What is the electric furnace's technology of slag-free steel tapping?

The technology of slag-free steel tapping in electric arc furnace

Sliding nozzle steel outlet

The sliding nozzle tap can be used in electric furnaces and converters. Its structure is similar to that of the ladle sliding nozzle, but it is relatively large and the operation is basically the same. The sliding nozzle device developed by the British Sheffield company was successfully applied to the tapping nozzle in a 90t electric furnace for the first time. The device is shown in the following figure. The tapping system of the nozzle mechanism is assembled by the Mg0-C inner tube and the seat brick, and it is concentric and closely matched with the nozzle of the sliding nozzle mechanism. The advantage is that the working environment is improved, frequent tapping trough repair work is eliminated, the tapping control is easy, and the residual amount of molten steel in the furnace is reduced to a minimum, and the service life of the slide plate can reach more than 30 times. At the same time, due to The fixed steel liquid level reduces the repair of the slag line, and the refractory materials are also significantly reduced.

The British type 1280 sliding water device (replaces the traditional tapping trough), the nozzle diameter is 200mm, the maximum pouring speed is 20t/min, and the tapping time is 4-5min.

This device prevents the slag from flowing into the ladle during tapping. In operation, when the molten steel discharged to the ladle reaches the required amount (displayed by the weighing equipment) or when slag appears, it is operated by the hydraulic system to slide the refractory material Closed, the cut-off time is only 1s, it can very accurately control the flow of molten steel, and can prevent any slag from being carried out, thereby improving the performance of the steel, and enabling the Sheffield Steel Plant to produce sulfur (S) and phosphorus (P) containing children. Low pure steel. According to the conventional production method of electric furnace, the ingot billet of this factory must be smelted with multiple charging. The effects obtained by using sliding water are as follows: 

1. Arbitrary discharge of slag, increasing output; 

2. Increasing alloy recovery rate and suitable temperature control; 

3. Investment can be recovered within 6 months; 

4. 1 set of refractory materials The maximum number of castings of the slide plate reaches 48 times.

150R-Sliding nozzle

High-efficiency electric furnace production requires tapping time of 1h or less, and slag-free tapping is required. At present, steel production plants generally recognize that the sliding water system is an effective technology to avoid steel tapping with slag. The effectiveness and reliability of the C15R sliding nozzle used in the French Tecreusot plant has been proven, and good results have been achieved. It includes: 

1. The temperature loss during tapping is reduced by 10℃; 

2. The nitrogen content is reduced to 2×10-6, the sulfur content is reduced to 50×106, and the nitrogen content in the ingot is 45×10-6;  

3. If there are 2~3 tons of molten steel remaining in the furnace after smelting, the steel can be tapped into the ladle furnace to achieve no slag; 

4. Power consumption is reduced by 10% (EAF and LF); 

5. Electrode consumption is reduced by 13%; 

6. The consumption of refractory materials is reduced by 16%; 

7. The consumption of lime and fluorite is reduced by 16%; 

8. The productivity is increased by 2%.

Continuous steelmaking method with slag steel separation

The slag steel is separated by the inversion method and the slagging method to achieve the purpose of slag-free tapping and pure steel smelting.