JPH0584592A - Cobalt-based filling alloy excellent in wear resistance and opponent attackability - Google Patents

Abstract

PURPOSE:To obtain the cladding alloy improved in wear resistance, opposite-side attackability and a filling property by adding specified components to the cobalt- based filling alloy used for reinforcing a face part of an engine valve or regulating the content thereof. CONSTITUTION:The cobalt-based filling alloy contains, by weight, 10-40% Cr, 10-30% Mo, 10-20% W, 0.5-5.0% Si, 0.05-3.0% C, 0.01-0.1% O, 0.001-0.12% Al, <=30% Fe, <=20% Ni and <=3% Mn. As necessary, 0.01-0.1% B is further added or one or more kinds selected from Ta, Nb, V, Ti, Zr and Hf are contained by <=2% in total. The balance contains Co and inevitable impurities, provided that the Co quantity is regulated to 30-70%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cobalt base gold alloy which is deposited on the face portion of an engine valve of an internal combustion engine.

[0002]

2. Description of the Related Art The face portion of an engine valve of an internal combustion engine is provided with a hard facing for welding cobalt base metal, which is excellent in wear resistance and has high hardness at high temperature and high resistance to high temperature corrosion, in order to cope with severe operating environments. Has been adopted.

Conventionally, Co--Cr has been used as the above-mentioned gold alloy.
-W type cast alloy Stellite 6 or Stellite 12, Co-Mo-Si type Triballoy T-400,
Furthermore, those in which the wear resistance is improved by adjusting Cr, W and C of the stellite alloy, and the metallurgical properties are improved by adjusting Al, B and O (JP-A-2-92495, JP-A-2-9249).
6) The shape of the stellite alloy powder and the amount of oxygen and nitrogen are regulated to improve the depositability (Japanese Patent Laid-Open No. 62-330).
90) and the like are used.

A photograph showing the metallographic structure of a stellite-based heli-metal alloy is shown in FIG. 3, and a photograph showing the metallographic structure of Trivalloy T-400 is shown in FIG. In FIG. 3, stellite is a black-rich (Cr, W) _{23 in the} white Co-rich matrix.
C ₆ or (Cr, W) ₇ C ₃ is dispersed and carbide strengthened. In FIG. 4, triballoy is reinforced with silicide by dispersing Co ₃ Mo ₂ Si in the gray portion in the Co rich matrix in the white portion.

[0005]

However, with the recent demand for higher performance of automobile engines, such as higher output, lower fuel consumption, and improved reliability, the operating environment of engine valves has become more severe than before. However, the wear resistance of the face portion has been insufficient in the engine valve which has been conventionally used and which is made up of stellite 6 or stellite 12 and the like.

Further, in recent years, in order to automate the depositing on the valve face portion of an internal combustion engine, a powder depositing is performed by using a high density energy source such as laser or plasma to make a deposit alloy into powder. Gold has attracted attention, and as a deposit material using this, a conventional alloy has been used in the form of powder. Therefore, in addition to the properties such as abrasion resistance that have been conventionally required for the metal-plating material, the metal-plating property has been widely taken up. ..

[0007] Further, the metallurgical alloy disclosed in Japanese Patent Laid-Open No. 62-33090 is a material that pays particular attention to plasma metallizing property, and is equivalent to Stellite 6 or Stellite 12 in wear resistance and opponent attacking property. Judged as a level. However, this metallurgy alloy aims to improve metallurgy by adjusting O and N, but O and N are elements that cause the generation of blowholes, etc. Therefore, the improvement of the richness is considered to be insufficient. In order to improve the metallurgy, it is desirable to more positively add an element such as O or N that removes an element that is a source of blowhole generation. In addition, it is necessary to consider not only blowholes but also good surface conditions (roughness of the surface, etc.) for the metallurgy, and like this metallurgy alloy, elements are added without depending only on the powder shape. By doing so, more reliable control is possible.

The metallurgical alloy disclosed in JP-A-2-92495-6 is basically composed of Cr, W, and
It is characterized by increasing the content of C and increasing hard carbide particles effective for ensuring wear resistance. However, strengthening by carbide, on the other hand, tends to improve the opponent attacking property, and Mo which is an element showing self-lubricity is added. Not including it also makes it easier to increase wear resistance as a total characteristic.

