JPH11192542A - Cast-in method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce problems of cracks in a diffusion layer, and to improve the bonding of a material to be cast-in with an aluminum alloy by forming the aluminized diffusion layer in a thin and uniform state. SOLUTION: A work hardened layer is formed by blowing aluminum particles against the surface of a material to be cast-in with compressed air of the prescribed time. The material to be cast-in is immersed in the molten aluminum alloy to be aluminized, and held in a mold, the molten aluminum alloy is poured into the mold to achieve the cast-in casting. The growing speed of a reactive layer during the aluminizing treatment is dropped by generating a work hardened layer on the surface of the material to be cast-in, and the reactive layer can be formed in a thin and uniform state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stuffing method, and more particularly, to a stuffing method in which a to-be-cast material made of an iron-based metal is aluminized and fusion-bonded to an aluminum alloy.

[0002]

2. Description of the Related Art A casting technique for combining and integrating a plurality of materials has been known. The composite material thus obtained exhibits excellent properties not found in a single material. For example, a to-be-cast material made of an iron-based metal is cast with an aluminum alloy, and both are integrated.

However, if the iron-based metal is cast with an aluminum alloy without any treatment, the surface of the iron-based metal is usually formed with an oxide film, so that it cannot be integrated with the aluminum alloy. Was. The deoxidizing treatment is extremely difficult, and the chemicals used for pickling and the like are toxic hazardous substances, and the work requires skill.

Therefore, it has been proposed to subject the surface of the material to be cast to aluminizing treatment before casting.
The aluminizing treatment is a treatment in which a to-be-stuffed material is immersed in molten aluminum or an aluminum alloy to cause a diffusion reaction between the surface of the to-be-stuffed material and aluminum. After the aluminizing treatment, the material to be cast is held in the mold, and the molten aluminum alloy is filled. As a result, the material to be cast and the aluminum alloy are fusion bonded.

[0005]

However, the diffusion layer formed by the aluminizing treatment is improved in thermal conductivity and mechanical strength by diffusion bonding of iron and aluminum, but is not so high in strength against impact and is fragile. Therefore, when the diffusion layer is thick, it becomes brittle, and the diffusion layer has a problem of cracking after casting.

Accordingly, the present invention provides a stuffing method in which a diffusion layer formed by aluminizing treatment is thinly and uniformly formed to reduce the problem of cracks in the diffusion layer and to improve the bonding between the stuffed material and the aluminum alloy. The purpose is to do.

[0007]

In order to achieve the above object, the present invention relates to a method for immersing a to-be-cast material made of an iron-based metal in a molten aluminum or aluminum alloy molten metal to form a surface of the to-be-stuffed material with aluminum. Aluminizing treatment is performed by taking out a diffusion reaction in the mold, and then the as-molded material is held in a mold, and molten aluminum alloy is filled in the mold to fuse the as-molded material and the aluminum alloy. In the assembling method for manufacturing an assembling product by bonding, before the aluminizing treatment, the assembling method in which particles made of metal or ceramic are sprayed on the surface of the assembling material to be cast to form a work hardened layer on the surface. Offers a way.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for forming inserts according to an embodiment of the present invention will be described with reference to FIGS.

First, a work hardening treatment is performed on the surface of an iron-based metal which is a material to be cast. This work hardening treatment is a type of forging performed by spraying particles made of metal or ceramic onto the surface of the material to be cast. Preferred metal particles are steel particles and stainless particles, and ceramic particles are silicon carbide,
Alumina particles and the like.

Next, an aluminizing treatment is performed by immersing the work-hardened material to be cast into a molten aluminum or aluminum alloy melt and taking out the surface of the material to be subjected to a diffusion reaction with aluminum. The mechanism by which the growth rate of the reaction layer (diffusion layer) on the steel sheet surface that is generated by the aluminizing treatment when a work-hardened layer is formed on the surface of an iron-based metal such as a steel sheet is considered to be due to the following phenomena. . When an iron-based metal is immersed in molten aluminum or an aluminum alloy (hereinafter, referred to as molten aluminum), aluminum is diffused into the iron-based metal and, at the same time, iron is dissolved in the molten aluminum. Since the work hardened layer has a high energy state,
It is believed that the dissolution of iron in the molten aluminum increases. Since the release of iron from the iron-based metal is larger than the inflow of aluminum from the molten aluminum, it is considered that the growth of the reaction layer generated by the diffusion of aluminum into the iron-based metal is low and the diffusion layer is thin. The molten aluminum is constantly stirred during the aluminizing treatment, and the volume of the molten aluminum is extremely large as compared with the volume of the iron-based metal, so that the concentration of iron near the iron-based metal can be ignored.

