nittetsu Welding Industry Co., Ltd.

Claims (1)

[Claims] 1. A composite structure wire in which a metal core material is coated in the longitudinal direction with a metal skin, and A is based on the total weight of the composite wire.
A composite wire for overlay welding on the surface of an Al-based material, containing 15% or more of 1 and having a melting point of the core material lower than that of the metal shell.