Therefore, Trivalloy T-4 is used as the next material.
An engine valve in which 00 is deposited on the face part is attracting attention. Although this alloy is excellent in wear resistance, it is slightly more aggressive against the opponent, and the deposit is also oxygen-acetylene using a deposit bar. There is a drawback that it is difficult to make money without the gas method.

That is, in Trivalloy T-400, the silicide (Co ₂ Mo ₂ Si) is used to secure the strength and to provide the lubricity at high temperature. A slower cooling rate is desirable. Also, since this silicide is hard and brittle, and cracks easily occur,
It is necessary to minimize the shrinkage stress that occurs during cooling during valve face plating.

For that purpose, the gas deposit is the best, and the deposit by high-density energy with a high cooling rate of plasma, laser, etc. is not preferable from the viewpoint of securing characteristics and manufacturability. In addition, since it is difficult to automate with gas filling, labor costs are high, and work environment problems such as fume generation are raised, and improvement of materials is desired. Therefore, it has been desired to develop a gold-plated alloy which is excellent in terms of wear resistance, opponent attack, gold-plating property and cost.

The present invention has been made to solve the above-mentioned problems of the conventional cobalt-based metallurgy alloy,
An object of the present invention is to provide a cobalt-based gold alloy that is plated on the face portion of an engine valve that is operated under high load, has excellent wear resistance and opponent attacking properties, and has good metal forming properties.

[0013]

Means for Solving the Problems The inventors have made diligent studies on the composition of conventional cobalt-based base metal alloys in order to improve their wear resistance, opponent attack and metal-plating properties under high load operation. Overlaid. As a result, it has been found that by increasing the Fe content, the toughness is improved and an oxide is formed, the effect as a lubricant is exhibited, and the wear resistance and the opponent attacking property are improved. Further, it was newly found that the addition of Al to regulate the O content can prevent the generation of blowholes, and the addition of B can improve the metal forming property and the bead shape. The present invention has been completed.

The cobalt-based high-purity gold alloy of the present invention, which is excellent in wear resistance and opponent attacking property, has a weight ratio of Cr: 10-40.
%, Mo; 30% over 10%, W: 1 to 20%, S
i; 0.5 to 5.0%, C; 0.05 to 3.0%, O;
0.01-0.1%, Al; 0.001-0.12%,
Fe: 30% or less, Ni: 20% or less, Mn: 3% or less, and the balance Co and unavoidable impurity elements (however,
The gist is that the Co amount is 30 to 70% by weight.

In the present invention, B: 0.01 to 0.1% is further added, or Ta, N is added if necessary.
1 or 2 selected from b, V, Ti, Zr and Hf
By including 2% or less in total of 2 or more kinds of seeds, it is possible to further improve the depositability, abrasion resistance and opponent attacking property.

[0016]

In the present invention, since Fe is contained in an amount of 30% or less, toughness is improved and an oxide is formed to exert an effect as a lubricant, and wear resistance and opponent attacking property are improved. .. Further, since Al is added and the O content is regulated, the metal-forming property is improved and it is possible to prevent the generation of bouleholes in the metal-plated part. Further, by containing B, it is possible to prevent O from entering from the outside, improve the metal forming property, and improve the bead shape.

The action and effect of each element contained in the present invention and the reason for limiting the composition range are as follows. Cr: 10 to 40% Cr is solid-solved in the Co-rich portion, and has effects of strengthening solid solution and improving oxidation resistance. Carbides are formed in the eutectic part to secure high-temperature strength and wear resistance. If the amount is less than 10%, the above properties cannot be sufficiently obtained, and if it exceeds 40%, the above-mentioned effect becomes excessive, the melting point of the alloy increases, the metallurgy deteriorates, and the cost also increases. .. These effects are
When the r content is 10 to 25%, the balance is excellent.

Mo: more than 10% and 30% Mo is mainly present in the eutectic part and forms carbides and silicides,
In addition to strengthening the material, it forms an oxide in a high temperature oxidizing atmosphere and exhibits the effect as a lubricant. That is, the wear resistance is improved. It is also present in the primary crystal part to a considerable extent, and improves strength and wear resistance. If the amount is 10% or less, the above effect cannot be sufficiently obtained, and if it exceeds 30%, the toughness is reduced due to the increase in strength, the opponent attack is deteriorated, and the metallurgical property is lowered due to the increase in the melting point of the alloy. Causes an increase in Kotos.

