It’s an indescribably hot atmosphere. Sweat drips like rain. Hot molten iron travels along the conveyor belt to cool down. The finished steel plates are rolled up into coils for delivery. I visited the POSCO in Gwangyang, Jeollanam-do, where automotive steel plates are produced.
On the 30th of last month, as the monsoon rains began to fall, I visited the POSCO Gwangyang Steelworks. The Gwangyang Steelworks opened in October 1983, and the first-phase facility was completed in May 1987, beginning steel production. According to POSCO’s 2022 data, out of the 34.22 million tons produced, 20.14 million tons were produced in Gwangyang. This shows how significant the Gwangyang Steelworks is to the company.
The total area of the Gwangyang Steelworks is 22 km² (approximately 6.66 million pyeong) as of last year. I took a company bus from the headquarters to the steelworks plant. On the way, various pipelines were visible above us. Trucks known colloquially as ‘E.T. trucks’ because the driver’s seat is lowered to transport heavy raw materials were seen passing by. Tracks can also be seen for quickly transporting materials by train. All of this is part of the connectivity that swiftly delivers raw materials like iron ore to the furnaces.
Generally, the stages of steel production are divided into four: the smelting process that produces molten iron, the steelmaking process that removes impurities from the molten iron, the casting process where liquid iron becomes solid steel, and the rolling process that forms the steel into sheets.
Among these stages, I visited the third hot strip mill where steel is created. Hot molten iron pours out onto the conveyor belt. The molten iron travels back and forth along the conveyor belt, which removes impurities as it goes.
Water is sprayed out from the rollers between the molten iron on the conveyor belt. The tour guide explained, “The water coming from the rollers can be seen as the role of a blacksmith; just like a blacksmith cools and flattens the molten iron to create steel.”
To cool down the hot molten iron, water was constantly sprayed from the rollers. Even though I was observing the conveyor belt 30 meters away, where molten iron at 1200 degrees Celsius was pouring out, the heat was almost unbearable. I was drenched in sweat, feeling as if I had stepped into a steam sauna.
The hot molten iron is molded into steel through the casting process and then rolled down to a thickness of 6mm from 250mm through the rolling process. Additionally, during the rolling process, plates that are like planks are rolled up into coils, just like paper towels, and shipped to customers.
After passing through the third hot strip mill, I visited the eco-friendly giga steel production line, 7GCL. Inside, the environment was neat, with only forklifts occasionally passing by. Steel plates hang down like laundry, the elongated plates go up the conveyor belt at the top and are smoothed out without any roughness on the surface.
The smoothed steel plate adjusts its thickness through the rolling process. Choi Ji-in, the guide at the plating department, emphasized that “temperature and time are crucial during the rolling process.”
The steel plates undergo zinc plating according to customer specifications for coating thickness. Choi added, “The plating process is conducted using an AI system.” The plated steel is briefly stored in a mini loop tower before being shipped after going through one more round of rolling and roughness reduction processes.
The 3rd hot strip mill and the giga steel plant operate without worker intervention. Automated machines allow workers to focus solely on ensuring that production runs smoothly from the central control room or addressing any mechanical issues.
POSCO is busily producing steel not only for Hyundai but also for other renowned global automakers. We hope to see even more famous global automotive brands adopting POSCO steel in the future.
Lee Sang-jin daedusj@autodiary.kr