Ingot Continuous Casting

Ingot Continuous casting is one of the ways to produce ingots and the first step in rolling production. The use of continuous casting is a very important and advanced metallurgical phenomenon in which the speed of ingot production is greatly increased and the metallurgical quality of ingots is also improved due to the uniformity and homogeneity of production. The uniformity and flawlessness of ingots in this method has caused production waste during rolling to be less and production to be more economical.

What is continuous casting of ingots?
Continuous casting of ingots is one of the common methods for converting raw fillets into metal products such as ingots, billets, slabs, etc. In this process, raw metals are transformed in the casting operation and converted into the desired products with different dimensions and thicknesses; the purpose of this operation is to convert various types of ingots into consumer products. Also, in continuous casting with molten materials, ingots, billets, and slabs can be produced; This casting model is effective for large and bulky parts. It is worth noting that the casting process is carried out continuously until the last stage, which is to cool the resulting metal products. The products obtained from continuous ingot casting are used as raw material.

Ingot Continuous casting process
The continuous ingot casting process includes the following:

1. Collecting the melt in the machine tank

In the first step, the molten metal is placed inside the furnace. It is better to take steps such as checking the alloy composition, degassing, and bringing the melt to the ideal temperature at the beginning of the work. Then, the molten metal is transferred to the tank.

2. Directing the melt to the tundish tank

In the second step, the melt is transferred to a fixed tank called the tundish with the help of a refractory pipe. The tundish is responsible for supplying the melt for the continuous operation of the casting machine while replacing the power source. Its other tasks include controlling the amount of melt and reducing the temperature.

3. Initial cooling of the metal

In this step, the molten metal in the tundish is transferred to copper molds by pipes. This mold provides its shaping and initial cooling. For the initial cooling of the metal, various cooling methods can be used, the easiest of which is the use of cold water. This resistant mold, with its oscillations, causes the metal to remain on the inner surface.

4. Formation of the strand layer

During cooling, a thin layer of metal freezes near the mold, which is known as the strand layer. Molten metal is still found inside the strand layers. For this reason, the strands are supported by the closed space of the cooling rails so that their shape does not change due to the pressure of the melt. Next, cool water is poured onto the strand layer so that the melt inside it freezes more quickly.

5. Secondary cooling of the metal

At this stage, the molten ingot is transferred to the secondary cooling zone below the mold. In this zone, the ingot is cooled with water in such a way that the freezing process proceeds to its core and after exiting it is completely solid.

6. Final formation

The melt is first transformed into the cross-section shape desired by the producers by passing through the copper die of the water mill. In the continuation of the continuous casting of the ingot, there are rollers that control its dimensions and make the cross-section move horizontally. Finally, as the temperature decreases and the melt solidifies, the final cross-sections are obtained. The rate of this product changes daily according to the changes in the iron and steel market. You can refer to the page above to see the price of iron ingots.

Post-production process
Since ingots are known as semi-finished products, they are usually subjected to various mechanical operations such as rolling, hammering and wire drawing after the casting process. In many factories, the ingots are transferred to the rolling section, which is located continuously after the casting unit, before they are completely cooled, and the required deformations are applied to them at the very initial stage. This approach helps to increase productivity and save time and energy.

Types of continuous ingot casting methods
The following three types of continuous casting methods can be mentioned:

Vertical continuous casting of ingots with a vertical secondary solidification section and its vertical cutting
Vertical continuous casting of ingots with a vertical secondary solidification section and bending and cutting to a horizontal position
Curved continuous casting of ingots with a curved secondary solidification section with a fixed or variable radius of curvature and its horizontal cutting
Principles of continuous casting

The principles of continuous casting are more or less the same in all the methods mentioned. In continuous casting of steels, according to the figure below, first, molten steel is poured continuously from the ladle into the tonde, which has been previously heated to a temperature of 1200 to 1300 degrees Celsius. When the surface of the molten steel in the tundish reaches a certain level, the molten material is poured continuously from the tundish into a mold whose bottom is able to move and whose copper wall is cooled by water. The solidification of the ingot begins from the wall and bottom of the mold and progresses towards its center. The size and shape of the mold depends on the size and shape of the ingot.

Cooling the ingot in continuous casting
To cool the ingot, usually 5 to 20 cubic meters of water, with a pressure of 0.6 MPa, are required per ton of steel to ensure proper solidification in the mold. During casting, to prevent the ingot from sticking to the mold wall, the mold is given a vertical oscillating motion with an oscillation amplitude of 15 to 30 mm. When the surface of the metal inside the mold reaches a certain height, the bottom of the mold is pulled down by a machine along with the ingot. At this stage, the molten ingot enters the secondary cooling zone located below the mold. In this zone, the ingot is cooled by water in such a way that the solidification process progresses to the core of the ingot and is completely solidified after leaving this zone. The secondary cooling zone (as shown) is designed in such a way that water is sprayed in powder form onto all surfaces of the ingot by nozzles with a pressure of about 0.2 to 0.3 MPa and cools it uniformly. Water consumption in this zone is usually about 0.5 to 0.8 cubic meters per ton of steel.