JPH0677829B2 - Manufacturing method of sliding parts - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a part that requires partially excellent slidability, such as a shoe member included in a mechanical device.

Conventional technology: As in the case of a swash plate type reciprocating pump, there are many mechanical members that require a surface area with excellent slidability. The following manufacturing method has been adopted in order to have excellent slidability in the required surface area of the mechanical member. First, the first method is a method in which a desired mechanical member is integrally manufactured from a block of a metal material having excellent slidability by an appropriate process means. Next, the second method is to form a basic body using a material selected from factors such as strength or production cost, and to provide a casting space only in a portion of the basic body where good slidability is required. . Then, a sliding material is cast into this casting space, and is cut and ground together with the basic body to obtain a desired mechanical member. This casting method is widely used. For example, a chrome-molybdenum steel for machine structure (SCM 440 H) is used to form a basic body with a casting space, and it is preheated to 800 ° C and copper-tin for sliding materials is used. Cast a system alloy (PBC2A). A method of finishing with a desired shape after cooling with water is commonly used. Furthermore, the third method is to melt the sliding material in a required portion of the basic body without
It is a method of binding by heating and pressurizing. This causes an atomic metal bond at the bonding interface and is called a diffusion bonding method.

Problems to be Solved: In these conventional techniques, the following points are problems, and a solution is desired.

In the case of the first method, even a portion not directly involved in sliding is integrally manufactured with a material that functions as a sliding material. Therefore, the amount of expensive copper alloy used is remarkably increased and the production cost is inevitably soared.

When forming the sliding portion by casting, which is the second method, there is a drawback that the material that can be cast is limited. That is, PBC2A
The copper-tin alloy represented by is castable,
Casting of copper-zinc alloy for sliding materials such as P31C is not possible. As a result, it is not possible to give the sliding portion any desired sliding characteristics. Further, the yield of materials is poor and the production cost is likely to rise.

When the sliding portion is joined to the basic body by the third method, that is, the diffusion joining method, each joining surface must be in a smooth state and in a clean state. Then, heating and pressurization must be performed in a vacuum at 800 ° C. or higher or in an inert gas atmosphere, which increases the equipment cost. further,
There were restrictions on the combination of materials that could be joined to each other, and overall the construction efficiency was low.

The present invention has been made in order to solve the problems of the prior art as described above, and makes it possible to join a sliding member having a low joining property and excellent sliding characteristics and improving productivity. An object of the present invention is to provide a method of manufacturing a sliding component that can be manufactured.

Means for Solving the Problems: The present invention uses a brazing filler metal having excellent diffusivity, melts only the brazing filler metal by current resistance heating, and simultaneously pressurizes to remove excess brazing filler metal from the joint portion, thereby forming a thin film. As a liquid phase, it is diffused to the bonding interface to obtain a strong bond. Next, the basic body to which the sliding member is joined is heat-treated to eliminate the influence of coarsening of metal crystal grains caused by resistance heating. That is, a method of manufacturing a sliding component according to the present invention is a method of manufacturing a sliding component in which a sliding member is joined to a surface of a basic body, and (a) a brazing filler metal is interposed in a required surface area of the basic body. The first step of applying the sliding member by (b) heating the brazing material while pressing the sliding member against the basic body by the pressure resistance heating means to melt the brazing material and form a thin film. A second step of diffusing the liquid as a liquid phase at the bonding interface to firmly bond the basic body and the sliding member, and (c) coarsening of metal crystal grains in the basic body bonded with the sliding member in an ammonia atmosphere. It is characterized by comprising a third step of maintaining the temperature for tempering for a required time.

When the sliding member is joined to the basic body, it is preferable that the basic body is preliminarily plated with the main component metal of the sliding member.

Action: By successively performing the joining of the basic body and the sliding member and the heat treatment after joining by such a pressure resistance heating means,
A sliding component having excellent slidability in a required surface area can be obtained. That is, the sliding portion is firmly adhered to the basic body,
Moreover, the heat treatment for homogenizing the joint portion including the joint interface, improving the structure of the sliding member and improving the fatigue strength is simultaneously performed.

According to the method of the present invention, even if the slidability is excellent, the bondability is low, and in the prior art, it was difficult to use as a sliding member for adhesion, such as P31C material, even in copper-rich copper-zinc alloy, than steel Can be joined to the core body. The bondability can be further improved by preliminarily plating the main body with the main composition metal of the sliding member (copper in the case of the copper-rich copper-zinc alloy described above).

Example: Hereinafter, a specific example of the method of the present invention will be described with reference to the drawings.

