JPS62133027A - Manufacture of sintered copper alloy having self lubricating property, material sheet and powder for sintered copper alloy - Google Patents

Abstract

PURPOSE:To manufacture the titled alloy superior in wear resistance and pressing strength, by mixing specified quantities of Mo and graphite to copper alloy powder having a specified compsn. contg. Ni, Sn, P, forming the mixture to sheet together with organic binder, then sintering it. CONSTITUTION:To copper alloy powder contg. by weight 5-30% Ni, 7-13% Sn, 0.3-2% P, as lubricating powder, 1-5% Mo powder and 1-2.5% graphite powder are mixed to prepare material powder. A suitable quantity of synthetic resin binder is added to the material powder, these are mixed by kneader, etc., to obtain mixture in which the material powders are uniformly dispersed in synthetic resin binder. Next, the mixture is formed to material sheet by rolling mill, etc. The sheet is charged in vacuum sintering furnace, etc., and heated. In this way, synthetic resin binder in material sheet is decomposed and removed, the material powder is sintered and the titled alloy providing superior wear resistance and high compressing strength is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (1) Industrial Application Field The present invention relates to a method for producing a sintered copper alloy having self-lubricating properties used for wear plates of press machines, etc. The present invention relates to raw material sheets and raw material powders for sintered copper alloys.

(2) Conventional technology Conventionally, as a method for manufacturing this type of sintered copper alloy, a method of sintering copper-based raw material powder containing 2.7 Kel, tin, phosphorus, and graphite has been known (Japanese Patent Publication No. 1983- (See Publication No. 52547).

(3) Problems to be Solved by the Invention The graphite functions as a lubricant, and in order to fully exhibit its function, a large amount of graphite powder is used in the conventional method.

As a result, there is a problem that the compressive strength of the sintered copper alloy is reduced, and the toughness and therefore the impact resistance of the sintered copper alloy are low due to the chemical components.

Furthermore, since the raw material powder is used in a powdered state,
There are also problems in that it is difficult to handle and interferes with the production efficiency of sintered copper alloys.

In view of the above, the present invention reduces the graphite content and supplements the reduced graphite bone with molybdenum, which has lubricity and contributes to improving wear resistance, and also exhibits the effect of improving toughness, thereby achieving excellent wear resistance. Another object of the present invention is to provide the above-mentioned manufacturing method capable of obtaining a self-lubricating sintered copper alloy having high compressive strength, a raw material sheet used for carrying out the method, and a raw material powder used similarly.

B0 Structure of the Invention (], ) Means for Solving the Problems The method for producing a sintered copper alloy having self-lubricating properties according to the present invention includes 5 to 30% by weight of nickel, 7 to 13% by weight of tin, and 0% of phosphorus.
．． A raw material consisting of a raw material powder, which is a mixture of copper alloy powder containing 3 to 2% by weight, with 1 to 5% by weight of molybdenum powder and 1 to 2.5% by weight of graphite powder as lubricating powder, and a synthetic resin binder. The method is characterized by using a step of obtaining a sheet; and a step of heating the raw material sheet to decompose the synthetic resin binder and sintering the raw material powder.

Further, the raw material sheet for sintered copper alloy according to the present invention contains 5 to 30% by weight of nickel, 7 to 13% by weight of tin, and phosphorus.
Consisting of raw material powder, which is a mixture of copper alloy powder containing 0.3 to 2% by weight, 1 to 5% by weight of molybdenum powder and 1 to 2.5% by weight of graphite powder as lubricating powder, and a synthetic resin binder. It is characterized by being

Further, the raw material powder for sintered copper alloy according to the present invention contains 5 to 30% by weight of nickel, 7 to 13% by weight of tin, and phosphorus.
It is characterized in that copper alloy powder containing 0.3 to 2% by weight is mixed with 1 to 5% by weight of molybdenum powder and 1 to 2.5% by weight of graphite powder as lubricating powder.

(2) Function Since a mixed powder of molybdenum powder and graphite powder is used as the lubricating powder, the graphite content is reduced in accordance with the molybdenum content, thereby improving the compressive strength and toughness of the sintered copper alloy. It becomes possible to improve the performance.

Furthermore, since the raw material powder is used in the form of a raw material sheet, the raw material powder can be easily handled.

Furthermore, the synthetic resin binder is decomposed by heating, and the decomposed gas is discharged from between the constituent powders of the raw material powder, ensuring that defects such as the formation of cavities caused by residual gas in the sintered copper alloy and the intrusion of harmful gas components are prevented. can be avoided.

