JP3337087B2 - Copper alloy with excellent high-temperature wear resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy having excellent wear resistance at high temperatures and a high thermal conductivity, and particularly to a sliding member for an engine or the like, for example, a valve seat (valve seat), a valve guide. The present invention relates to a copper alloy excellent in oxidation resistance and high-temperature wear resistance that is suitably used as a material such as a (valve guide member).

[0002]

2. Description of the Related Art In recent years, automobile engines have been improved in performance.
As the output has increased, the engine valve seat,
The temperature of the valve guide tends to be high, and the sliding surface pressure tends to be higher than before. In addition, in order to achieve both high output and good fuel economy, good heat transfer is required in valve seats and valve guides.

[0003] Therefore, as a material for these components, a material having good wear resistance and thermal conductivity has been required.

[0004] Conventionally, these materials have been researched and developed mainly on Cu alloys. For example, JIS Al which is strengthened by adding Ni and Fe to aluminum bronze is used.
BC1-4, in particular, AlBC3 ("Non-ferrous metal materials", Masataka Sugiyama, Corona Publishing Co., Ltd., 1973, 14th edition, p. 73), and AISI C95500 ("Me
tals Handbook 9th Edition
Vol. 2] American Society f
or Metals 1979, p. 433) has been used as a material for valve seats and the like.

When these conventional alloys are used as materials for valve seats and valve guides of engines that require the above-mentioned characteristics in recent years, their wear resistance at high temperatures is not sufficient, so that they are used under severe conditions. At the time of practical use, there was a problem that wear was remarkable and it was difficult to respond sufficiently.

Therefore, the present inventors first described that, by weight%,
Al: 1.0 to 15.0%, Ti: 0.3 to 8.0%,
Co: 0.5 to 10.0%, having a composition consisting of the balance Cu and impurities, and an intermetallic compound consisting of two or more of Al, Ti, Co, and Cu, for example, Al-Ti, Cu-T
i, Co-Ti, Al-Ti-Co, Al-Ti-Cu
A copper alloy excellent in high-temperature abrasion resistance having a structure in which at least one kind of an intermetallic compound composed of the above-mentioned intermetallic compounds is dispersed has been developed (not disclosed at the time of filing this application).

[0007]

SUMMARY OF THE INVENTION The copper alloy according to the above-mentioned invention is characterized in that Al, Ti and the like are contained in a Cu alloy to reduce intermetallic compounds such as Al-Ti, Cu-Ti and Al-Ti-Co. By having a uniformly dispersed structure, it has excellent wear resistance at high temperatures and high thermal conductivity, making it suitable as a material for valve seats and valve guides, but also as a getter agent for oxygen. Since Ti of the IVa group element to be used is contained as an essential constituent element, when the powder having such an alloy composition is laser clad in the air, the powder may become brittle when selectively oxidized. The problem is that when fuel such as leaded gasoline is used, wear may be promoted when Ti is selectively corroded by corrosive combustion components. Was Tsu.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and has excellent wear resistance at high temperatures, and has excellent wear resistance and thermal conductivity at high temperatures. Ti is a suitable material for valve seats and valve guides of engines that require
High-temperature wear-resistant copper alloy capable of obtaining valve seats and valve guides having excellent durability without Ti being selectively oxidized or selectively corroded because it does not contain Ti as an essential constituent element It is intended to provide.

[0009]

In the prior invention made by the present inventors, based on an aluminum bronze alloy, Al: 1.0 to 15.0% and Ti: 0.3 to 0.3% by weight.
By using a copper alloy having a composition of 8.0%, Co: 0.5 to 10.0%, the balance of Cu and impurities, Ti
It has been found that a structure in which at least one of binary or ternary intermetallic compounds composed of Al and Cu, Co, and Al is uniformly dispersed is obtained, and as a result, excellent high-temperature wear resistance is exhibited. Was.

[0010] This result indicates that in the copper alloy, the structure in which the very hard fine intermetallic compound of the above-mentioned component system is uniformly dispersed in the matrix of the aluminum bronze alloy component having a high high-temperature hardness is important for the valve seat and the valve guide. It shows that it is effective in suppressing adhesive wear and abrasive wear, which are important wear factors.