Using a bar of SCM 440 H (chromium-molybdenum steel for machine structure), a basic body was created, and after the material was refined, electrical plating of copper was applied. P31C was selected as a sliding member to be bonded to this basic body, and cut into a size corresponding to the sliding surface of the basic body. P31C is a copper-rich zinc alloy with the composition shown in Table 1.

Next, as shown in FIG. 1, a brazing material 3 was interposed between the basic body 1 and the sliding member 2 and sandwiched between the pressure electrodes 10 and 10. The pressure electrodes 10 can press each other in the P direction,
Water cooled copper electrodes are preferred. 10 'is a heat insulating material such as a tungsten plate, and 11 is a power source.

Using such pressure and resistance heating device, current density 60 ~ 20
0A / mm ² , energizing time 20 to 200 cycles (1 cycle is 1/60
Seconds), and the sliding member 2 was joined to the basic body 1 under the conditions of a pressing force of 4 to 9 kg / mm ² . As the brazing material 3, a brazing material containing a highly diffusible element such as Si, B, P and Cr was used.

At the time of this joining, if necessary, the concentricity of the basic body and the sliding member was adjusted, and after the joining, the joining failure was eliminated by a flaw inspection. After that, both the base body portion and the sliding member portion were subjected to finish processing to form the shape of the sliding portion as a mechanical member.

The copper plating applied to the main body 1 in advance has a plating film thickness of 10μ.
If it exceeds m, the shear strength at the joint interface of the sliding members will increase.
Even with the P31C alloy having a bonding property of 15 Kg / mm ² or more, sufficient bonding strength is exhibited as a sliding part. this is,
It has the same bond strength as PBC2A alloy (copper-tin alloy), which has good bondability to steel materials.

The shape of the sliding parts that had been finished was held at 570 ° C. for 5 and a half hours in an ammonia atmosphere. A heat treatment was performed together with the soft nitriding to obtain sliding parts. The heat treatment for adjusting the coarsening of the metal crystal grains is performed at a temperature of 500 to 620 ° C.
It is preferably within a range of holding for 8 hours.

The sliding parts obtained by the method of the present invention have excellent sliding surface area characteristics. The sliding characteristics largely depend on the metal structure. 2 to 4 show changes in the metallographic structure of the P31C material which are excellent in effects when applied to the method of the present invention. Second
The figure shows the state before joining (as cast), FIG. 3 shows the state immediately after joining to the basic body, and FIG. 4 shows the state after heat treatment. Before joining, the α and β phases have a uniform and fine structure. However, immediately after joining, coarsening of crystal grains occurs in the structure. When heat treatment is applied to this, the structure becomes almost the same as before joining. From this result, it is clear that the sliding property brought about by the state of the structure is deteriorated immediately after the bonding, but is recovered by the heat treatment.

Next, FIGS. 5 to 6 show the structure of the bonded interface portion. In the state immediately after joining in FIG. 5, the boundaries between the trunk body, the plating layer, and the sliding body are clearly visible. In FIG. 6 showing the state after the heat treatment, it was confirmed that sufficient diffusion occurred between the plating layer and the sliding material, resulting in a strong joint.

Effect of the Invention: As a result of the above, according to the method of the present invention, there is no difference in static strength, but fatigue strength is improved. Further, since the thermal conductivity is improved, the sliding characteristics can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a concrete implementation of the method of the present invention, FIGS. 2 to 6 are micrographs of a metal structure in the method of the present invention, and FIG. FIG. 3 shows the state immediately after joining, FIG. 4 shows the state after the heat treatment, FIG. 5 shows the state immediately after joining the joint interface portion, and FIG. 6 shows the state after the heat treatment. 1 ... Core body, 2 ... Sliding member 3 ... Brazing material, 10 ... Pressurizing electrode 11 ... Power supply

Claims (2)

[Claims] 1. A method of manufacturing a sliding component, in which a sliding member is joined to the surface of a basic body, comprising: (a) applying the sliding member to a required surface area of the basic body via a brazing material. Step (b): The brazing material is heated while pressing the sliding member against the basic body by the pressure resistance heating means, whereby the brazing material is melted and diffused as a thin film liquid phase at the bonding interface. Second step of firmly joining the base body and the sliding member, and (c) required time at a temperature for tempering the coarsening of the metal crystal grains in the base body to which the sliding member is joined under an ammonia atmosphere. A method of manufacturing a sliding component, comprising a third step of holding. 2. The sliding member according to claim 1, wherein when the sliding member is joined to the basic body, the basic body is preliminarily plated with a main component metal of the sliding member. Manufacturing method of moving parts.