The reason for limiting the blending amount of each chemical component as described above and the role of each chemical component are as follows.

Nickel functions as a brazing material and has the effect of improving the sinterability of the raw material powder and the strength of the copper matrix, but if the amount is less than 5% by weight, the above effects cannot be obtained, and if the amount is less than 30% by weight. Even if the amount exceeds the above, no improvement in the above effect can be expected, and furthermore, the cost will increase.

Tin alloys with copper and exhibits the effect of improving the strength and wear resistance of the copper matrix, but if the content is less than 7% by weight, the above effects cannot be obtained, and if the content exceeds 13% by weight, the copper alloy The melting point of the sintered copper alloy decreases, and the shape retention of the sintered copper alloy deteriorates.

Phosphorus precipitates in the copper matrix and has the effect of improving its strength and wear resistance, but when the amount of phosphorus is 0.3
If it is less than 2% by weight, the melting point of the copper alloy will increase and the sinterability of the raw material powder will deteriorate, and if it exceeds 2% by weight, the melting point of the copper alloy will decrease and the shape retention of the sintered copper alloy will deteriorate.

Molybdenum has the effect of strongly bonding with copper alloys and improving the toughness, wear resistance, and lubricity of sintered copper alloys, but if the amount of molybdenum is less than 1% by weight, the above effects cannot be obtained; If it exceeds 5% by weight, it becomes difficult to form the raw material sheet, and the sintering strength and density of the sintered copper alloy decrease.

Graphite has the effect of improving the lubricity of the sintered copper alloy, but if the amount is less than 1% by weight, the above effect cannot be obtained, and if it exceeds 2.5% by weight, it will cause compression of the sintered copper alloy. Strength decreases.

(3) Embodiment FIG. 1 shows the construction of a sliding member, in which the sliding member I consists of a base material 2 and a self-lubricating sintered copper alloy 3 welded to its negative surface. The sintered copper alloy 3 is welded to the base material 2 during sintering.

Next, a method for manufacturing the sliding member 1 will be explained with reference to FIGS. 2 and 3.

i. 25% by weight of nickel, tin obtained by the spraying method for manufacturing raw material sheets.
Copper alloy powder consisting of 10% by weight, 1.1% by weight of phosphorus and the balance copper, with a particle size that can pass through a standard sieve of 110 sieve; 92% by weight, which can pass through a standard sieve of 270 sieve, obtained by a mechanical grinding method. From 2.5% by weight of molybdenum powder with a particle size that can pass through a standard sieve of 28 meshes but not 65 meshes, obtained by mechanical grinding method. and 3% by weight of a synthetic resin binder obtained by mixing a tetrafluoroethylene resin and an acrylic resin at a ratio of 1:1 and adding 50% by weight of water to the mixed resin to form an emulsion. As shown in Figure 81, they are put into a kneader 4 and mixed for 3 minutes to obtain a mixture M in which the raw material powder is uniformly dispersed in a synthetic resin binder.

As shown in FIG. 2 (bl), the mixture M is transferred onto a heater 5 and heated to 80 to 150°C to evaporate water and dry it.

As shown in FIG. 2 (C1), the heated mixture M is passed through the roll machine 6 several times to obtain a raw material sheet S having a thickness of 2 to 3 am.

As shown in FIG. 2(d), the raw material sheet S is transferred onto the heater 5 and heated at 80 to 120° C. for 30 minutes to remove distortion during roll forming.

The density of the raw material sheet S is 4.8 g/cro3, as shown in Figure 2.
It is stored by winding it into a roll as shown in fe).

ii. Manufacture of sliding member As shown in FIG. 2(f), from the raw material sheet S,
1. Cut the raw material plate P with a width of 200 mm, and cut the raw material plate P into a J [S 5S
It is attached to the upper surface of the net board base material 2 represented by 41 using acrylic adhesive, and the upper surface is 210 fins vertically and 21 fins horizontally.
It is covered with a breathable degassing sheet 6 made of ceramic fiber (trade name Kao Wool) with a thickness of 0.0 and 2.
Pressurizing body 7 made of the same material as the above for Dragon and Tsuru with a thickness of 3B.
Place.

