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Technical requirements for the crucible mold of the induction melting furnace

Technical requirements for the crucible mold of the induction melting furnace

The crucible mold must have sufficient strength during the construction and sintering process, and it must not be deformed during the construction process to ensure that it can transmit vibration energy to the lining material to compact the lining material. The hot surface of the lining material must be in the sintering process. It will not be melted before formation, and will not be locally deformed or melted by the influence of the magnetic field.

Once the above situation occurs, it will cause the lining material to be filled into the void formed by the deformation of the mold, resulting in a decrease in the density of the lining, thereby affecting the strength of the lining and shortening the life of the lining.

According to practical experience, the 6-ton furnace crucible mold uses an electric vibrator to shake the original 6mm steel plate crucible mold to 10mm in real time, and the 20-ton induction melting furnace crucible mold uses 10mm thick A3 steel plate welding to ensure that the crucible mold has strong strength , The vibrator is not easy to deform during the hammering and beating process, and the vibration energy can be transferred to the furnace lining material through the crucible mold to achieve the purpose of compacting the furnace lining, thereby ensuring the strength of the furnace lining and ensuring the service life of the furnace lining.

The structural characteristics of the crucible mold have a direct impact on the life of the furnace lining, so pay attention to the following aspects:

1. The circumference of the main body of the crucible mold

The circumference of the main body of the crucible mold can be designed to have a slope with a thin top and a thick bottom, or a straight cylindrical shape without slope. The slope is generally controlled at 1~4°, the size of the straight cylindrical crucible mold should be greater than or equal to the safe thickness of the thin part of the furnace lining.

2. Determination of the height of the crucible mold

It is generally believed that the length of the crucible mold from the bottom of the furnace lining thickness to the size of the upper part of the furnace body. However, the following factors should be fully considered in the actual process: melting efficiency, smelting materials, lining corrosion parts of the intermediate frequency furnace, and furnace cover.

Under normal circumstances, the bottom of the intermediate frequency furnace for producing gray iron or ductile iron is not very corroded (about 30-50mm), and the upper edge of the lower turn of the induction coil can be pressed.

At the same time, the height of the entire crucible mold should be the distance from the upper plane of the furnace bottom lining to the vertical height of the furnace along the plane plus the height of about 50mm above the furnace along the plane. This height is conducive to the full furnace iron sintering furnace lining, and the specific height does not affect Close the furnace lid.

3. The size and shape of the corner

This is easy to produce; elephant feet; defects, and it is under the lining of the furnace for a long time to be wrapped in molten iron and cannot be observed, so it must be designed accordingly. When the inclination angle is too large, the thickness of the lining can be increased, but it is easy to cause the lining to be knotted, and the mechanical damage of the feeding is also severe; and when it is followed; the small bevel angle is large; after the principle, the later lining is easy to knot here. It is compact, and can really exert the powerful effects of anti-pumping, corrosion resistance and compression resistance at the slope of the furnace lining during the melting process, thereby avoiding “elephant feet” defects and increasing the service life of the furnace lining.

IMG_257 4. Drill the vent hole and bottom shape

Diamond-shaped holes should be drilled at the bottom, slope and side walls of the crucible mold at an interval of 200~300mm, which is conducive to the discharge of moisture in the furnace lining material during the baking stage and increases the resistance, and improves the heating and baking effect.

The diameter of the hole is preferably 3mm. If it is too small, the exhaust effect will be poor, and if it is too large, it will cause a large amount of lining powder to be ejected from the hole when the furnace is vibrated.

The bottom plane of the crucible mold can not be recessed inward, horizontal, or protruded about 1mm from the center, so as to avoid the air gap and structural stress at the bottom of the furnace after the furnace is built, which may cause “bottom explosion” during baking and sintering.

5. The rest

All welds must be polished smoothly and no welding solvent or sharp corners are allowed; the tolerance and concentricity of the outer circle of the crucible mold should be controlled within 5mm; the crucible mold must be shot blasted before use.