JPS59219468A - Aluminum sliding member and its manufacture - Google Patents

Abstract

PURPOSE:To obtain an Al sliding member provided with wear resistance only at the necessary part by coating the surface of an Al substrate with fine powder of metallic Si, an Al-Si alloy or the like and by melting the powder layer and the surface of the substrate to form a high-Si hypereutectic Al alloy. CONSTITUTION:The surface of an Al or Al alloy substrate is coated with fine powder of metallic Si, an Al-Si alloy or an Al-Si mixture having <= 100mesh. The coated surface is irradiated with laser beams, electron beams or plasma arc having high density energy to melt the powder layer and the surface of the substrate by rapid heating, and a high-Si hypereutectic Al alloy contg. proeutectic Si dispersed finely in only the surface layer is formed by the melting. By this method an Al sliding member having superior wear resistance over the surface of the substrate is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to surface treatment of aluminum or aluminum alloy, in which a high-density energy source is used to disperse primary silicon particles having excellent wear resistance on the surface of the base material. The present invention relates to an aluminum sliding member formed with a hypereutectic aluminum alloy layer and a method for manufacturing the same.

Aluminum or aluminum alloy is a ferrous material,
Although it has advantages such as low specific gravity, good thermal conductivity, low melting point, good workability, and good machinability, when used as a sliding member, it has better wear resistance than iron-based materials. Since it has the disadvantage of poor scuffing resistance, its application to the field of use as a sliding member is limited.

In addition, as a cast aluminum alloy with wear resistance, there is a high-silicon hypereutectic aluminum alloy with finely dispersed primary silicon, which has the lowest coefficient of thermal expansion among aluminum alloys and has excellent wear resistance. From the standpoint of improving fuel back, it can be used in place of conventional iron-based materials for the pistons, crankcases, cylinders, cylinder liners, cylinder blocks, etc. of automobile parts that require wear resistance, for the purpose of weight reduction. However, the high-silicon hypereutectic aluminum alloy produced by the import process is prone to stress unevenness due to the segregation of primary silicon, deterioration of machinability, and even casting defects, as well as primary crystal Mi7 and Lyon particles. It is extremely difficult to manufacture compared to other aluminum alloys, such as requiring improved processing to make it finer, so its range of application is limited despite its various excellent properties. This is the current situation.

Based on the characteristics of aluminum or aluminum alloys as described above, the present invention is based on the characteristics of aluminum or aluminum alloys as described above. Only the parts that require wear resistance of general aluminum or aluminum alloys, which are easy to manufacture, are made from high-silicon hypereutectic aluminum alloys. This is an attempt to manufacture a sliding part shrine.

The sliding part of the present invention and its manufacturing method will be explained in detail below.

First, a coating material for forming a high-silicon hypereutectic aluminum alloy layer is coated in powder or paste form on the surface of an aluminum or aluminum alloy base material whose surface has been polished. Depending on the silicon content of the base material, a metallic silicon powder, an alloy powder of aluminum, ram, and silicon, or a mixed powder of aluminum and silicon is used as the coating material. The particle size of the coating material and the thickness of the coating layer are determined by the capacity of the heating source and the thickness of the alloy layer to be formed. The finer the grain size of the coating material, the better; if it is coarser than 100 mesh, it will be difficult to alloy with the base material, so the grain size should be as fine as 100 mesh or less. The thickness of the coating layer is generally 0.1 mm to 2 mm.
mm is appropriate. As a heat source for forming a high-silicon hypereutectic aluminum alloy layer on the surface of the base material, it is possible to rapidly heat only the surface layer without heating the entire base material, and to achieve molten alloying, and rapid cooling of the base material. Laser beams, electron beams, and plasma arcs having high density energy are suitable so that primary silicon particles can be made finer.