[0011] However, Ti, which can be expected to precipitate these intermetallic compounds, and not only IV, such as Zr, but also
In the case of group a elements, oxidation resistance and corrosion resistance are problematic.

Therefore, in the present invention, whether V, Nb, or Ta, which is a Group Va element, is contained in place of Ti is effective in suppressing the oxidation resistance and wear resistance. As a result of a series of studies on the effects on the high-temperature wear resistance, it was found that the following composition and the particle size of the intermetallic compound can satisfy all the characteristics.

That is, the copper alloy excellent in high-temperature wear resistance according to the first aspect of the present invention has an Al content of 1.0 to 1.0% by weight.
15.0%, V, Nb, T, which are elements of group Va in the periodic table
at least one of a: 0.1 to 5.0%, with the balance being Cu
And a copper alloy having excellent high-temperature wear resistance according to claim 2 of the present invention,
15.0%, Co: 0.5 to 10.0%, Periodic Table of Elements V
At least one of group a elements V, Nb and Ta:
0.1 to 5.0%, with the balance being Cu and impurities.

In a copper alloy ingot or powder having the above composition, one or more of Va group elements and Cu, A
At least one of the intermetallic compounds consisting of one or more of the l and Co elements has a structure in which the particles are precipitated or dispersed as spheres or aggregates having a particle size of about 10 μm. In addition to exhibiting abrasion properties, it has been found that laser build-up in the atmosphere is greatly improved by improving oxidation resistance, and that a valve seat has a great effect in suppressing corrosion and abrasion in leaded gasoline and the like.

Further, as in the prior application, the copper alloy excellent in high-temperature wear resistance according to claim 3 of the present invention is obtained by further adding one or two types of Fe and Ni to the copper alloy of claim 1 or 2. The copper alloy excellent in high-temperature wear resistance according to claim 4 of the present invention is contained in 0.5 to 12.0%.
Mn is further added to the copper alloy of 2 or 3 by 1.0 to 10.0%.
By containing it, the wear resistance can be further improved.

These copper alloys were confirmed to have good manufacturability, excellent abrasion resistance and corrosion resistance, and suitable for various high-performance sliding members for internal combustion engines. Above all, it was confirmed that the valve seat, which is the seat portion of the valve face, and the valve guide that slides with the valve stem exhibited excellent performance.

Next, the reason why the component composition (% by weight) of the copper alloy according to the present invention is limited as described above will be described.

Al: Al in the copper alloy of the present invention is
By increasing the high-temperature strength and high-temperature hardness by forming a solid solution in the matrix, there is an effect of improving high-temperature wear resistance,
It has the effect of bonding with a group Va element of the periodic table, Co, Fe, Ni, etc., which will be described later, to precipitate a composite intermetallic compound, thereby improving heat resistance and abrasion resistance. %, The effect is not sufficiently obtained. On the other hand, if the content is more than 15.0%, embrittlement is caused and thermal conductivity is reduced.
5.0%.

Co: Co in the copper alloy of the present invention is
It has the effect of improving the heat resistance by forming a solid solution in the matrix, forming an intermetallic compound with Cu, or forming various complex intermetallic compounds together with a Va group element and Cu and Al elements to provide heat resistance and wear resistance. Has the effect of improving the properties. However, if the content is less than 0.5%, the above effect cannot be sufficiently obtained. On the other hand, if the content exceeds 10.0%, the thermal conductivity decreases, so Co is added. In this case, the content was determined to be 0.5 to 10.0%.

Group Va element: The group Va element components such as V, Nb and Ta in the copper alloy of the present invention are Cu, Al, C
o, a spherical or massive Va-group element-rich intermetallic compound having a particle size of about 10 μm, and an amount of a Va-group element in which very fine precipitates having a particle size of about 1 μm are arranged in a resin or petal shape. And has an effect of significantly increasing the high-temperature wear resistance and abrasive wear resistance. However, if the total content of the Va group element is less than 0.1%, the above effect cannot be sufficiently obtained. On the other hand, if the total content is more than 5.0%, it is not dissolved in the aluminum bronze base material and segregates. Group element content 0.1
To 5.0%.

