Factors Affecting Ladle Pouring Rate

In practice, most steel mills use chromium-based drainage sand. This sand offers advantages such as low flotation, high self-opening rate, excessive sintering, ease of operation, and relative safety. The ladle pouring rate is influenced by the sand's material, including its composition, particle size, and moisture content.

Factor 1 : Characters of ladle  filler sand 

In terms of material, chromium-based ladle filler sand is generally superior to other silica-based sands. Chrome-graphite composites offer high thermal conductivity and excellent fluidity, facilitating automatic pouring.

In terms of sand composition, finer quartz particles in chromium-based ladle filler sand result in more liquid phase during sintering, leading to denser sintering. A wider particle size distribution improves the sand's fluidity.

In terms of moisture content, a moderate moisture content is recommended. Excessive water content will result in increased steam generation from evaporation during heating, leading to more severe outward expansion and a looser sintering structure. This makes it more likely that molten steel will seep between the ladle filler sandparticles, hindering automatic ladle pouring.

Factor 2: Influencing the Ladle Opening Rate

Steel Grade: Steels with high carbon content have higher automatic pouring rates, while steels with high aluminum and manganese content have relatively lower automatic pouring rates, significantly exacerbating sintering of the drainage sand.

Factor 3: Influencing the Ladle Opening Rate

1. The larger the ladle, the more conducive it is to automatic pouring.

2. The automatic pouring rate of a normal turnover ladle is significantly higher than that of a non-turnover ladle.

3. Changing the ladle nozzle shape from a stepped to a tapered or streamlined shape facilitates the smooth descent of the drainage sand, significantly improving the automatic pouring rate. The nozzle diameter also affects the ladle's automatic pouring rate. A nozzle diameter that is too small will restrict the flow of the drainage sand, hindering automatic pouring.

4. Aluminum-carbon seat bricks have a higher automatic pouring rate than corundum seat bricks.

5. When the ladle seat brick is located at the edge of the tapping stream, automatic pouring will be affected. If the tapping hole is positioned at a certain angle, the automatic pouring rate will be improved accordingly.

6. When the seat brick is flush with the ladle bottom, there is no dead zone at the bottom of the ladle. During argon blowing, the molten steel at the bottom circulates fully, preventing cold steel from forming at the nozzle, which facilitates automatic pouring. Sealing the brick above or below the ladle bottom is not conducive to automatic pouring.

4 Factors Affecting Ladle Opening Rate 

1. When the ladle temperature is between 1500-1600°C, the automatic opening rate is higher than when the ladle temperature is between 1000-1500°C.

2. Reducing the ladle's residence time and properly stirring the molten steel are crucial for automatic opening. Research has found that when the ladle's residence time exceeds 80 minutes, the opening rate of chromium ladle filler sandbegins to decline.

3. Clean the ladle. A clean ladle will improve the opening rate. The cleaning areas should be the ladle interior, the nozzle interior, and the lower nozzle area.

4. Adding an appropriate amount of ladle filler sandis also important for improving the automatic opening rate of the ladle. The amount of ladle filler sandadded should be as shown in Figure 9(a).

5. The ladle filler sand should be added by using a long tube funnel to make the ladle filler sandflow down from the top, which ensures the accuracy of ladle filler sandplacement and reduces ladle filler sand consumption.