JPH02258156A - Casting method for internal chill - Google Patents

Abstract

PURPOSE:To obtain a perfect combined layer, where molten metal and internally chilled member is integrally melted, by pouring the molten metal while applying ultrasonic vibration to the internally chilled member of a mold at the time of forming an integrated casting body with the integrally chilled member after setting the internally chilled member in the mold and then pouring the molten metal into the mold. CONSTITUTION:By working an ultrasonic oscillator 9, the ultrasonic wave having the prescribed frequency corresponding to material and thickness of the internally chilled member 2 and kind, temp., etc., of the casting metal, is worked. The vibration of the ultrasonic oscillator 9 is transferred to a reinforcing cylinder as the internally chilled member 2 through a piezoelectric transducer 8. Molten high chromium cast iron as the casting metal 5 is poured into the mold 1 under condition of applying the vibration. The oxide layer formed on surface of the internally chilled member 2 is detached and fallen down with the vibration successively and the clean bonding surface is obtd. and the adhesibility of both metals is improved. Further, as the result of obtaining the structure having fine crystal grain diameter on the surface of the internally chilled member, mechanical characteristics of strength, hardness, wear resistance, etc., are improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a cast-in casting method, and in particular, the bond between the cast-in member and the cast metal is excellent, and there are no pinholes, gas holes, etc. This invention relates to a cast-in casting method that reduces the occurrence of casting defects.

(Prior art) A cast-in member is formed in advance from one of two metal bodies having the same or different material properties, and then the inner or outer surfaces or the inner and outer surfaces of the cast-in member are A cast-in casting method, in which molten metal of another metal is poured on both sides and welded together, is widely used.

For example, injection cylinders for plastic injection molding machines are manufactured by the above-mentioned cast-in casting method.

In general, in plastic processing machines, an injection molding machine is used that kneads an organic substance as a plastic raw material and a ceramic material as an aggregate and extrudes the mixture into a predetermined shape. The cylinder parts of the raw material kneading section and the injection section of this injection molding machine are susceptible to corrosion and wear because they are in direct contact with the violently moving raw materials.In particular, the cylinder parts are susceptible to interaction with the cylinder skeletal parts. If it is subjected to severe wear, it may be damaged early.

As a countermeasure, materials with excellent wear resistance, such as nitrided steel and shell steel, were used as constituent materials for injection cylinders, but in recent years, materials such as 27% chromium cast iron, which has even better corrosion and wear resistance, have been used. High-temperature cast iron is being adopted.

However, since high chromium cast iron has extremely poor machinability, only the cylinder body, which requires particularly high wear resistance and corrosion resistance, is formed from high chromium cast iron, and the outer periphery of the cylinder body has poor machinability and weldability. An integral injection cylinder is formed by closely contacting the reinforcing cylinders with steel materials of good quality.

If this reinforced cylinder made of steel and the cylinder body made of high chromium cast iron are joined by welding, the cylinder body made of high chromium cast iron, which is susceptible to thermal shock, is likely to crack. Therefore, injection cylinders are formed by a cast-in casting method in which a reinforcing cylinder is made of steel in advance, and then the inner circumference is filled with molten high-chromium cast iron to form an integral cast body.

(Problem to be solved by the invention) However, in the conventional cast-in & R manufacturing method, it is difficult to remove the oxide that forms and covers the contact boundary between the cast-in member and the molten metal, and it tends to remain in that part. There was a drawback that the molten metal penetrated into every corner and the bond between the two metals was incomplete at the boundary.Furthermore, casting defects such as pinholes and gas holes were likely to occur, which affected the strong electric properties of the component. However, it had the disadvantage of a short lifespan.

The present invention has been made to solve and overcome the above-mentioned problems, and when a purchased metal or a similar metal is cast to form an integral cast body, molten metal is generated in the encased part at the boundary with the molten metal. The object of the present invention is to provide a cast-in casting method that can accelerate the removal of the oxide layer, obtain complete bonding of the cast-in member and molten metal at the boundary, and form a high-strength cast body. shall be.

[Structure of the invention]

(Means for Solving and Overcoming the Problems) In order to achieve the above object, the present invention disposes a cast-in member in a mold, pours cast metal into the mold, and forms a cast body integral with the cast-in member. The cast-in casting method is characterized in that the cast metal is drained while applying ultrasonic vibration to the cast-in member or the mold.

(Function) According to the cast-in casting method having the above configuration, since the cast metal is poured while applying ultrasonic vibration to the cast-in member or the mold, the cast metal is generated at the contact interface between the cast-in member and the cast metal. The activated oxide layer is effectively peeled off and removed by ultrasonic vibration.

In the Song Dynasty, the molten metal of the cast metal sufficiently wraps around the surface of the cast-in member, and the two melt into each other to form a complete bonding layer, resulting in a long-life cast body with excellent strength characteristics. be able to.

Furthermore, since the interface between the cast metal and the cast-in member is purified by ultrasonic vibration, casting defects such as gas balls and pinholes are less likely to occur, and a high-quality cast body can be obtained.

Furthermore, by interposing the M impact between the cast-in member and the sand mold at the mold door, the vibrations caused by the ultrasonic waves applied to the cast-in member are absorbed by the cushioning material, so that the sand mold collapses due to vibration. There is little sleet, and casting work can be performed safely and with high precision.

(Example) Next, an example of the present invention will be described with reference to the attached four drawings. FIG. 1 is a sectional view showing an embodiment of the cast-in casting method according to the present invention, and shows an example in which an injection cylinder of an injection molding machine is cast-in.

