Construction, baking and application of dry ramming material for 10 ton medium f
Date：2020-09-27 / Hits：333
1、 Preliminary work of furnace building
Including the inspection and treatment of water cooling, induction coil, support bakelite and coil cement.
Requirements: 1. All parts must be firmly connected;
2. The water supply device itself is firmly connected without water leakage;
3. There is no surplus metal residue on the wire coil itself, and the inner cylindrical surface formed must be smooth without bumps. A good connection is formed between each turn of the coil;
4. The cement of the coil must be dry and free from leaks and cracks.
Objective: to minimize the cracks caused by insulation, leakage and leakage of furnace body, and the influence of cylinder surface in furnace body on natural shrinkage of furnace lining, so as to avoid affecting furnace life and even production safety.
2、 Furnace building operation
It includes bedding stone cotton cloth, making furnace bottom and wall, building furnace mouth and mouth.
Requirements: 1. The inner layer of asbestos cloth in furnace wall must be placed and leveled, and there is no overlap between the inner layer and the furnace wall;
2. The wire ends of unpacking and the scrap iron on the hearth must not be poured into the furnace with burden;
3. The process of manual knotting at the bottom of furnace must be solid, and it must be done repeatedly and repeatedly, and it should be done in layers and in several times. (generally, 10 tons of medium frequency furnace is divided into 2 ~ 3 knots), that is, 27 bales are laid off for the first time, the furnace charge is leveled with a level ruler, and then fork is used Then tie the knot with the automatic bottom plate vibrator (20 minutes), and then use the fork to scratch the surface. For the second time, 27 bales of the same material are cut, and the knot is made in the same way;
4. After the bottom of the furnace is laid, the bottom shall be leveled with the level, and the charge on the surface shall be scratched;
5. Then it is hoisted into the steel pot. The position of the steel pot must be placed evenly in the middle as far as possible, and it is better to put it in one time;
6. After placing the steel pot, pour the charging hole into the furnace wall area as evenly as possible, level and degass with fork repeatedly, and pay attention not to have any sundries.
7. After full charging, the automatic blowing tool is used to tie at the bottom for 20 ~ 25min, and then the blowing tool is raised by 10cm, and the same knot is made for 20 ~ 25min. After that, every 10cm knot is tied for 15 ~ 20min until 30cm below the furnace surface. At the same time, the sinking part of furnace charge caused by knocking process shall be filled and supplied in time;
8. The upper part of the furnace wall should be tied manually with manual blowing tools;
9. It is specially suggested that the width of blowing tools should be adjusted in time during the whole process of furnace wall knotting;
10. Finally, the furnace surface and mouth are made and dried.
Objective: to avoid or reduce the influence of factors on furnace life as far as possible.
3、 Baking and sintering
Requirements: 1. The waste used in oven drying must be solid small material with dense and lunch break, and the amount added is about 2 tons, and it should be solid;
2. At the beginning, it must be baked slowly with low power;
3. During baking, the power should be strictly controlled to avoid sand dropping due to melting of two steel pans due to excessive power;
4. Bake the oven red for about 3 hours, fully dry the oven and preheat the furnace body. At the same time, the furnace mouth is also baked with wood and other materials;
5. When injecting the molten steel into the West Road, the falling point and flow rate of molten steel in the ladle should be well controlled, and the molten steel flow rate should not be too fast or too high;
6. When the power is increased to 1680 ~ 1700 ℃, holding time is 2 hours and tapping is carried out;
7. For the rolling of molten steel caused by rapid melting of fast material in the heating process, the power should be adjusted timely according to the situation.
Objective: the molten steel washing is one of the key factors affecting the furnace life. The oven is sufficient and the sintering is done in place. The general principle is that the temperature is slowly raised in the low temperature stage, and the duration is strictly in accordance with the requirements.
4、 Precautions for furnace workers
1. In the first furnace every day, the furnace body should be preheated slowly with low power. Dust is a good working habit and cannot be fast;
2. The lump size of the charge should not be too large to impact the furnace wall or bottom and lose the lining;
3. The charge should be added in small batches and several times as far as possible, and the slag should be removed frequently;
4. As far as possible, more materials should be added into the furnace within the power range of the machine, so as to avoid drinking on an empty stomach or turning a small amount of material with high power;
5. Try to avoid liquid steel rolling and splashing. If rolling occurs, control the power well;
6. Furnace mouth and mouth should be inspected and repaired frequently to avoid unnecessary loss caused by steel leakage;
7. The test and sampling should be timely and diligent. The furnace should not waste resources while waiting for the test results, and the tapping time should be reduced as much as possible;
8. Temperature measurement should be timely, diligent and solid, strictly control the temperature;
9. During slag pouring or tapping, the speed and rhythm of the lifting and turning mechanism should be strictly controlled. After tapping, the furnace body should be leveled in time to avoid the uneven effect of inertia or gravity on furnace lining and radiation baking of a small amount of molten steel on the back wall;
10. Master the furnace condition at any time, pay attention to the corrosion and crack condition of furnace lining, and observe the maximum melting power and current of electric furnace and the turnover of molten steel, and report in time.
5、 The right time to stop and dismantle the furnace
It can be said that if the furnace lining is 75 heats and can be used for about 65 ~ 70 heats, it is a good level to decide to stop the furnace. Never blindly pursue. Therefore, if there are dark spots or obvious cracks, erosion and spalling of furnace lining, and the power and current delivered by the electric furnace reach or even exceed 5 ~ 10% of the rated value, the rolling of molten steel is obviously more severe than usual, so it is necessary to consider dismantling the furnace.
6、 Summary
It is possible to achieve high furnace life, but it is a system engineering, all links have more or less influence on the lining life, but there are primary and secondary. The pursuit of high furnace life is not our only goal. Many factors such as efficiency, safety and comprehensive cost must be considered comprehensively.