Fe, Ni: F in the copper alloy of the present invention
e and Ni mainly form an intermetallic compound with an Al or Va group element to improve the heat resistance and wear resistance of the copper alloy. However, if the content is less than 0.5%, the above effect cannot be sufficiently obtained. On the other hand, if the content exceeds 12.0%, the thermal conductivity deteriorates and the material becomes brittle.
Is added, the total content of one or two is 0.5
１12.0%.

Mn: Mn in the copper alloy of the present invention is
It also has the effect of increasing the strength by granulating the structure of aluminum bronze and preventing the alloy from being slowly cooled and embrittled. Further, it has the effect of forming a solid solution in the matrix to improve the strength and wear resistance. However, if the content is less than 1.0%, the above effect cannot be sufficiently obtained, while if the content exceeds 10.0%, embrittlement occurs.
When Mn is added, its content is 1.0 to 10.0%
It was decided.

[0023]

The copper alloy according to the present invention has an Al content of 1.0
１５15.0%, V, Nb,
At least one of Ta: 0.1 to 5.0%, in some cases Co: 0.5 to 10.0%, and in some cases, one or two of Fe and Ni: 0.5 to 12.
0%, and in some cases, Mn: 1.0 to 10.0%
Having a composition consisting of the balance Cu and impurities,
An intermetallic compound composed of at least one of Al, Co, Fe, Ni, and Cu and at least one of Va group elements, for example, Al-
V, Cu-V, Al-Nb, Cu-Nb, Al-Ta,
Cu-Ta, Al-Cu-V, Al-Co-V, Cu-
Co-V, Al-Cu-Nb, Al-Co-Nb, Cu
-Co-Nb, Al-Cu-Ta, Al-Co-Ta,
At least one of the intermetallic compounds made of Cu—Co—Ta or the like is dispersed as spheres or aggregates having a particle size of about 10 μm, and in some cases, Al, Co, Fe, Ni, C
intermetallic compound consisting of two or more kinds of u, for example, Cu-C
O, Fe-Al, Ni-Al, Al-Fe-Ni and other intermetallic compounds have a structure in which they are dispersed as spheres or aggregates having a particle size of about 10 μm, so that they have excellent wear resistance at high temperatures. In addition to exhibiting oxidation resistance and corrosion and wear resistance, when the valve seat is formed by laser cladding, laser cladding in the atmosphere is greatly improved, and leaded gasoline etc. Corrosion and abrasion due to deposits and abrasion powder are greatly improved, and the sliding wear is not limited to valve seats and is not limited to various types of high-temperature environments such as engines. It becomes suitable as a moving member.

[0024]

Examples 1 to 6; Comparative Examples 1 and 2 Cu having the composition shown in Examples 1 to 6 of Table 1 and Comparative Examples 1 and 2 of Table 2 was placed in a graphite crucible using a high-frequency induction melting furnace. After smelting the molten alloy and casting it into an ingot,
Each of the ingots is subjected to hot forging and hot extrusion at 780 ° C., and then the extruded material is subjected to cutting to obtain the valve seats of Examples 1 to 6 of the present invention and the valve seats of Comparative Examples 1 and 2. Made. These valve seats were pressed into the exhaust side of an aluminum alloy cylinder head for a real engine.

Example 7 Comparative Example 3 Using a high-frequency induction melting furnace, a Cu alloy melt having the composition shown in Example 7 in Table 1 and Comparative Example 3 in Table 2 was melted in a graphite crucible, and each alloy was melted. The molten metal was powderized by gas atomization, subjected to dehydration treatment and particle size distribution adjustment to obtain powder for powder metallurgy, a lubricant was added to each powder, and dewaxing and sintering were performed after molding. 7 and the valve seat of Comparative Example 3 were produced. These valve seats were also pressed into the exhaust side of an aluminum alloy cylinder head for a real engine.

Examples 8 and 9; Comparative Example 4 Using a high-frequency induction melting furnace, molten Cu alloys having the compositions shown in Examples 8 and 9 of Table 2 and Comparative Example 4 were melted in a graphite crucible. The molten alloy was pulverized by gas atomization, dewatered and degassed, and subjected to particle size adjustment to prepare powder for overlay. And these powders
Immediately using a kW CO ₂ gas laser, the exhaust valve seat portion of the aluminum alloy cylinder head was overlaid with a thickness of 3 mm or more in the processed recess. Thereafter, machining was performed to produce a cylinder head provided with the valve seats of Examples 8 and 9 and Comparative Example 4.