The pressurizing body 7 is used to press the raw material powder during sintering to improve the density of the sintered copper alloy 3, but if this pressurizing body 7 is placed directly on the raw material plate P, the synthesis The degassing performance of the cracked gas generated from the resin binder and the like is poor, and the raw material powder at the outer periphery of the raw material plate P that has lost its binding strength is scattered by the ejection pressure of the cracked gas. Therefore, the sheet 6, which is larger than the raw material plate P, is interposed between the pressurizing body 7 and the raw material plate P, and a gas discharge path is formed using its breathability.
It also prevents the raw material powder from scattering. In order to fully achieve this purpose, the size of the raw material plate P and the sheet 6 must be
There is a correlation between the thickness of For example, when the thickness of the raw material plate P is 21 m, its size is 800 mm in length and 80 mm in width.
Then, the thickness of sheet 6 is 1■-1 length 2001, width 200
With a quotient of 1, the thickness of the sheet 6 is 2. In addition, if the size of the raw material plate P having the above-mentioned thickness is less than 60 mm in length and 60 mm in width, the decomposition gas may be absorbed even without the sheet 6 in cases where the thermal decomposition of synthetic resin binder etc. is extremely slow. Evacuation is easy and the raw material powder does not scatter.

The degassing sheet 6 is required to have non-adhesive properties to the powder and the pressurizing body 7 at the sintering temperature of the raw material powder. In addition to the ceramic fibers, there are 8 other materials that meet this requirement, such as asbestos and rock wool. In addition, when the sheet 6 is not used, a mold release agent is applied to the pressurizing body 7 in order to prevent the pressurizing body 7 from fusing to the raw material powder. A method such as interposing a ceramic body such as the like is adopted.

The laminate was placed in a vacuum sintering furnace 8, and the synthetic resin binder and acrylic adhesive were thermally decomposed, the raw material powder was sintered, and the sintered copper alloy was welded to the base material under the heating conditions shown in FIG. conduct. Nitrogen gas is used as a carrier gas, and the degree of vacuum is ITorr.

+a+ First heating zone (FIG. 3 AI) This heating zone A is from room temperature to 600°C. The temperature increase rate from room temperature is 20° C./min, and the inside of the furnace is maintained at a constant temperature of 600° C. for 60 minutes.

In this heating zone A1, the moisture in the laminate is first evaporated, and then the tetrafluoroethylene resin, the acrylic resin, and the acrylic adhesive in the synthetic resin binder are thermally decomposed in the range of 560 to 600°C. Gasify. The cracked gas is discharged through the sheet 6 from between the constituent powders of the raw material powder. The sheet 6 prevents the raw material powder that has lost its bonding strength from scattering around the outer periphery of the base material 2 .

fbl Second heating zone (Fig. 3 A2) This heating zone A2 is approximately 900°C. The temperature increase rate from the first heating zone A1 is 20° C./min, and the inside of the furnace is maintained at a constant temperature of approximately 900° C. for 30 minutes. In this heating zone A2, the raw material powder and the base material 2 are heated uniformly.

fcl Third heating zone (A3 in FIG. 3) This heating zone A is approximately 1020°C. The temperature increase rate from the second heating zone A2 is 10°C/min, and the temperature inside the furnace is approximately 1020°C.
The temperature was maintained at constant temperature for 30 minutes. This heating zone A
3 is a method phase temperature range where a solid phase and a liquid phase coexist in the raw material powder, the pores between the same phase are filled with the liquid phase, and the fluidity of the liquid phase is promoted by the pressure of the pressurizing body 7, resulting in sintering. The sintering progresses and a sintered copper alloy 3 with high density is obtained. At the same time, the sintered copper alloy 3 is welded to the base material 2. In this case, nickel is alloyed with phosphorus, and its function as a brazing material ensures that the sintered copper alloy 3 is welded to the base material 2.

In this heating zone A:I, since the flow of the liquid phase in the raw material powder is slow, floating and segregation of graphite does not occur, and therefore the lubricity of the sintered copper alloy becomes uniform throughout.

+d+ Cooling zone (Fig. 3B) Nitrogen gas is introduced into the vacuum sintering furnace 8 until the internal pressure reaches 500 mmHg, and the nitrogen gas is circulated by a cooling fan to cool the sintered copper alloy 3, base material 2, etc. to cool down.

The sliding member 1 shown in FIG. 1 is obtained through the heating and cooling process described above.

Sintered copper alloy 3 had a density of 6.3 g/am', a Rockwell hardness of HR835 or more, and a porosity of 13%, and no chipping occurred on the outer periphery.

After subjecting the sliding member 1 to mechanical processing and oil impregnation treatment, a functional test was conducted using it as a wear plate of a press machine, and the results shown in Table 3 were obtained. In the table, A corresponds to the sliding member obtained through the above process, and B corresponds to a sliding member obtained by embedding graphite in cast iron as a comparative example.

