JPS61245962A - Improvement of quality of casting metal - Google Patents

Abstract

PURPOSE:To prevent the generation of defects such as cavities and nonuniform density by passing magnetic lines of force and electric current to the metallic atoms and initial crystal grains of a molten metal under casting in the direction conforming to the Fleming''s left-hand rule in such a manner that electromagnetic force is generated in a specific direction thereby applying continuously the electromagnetic force to said atoms and crystal grains. CONSTITUTION:A casting mold 2 is placed in an outside frame 1 consisting of a non-ferrous material and electrodes 3, 4 which consist of a heat resistant material and face the inside of the short sides are respectively fixed and attached to the inside surface of the mold 2. A U-shaped electromagnet 6 wound with a coil 5 is fixed and attached to installing bases 7, 8 in such a manner that the N and S poles thereof face both long sides. DC power sources 9, 10 and electromagnetic force control switches 11, 12 are connected and prepd. The molten metal 13 is poured into the mold and at the same time the switches 11, 12 are closed to generate the downward electromagnetic force in the molten metal 13. The internal pressure and density proportional to the depth of the molten metal 13 are assisted in the above-mentioned manner, by which the discharge of foam and impurities and the growth of the crystal grains with good quality are made possible.

Description

[Detailed description of the invention] The present invention relates to a method for improving the quality of cast metal.

Conventional cast metals lack homogeneity in density and suffer from defects such as cavities and cracks, which reduce the quality of cast products.

The present invention can improve these conventional drawbacks by directing magnetic lines of force and current in a direction according to Fleming's left-hand rule, so that electromagnetic force is generated in a specific direction on the metal atoms and initial crystal grains of the molten metal during casting. It circulates and continuously applies electromagnetic force,
A method for improving the quality of cast metal, which promotes internal pressure and density proportional to the depth of the molten metal, eliminates air bubbles and impurities, prevents the formation of cavities, fosters high-quality growth of crystal grains, and enables casting of thin walls, small diameters, and complex shapes. It is.

In the present invention, a mold is placed in an outer frame made of non-ferrous metal material, and a U-shaped electromagnet is placed close to the outer frame or the long side of the mold, with the north and south poles facing each other and fixed, so that the lines of magnetic force can reach the whole or local part of the molten metal over the shortest distance. The two electrodes are fixedly mounted so that the line connecting the center point of the pole surface intersects at right angles to the magnetic field line, closely facing both ends of the molten metal, and a DC power source is connected via an electromagnetic force control device so that electromagnetic force is generated in a specific direction. This is what I did.

The first example of the method of applying hot electromagnetic force to the entire molten metal is shown below.
To explain with a diagram, a mold 2 is placed inside a non-ferrous material outer frame 1!
A U-shaped electromagnet 6 has heat-resistant material electrodes A4 fixedly attached to the inner surface of the mold 2, facing inward on the short sides of 1, and around which a coil 5 is wound.
Fixedly mount it on the installation stand 7.8 with the NS pole facing both sides of the long side of the outer frame 1, prepare to connect the DC'iltI7ji9, IO and the electromagnetic force control switch 11.12, and inject @@13 and switch at the same time. 11.12 closed and melted @1
This method consists of generating an electromagnetic force in the downward direction by 31 mm and continuously energizing the entire m0 until the solidification is completed.The electromagnetic force acts on the entire molten metal atoms and initial crystal grains, adds to the gravitational pressure inside the molten metal, and causes the molten metal to melt. The internal pressure is proportional to the depth, and air bubbles and impurities are discharged toward the outer surface of the molten metal, and the molten metal is sent through the molten metal to homogenize it, thereby preventing the formation of cavities. It is also a casting method that promotes smooth grain growth and prevents cracking.

The second embodiment of the method of applying electromagnetic force to a local area of molten metal is shown below.
To explain with reference to the drawings and FIG. 3, an inverted A-shaped mold 15 is placed inside the outer frame 14, and heat-resistant electrodes 17 and 18 are attached to the inner surface and bottom of the horizontal bar 16 so as to be in close contact with the wire ring. The extension magnetic pole 2Z23 is attached and extended to the electromagnet 21 wound with 20 wires, and the attachment is fixed so that the vicinity of the lower tip intersects the electrode 17.18 at right angles and surrounds the internal melt @19 of the horizontal bar 16.

When a direct current is applied to the wire ring 20 and the IIL bridge 17.18, and the metal is injected from the sprue 24, the molten metal fills the horizontal bar 16, and electromagnetic force acts continuously in the direction of Fleming's left-hand rule, causing the molten metal 19 to move to the left. This is to prevent the formation of blowholes at the three-pronged portion between the horizontal horizontal beam and the vertical portion.Extended magnetic pole 222
A heat insulating material is placed between the tip of the magnetic pole material and the molten metal to prevent the temperature of the magnetic pole material from rising. In FIGS. 2 and 3, the DC [ISi and control switches are the same as in FIG. 1, so they are omitted.

The present invention can prevent the occurrence of defects such as cavities and density inhomogeneity, which are the fate of metal casting, reducing the number of rejected castings, improving product yield, and making it possible to produce products with shapes that were previously considered difficult to cast. Also, casting of non-ferrous metals with light specific gravity has a great effect on preventing multiple defects.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the method of applying the present invention to the entire molten metal;
FIG. 2 is a perspective view of a method of applying the present invention to a local area of molten metal;
FIG. 3 is a 1-1 sectional view of FIG. 2.

Claims (1)

[Claims] Electromagnetic force is generated in a specific direction in the metal atoms and initial crystal grains of the molten metal during casting, so that magnetic lines of force and current are passed in the direction according to Fleming's left-hand rule, and electromagnetic force is continuously applied to create an internal pressure proportional to the depth of the molten metal. A method for improving the quality of cast metal, which promotes density, eliminates air bubbles and impurities, prevents the formation of cavities, fosters high-quality growth of crystal grains, and casts thin walls, small diameters, and complex shapes.