Structure Observation Examples The intermetallic compounds deposited in the valve seats of Examples 1 to 9 and Comparative Examples 1 to 4 manufactured as described above were examined. The results are shown in Tables 3 and 4. When the volume ratio of the precipitated intermetallic compound was examined, the results are also shown in Tables 3 and 4.

Through the above examples, it has been found that the deposition amount of the intermetallic compound mainly composed of Va elements such as V, Nb, Ta, etc. is preferably 1% to 50% by volume. Was.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

The actual engine durability test Examples built above Examples 1-9, the actual cylinder head engines obtained in Comparative Examples 1 to 4 in an actual engine, a durability test was carried out as shown in Table 5 below.

[0034]

[Table 5]

Tables 3 and 4 show the results of measuring the amount of wear (wear depth) of each valve sheet and observing the friction surface after the durability test. However, in the valve seat of Comparative Example 4, the build-up portion was peeled off and dropped off from the aluminum alloy cylinder head at the endurance of 60 hours, and the engine stopped.
The amount of wear could not be measured.

As is evident from the results shown in Tables 1 to 4, all of the valve seats of Examples 1 to 9 of the present invention have a small amount of abrasion, exhibit excellent abrasion resistance, and have a high scanning performance. In the observation of the friction surface with an electron microscope, only a shallow wear mark caused by slip was observed, but no abnormal form such as corrosion was observed.

Further, in the valve seat of Embodiment 7 which is a sintered material, there is not much difference in abrasion resistance as compared with the valve seat of Embodiment 6 which is an ingot material, but the product is close to the final shape (n
Since it can be manufactured by ear-net-shape, there is an advantage that the processing efficiency and material yield during mass production are high.

On the other hand, Embodiments 8 and 9 which are laser overlay materials
The valve seat of No. 1 shows more excellent wear resistance than the above-mentioned sintered material and ingot material. This is because, when the molten alloy powder is put on a cylinder head material made of aluminum alloy with high thermal conductivity, it is rapidly cooled and solidified instantaneously in laser cladding, so that it becomes harder than the molten material or sintered material. Is considered as one factor.

With respect to these valve seats of the present invention,
As is clear from the valve seats of Comparative Examples 1 and 2 which are ingot materials and the valve seats of Comparative Example 3 which is a sintered material, the valve seats of Comparative Examples 1 to 4 were considerably worn, In the valve seat of Comparative Example 4 which was a filling material, there was a problem that the valve sheet was peeled off during the durability.

When the friction surfaces of the valve seats of Comparative Examples 1 to 3 were observed with a scanning electron microscope, a large number of pits were found in all of the valve seats. Further, when a characteristic X-ray image of the Ti element and the Cl and Br elements was observed in these pit portions, these elements were segregated around the pits.

From these results, it was found that the Ti element contained in the valve seat of the comparative example was composed of PbCl ₂ and PbBr ₂ , which are combustion products of ethylene dichloride and ethylene dibromide, which are the lead scavengers contained in the leaded gasoline fuel. As pits (pitting) formed by mixing in the gas, depositing on the sheet surface and reacting with these Cl and Br on the friction surface by a tribo-chemical reaction. it is conceivable that.

In addition, in the valve seat of Comparative Example 4, which is a build-up material, the oxidation of Ti during laser build-up in the atmosphere and the halogen corrosion action during the durability test overlapped, and the build-up portion was significantly embrittled. It is thought that it peeled off.

In any case, the valve seat of the comparative example containing Ti, which is also used as a getter agent for oxygen, is inferior in corrosion resistance to a halogen element and oxidation resistance when building up in the air, thus causing the above problem. It is clear that

On the other hand, in the valve seat of the present invention, such a problem does not occur because Ti of the IVa group is not contained.

In order to promote the precipitation of a hard intermetallic compound which plays a major role in improving the wear resistance, the present invention results from the inclusion of V, Nb and Ta, which are elements of the Va group, in the Cu alloy. A spherical or massive intermetallic compound having a particle size of about 10 μm, which was not found in the valve seat of the comparative example, was formed.

