[Report] Special Alloys Forged at 1,600 Degrees... SeAH Accelerates Aerospace Ambitions

Changwon No. 3 Steelmaking Plant: 1,600-Degree Molten Steel in Action
Vertical Casting and Triple Refining Yield "High-Purity Alloys"
SeAH’s Bold Move in the Global Special Alloy Market

On October 20, at SeAH Changwon Special Steel's No. 3 Steelmaking Plant in Changwon, Gyeongsangnam-do, the atmosphere remained intensely hot even after lunchtime had ended. The moment you entered the plant, you were met with a blast of 1,600-degree heat. When the lid of the electric furnace opened, molten steel, glowing red, surged inside. As the molten scrap metal met the oxygen in the air, sparks erupted, and the liquefied scrap churned like magma. The sound of steel pierced the air, reminiscent of an engine exploding.

At SeAH Changwon Special Steel's No. 3 Steelmaking Plant, an average of more than 20 batches of 60 tons of molten steel are produced each day. Scrap metal is melted to burn off impurities, then further refined and alloyed. Before entering the forging or rolling process, this is the stage where the 'veins' of the metal are purified. This is the starting point for high-strength alloys for defense and aerospace applications, which SeAH Group has identified as its next-generation growth engines.

Scrap metal melting work is underway in a 1600-degree 60-ton electric furnace at a steel mill. Provided by SeAH Holdings

The Heart of Special Steel Refinement, the Starting Point of Aerospace Alloys

The molten steel produced that day was directed to the vertical casting machine, which SeAH Changwon Special Steel uniquely operates in Korea. Unlike conventional curved casting, SeAH’s casting machine stands vertically. Because the molten steel falls straight down in the direction of gravity and solidifies, there is almost no internal stress or distortion. The result is a bloom-a thick, square steel ingot for forging or rolling-with minimal deformation and a uniform crystalline structure. A plant official explained, "The vertical casting machine ensures uniform stress distribution, resulting in fewer cracks and making it ideal for producing products like aerospace alloys, where homogeneity is critical."

High-purity molten steel is also produced in the plant’s Vacuum Induction Melting (VIM) furnace. This device melts steel in a vacuum that does not permit even a single drop of air, preventing oxygen or nitrogen from entering and ensuring a uniform metal structure. Next to it are the Vacuum Arc Remelting (VAR) and Electro-Slag Remelting (ESR) furnaces. VAR remelts the metal with high-temperature current to eliminate micro-bubbles, while ESR filters out impurities through a slag filter. This is how SeAH was able to perfect the so-called 'Korean special steel.' SeAH Changwon Special Steel refers to this as the "refining stage." As a single batch of molten steel passes through these three processes, it becomes increasingly pure, ultimately resulting in a 'high-purity alloy' with less than 0.01% impurities. Alloys capable of withstanding extreme environments-such as those found in missiles, fighter jets, and submarines-are born here.

On one side of the special steel plant, a self-propelled artillery barrel, having completed heat treatment in the furnace, was slowly moving. The moment the steel, heated to 900 degrees Celsius, was submerged in water, jets inside the tank sprayed water in all directions, causing the surface to churn as if boiling. The cooling water enveloped the barrel in a cloud of white steam, obscuring visibility. This is the 'quenching' process, which rapidly drops the temperature to reduce internal stress and create strength that can withstand impact. A site official explained, "You must control everything-the water pressure, spray angle, and cooling speed-to prevent cracks from forming."

A quenching heat treatment process is underway, heating the barrel product to approximately 900 degrees Celsius and then cooling it to room temperature with water. Provided by SeAH Holdings

Leaving the heat behind, the forging plant was busy shaping metal by hammering it into form. Presses weighing thousands of tons pressed steel ingots into shape. The 'wing spar,' an aircraft wing structural component jointly developed with affiliate SeAH Aerospace & Defense Materials, is also produced here. Heated metal is struck by hammers, gradually spreading out and taking on the shape of a wing skeleton. SeAH presses a single piece of steel dozens of times through forging. This is to eliminate grain boundaries and control internal micro-cracks. This repetition is the essence of SeAH’s technological prowess.

At the small rolling mill, long steel bars passed over rollers, becoming progressively thinner. At the end of the plant, bundles of wire rod spun as they were wound. These wire rods are used in automobile engine valves, aircraft bearings, and defense springs. As one official put it, "We’re not just making wire; we’re building the technology to control cracks." For SeAH, 'wire' is not just metal, but the result of precision control.

Accelerating into Aerospace: Expanding the Special Alloy Market Beyond Defense

Inside the plant, some workers continued melting scrap metal, while others refined alloys. They are now moving beyond defense into the new industry of aerospace. Since this year, SeAH Changwon Special Steel has established a dedicated aerospace research team, focusing on developing high-temperature-resistant nickel and titanium alloys. According to the company, it will not be long before alloys that can withstand 1,600 degrees Celsius support the structures of fighter jet engines and spacecraft.

A process for producing wire rod is underway at a small rolling mill. Photo by SeAH Holdings

The global special alloy market itself is now shifting toward aerospace and defense. According to The Business Research Company, the global special alloy market is expected to reach $72.8 billion (about 103 trillion won) by 2032, more than doubling from $34.3 billion in 2023 over the span of ten years. Since the Russia-Ukraine war, the value of national security and strategic industries has grown rapidly, and supply chains for aerospace and defense materials are quickly being reorganized around allied nations.

This is also why SeAH Group has chosen special alloys as its future growth engine. The company aims to fill the gap in the U.S. market-where more than half of global special alloy demand exists-by replacing Russian and Chinese products with high-purity Korean alloys. Over the past two years, SeAH Changwon Special Steel has increased its research and development investment from 18.4 billion won in 2022 to 32.6 billion won this year, advancing its technology for aerospace alloys.

SeAH Changwon Special Steel has already secured ultra-precise melting and remelting technology for titanium and nickel-based alloys. It has also established the foundation to mass-produce highly homogeneous materials through the country’s first vertical casting-based bloom casting process. The goal is clear: to become a materials company that anchors the core supply chain of the aerospace industry. A company official stated, "The alloys produced by SeAH Changwon Special Steel will soon form the heart of aircraft soaring through the skies and rockets heading into space. The foundation is already in place for us to become a global leader in high-value-added special alloys."