In addition, the mating material of cast iron and graphite has the same structure as Comparative Example B.

Table I As is clear from Table (■), sliding member A has approximately the same wear resistance as Comparative Example B, and has excellent sliding properties.

Table ■ shows that the blending amounts of molybdenum powder (Mo) and graphite powder (G) were varied in copper alloy powder containing 28.7% by weight of nickel, 8.5% by weight of tin, and 0.63% by weight of phosphorus. A raw material sheet is manufactured in the same manner as described above using raw material powder, and the raw material sheet cut from the raw material sheet is
The Rockwell hardness HRB of a sintered copper alloy obtained by vacuum sintering under sintering conditions of heating at 40° C12O for minutes is shown.

Table ■ As is clear from Table ■, the hardness of the sintered copper alloy improves as the graphite content decreases, and at the same graphite content, the hardness improves as the molybdenum content increases. This improves the wear resistance of the sintered copper alloy.

FIG. 4 shows the compressive strength of the sintered copper alloy, and it is clear that this compressive strength is independent of the molybdenum content and decreases with increasing graphite content. The compressive strength required for sliding parts such as press wear plates is 17 to 2.
5 kg/mm2, and in order to satisfy this, it is necessary to set the graphite content to 1 to 285% by weight.

The synthetic resin binder is blended in an amount of 1 to 4% by weight based on the raw material powder. The reason for this is that when the amount of synthetic resin binder is less than 1% by weight, the shape retention of the raw material sheet is poor, and the binding force between the raw material powders becomes weak, causing the powder to fall off, whereas when it exceeds 4% by weight. This increases the porosity of the sintered copper alloy, resulting in a decrease in density and deterioration of shape accuracy, and increases residual carbon, which inhibits sinterability and causes poor welding of the sintered copper alloy to the base material. Because it invites you.

C8 Effects of the Invention According to the present invention, since a mixed powder of molybdenum powder and graphite powder is used as the lubricating powder, the content of graphite can be reduced in accordance with the content of molybdenum. A self-lubricating sintered copper alloy with good wear resistance can be obtained which has excellent compressive strength based on the reduction of the amount and also has improved toughness and therefore impact resistance properties based on the addition of molybdenum. .

Further, according to the second invention, since the raw material powder is used in the form of a raw material sheet, the raw material powder can be easily handled and the production efficiency of the sintered copper alloy can be improved.

In this case, the synthetic resin binder is decomposed by heating and the decomposed gas is emitted from between the constituent powders of the raw material powder, resulting in problems such as the formation of cavities due to residual gas in the sintered copper alloy and the intrusion of harmful gas components. can be definitely avoided.

Furthermore, according to the third invention, a self-lubricating sintered copper alloy having excellent compressive strength, toughness and wear resistance can be obtained.

[Brief explanation of drawings]

Figure 1 is a perspective view of the sliding member, Figure 2 is an explanatory diagram of the manufacturing process of the sliding member, Figure 3 is a graph showing the relationship between time and temperature in the sintering process, and Figure 4 is a graph showing the relationship between time and temperature in the sintered copper alloy. It is a graph showing the relationship between graphite content and compressive strength. S...Raw material sheet, 3...For sintered copper alloy.
Applicant Honda Motor Co., Ltd. Figure 3 Figure 4 Graphite content (wt%) Figure 2 (a) (b) (f) (d)

Claims (3)

[Claims] (1) Nickel 5-30% by weight, tin 7-13% by weight
and copper alloy powder containing 0.3 to 2% by weight of phosphorus,
On the other hand, a step of obtaining a raw material sheet made of a synthetic resin binder and a raw material powder mixed with 1 to 5% by weight of molybdenum powder and 1 to 2.5% by weight of graphite powder as lubricating powder; A method for producing a sintered copper alloy having self-lubricating properties, comprising: decomposing a synthetic resin binder and sintering the raw material powder. (2) Nickel 5-30% by weight, tin 7-13% by weight
and copper alloy powder containing 0.3 to 2% by weight of phosphorus,
On the other hand, a raw material sheet for a sintered copper alloy is made of a raw material powder mixed with 1 to 5% by weight of molybdenum powder and 1 to 2.5% by weight of graphite powder as lubricating powder, and a synthetic resin binder. (3) Nickel 5-30% by weight, tin 7-13% by weight
and copper alloy powder containing 0.3 to 2% by weight of phosphorus,
On the other hand, a raw material powder for a sintered copper alloy is prepared by mixing 1 to 5% by weight of molybdenum powder and 1 to 2.5% by weight of graphite powder as lubricating powder.