JPH02168073A - Manufacture of aluminum alloy slide member - Google Patents

Abstract

PURPOSE:To enable improvement of wear resistance throughout the whole of a slide part for a long period by a method wherein an aluminum ground surface is corroded in a state that silicon particles are formed in a protruding state on a slide part surface, and a formed etch pit is filled with a solid lubri cant. CONSTITUTION:After casting of a slide member 10, a proper part of the surface of a liner part specified as a slide surface 16 is finish-formed in a given shape. Under a state in which the slide surface 16 is smoothed, crystal silicon particles 14 are exposed so as to be formed flush with the surface of an aluminum ground 12. After smoothing of the slide surface 16, only the surface of the ground 12 is etched without melting the particles 14. As a result, the particles 14 are exposed in a state to be relatively protruded approximately 2-3mum from the ground 12 surface. The ground 12 surface is corroded by electrolytic etching, and a number of etch pits 18 are formed in a depth of approximate 2-3mum in the ground 12 surface. Finally, by rubbing the pit 18 with a solid lubricant 20, the slide surface 16 is formed in a state that each pit 18 is filled with the solid lubricant 20.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a manufacturing method for manufacturing a sliding member, such as a liner portion of an aluminum alloy cylinder block, with improved wear resistance. Regarding.

[Prior Art] Conventionally, as a technique for manufacturing sliding members such as the liner portion of an aluminum alloy cylinder block with improved wear resistance, there has been a technique disclosed in Japanese Patent Publication No. 1981-8173. First, a cylinder block with an integral liner part is cast using an aluminum-silicon hypereutectic alloy, and after grinding into a predetermined shape, the surface of the sliding part corresponding to the liner part is etched with alkali. It is already known that the initial silicon particles are exposed on the surface of the sliding part (sliding surface). In this conventional technology, since the silicon particles exposed on the sliding surface have high hardness, the silicon particles prevent wear caused by sliding, and as a result, wear resistance is improved. It is something we try to improve.

[Problems to be Solved by the Invention] Although wear resistance is certainly improved in such conventional technology, the generation distribution state of such silicon particles is dense and dense, and the generation state of these silicon particles is In the sparsely populated areas, the aluminum fabric is exposed, and this area directly functions as a sliding surface.

As a result, simply applying the prior art does not achieve reliable wear resistance, and there is a problem in that the liner portion of the cylinder block wears out on one side.

This invention was made in view of the above-mentioned problems, and an object of the invention is to provide a method for manufacturing an aluminum alloy sliding member that can improve long-term wear resistance over the entire sliding part. It is to be.

[Means for Solving the Problems] In order to solve the above-mentioned problems and achieve the objectives, a method for manufacturing an aluminum alloy sliding member according to the present invention involves casting a member using an aluminum-silicon hypereutectic alloy. A first step, a second step of grinding the member cast in the first step into a predetermined shape, and after grinding in the second step,
A third step is to alkali-etch the surface to expose the silicon particles protruding from the surface of the member, and after exposing the protruding silicon particles in this third step, the member is etched using an electrolytic solution containing anion ions. A fourth step of electrolytically etching the surface to cause pitting corrosion on the surface of the aluminum fabric, and a fifth step of inserting a solid lubricant into the pitting area after the pitting corrosion occurs in the fourth step. It is characterized by the following:

[Function] In the method for manufacturing an aluminum alloy sliding member configured as described above, as in the conventional method, on the surface of the sliding part,
With the silicon particles protruding, the surface of the aluminum fabric is pitted, and a solid lubricant is inserted into the etch bits formed by this pitting.
Even if silicon particles are sparsely generated on the surface of the aluminum fabric, the presence of the solid lubricant will maintain good wear resistance in this area, and will definitely improve the wear resistance as a whole. becomes.

[Example] Below, the configuration of an example of the method for manufacturing an aluminum alloy sliding member according to the present invention will be described in detail with reference to the accompanying drawings.

First, a schematic configuration of the manufacturing method of this embodiment will be explained.