W: 1 to 20% W is present in the eutectic part and mainly forms carbides. This secures strength and wear resistance at high temperatures. The amount is 1%
If it is less than 20%, the above effect cannot be sufficiently obtained. On the contrary, if it exceeds 20%, the strength is improved, the toughness is reduced, the opponent attack is deteriorated, and the melting point of the alloy is increased, and the metallurgy is decreased, and the cost is increased. cause. These effects have a content of 1
Good balance and excellent at 10%.

Si: 0.5 to 5.0% Si is mainly present in the eutectic part and forms a silicide. Also,
By lowering the melting point of the alloy, the flowability of the molten metal during plating is improved, which has the effect of improving the plating property. It also has the effect of reducing non-metallic inclusions. If the amount is less than 0.5%, the above effect cannot be obtained, and if it exceeds 5.0%, excessive formation of silicide reduces the toughness and causes a reduction in opponent attack. These effects are especially 0.5-3.
Excellent balance and excellent at 5%.

C: 0.05 to 3.0% C forms a carbide in the eutectic part and improves strength and wear resistance. If it is less than 0.05%, carbide formation is insufficient,
On the other hand, if it exceeds 3.0%, the carbides become excessive and the strength is improved, but the toughness is lowered and the opponent attacking property and the metal forming property are deteriorated. These effects are excellent in a well-balanced manner, especially at 0.1 to 2.0%.

O: 0.01 to 0.1% O forms an oxide film on the bead surface after depositing metal, and has the effect of preventing O from entering from the outside, which causes blowholes. In order to bring out this effect, it is necessary to contain 0.01% or more, but on the contrary, if added excessively, blowholes themselves will be formed, so the upper limit was made 0.1%.

Al: 0.001 to 0.12% Al combines with O existing in the metal alloy powder to suppress blowhole generation and blows by forming an oxide protective film on the bead surface after metal plating. It also has an effect of preventing O 2 from entering from the outside which causes holes. The amount is 0.00
If it is less than 1%, a sufficient effect cannot be expected, and if it exceeds 0.12%, the bead shape is deteriorated. These effects are particularly effective at 0.005 to 0.12%.

Fe: 30% or less Fe has the effect of mainly improving the toughness of the material. In addition, it forms an oxide in an oxidizing atmosphere and exhibits an effect as a lubricant. For this purpose, up to 30% may be added. However, excessive addition makes it difficult to secure strength, so the upper limit was made 30%.

Ni: 20% or less Ni enhances the toughness of the material and makes it possible to secure the corrosion resistance under the condition of relatively low temperature. 20% for this purpose
You can add up to. However, excessive addition makes it difficult to secure wear resistance, so the upper limit was made 20%.

Mn: 3% or less Although the addition of Mn shows some improvement in the flowability of the molten metal, the wear resistance and strength decrease as the content increases, so the upper limit was made 3%.

B: 0.01 to 0.1% B is added to the alloy powder as required, and is effective in improving the metallurgical property, that is, in improving the bead shape, and particularly in improving the roughness of the bead surface. B does not need to be added particularly when the O and Al contents are small and when the amount of O penetrating from the outside into the metal deposit is small. When B is added, its amount is 0.0
If it is less than 1%, the above effect is not expected, and if it exceeds 0.1%, the melting point of the protective film formed on the bead surface is lowered, and the effect of preventing O intrusion from the outside is lowered. In addition, regarding the amount of B added, it is desirable that the weight ratio of (O + Al) / B is 1 to 20 in relation to the amount of O and the amount of Al. If this ratio is smaller than 1, the melting point of the protective film formed on the surface is lowered, so that the function of preventing O intrusion is reduced, and if it is larger than 20, the effect of improving the bead shape is not expected.

Ta, Nb, V, Ti, Zr, Hf; 2%
Hereinafter, these elements are elements that contribute to wear resistance, oxidation resistance, or depositability, and therefore, for this purpose, up to 2% in total may be contained. However, if it exceeds 2%, the productivity is deteriorated and the cost is increased. Therefore, the upper limit is 2%.
And

Co: Remainder (however, 30 to 70%) Co base material is most suitable for satisfying the effects of wear resistance, opponent attack, and metal-plating property, etc., brought about by each element in a well-balanced manner. And its content is 30
Must be between ~ 70%.