As shown in FIG. 1, the casting apparatus for carrying out the method of the present embodiment has a cylindrical cast-in member 2 made of steel disposed inside a sand mold 1a serving as a mold 1, and extends in the axial direction of the central part. It is formed by fixing the columnar core 3. There is a loose v between the lower end of the cast-in member 2 and the sand mold 1a that receives the load of the cast-in member 2.
It is filled with ceramic fibers 48 as M04.

A sprue 6 for injecting the cast metal 5 into the mold 1 is provided on the side of the mold 1, while a sprue 6 for injecting the cast metal 5 into the mold 1 is provided at the bottom.
A pipe 7 is installed to guide the mold 1 into the cavity of the mold 1. Further, an ultrasonic oscillator 9 is fixed to the upper edge of the cast-in member 2 via a vibrator 8 .

When starting the casting work, first the ultrasonic oscillator 9 is activated. The frequency of the ultrasonic wave varies depending on the material, thickness, type of cast metal, temperature, etc. of the cast-in member 2, but generally, the cast metal 5 such as high chromium cast iron is cast into the cast-in member 2 made of steel. If so, it is best to adjust it to 15-25kHz.

However, when applying vibration using high-pressure air, it is difficult to adjust the frequency and amplitude, and in the case of thick cast-in parts, there are problems such as the entire part melting, resulting in poor results. I couldn't get it.

The vibration of the ultrasonic oscillator 9 is transmitted to the cast-in member 2 via the vibrator 8.
It is transmitted to the reinforced cylinder as. With this vibration applied, molten high chromium cast iron as the cast metal 5 is poured into the mold 1.

The reason why the reinforced cylinder made of steel was used as the cast-in member 2 is that the high chromium cast iron that forms the cylinder body is very susceptible to thermal shock and easily cracks, so a method of injecting it later as molten metal was adopted. This is to prevent cracking.

By pouring the cast metal 5 while applying ultrahigh wave vibrations, the high-temperature, high-chromium U iron molten metal sufficiently circulates around the surface of the cast-in member 2, and a portion of it is poured into the cast-in member 2. Because it melts into the material, a strong bonding layer can be obtained.

Further, since the oxide layer formed on the surface of the cast-in member 2 is peeled off and fallen off by successive vibrations, a clean bonding surface is obtained and the adhesion between the two metals is greatly improved.

As a result of the destruction and precipitation of the solidified layer of rough oxides, a structure with fine crystal grains is obtained on the surface of the cast-in part 2, resulting in poor mechanical properties such as strength, hardness, and wear resistance. Significantly improved.

Furthermore, the cast metal 5 poured into the cavity of the mold 1
sequentially from the bottom of the cast-in member 2 having a clean surface,
Because it solidifies, there are fewer casting defects such as shrinkage cavities and gas holes, and high-quality cast bodies can be manufactured.

Furthermore, when a ceramic fiber bar 48 is interposed as a buffer material 4 between the sand mold 1a and the cast-in member 2, the ultrasonic vibrations applied to the cast-in member 2 are absorbed by the ceramic fibers 4a. Therefore, there is little risk that the sand mold 1a will be destroyed by vibration, and the casting operation can be carried out safely and with high precision.

In addition, although this example shows an example in which ultrasonic vibrations are directly applied to the cast-in member 2, when a highly rigid mold is used as the mold 1, ultrasonic vibrations may be applied to the mold. It is also possible to add vibration to the cast-in member 2 indirectly through the mold.

As described above, according to this embodiment, by pouring the metal while applying ultrasonic vibration, it is possible to increase the degree of bonding between the cast-in member 2 and the cast metal 5, and also improve the mechanical properties of the cast metal. This improves the casting process and prevents the occurrence of casting defects, which greatly contributes to extending the life and improving the quality of the cast body. Particularly when applied to a member that is subjected to repeated loads under high vibration conditions, such as the injection cylinder of a plastic injection molding machine, there is no deterioration of the bond between the cast-in member and the cast metal, and it exhibits an excellent effect.

[Effects of the Invention] As explained above, according to the cast-in casting method according to the present invention, since the cast metal is poured while applying ultrasonic vibration to the cast-in member or the mold, the relationship between the cast-in member and the cast metal is The oxide layer generated and adsorbed at the contact interface is effectively peeled off and removed by ultrasonic vibration. As a result, the molten metal of the cast metal sufficiently wraps around the surface of the cast-in part, and the two interact with each other. It is possible to form a complete bonding layer by melting, and it is possible to obtain a long-life cast body with excellent anti-corrosive properties.

Furthermore, since the interface between the cast metal and the cast-in member is purified by ultrasonic vibration, casting defects such as gas balls and pinholes are less likely to occur, resulting in a high-quality cast body.

Furthermore, by interposing a buffer material between the cast-in member and the sand mold serving as the casting mold, the vibrations caused by the ultrasonic waves applied to the cast-in member are absorbed by the buffer material, so there is no risk of the sand mold collapsing due to vibration. The casting work can be carried out safely and with high precision.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the cast-in casting method according to the present invention. 1... Mold, 1a... Sand mold, 2... Cast-in member,
3... Columnar core, 4... 11 Rain material, 4a... Ceramic fiber, 5... Cast metal, 6... Sprue,
7... Cough, 8... Vibrator, 9... Ultrasonic oscillator.

Claims (1)

[Claims] 1. In a cast-in casting method in which a cast-in member is disposed in a mold and a cast metal is poured into the mold to form a cast body integral with the cast-in member, the cast-in member or A cast-in casting method characterized by pouring cast metal into a mold while applying ultrasonic vibrations. 2. A claim characterized in that when a sand mold is used as a casting mold, a cushioning material is interposed between the sand mold that receives the load of the cast-in member and the cast-in member, and ultrasonic vibrations are applied to the cast-in member. The cast-in casting method according to item 1.