As a representative structure, FIG. 1 shows the observation result (400 times) of the valve sheet of Comparative Example 2 by an optical microscope, and FIG. 2 shows the observation result of the valve sheet of Example 6 of the present invention by a scanning electron microscope (1000 times). Times).

The fine intermetallic compound denoted by reference symbol B in FIG. 2 has a form similar to that of the intermetallic compound shown in FIG. On the other hand, the spherical intermetallic compound having a particle diameter of about 10 μm shown by the symbol A in FIG. 2 does not exist in FIG. Therefore, the large spherical precipitates present in FIG. 2 also provided a significant improvement effect on abrasive wear caused by deposits and wear powder, which also indicates that the valve seat of the present invention example shows excellent wear resistance. It is thought that they are connected.

As described above, the copper alloys of the examples of the present invention exhibited excellent wear resistance, oxidation resistance and corrosion resistance at high temperatures. In this embodiment, the valve seat has been described as an example. However, a valve guide can be manufactured by a casting-forging-extrusion process or sintering, and other similar characteristics are required. The present invention can be applied to sliding members for engines and the like, and has a wide range of use.

[0049]

The copper alloy according to the present invention has an Al content of 1.0.
１５15.0%, V, Nb,
At least one of Ta: 0.1 to 5.0%, in some cases Co: 0.5 to 10.0%, and in some cases, one or two of Fe and Ni: 0.5 to 12.
0%, and in some cases, Mn: 1.0 to 10.0%
Having a composition consisting of the balance Cu and impurities,
At least one of the intermetallic compounds composed of at least one of Al, Co, Fe, Ni, and Cu and at least one of the Va group elements.
The seeds are dispersed as spheres or aggregates having a particle size of about 10 μm, and in some cases, Al, Co, Fe, Ni, Cu
Since it has a structure in which the intermetallic compound composed of more than one kind is dispersed as a sphere or a lump having a particle size of about 10 μm, it exhibits excellent wear resistance at high temperatures, and has oxidation resistance and corrosion wear resistance. Improved copper alloy with high thermal conductivity.Excellent wear resistance at high temperatures, especially when used as a material for engine valve seats and valve guides. Not only has excellent wear resistance, but also has high thermal conductivity and excellent thermal conductivity, contributing to higher output and lower fuel consumption of the engine. A remarkably excellent effect is obtained that the material is suitable as a material for a sliding member or the like.

[Brief description of the drawings]

FIG. 1 is a photograph showing an observation result (400 times) of an optical microscope of a valve seat of Comparative Example 2.

FIG. 2 is a photograph showing a result of observation of a valve seat of Example 6 of the present invention by a scanning electron microscope (× 1000).

Continuation of front page (56) References JP-A-2-108492 (JP, A) JP-A-2-50929 (JP, A) JP-A-58-1881838 (JP, A) JP-A-61-207539 (JP, A) , A) JP 39-9676 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C22C 9/01

Claims (4)

(57) [Claims] 1. Al: 1.0 to 15.0% by weight,
At least one of V, Nb and Ta, which is a group Va element of the periodic table, has a composition of 0.1 to 5.0%, the balance being Cu and impurities, and at least one of Al and Cu and a group Va element. Of at least about 10 μm in particle diameter
Is a copper alloy excellent in high-temperature abrasion resistance, characterized by having a structure in which at least one kind of massive intermetallic compound is dispersed. 2. Co: contains 0.5 to 10.0% of A;
The copper alloy excellent in high-temperature wear resistance according to claim 1, wherein the copper alloy has a structure in which at least one kind of an intermetallic compound composed of at least one kind of l, Co, Cu and at least one kind of Va group element is dispersed. 3. One or two of Fe and Ni: 0.
Al, Co, Fe, Ni, C
3. The copper alloy excellent in high-temperature wear resistance according to claim 1 or 2, having a structure in which at least one kind of an intermetallic compound composed of at least one kind of u and at least one kind of a Va group element is dispersed. 4. The copper alloy excellent in high-temperature wear resistance according to claim 1, containing Mn: 1.0 to 10.0%.