[0030]

EXAMPLES Examples of the present invention will be described in comparison with conventional examples and comparative examples to clarify the effects of the present invention. The cobalt-based Morigane alloy of chemical components shown in Table 1 were melted, the molten alloy was pulverized by a gas atomization method using N ₂ gas, it was cooled in N ₂ gas atmosphere, Co-base alloy powder Morigane A powder was obtained.

In Table 1, No. Nos. 1 to 9 are examples of the present invention. Nos. 6 and 7 contain B, No. No. 8 contains Nb and Ta, No. 8
No. 9 is V, Zr, Ti containing B in addition.
In addition, No. Nos. 10 to 13 are conventional examples. 10
Stellite 12, No. 11 is Triballoy T400,
No. No. 12 of JP-A-62-33090, No. No. 13 is a conventional material corresponding to JP-A-2-92495.
No. Nos. 14 to 16 are comparative examples. No. 14 has an O content higher than the composition range of the present invention and does not contain Al. No. 15 contains B and has an O content higher than the composition range of the present invention and does not contain Al. No. 16 has a high Al content.

[0032]

[Table 1]

Each of the powders obtained as described above was sieved through -80 to +350 mesh, and a plate-shaped test piece was subjected to plasma plating at an output of 130 A and a processing speed of 3 mm / sec to observe the bead shape. The presence or absence of blowholes in the deposit was examined by X-ray. The results are shown in Table 2.
And shown in Table 3.

[0034]

[Table 2]

[0035]

[Table 3]

As is clear from Table 3, the conventional material N
o. 12 has a few blowholes, and the comparative material N
o. Since Nos. 14 and 15 had a high O content, the bead shape was non-uniform and blow holes were observed.
In No. 16, the bead shape was poor although there were no blow holes because the Al content was high.

On the other hand, the case of No. 1-9
As shown in Table 2, although the bead surface had some roughness, the bead shape was generally good and no blowhole was observed.

The face portion 2 of the engine valve 1 as shown in FIG. 2 has No. 1 of the chemical composition shown in Table 1 as an example of the present invention. The cobalt-based gold alloys 1 to 9 were plated by the plasma plating method (output 130A, processing speed 8 mm / sec). FIG. 1 is a photomicrograph showing the metallographic structure of the metal deposit of the example. For comparison, the conventional example No. 10-13
Stellite 12, Triballoy T-400, JP-A-62-62
No. 33090, Heikin alloy, JP-A-2-92495.
With respect to the gold alloy disclosed in the publication, the face portion 2 of the engine valve 1 was similarly gold plated.

Using these engine valves,
Using a 00 cc gasoline engine, a 300-hour actual machine durability test was conducted. With respect to the engine valve after the actual machine durability test, the valve stem protrusion amount, the valve face wear amount, and the valve seat wear amount were measured. The valve stem protrusion amount is a total amount of the valve face wear amount (wear resistance) and the valve seat wear amount (opposite attacking property).

The result obtained is the limit reference value of the wear amount of 1
An index of 00 is shown in Tables 4 and 5.
Further, the manufacturability (including cost) of the powder required for the plasma plating process and the plating property in the plasma plating process are also shown in Tables 6 and 7 for comparison with the evaluation of the actual machine durability test. In Tables 6 and 7, ⊚ for powder manufacturability and depositability is excellent, ∘ indicates normal, and Δ indicates a little difficulty.

[0041]

[Table 4]

[0042]

[Table 5]

[0043]

[Table 6]

[0044]

[Table 7]

As shown in Tables 4 and 5, as a result of the actual machine durability test, No. 10 stellite 12
The valve seat wear amount was small, but the stem protrusion amount and the face wear amount were 100 or more. Also,
No. The triballoy No. 11 had a small amount of face wear, but had a high opponent attacking property, and both the stem protrusion amount and the valve seat wear amount were 100 or more.

No. 1 of the conventional example. JP-A-62-330
No. 90 bulletin alloy and No. 90. Japanese Unexamined Patent Publication No. 2-9
The helicopter alloy of Japanese Patent No. 2495 has a low opponent attack property, but the stem protrusion amount and the face wear amount are 100 or more.

