Instructions for use of induction furnace ramming material

This product is a dry ramming material, please operate according to the following instructions: Thank you.

Furnace lining material The simple steps of sintering are as follows:

Raise the temperature to 900°C at a rate of 250°C/hour, (hold the iron and red only in a non-melting state for 3-4 hours, depending on the size of the furnace)

Continue to heat up to 1300°C at a rate of 200°C/hour and keep it warm for 2-3 hours (according to the size of the furnace)

The temperature is increased to 1550°C at a rate of 200°C/hour and kept for 3-4 hours, then molten iron is tapped.

1. Before dry knotting the furnace lining, first lay a layer of mica paper in the furnace coil insulation layer. Lay another layer of asbestos cloth, and manually level and compact each layer of material when laying.

2. Knotted furnace bottom: The thickness of the furnace bottom is about 200mm-280mm, and it is filled with sand in two to three times. During manual knotting, the density of various places is prevented from being uneven, and the furnace lining after baking and sintering is not dense. Therefore, the thickness of the feed must be strictly controlled. Generally, the thickness of the sand filling is not more than 100mm/each time, and the furnace wall is controlled within 60mm. Multiple people are divided into shifts, 4-6 people per shift, and 30 minutes for each knot to replace, around the furnace Rotate slowly and apply evenly to avoid uneven density.

3. When the knot at the bottom of the furnace reaches the required height, it will be flattened and the crucible mold can be placed. In this regard, care should be taken to ensure that the crucible mold is concentric with the induction coil, adjusted vertically up and down, and the shape is as close as possible to the bottom of the built furnace. After adjusting the peripheral gap to be equal, use three wooden wedges to clamp, and the middle hoisting weight is pressed on to avoid the furnace wall. When knotting, the lining material is displaced.

4. Knotting furnace wall: the thickness of the furnace lining is 90mm-120mm, adding dry knotting material in batches, the cloth is uniform, the thickness of the filler is not more than 60 mm, and the knotting is 15 minutes (manual knotting) until it is level with the upper edge of the induction ring together. The crucible mold must not be taken out after the knotting is completed, and it acts as induction heating during drying and sintering.

5. Baking and sintering specifications: in order to obtain the three-layer structure of the furnace lining, the baking and sintering process is roughly divided into three stages: pay attention to the iron pins and small iron materials added to the furnace during the baking and sintering. , Do not add large pieces of iron, iron with tips, or teeth.

Baking stage: keep the temperature at 200 current for 20 minutes and 300 current for 25 minutes, keep the crucible mold heated to 900°C, keep the intermediate frequency furnace of 1 ton or less for 180 minutes; keep the intermediate frequency furnace of more than 1 ton for 300 minutes, The purpose is to completely remove the moisture in the furnace lining.

6. ​​Semi-sintering stage: heat preservation at 400 current for 60 minutes, 500 current heat preservation for 30 minutes, and 600 current heat preservation for 30 minutes. The heating rate must be controlled to prevent cracks.

7. Complete sintering stage: high temperature sintering, the sintered structure of the crucible is the basis for improving its service life. The sintering temperature is different, the thickness of the sintering layer is insufficient, and the service life is significantly reduced.

In the 8.2T intermediate frequency furnace, about 950 kilograms of iron pins are added during the baking process to enhance the heating effect of the induction coil. As the baking and sintering continue, a relatively stable electromagnetic force is generated through low-power transmission to stir the molten iron to fill the furnace. , Raise the furnace temperature to 1500℃-1600℃, hold the intermediate frequency furnace of 1 ton or less for 120 minutes; hold the intermediate frequency furnace of more than 1 ton for 240 minutes, so that the furnace lining is heated evenly up and down, forming a strong sintered layer to prevent molten iron from being washed Furnace wall. Strictly control the temperature of the three phase change zones of the lining material to promote the full phase change of the lining material and improve the first sintering strength of the lining.