In this manufacturing method, first, an aluminum-silicon hypereutectic alloy is formed into a predetermined shape.
A casting process (first process) for casting an engine cylinder block as a sliding member is performed. Here, the shape of this cylinder block is set so that the liner portion is integrated into a long shape. In this way, the sliding member 10
As shown in FIG. 1A, primary silicon particles 14 having a particle size of about 10 to 20 μm are dispersed in the aluminum material 12 in a cooled state after casting. It will precipitate in the state.

After the sliding member 10 is cast in this manner, a finishing step (second step) is performed to finish and form a portion corresponding to the surface of the liner section defined as the sliding surface 16 into a predetermined shape. . This finishing step is performed by puff polishing to smooth the surface with a predetermined curvature. In the state where the sliding surface 16 is smoothed in this way, as shown in FIG. will be exposed to do so.

After the sliding surface 16 has been smoothed in this way, the first etching step (third step) of the sliding surface 16 is performed. In this first etching step, only the surface of the aluminum material 12 is etched without melting the primary silicon particles 14. As a result, as shown in FIG. 1C, the primary silicon particles 14 are exposed while protruding from the surface of the aluminum material 12 by about 2 to 3 μm.

After such a first etching step is performed, a second etching step (fourth etching step) of the sliding surface 16 is performed.
step) is executed. This second etching step is
This is defined by an electrolytic etching operation, and the surface of the aluminum material 12 is pitted by this electrolytic etching, and as shown in FIG. Etch bits 18 will be formed.

Finally, after such a second etching step is performed, a step (fifth step) of rubbing the fixing lubricant 20 into these etch bits 18 is performed. As a result, as shown in FIG. 1E, a sliding surface 16 is formed in each etch bit 18 in which the fixed lubricant 20 has entered.

The details of one embodiment of the manufacturing method configured as described above are as follows.
This will be explained below.

First, in the casting process, the aluminum-silicon hypereutectic alloy is constructed with the components shown in the table below.

Table (% by weight) Here, during melting, P-Cu is added to make the primary silicon particles 14 finer.

In the finishing process, the surface 16 of the sliding member 10 is first rough-processed into a predetermined shape by machining and grinding, and then polished by puff polishing. Here, in the grinding process, the surface roughness (R
, , ) are set to about 2.5 μm, and in polishing, the surface roughness (R, , ) is set to about 0.5 μm. Furthermore, in the first etching step,
First, a degreasing operation is performed, and then an etching operation is performed under the following conditions.

Etching solution: Mixture of 5% NaOH and sodium gluconate solution (concentration: 5 g/l) Etching temperature: 50°C Etching time = 15 to 20 seconds After such etching work has been performed, first, as a post-treatment, , water washing was performed, followed by pickling (washing solution: 5% HNO, aqueous solution, washing temperature, 50°C
, washing time of 30 to 40 seconds), and finally, washing with water is performed.

In the second etching step, degreasing is first performed, and then electrolytic etching is performed under the following conditions.

Etching solution: 5g of NaF (sodium fluoride),
Liquid mixed in a mixed solution of 10 cc of HCj2, 15 cc of HNOs, and 975 cc of H,O Applied voltage: O, lV Application time: 5 minutes After such etching work is performed, washing with water is performed as a post-treatment. will be carried out.

In the rubbing step, Ma S (molybdenum disulfide) is used as the fixed lubricant 2o.

Regarding the wear resistance of the sliding member 1o as an aminium alloy sliding member manufactured by the manufacturing method of the example configured as above, the test piece (comparative example) manufactured by the conventional manufacturing method was compared. A comparison and explanation will be given in the wear test.

The sliding member 1° used in this wear test was cut out into a predetermined shape from the liner part of the cylinder block manufactured by the manufacturing method of this example, and the test piece used in this comparative example was In the manufacturing method in this embodiment, a sliding member obtained by performing only a casting process, a finishing process, and a first etching process is cut into a predetermined shape.

Further, this test regarding the abrasion resistance is carried out using a reciprocating sliding abrasion tester 22 shown in FIG. As shown in the figure, this testing machine 22 includes a sliding member holder 26 fixed on a base 24 and on which the sliding member 10 is placed. Note that this sliding member 10 is attached with the sliding surface 16 formed to have wear resistance facing upward.

