JP2677412B2 - Filler for surface hardening of aluminum materials - Google Patents

Description

TECHNICAL FIELD The present invention relates to a filler material, and more particularly to a filler material used to harden the surface of an aluminum material to form an aluminum alloy material having excellent wear resistance.

In this specification, the term aluminum is used to include its alloy.

As is well known in the prior art, aluminum is significantly lighter than commonly used iron-based materials, etc., and also has excellent heat conduction characteristics and excellent corrosion resistance. It is becoming widely used as a mechanical part. However, aluminum is generally inferior in wear resistance to iron-based materials, which is a major obstacle when replacing iron-based members with Al alloy members for the purpose of weight reduction in automobiles and the like.

Therefore, conventionally, as a measure for improving the wear resistance of an aluminum material applied to a site where the wear resistance is required, an attempt has been made to form a surface hardened layer having excellent wear resistance on the surface of the aluminum material. As one of the methods for forming such a surface-hardened layer, the present applicant has previously proposed that one kind of B, Si, and Ge as a wettability improving element and metal or hard particles externally supplied to the surface of an aluminum material. Alternatively, a method has been proposed in which a surface of an aluminum material is alloyed by irradiating a high-density energy heat source such as a laser beam together with two or more kinds and locally melting it (Japanese Patent Application No. 63-304518). According to this method, a surface-alloyed layer having a high hardness can be obtained, and there is no risk of peeling of the layer. Therefore, it is possible to provide an aluminum material suitable as a wear resistant product.

However, the above method has the following drawbacks in forming the alloyed layer.

That is, in the above method, metal or hard particles or B
To supply the aluminum material surface to the aluminum material surface, mix these powders and apply them to the aluminum material surface in advance using a binder before irradiating the laser beam, or melt the mixed powder while irradiating the laser beam etc. However, in the former coating method, the mixed powder applied may drop or come off depending on the welding position.
Also, the coating workability was not good. Furthermore, there is a possibility that defects such as pores may remain in the surface hardened layer depending on the kind of binder. On the other hand, in the latter direct injection method, it is difficult to continuously and stably supply the mixed powder to the melting portion, and particularly when the amount is small, the difficulty is particularly increased. There is also a method of supplying the mixed powder by placing it on a carrier gas of a melting heat source as one of the direct charging methods, but in this case, the irradiation of the heat source is affected, or an arbitrary amount is supplied to a target position. However, there were drawbacks such as difficulty.

The present invention has been made to solve such drawbacks all at once, and the mixed powder for forming the surface hardened layer can be stably supplied to a target position without being restricted by the welding posture, and thus the aluminum material can be used. The object of the present invention is to reliably and efficiently form a surface-hardened layer on the surface of, and to provide a material therefor.

Means for Solving the Problems As a material for achieving the above object, the present invention shows, in reference to the reference numerals in the drawings, one kind or two or more kinds in an inner hollow part (2a) of an aluminum skin material (2). A filler metal (1) for surface hardening of an aluminum material, characterized in that a mixed powder (3) of the above metal or hard particles and one or more kinds of B, Si and Ge is contained in a filled state. Is provided.

As shown in FIG. 1, a filler material (1) according to the present invention
Are generally provided as welding rods or cores. Usually, the outer diameter is set to about 2.4 to 3.2 mm when used for TIG welding, and the outer diameter is set to about 1.2 to 2.4 mm when used for MIG welding. The filler material (1) has a hollow portion (2
an aluminum skin (2) having a) and the hollow part (2)
The mixed powder (3) housed in a) in a). In this way, the mixed powder (3) is contained in the inner hollow portion of the aluminum skin material (2) in a filled state in order to keep the mixed powder in a fixed state. Here, the composition of the aluminum skin material (2) is not particularly limited, and pure Al, 5052 alloy, 5083 alloy or other alloys may be appropriately used in relation to the composition of the aluminum material on which the surface hardened layer is to be formed. Accept and use.

Of the mixed powder (3) housed in the inner hollow part (2a) of the aluminum skin material (2) in a filled state, the metal powder is melted and crystallized as an intermetallic compound in the Al matrix of the aluminum alloy material and has an extremely high hardness. Plays the role of forming a chemical layer. Therefore, any metal may be used as long as it forms an intermetallic compound with Al by melting. As an example, each element such as Ni, Mn, Fe, Ti, V, Cr, Zr, Nb, Mo, Hf, and Ta can be cited. Further, it is not always necessary to use a simple metal, and it is supplied in the form of an intermetallic compound, and Al is melted.
It may be one that reacts with Al to form an Al-based intermetallic compound. On the other hand, the hard particles play a role of alloying on the surface of the base material to form an alloyed layer having high hardness. Such hard particles include carbides such as TiC, WC, ZrC, NbC and T
Nitride such as iN, ZrN, CrN and other ceramics may be mentioned. One of these metals or hard particles may be used alone, or two or more of these metals or hard particles may be used in combination. Further, metal and hard particles may be combined.