As described above, the aluminizing treatment is necessary for integrating the iron-based metal and aluminum. However, if the reaction layer is too thick, the brittleness of the reaction layer causes cracks, and as a result, the iron-based metal and aluminum are not combined. Will be reduced. Since the work hardening process is performed first, the diffusion layer can be formed thin in the aluminizing process, and the possibility of cracking can be reduced.

Next, the aluminized as-cast material is held in a mold, a molten aluminum alloy is filled into the mold, and the as-molded material and the aluminum alloy are fusion-bonded to form a as-molded product. To manufacture.

Experiment 1 In order to investigate the relationship between the work hardening treatment and the thickness of the reaction layer,
Prepare JIS-SPCC as an iron-based cast-filled material,
Further, a molten aluminum alloy used in the aluminizing treatment was prepared. Instead of performing various work hardening treatments on the to-be-cast material, four kinds of molten aluminum alloys having different iron contents were prepared. The first molten aluminum alloy is a molten aluminum alloy having an iron content of zero composed of aluminum and silicon, and the second to fourth molten aluminum alloys are aluminum alloys composed of aluminum and silicon. By adding an aluminum alloy composed of iron and iron, the content of iron in the molten aluminum alloy can be reduced to 1% by weight, 3% by weight,
It is adjusted to% by weight.

In the aluminizing treatment, the molten aluminum alloy is kept at 700 ° C.
This was done by dipping for seconds. As is apparent from the graph shown in FIG. 1, as the iron content in the molten aluminum increases, the thickness of the reaction layer increases. This is because, when the iron content in the molten aluminum increases, the dissolution of iron from the iron-based metal to be treated into the molten aluminum is suppressed, and conversely, a reaction layer is formed by the diffusion of aluminum into the iron-based metal material to be treated. Is to increase. A low iron content in the molten aluminum is synonymous with a high work energy state of the work hardened layer and an increase in the dissolution of iron in the molten aluminum. It can be equivalently grasped by the data shown in FIG.

Experiment 2 Next, the relationship between the conditions of the work hardening treatment and the hardness of the work hardened layer of the material to be cast was examined by experiments. First, JIS SPCC
A steel sheet was prepared as a material to be cast, and alumina Al ₂ O ₃ particles having a particle size of # 80 were sprayed on the surface of the steel sheet at a compressed air pressure of 3 kgf / cm ² as particles for forming a work hardened layer. Spray time of 2 seconds (Sample A) and 5 seconds (Sample B)
The Vickers hardness of the work hardened layer on the surface of the steel sheet generated as described above was measured. As a comparative material, Vickers hardness of a JIS SPCC steel sheet not subjected to a work hardening treatment was measured. Table 1 shows the experimental results.

[0016]

[Table 1] As apparent from Table 1, although Vickers hardness when not subjected to work hardening process was 144H _V, a sample A in 191 h _V Sample B In 293H _V, the the longer particles blowing time It can be seen that the hardness of the cast-in material increases.

Experiment 3 Next, the relationship between the aluminizing conditions and the thickness of the reaction layer of the material to be cast was examined by experiment for the samples A and B and the comparative material. Specifically, purity 99.7
%, Immersion time in molten aluminum at a temperature of 690 ° C.
The cast material was immersed at 0, 60, and 120 seconds, and the thickness of the reaction layer caused by the difference in the immersion time and the difference in the work hardening treatment was measured. Table 2 shows the experimental results.

[0018]

[Table 2] The graph shown in FIG. 2 shows the relationship between the immersion time and the thickness of the reaction layer for each sample based on Table 2. As is clear from the graph, the immersion time was 30
It can be seen that the thickness of the reaction layer produced increases almost from 60 seconds to 120 seconds, in each case. Also, it can be seen that as the hardness of the work hardened layer increases, the thickness of the reaction layer decreases.