On the other hand, in the embodiment of the present invention, the face wear amount is 5 to 90 and the wear resistance is excellent, and the valve seat wear amount is 5 to 95 with respect to the opponent attacking property. The protrusion amount was also 20 to 70, and it was confirmed that an engine valve excellent in wear resistance and opponent attacking property was obtained according to the present invention.

Further, as is clear from Tables 6 and 7, the powder manufacturability and the depositability of the example of the present invention were at a good level as compared with the conventional example, and it was found that there was no difference. did. In this example, the plasma plating method was used for the metal plating.
Using an O ₂ laser, an output of 2.7 KW) and an oxygen-acetylene gas method, a face portion of an engine valve was similarly plated, and an actual machine durability test was performed under the same conditions. It was confirmed that it was obtained.

[0049]

As described above in detail, the cobalt-based high-purity gold alloy of the present invention, which is excellent in wear resistance and opponent attacking property, contains 30% Fe based on the cobalt-based alloy stellite.
%, The toughness is improved and an oxide is formed to exert an effect as a lubricant, and the contained Cr, Mo and W solid solution strengthen the Co-rich matrix, and C and Si. When it is deposited on the face portion of an engine valve that is operated under high load, the wear resistance of the engine valve is improved and at the same time the opponent attack is satisfied. Further, since Al is added to regulate the O content, the metal-forming property is improved and the generation of blow holes in the metal-plated portion can be prevented. further,
By containing B as necessary, O can be prevented from entering from the outside, and the bead shape can be improved by improving the metallurgy.

[Brief description of drawings]

FIG. 1 is a micrograph showing a metal structure of a metal-filled portion according to an example of the present invention at 400 times magnification.

FIG. 2 is a partial side sectional view of an engine valve used in an embodiment of the present invention.

FIG. 3 shows a conventional metallographic structure of stellite using stellite.
It is a microscope photograph represented at 00 times.

FIG. 4 shows a conventional metallographic structure of a trivaloy using Triballoy.
It is a microscope photograph represented at 00 times.

[Explanation of symbols]

 1 engine valve 2 face part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyoshi Yoshida, Toyota City, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Masahiro Nakagawa, No. 1, Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. ( 72) Inventor Kazuhiko Mori Toyota Automobile Co., Ltd., 1 Toyota Town, Aichi Prefecture (72) Inventor Hiroyuki Murase 1 Toyota Town, Toyota Automobile Co., Ltd., Aichi Prefecture (72) Inventor Atsushi Taguchi Aichi Prefecture 1-1-1, Kyowa-cho, Obu-shi Aisan Kogyo Co., Ltd. (72) Inventor Kensuke Hidaka 6 Iwakura-Tadachi-cho, Sakyo-ku, Kyoto-shi, Kyoto (72) Ken-ichi Tanaka Kawaguchi, Yawata-shi, Kyoto No. 19 Beach (72) Inventor Yoshio Kodaira No. 318 Ichinotsubo, Makishima Town, Uji City, Kyoto Prefecture

Claims (3)

[Claims] 1. Cr: 10-40% by weight, Mo; 1
30% over 0%, W: 1-20%, Si: 0.5-
5.0%, C; 0.05 to 3.0%, O; 0.01 to
0.1%, Al; 0.001-0.12%, Fe; 30
% Or less, Ni; 20% or less, Mn; 3% or less,
The balance is Co and unavoidable impurity elements (however, the amount of Co is 3
Cobalt-based gold alloy having excellent wear resistance and opponent attacking property, which is characterized by comprising 0 to 70% by weight. 2. A weight ratio of Cr: 10 to 40% and Mo: 1
30% over 0%, W: 1-20%, Si: 0.5-
5.0%, C; 0.05 to 3.0%, O; 0.01 to
0.1%, Al; 0.001-0.12%, Fe; 30
% Or less, Ni; 20% or less, Mn; 3% or less,
Further, B; 0.01 to 0.1% is contained, and the balance is composed of Co and unavoidable impurity elements (however, the Co amount is 30 to 70% by weight), which is excellent in wear resistance and opponent attacking property. Cobalt based gold alloy. 3. The method according to claim 1 or 2, wherein the content of one or more selected from Ta, Nb, V, Ti, Zr and Hf is 2% or less in total. Cobalt-based gold alloy with excellent wear resistance and aggressiveness against opponents.