Further, B, Si, and Ge in the mixed powder (3) have a role of improving the wettability of the metal or the hard particles to the aluminum material at the time of welding the filler material to the aluminum material and promoting the reaction with Al. Fulfill That is, when the metal powder alone is used, the surface tension of the metal is large during melting and, therefore, the wettability is poor, and it is difficult to react with the aluminum material. On the other hand, even in the case of hard particles, the wettability with an aluminum material is not good. Therefore, one or more of B, Si, and Ge are supplied, and these are simultaneously melted. These B, Si and Ge are mutually equivalent in terms of imparting a wettability improving effect, and it is sufficient to contain at least one of them, but the total amount of the metal or hard particles and the wettability improving element in the mixed powder is sufficient. The weight ratio of 99: 1 to 70:30 is preferable. If the amount of the wettability-improving element is less than this range, the reaction between the metal or hard particles and the base material Al may not be sufficiently promoted, and on the contrary, if the amount is too large, the reaction promotion effect may be obtained but the cost may be increased. Because. Further, in order to further improve the wettability, Al powder having a particle size of about 50 to 200 μm may be mixed with about 5 to 30% together with one or more kinds of B, Si and Ge.

The filler material (1) shown in FIG. 1 may be manufactured, for example, as follows. That is, a long plate-shaped aluminum skin material (2) having a predetermined thickness as shown in FIG. 2 is formed into a semicircular cross section shown in FIG. 3 by roll forming, and the mixed powder (3 ) Is filled, and then, as shown in FIG. 4, it is further formed into a circular cross section and the both end closing portions (4) are welded. It should be noted that after that, drawing processing or the like may be performed as necessary. Here, filler material (1)
The quantitative ratio between the aluminum and the mixed powder (3) can be changed by changing the wall thickness of the skin material (2). By providing the aluminum core material (5) having the same composition as the skin material at the axial center of the filler material (1) as shown in FIG. 5 without changing the thickness of the aluminum skin material (2). You may change the ratio of aluminum and mixed powder. Further, as shown in FIG. 6, two or more hollow portions (2a) (2a) in the axial direction are provided inside the aluminum skin (2).
.. may be provided to contain the mixed powder (3) in a filled state. 5 and 6, parts having the same names as those of the filler material shown in FIG. 1 are designated by the same reference numerals.

The filler material according to the present invention is supplied to the surface-melting portion of the aluminum material by means of TIG welding, MIG welding or the like as in ordinary welding. After melting, the molten part of the aluminum material solidifies in a short time, and when the filler metal mixed powder contains metal powder, an intermetallic compound in the Al matrix, for example,
TiAl ₃ , ZrAl ₃ , NiAl, NiAl ₃ , Ni ₂ Al ₃ , FeAl ₃ , Fe ₄ A
An alloyed layer in which l ₁₃ , MnAl ₆ , HfAl ₃ , NbAl ₃ , CrAl ₇ or the like crystallizes uniformly or densely is formed on the surface. On the other hand, when hard particles are contained, the particles are uniformly dispersed or agglomerated in the Al matrix to form an alloyed layer. Thus, the above-mentioned intermetallic compound generally has a high hardness, and the hard particles themselves have excellent hardness, so that the alloyed layer exhibits high hardness as a whole, Has wear resistance. At the same time, B and Si in the filler metal mixed powder,
Although Ge exerts the effect of improving wettability, it itself also forms an Al-B intermetallic compound (presumed to be AlB ₂ ) in the Al matrix.
It also crystallizes as a Si or Ge phase and contributes to improving the hardness of the alloyed layer. The harder the intermetallic compound or hard particles in the Al matrix, the harder the alloying layer.

The aluminum material having the hard alloyed layer formed on the surface thereof is then machined into a final product shape if necessary and put into practical use as a wear resistant part. The composition of this aluminum material is not particularly limited, not to mention pure Al.
2000 series other aluminum wrought materials or AC8A, AC2B
Aluminum casting materials and the like can be used as appropriate.