Further, this testing machine 22 further includes a sliding member holder 30 that is driven back and forth while pressing the sliding member 28 that slides against the sliding member 10 with a predetermined pressure, and a sliding member holder 30 that is not shown in the drawings. A drive mechanism for reciprocating the sliding member holder 30 is provided. The sliding contact member 28 corresponds to a piston ring in an engine, and its surface is chrome plated.

Here, the test conditions in this tester 22 are as follows.

Surface pressure: 0, 25 kg/mm2 Reciprocating distance:
10 mm Friction speed; 70 o cycles/min repetition rate, 20,000 cycles Atmosphere: The results of a wear test conducted in the air and in a dry manner are shown in Figure 3.

This result shows the respective wear loss when the weight was measured after performing the above-mentioned wear test. That is, this wear loss is a factor that directly indicates the amount of wear due to sliding between the two.

As is clear from FIG. 3, the amount of wear of the sliding member 10 manufactured by the manufacturing method of this example can be suppressed to about half that of the comparative example manufactured by the conventional manufacturing method. It turns out. This means that when the manufacturing method of this example is adopted, the wear resistance can be approximately twice as high as that of the conventional comparative example. That is, in this example, it was confirmed that the wear resistance was improved.

Here, the reason why the wear resistance was improved in this example is simply that the first
Compared to the case where steps up to the etching step are performed, in this example, the primary silicon particles 14 are exposed in a protruding state, and the fixed lubricant 20 is rubbed into the surface of the aluminum fabric 12. Since pitting corrosion parts (etch bits) 18 are formed, even if these primary silicon particles 14 are precipitated in a sparse state, the surface of the aluminum fabric 12 directly contacts the sliding member, ie, the piston ring. Even if sliding occurs with solid lubricant 20
Due to the presence of
The amount of wear is suppressed to a low level, and wear resistance is improved.

It goes without saying that this invention is not limited to the configuration of the one embodiment described above, and can be modified in various ways without departing from the gist of the invention.

[Effects of the Invention] As detailed above, the method for manufacturing an aminium alloy sliding member according to the present invention includes a first step of casting a member using an aluminum-silicon hypereutectic alloy, and this first step. a second step of grinding the cast member into a predetermined shape;
After grinding in the second step, the surface is alkali etched to expose the silicon particles in a protruding state on the surface of the member, and in this third step, the silicon particles are exposed in a protruding state. After that, there is a fourth step in which the surface of the member is electrolytically etched using an electrolytic solution containing anion ions to pit the surface of the aluminum fabric, and after the pitting occurs in this fourth step, the inside of the pitted portion is etched. , and a fifth step of introducing a solid lubricant.

Therefore, according to the present invention, there is provided a method for manufacturing an aluminum alloy sliding member that can improve wear resistance over a long period of time over the entire sliding portion.

[Brief explanation of the drawing]

1A to 1E are an embodiment of the method for manufacturing an aluminum alloy sliding member according to the present invention; FIG. 2 is a front view schematically showing the configuration of a reciprocating sliding wear tester; and FIG. The figure shows the amount of wear of the sliding member manufactured by the manufacturing method of this embodiment when tested by the reciprocating sliding wear tester shown in Figure 2, and the amount of wear of the sliding member manufactured by the conventional manufacturing method. It is a graph showing a comparison with the amount of wear of pieces. In the figure, 10...Sliding member, 12...Aluminum fabric, 14...Primary silicon particles, 16...Sliding surface, 18...Etched bit, 20...Solid lubricant ,2
2... Reciprocating sliding wear tester, 24... Base,
26...Sliding member holder, 28...Sliding contact member, 3o
...It is a sliding contact member holder. Figure 1E

Claims (1)

[Claims] A first step of casting a member using an aluminum-silicon hypereutectic alloy; a second step of grinding the member cast in the first step into a predetermined shape; After grinding in the process, the surface is alkali etched to expose the silicon particles in a protruding state on the surface of the member. In this third process, after the silicon particles are exposed in a protruding state, an anion is removed. A fourth step of electrolytically etching the surface of the member using an electrolytic solution containing ions to cause pitting on the surface of the aluminum fabric; A method for manufacturing an aluminum alloy sliding member, comprising a fifth step of introducing an agent.