From the above, it can be seen that the formation of a work hardened layer on the surface of a steel sheet reduces the diffusion reaction rate and suppresses the thickness of the reaction layer.

FIGS. 3 to 5 show a metal structure when the immersion time of the sample A, the sample B, and the comparative material is 30 seconds.
It is a micrograph of 0 time. In these figures, the gray part on the right side is the cast-filled material 1 and the streak-like white part 2
Is a reaction layer, and the black portion on the left is a space. The surface (left side surface) of the white portion 2 has a wavy shape, which is a trace of collision of particles when forming a work hardened layer. As is clear from these photographs, the comparative material having no work hardened layer had a reaction layer 2 as compared with the samples A and B.
Is formed thicker, which indicates that the reaction layer of sample B is formed thinner than the reaction layer of sample A.

The method of assembling according to the present invention is not limited to the above embodiment, and various modifications and improvements can be made within the scope of the claims.

[0022]

According to the method for assembling cast iron according to claim 1,
Particles made of metal or ceramics are sprayed on the surface of the stuffed material to form a work hardened layer on the surface, so that when the stuffed material is immersed in molten aluminum or aluminum alloy, It is possible to reduce the speed of the diffusion reaction with an aluminum alloy or the like in the above, and to suppress the growth of a relatively fragile reaction layer generated by the diffusion reaction, thereby forming a thin and uniform reaction layer. As a result, the brittleness of the reaction layer is improved, and the occurrence and breakage of defective products due to cracks in the reaction layer after casting is significantly reduced, and the reliability of the product is dramatically improved. Inexpensive products can be manufactured.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the content of iron in a molten aluminum alloy and the thickness of a reaction layer in an aluminizing treatment.

FIG. 2 is a graph showing the relationship between the immersion time and the thickness of a reaction layer in cast as-molded materials A and B subjected to a work hardening treatment and a comparative material not subjected to a work hardening treatment.

FIG. 3 is a metallographic microscope showing a reaction layer formed by spraying alumina particles on a surface to be treated of a stuffed material for 2 seconds, and then immersing the stuffed material in molten aluminum to cause a diffusion reaction. Photo.

FIG. 4 is a metallographic microscope showing a reaction layer formed by spraying alumina particles on a surface to be processed of a to-be-molded material for 5 seconds, and then immersing the to-be-molded material in molten aluminum to cause a diffusion reaction. Photo.

FIG. 5 is a metallographic micrograph showing a reaction layer formed by immersing a cast towel in molten aluminum and causing a diffusion reaction without subjecting the cast towel to a work hardening treatment.

[Explanation of symbols]

 1 Cast-filled material 2 Reaction layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norihito Iwata 3-25-1 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Isuzu Motors, Inc. Kawasaki Plant (72) Inventor Suguru Liu Eighth shelf, Fujisawa-shi, Kanagawa Prefecture Isuzu Motors Co., Ltd. Fujisawa Plant (72) Inventor Nobuaki Shinya 3-25-1 Tonomachi, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Isuzu Motors Co., Ltd. Kawasaki Plant (72) Inventor Masami Ueno 3 Tonomachi, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture -25-1 Isuzu Motors Corporation Kawasaki Plant (72) Inventor Makoto Nitta 3-15-1 Sotokanda, Chiyoda-ku, Tokyo Ryobi Corporation Tokyo Head Office (72) Inventor Naomi Nishi Outside Chiyoda-ku, Tokyo 3-15-1 Kanda Ryobi Co., Ltd. Tokyo Head Office

Claims (1)

[Claims] An aluminizing treatment is carried out by immersing a to-be-cast material made of an iron-based metal in a molten aluminum or a molten aluminum alloy, causing the surface of the to-be-stuffed material to undergo a diffusion reaction with aluminum, and taking out the material. A method for producing a cast-in product by holding a cast-to-be-stuffed material in a mold, filling an aluminum alloy melt into the mold, and fusing and joining the cast-to-be-stuffed material and the aluminum alloy, comprising: A method of assembling, characterized in that prior to the Ising treatment, particles of metal or ceramics are sprayed on the surface of the as-cast material to form a work hardened layer on the surface.