EFFECTS OF THE INVENTION As described above, the present invention is one or more kinds of metal or hard particles and one or two kinds of B, Si and Ge.
Since the mixed powder with the seeds or more is to provide the filler material contained in the aluminum skin material in a filled state, by welding the surface of the aluminum material using the filler material, Al is added to the Al matrix. It is possible to form an extremely hard alloyed layer in which the intermetallic compound is crystallized or the hard particles are alloyed. As a result, it is possible to provide an aluminum material suitable as a wear resistant part required for automobiles and the like. Moreover, when the above-mentioned hardened layer is formed on the aluminum material, mixed powder of metal, B or the like is supplied as a filler material. Therefore, unlike the conventional coating method, the mixed powder applied may be different depending on the welding position. It is possible to eliminate the inconvenience of dropping or peeling, and to form a surface-hardened layer without being restricted by the welding position. For example, even when the aluminum material is a rotating object, Can be formed. Further, since it is not necessary to use a binder for applying and holding the mixed powder, it is possible to remove the possibility that defects such as pores remain in the surface hardened layer. Further, since the coating process itself is not required, the work efficiency can be improved and the productivity can be improved. Further, in the coating method, the heat source is directly applied to the powder, so that the cleaning effect of the aluminum material cannot be obtained, but the filler material according to the present invention can be expected to have the cleaning effect of the aluminum material when an AC power source or the like is used. Furthermore, since the supply amount of the mixed powder can be easily adjusted by supplying it as a filler material, an arbitrary amount of the mixed powder can be continuously and stably supplied to the target position regardless of the supply amount. it can.

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

Along with the hollow core of the aluminum skin made of A1100, multiple long fillers were manufactured in which the mixed powder of metal, hard particles and wettability-improving element combined as shown in Table 1 was packed. did. The filler material was manufactured by forming a large diameter member by roll forming as described with reference to FIGS. 2 to 4 and then performing drawing. Filler material (1)
Has an outer diameter of 1.6 mm and the aluminum skin (2) has a wall thickness of 0.5 mm
And

On the other hand, as an aluminum material for forming a surface hardened layer
A plurality of 7.5 mm thick × 40 mm wide × 100 mm long test pieces made of AC8A casting alloy were prepared. Then, as shown in FIG. 7, a shallow groove (7) having a depth of 0.5 mm was formed in the longitudinal direction of the central portion of each test piece (6).

Next, as shown in the figure, a TIG welding machine (8) is used to continuously supply the filler metal from the filler material feeder (9) while semi-automatic TIG welding the groove (7) of the test piece. I went. In the figure, (10) is the weld. The welding speed was 100 mm / min.

After welding, when the microstructure of the solidified welded portion was examined, an alloyed layer was formed over the entire groove portion of the test pieces of Sample Nos. 1 to 12. Moreover, these alloyed layers have intermetallic compounds, hard particles, relatively uniformly densely crystallized or dispersed portions and agglomerated portions, and the hardness of the entire alloyed layer is as shown in Table 1. It was Moreover, no cracks or pores were found in the alloyed layer or at the interface between the alloyed layer and the aluminum material. In contrast, the sample
In No. 13, it was confirmed that a hexagonal crack was observed on the surface, a part was peeled off, and there was a molten area only for the base material Al directly under the alloying layer, and the wettability with Al was poor. . Further, in Sample No. 14, discontinuous holes were formed on the surface, and just below the alloying layer, there was also a molten region of only the base material Al.
It had poor wettability with.

On the other hand, when the hardness of the aluminum material alone was investigated, Hv
It was 30 (load 5 kg).

As can be seen from the above test results, when the additive according to the present invention is used, it is possible to easily and reliably form an alloyed layer having extremely high hardness and therefore naturally excellent wear resistance on the surface of the aluminum material. I was able to confirm.

[Brief description of the drawings]

FIG. 1 is a sectional perspective view showing an example of the filler material according to the present invention, and FIGS. 2 to 4 are for explaining a manufacturing process of the filler material shown in FIG. Is a cross-sectional view of the aluminum skin material in a plate state, FIG. 3 is a cross-sectional view of a semi-circular shape filled with mixed powder, and FIG. 4 is a cross-sectional view of the aluminum material with both ends closed. FIG. 5 is a sectional view showing a modified example of the filler metal, FIG. 6 is a sectional view showing another modified example, and FIG. 7 is a perspective view schematically showing the welding process of the test piece in the example. (1) …… filler metal, (2) …… aluminum skin, (2
a) ... Hollow part, (3) ... Mixed powder.

Claims (2)

(57) [Claims] 1. A mixed powder of one or more kinds of metal and one or more kinds of B, Si, Ge is contained in a filling state in an inner hollow part of an aluminum skin. A filler metal for surface hardening of aluminum materials. 2. A mixture powder of one or more kinds of hard particles and one or more kinds of B, Si, Ge is contained in a filled state in an inner hollow part of an aluminum skin material. A characteristic filler metal for surface hardening of aluminum materials.