Number of locations on earth which can make 600 ton steel ingots: 1. How is that possible? I guess even in 2008 materials science pales in comparison with making massive blocks of steel.
The Japan Steel factory’s rusting, corrugated-metal warehouses, blackened by soot, belie the precision and patience required to fashion a 600-ton steel ingot into a tube with walls 30 centimeters (12 inches) thick. Blue-clad workers, some wearing balaclavas to keep warm, draw on knowledge built up when Japan Steel made the 18-inch gun barrel — the world’s largest at the time — for the World War II battleship Yamato. A 1945 attack on the Muroran plant killed more than 200 workers.
“Our accumulated technology for cannon barrels helped us make this technical breakthrough in forging,” plant manager Sato said.
The company’s basic product, steel of the highest quality, has the same enduring appeal as the samurai swords still fashioned in limited quantities by craftsmen at the plant.
15,000 Tons
To make the 600-ton ingot, workers heat steel scrap in an electric furnace to as high as 2,000 degrees Celsius (3,600 degrees Fahrenheit). Then they fill each of five giant ladles with 120 tons of the orange-hot molten metal. Argon gas is injected to eliminate impurities, and manganese, chromium and nickel are added to make the steel harder.
The mixture is poured into a blackened casing to form ingots 4.2 meters wide in the rough shape of a cylinder. Five times over three weeks, the ingots are pressed, reheated and re-pressed under 15,000 tons applied by a machine that rotates them gradually, making the floor tremble as it works.
The heavy forging is needed to make the steel uniformly strong by aligning the crystal lattices of atoms that make up the metal, known as the grain. In a casting, they would be jumbled.
It would take any competitor more than five years to catch up with Japan Steel’s technology, said the company’s chief executive officer, Masahisa Nagata.
via Bloomberg
