Selection of ladle

According to the smelting conditions, there are two types of ladle: standard type and short and fat type.

Standard and chunky bag types — **Standard and Chunky Bag Types**

1、Heat transfer calculation

Establish the mathematical model of ladle, according to the structural characteristics of the ladle, the heat transfer calculation of the ladle to do the following assumptions.

1) The wall of ladle is regarded as an infinite cylinder wall, the bottom of ladle and the surface of liquid steel are regarded as an infinite flat wall; 2) The thermal conductivity of ladle wall and bottom is calculated according to one-dimensional steady state thermal conductivity.

2) The thermal conductivity of the ladle wall and bottom is calculated according to the one-dimensional steady state thermal conductivity.

3) Neglect the contact thermal resistance between the refractory materials and between the refractory materials and the steel shell in each layer of the ladle.

4) The physical parameters of the refractory used in the ladle do not change with temperature.

5) The heat is only transferred from inside to outside along the thickness direction, while the other directions are uniform.

2、Standard type ladle heat transfer calculation

The thermal conductivity of the ladle wall thermal conductivity of aluminum-magnesium spinel castables take 0.7W/(m-K); λ steel shell for the thermal conductivity of the shell, Q345 steel thermal conductivity 48W/(m-K); d1 for the diameter of the steel in the cylindrical ladle, conical ladle to take the middle of the diameter of the steel above and below the value of 2418mm; d2 for the cylinder ladle in the diameter of the refractory material, conical ladle to take the middle of the diameter of refractory material. 2898mm; d3 for the cylindrical ladle inner package south shell outer diameter, conical ladle to take the middle value of the outer diameter of the shell, 2948mm; l for the height of the cylindrical ladle steel, conical ladle approximation to take the height of the steel, 2490mm.

Analysis of results

1、Economic analysis of heat transfer

Calculated fat type ladle than the standard type ladle to dissipate 12% more heat.

And with the upgrading of variety structure, most of the steel needs to go through the refining furnace or even VD furnace or RH vacuum refining furnace production, ladle on-line use of time increased significantly, the actual energy consumption is greater than the theoretical value.

2、Other economic analysis

Steel structure investment fat and standard ladle steel structure quality of 19.8t and 14.6t (see table 3), according to each converter equipped with 10 ~ 12 ladle, steel structure at 10,000 yuan / t calculation, the use of fat ladle investment increase (52 ~ 62.4) million yuan.

3、Comparison of metallurgical functions

Steel ladle is one of the important equipment for steel production. With the improvement and development of smelting process, has changed from the early simple metallurgical equipment into an important process equipment, which refining process needs to be at the bottom of the argon blowing, thus promoting the uplift of inclusions, uniform composition of molten steel, improve the purity of molten steel and other aspects of the role. The role of secondary refining outside the furnace in modern metallurgy is becoming more and more obvious. According to research data show that the gas flow rate is certain, the deeper the melt pool, the gas has a buoyant potential energy is greater, and the gas up to the slag interface due to pressure reduction thermostatic expansion of the work increased, which is conducive to improving the gas stirring capacity.

4、Final conclusions

(1) By comparing the two types of ladle, the standard ladle has a greater advantage in terms of investment cost and operation cost.

(2) The standard ladle has more advantages in energy consumption, which can reduce the temperature drop of molten steel and save electricity consumption.

(3) Standard ladle has greater advantages in metallurgical effect, can reduce the dead zone of steel, remove inclusions.

(4) The standard ladle can reduce the eddy current slagging and improve the purity of molten steel.