Including the inspection and treatment of water cooling, induction coil, support bakelite and coil cement.
Requirements: 1. All parts must be firmly connected;
2. The water supply device itself is firmly connected without water leakage;
3. There is no surplus metal residue on the wire coil itself, and the inner cylindrical surface formed must be smooth without bumps. A good connection is formed between each turn of the coil;
4. The cement of the coil must be dry and free from leaks and cracks.
Objective: to minimize the cracks caused by insulation, leakage and leakage of furnace body, and the influence of cylinder surface in furnace body on natural shrinkage of furnace lining, so as to avoid affecting furnace life and even production safety.
2、 Furnace building operation
It includes bedding stone cotton cloth, making furnace bottom and wall, building furnace mouth and mouth.
Requirements: 1. The inner layer of asbestos cloth in furnace wall must be placed and leveled, and there is no overlap between the inner layer and the furnace wall;
2. The wire ends of unpacking and the scrap iron on the hearth must not be poured into the furnace with burden;
3. The process of manual knotting at the bottom of furnace must be solid, and it must be done repeatedly and repeatedly, and it should be done in layers and in several times. (generally, 10 tons of medium frequency furnace is divided into 2 ~ 3 knots), that is, 27 bales are laid off for the first time, the furnace charge is leveled with a level ruler, and then fork is used Then tie the knot with the automatic bottom plate vibrator (20 minutes), and then use the fork to scratch the surface. For the second time, 27 bales of the same material are cut, and the knot is made in the same way;
4. After the bottom of the furnace is laid, the bottom shall be leveled with the level, and the charge on the surface shall be scratched;
5. Then it is hoisted into the steel pot. The position of the steel pot must be placed evenly in the middle as far as possible, and it is better to put it in one time;
6. After placing the steel pot, pour the charging hole into the furnace wall area as evenly as possible, level and degass with fork repeatedly, and pay attention not to have any sundries.
7. After full charging, the automatic blowing tool is used to tie at the bottom for 20 ~ 25min, and then the blowing tool is raised by 10cm, and the same knot is made for 20 ~ 25min. After that, every 10cm knot is tied for 15 ~ 20min until 30cm below the furnace surface. At the same time, the sinking part of furnace charge caused by knocking process shall be filled and supplied in time;
8. The upper part of the furnace wall should be tied manually with manual blowing tools;
9. It is specially suggested that the width of blowing tools should be adjusted in time during the whole process of furnace wall knotting;
10. Finally, the furnace surface and mouth are made and dried.
Objective: to avoid or reduce the influence of factors on furnace life as far as possible.
3、 Baking and sintering
Requirements: 1. The waste used in oven drying must be solid small material with dense and lunch break, and the amount added is about 2 tons, and it should be solid;
2. At the beginning, it must be baked slowly with low power;
3. During baking, the power should be strictly controlled to avoid sand dropping due to melting of two steel pans due to excessive power;
4. Bake the oven red for about 3 hours, fully dry the oven and preheat the furnace body. At the same time, the furnace mouth is also baked with wood and other materials;
5. When injecting the molten steel into the West Road, the falling point and flow rate of molten steel in the ladle should be well controlled, and the molten steel flow rate should not be too fast or too high;
6. When the power is increased to 1680 ~ 1700 ℃, holding time is 2 hours and tapping is carried out;
7. For the rolling of molten steel caused by rapid melting of fast material in the heating process, the power should be adjusted timely according to the situation.
Objective: the molten steel washing is one of the key factors affecting the furnace life. The oven is sufficient and the sintering is done in place. The general principle is that the temperature is slowly raised in the low temperature stage, and the duration is strictly in accordance with the requirements.
4、 Precautions for furnace workers
1. In the first furnace every day, the furnace body should be preheated slowly with low power. Dust is a good working habit and cannot be fast;
2. The lump size of the charge should not be too large to impact the furnace wall or bottom and lose the lining;
3. The charge should be added in small batches and several times as far as possible, and the slag should be removed frequently;
4. As far as possible, more materials should be added into the furnace within the power range of the machine, so as to avoid drinking on an empty stomach or turning a small amount of material with high power;
5. Try to avoid liquid steel rolling and splashing. If rolling occurs, control the power well;
6. Furnace mouth and mouth should be inspected and repaired frequently to avoid unnecessary loss caused by steel leakage;
7. The test and sampling should be timely and diligent. The furnace should not waste resources while waiting for the test results, and the tapping time should be reduced as much as possible;
8. Temperature measurement should be timely, diligent and solid, strictly control the temperature;
9. During slag pouring or tapping, the speed and rhythm of the lifting and turning mechanism should be strictly controlled. After tapping, the furnace body should be leveled in time to avoid the uneven effect of inertia or gravity on furnace lining and radiation baking of a small amount of molten steel on the back wall;
10. Master the furnace condition at any time, pay attention to the corrosion and crack condition of furnace lining, and observe the maximum melting power and current of electric furnace and the turnover of molten steel, and report in time.
5、 The right time to stop and dismantle the furnace
It can be said that if the furnace lining is 75 heats and can be used for about 65 ~ 70 heats, it is a good level to decide to stop the furnace. Never blindly pursue. Therefore, if there are dark spots or obvious cracks, erosion and spalling of furnace lining, and the power and current delivered by the electric furnace reach or even exceed 5 ~ 10% of the rated value, the rolling of molten steel is obviously more severe than usual, so it is necessary to consider dismantling the furnace.
6、 Summary
It is possible to achieve high furnace life, but it is a system engineering, all links have more or less influence on the lining life, but there are primary and secondary. The pursuit of high furnace life is not our only goal. Many factors such as efficiency, safety and comprehensive cost must be considered comprehensively.