Learn refining furnace working principle, main equipment and preparation

The refining furnace is the key equipment of the refining technology outside the furnace. The refining furnace has the function of stirring the molten pool, which can adjust the composition and temperature of molten steel, and promote the reaction of inclusions and slag. The refining furnace adapts to the strict requirements of continuous casting production for high-quality molten steel, improves the quality of the casting billet, and can provide continuous molten steel with timing, constant temperature, quantitative and constant quality, and is an important factor in coordinating steelmaking and continuous and stable production.

Ladle refining working principle 

Vacuum + argon blowing method is used for degassing, argon blowing stirring + alloy addition + slag adjustment function is used for composition adjustment, and chemical heating, arc heating, induction heating, etc. are used for temperature adjustment.

The removal of inclusions is by means of molten steel blowing argon, stirring and floating and inclusion denaturation.

Ladle refining furnace electrode system equipment

The electrode system of the refining furnace consists of transformer, short net, water-cooled cable, cross arm, electrode holder, electrode lift, electrode rotation, electrode lock, plc, etc.

1. The transformer is a special transformer: delta connection. The high voltage vacuum circuit breaker is located in the high distribution room and can be operated locally and remotely. High-voltage 35kv input and output are divided into multiple gears and voltages, which are adjusted according to the production process. The operation mode is two-place operation. Main console and screen operation. You can adjust the gear, current setting, sensitivity adjustment, etc. Electrode lift is controlled by proportional valve and solenoid valve, and is operated by main console and outdoor console.

2. The rotation of the electrode is also controlled by the proportional valve. The locking of the electrode and the opening of the gripper are controlled by the solenoid valve, which is operated on the outdoor console. In order to cool the transformer, an oil-water cooler is also set up to use two motors to force oil circulation to cool. Use the plc of s7-300 to control.

3. There are two limit positions for electrode rotation and electrode locking. There are only three upper limit positions for electrode lift.

Lead refining furnace hydraulic system

The hydraulic system is used to drive the electrode lifting, the furnace cover lifting, the electrode rotation and the electrode relaxation. It consists of the main hydraulic source device (motor, hydraulic pump, oil tank and hydraulic accessories), various control circuits (oil filter circuit, oil spill circuit, electrode lifting circuit, furnace cover lifting circuit, electrode rotation circuit, electrode relaxation circuit) and circulating pump device. , accident accumulators, etc.

Preparation work before refining treatment in refining furnace

Preparation before refining treatment:

1. Check whether each system is operating normally.

2. Check whether there is stagnant water or damp residue in the accident pit.

3. Check the preparation of various raw materials and operating tools, and confirm the variety of high-level silos and the composition of various ferroalloys.

4. If the electrode is not long enough and the electrode seam is ≥3mm, it must be loosened or the electrode should be replaced. When replacing the electrode, use compressed air to blow clean the electrode chuck and electrode joint, and pay attention to prevent the electrode chuck from loosening.

5. Understand the use of ladle, confirm the package number and age.

6. Confirm the tapping amount of the electric furnace, the composition of the end point, the alloy, slag, and the type and quantity of the recarburizer added after the furnace alloying.

Precautions for steelmaking in refining furnaces

1. The retention time of white slag should not be less than 15 minutes. Except for the first one, sampling must be guaranteed under the condition of white slag.

2. Except for the steel slag mixing and carburizing operation before heating, the molten steel should not be exposed to the air at other times.

3. The total refining time (starting to blow argon when entering the refining position to the end of soft argon blowing before hanging the bag) is not less than 35 minutes.

4. In principle, it is not suitable for smelting if the molten steel volume is less than 60 tons or more than 100 tons.

5. The temperature of the lifting bag can be increased by 5-10℃ depending on the situation of the new bag and the ladle with the bottom of the bag.

6. During the smelting process, if it is found that the wall of the bag is red or the bottom of the bag is leaking, the power must be cut off immediately, and the ladle should be opened to the lifting position for processing.