9. Blue fire outside the coil, black inside the furnace lining, cracking of the furnace lining material and other causes. as follows:

Solution: After the lining material is knotted, iron needs to be added for baking. It is required to add bread iron. Fill up the furnace. Never add oily iron pins, iron beans, or mechanical iron. Because the lining material of the first furnace was not sintered. Oily materials will emit a lot of smoke and carbon monoxide when heated at high temperatures. Through high pressure, a large amount of smoke and carbon monoxide will be pressed into the furnace lining material and discharged to the outside of the furnace through the furnace lining material. A lot of flue gas residue will be left in the furnace lining for a long time, making the furnace lining black. The adhesive in the furnace lining loses its bonding effectiveness, and the furnace lining becomes loose. There is a phenomenon of furnace wear. If there is oily material in the factory, it can be used after the furnace lining material is completely sintered. (Use after 10 furnaces).

10. Starter switchboard: keep warm for 30 minutes from the current 200 DC current. 300 DC current insulation for 30 minutes. 400 DC current hold for 40 minutes. Keep 500 DC current for 30 minutes. 600 DC current hold for 40 minutes. After opening to normal melting. Fill the furnace with molten iron. The temperature rises to 1500 degrees-1600 degrees. The intermediate frequency furnace of 1 ton or less is kept for 120 minutes; the intermediate frequency furnace of 1 ton or more is kept for 240 minutes, and the baking ends.

11. Precautions for cold stove start: cold stove start. Start with 100 direct current; 200 direct current for 20 minutes; 300 direct current for 25 minutes; 400 direct current for 40 minutes; 500 direct current for 30 minutes; 600 direct current for 30 minutes. Then it works normally.

12. Precautions for hot furnace shutdown: hot furnace shutdown. For the last furnace, raise the furnace temperature and clean the glaze around the furnace mouth. The molten iron in the furnace must be poured out. Observe the condition of the furnace wall. The blackened part of the furnace body indicates that the furnace lining has become thinner. Pay attention to this part when you open the furnace next time. Cover the furnace mouth with an iron plate. Make the lining shrink slowly.

13. The melting material should be clean, dry, and non-greasy materials in order to build the sintering layer of the furnace wall.

14. The first few furnaces prevent high-power transmission and smelting. High-power will generate a large electromagnetic stirring force, which will wash away the sintered layer of the furnace lining that is not completely strong.

15. The iron should be light, and the iron should be evenly applied, so as to avoid touching the furnace wall and easily damage the thin sintered layer, forming the furnace lining and affecting the life of the furnace lining. The average iron addition can balance the furnace temperature.

16. Slagging must be done frequently during operation. The melting point of the slag is higher than the melting point of the molten material, the slag is crusted, and the iron material cannot contact the timely solution, making it difficult to melt. The furnace substrate is corroded by high temperature.

17. The new furnace should be smelted continuously as much as possible to avoid cracks caused by intermittent smelting. Generally smelt continuously for 1 week.

18. Try to avoid high temperature smelting during the smelting process. Avoid overheating of the furnace lining.

19. When the furnace needs to be shut down for a long time due to malfunctions during use, the molten iron in the furnace should be emptied.

20. Try to use clean charge for the new furnace.

21. Maintain and maintain electric furnace equipment. During use, pay attention to the condition of the furnace.

22. When the furnace is shut down for cooling, the furnace should be empty and the furnace cover should be covered to make the furnace lining uniform up and down during cooling, so as to ensure the service life of the furnace

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The life of the lining material is “three points in the material, seven points in the use”. Effectively improve the life of furnace lining materials, in addition to selecting suitable materials for furnace lining materials, implementing strict furnace building and baking operations, formulating scientific and reasonable smelting processes, adopting new auxiliary materials, meticulous operation, and meticulous maintenance. Lining life is an effective way to save energy and reduce consumption. Lingshou Shuangyuan Mineral Products Processing Factory is willing to make progress hand in hand with you. Create a better future.