When irradiating with these heat sources, it is preferable to carry out the irradiation in an inert gas atmosphere or vacuum in order to prevent bubbles from being entrained in the surface layer, and for example, nitrogen gas or argon gas is used. The alloy layer formed on the surface of the base material through the above treatment has a structure in which hard primary silicon is dispersed, similar to a high-silicon hypereutectic aluminum alloy, and the heat conduction to the base material is rapid, resulting in rapid cooling. It is also possible to make the crystalline silicon finer and the matrix finer, thereby increasing hardness and improving wear resistance.

As described above, the bleed invention does not lose any of its base material properties even when irradiated with a heat source, so it is an excellent material that has both the excellent wear resistance of the surface layer and the properties of aluminum or aluminum alloy as a base material. An aluminum sliding member could be obtained.

The present invention will be explained in detail below.

EXAMPLE An AC4B alloy whose surface was polished with #240 emery paper was used as a base material, and metallic silicon powder of 250 mesos or less was used as a coating material.

The coating layer thickness was 1.0 mm. Using a co-laser as a heat source, in a N gas atmosphere, laser output 1.2 k
n, beam diameter 3 mmφ and scanning speed 50 mm/min
The treatment was carried out under the following conditions. The resulting silicon-rich hypereutectic aluminum alloy layer had a thickness of 0.15 mm, as shown in the metallurgical micrograph of FIG.

A reciprocating abrasion tester as shown in FIG. 2 was used for the abrasion test. A hard chrome-plated pin (BL) with a barrel-shaped tip was used as the mating material. Both the pin (b) and the key plate test piece fal of the aluminum sliding member according to the present invention were polished to a finish roughness of approximately 1 μRZ. The load was 10 kgf, the speed was 600 cycles per minute, the friction distance was 3000 m, and lubrication was performed using hydraulic bearing oil.

The amount of wear was determined by rotation using a roughness meter. As comparison materials, alloys of hypereutectic A6 and 17% St, and cast iron equivalents to AC4B and FC25, which are the base materials of the present invention, were used. As shown in FIG. 3, the test results show that the sliding member according to the present invention has hypereutectic A.
β-17 also shows wear characteristics superior to the si^ alloy, and it is clear that the test piece ta+ itself and the mating pin (bl) have less wear.

As described above, according to the present invention, when aluminum or an aluminum alloy is used as a sliding member, it is not necessary to make the entire member a high-silicon hypereutectic aluminum alloy, which is difficult to manufacture. It is possible to easily form the alloy layer only on the moving parts. The base material may be aluminum, aluminum, or a nickel alloy cast by mixing aluminum, aluminum, alloy, or FRM, which is easy to manufacture, and is extremely economically advantageous, and can be expected to be applied to a wide range of fields.

[Brief explanation of the drawing]

FIG. 1 is a metallurgical micrograph of a high-silicon hypereutectic aluminum alloy layer obtained by the present invention. Figure 2 is a schematic diagram of a reciprocating wear tester. FIG. 3 shows the abrasion test results of the example. a...Test piece b...Mating pin C...Loading device agent Patent attorney Yuyoto - 1 other person Figure 1 Figure 2 Figure A Figure 3 Award

Claims (2)

[Claims] (1) An aluminum sliding member in which a high-silicon hypereutectic aluminum alloy layer with finely dispersed primary silicon is formed only on the surface of an aluminum or aluminum alloy base material. (2) The surface of the aluminum or aluminum alloy base material is coated with metallic silicon powder with a fine particle size of 100 mesos or less, aluminum and silicon alloy powder, or mixed powder of aluminum and metallic silicon, and the coating layer is coated with a high-density Laser beam of heat source with energy,
By irradiating electron beam, plasma arc, etc. to melt only the mtA and the surface of the base material, the surface of the base material and the silicon of the coating material are alloyed, and only the surface layer is made of a high-quality material with finely dispersed primary silicon. A method for manufacturing an aluminum sliding member, characterized in that it is made of a silicon hypereutectic aluminum alloy.