Birth of steel in stars
Would you believe it if you were told that the story of steel began in the stars, long before the man-kind walked on a planet called Earth? Or say even before the Earth ever existed? Yes, steel found its way into planetary bodies with the explosions and rebirths of cosmic elements.
In order to learn about steel, it’s important to understand first, that steel contains a 98-99 % concentration of iron. Iron is found in meteorites and ore which is found in the ground was gathered as the cosmic melting pot. It’s believed that iron found in meteorites has higher nickel content than Iron found in the ground. As per Carter’s discovery, iron is an element which was made in heaven and fell from the sky in the Bronze Age era in the form of iron goods and King Tut’s dagger.
Invention of iron before steel and Before Christ
lron was found in 2500 B.C. by tribesmen in the Near East. The iron was mixed with stones and minerals which made very difficult to separate the iron from the ore. It took almost 700 years for tribesmen to discover how to separate iron its ore, and that’s when the Iron Age began. In 1800 B.C., people along the Black Sea called Chalybes discovered the invention of unrivaled iron weapons. The Chalybes would put iron ores in the hearths, hammer them and soften them by firing. The outcome of this process was the discovery of wrought iron; which is now the most used steel types in all the industries.
Later, in 500 B.C., the Chinese developed tall furnaces which burned iron and wood together which created a liquid which was poured into carved molds in shapes of statues and cooking tools. This new form of iron was called cast iron. However, neither wrought iron nor cast iron was considered to be a perfect mixture.
In 400 B.C., metalworkers in India found a perfect mixture of carbon with iron using a smelting method. The mixture incorporated the mélange of wrought iron bars and charcoal bits.
Iron and coal
The very first blast furnace ever made is believed to have looked like an hourglass. Along the Rhine Valley, metalworkers developed a great blast furnace which would get extremely hot. It would accommodate a huge quantity of iron ore and charge, which in turn make iron absorb carbon much more effective. The mixture turned into cast iron which could be easily molded.
The way to modern steel
After the Second World War, iron and steel took on a larger role. In the 20″ century Swiss engineer named Robert Durrer blasted pure oxygen-into furnace as per the Bessemer process. The furnace had 20 % oxygen; and Durrer found it was a highly effective way to remove carbon from molten iron. He also discovered it was easier to melt cold scrap steel into pig iron, which in turn could later be recycled back into the steelmaking process.
Stainless steel and American mills
A British metallurgist named Harry Brearly was looking for an effective way to retain the life of gun barrels. He experimented to preserve the gun barrels with steel and chromium alloys. He found mixing chromium with steel was acid and weathering resistant. He later sold the same alloy in the market; naming it as Stainless Steel. It was in the late 20″ century, after closure of Bethlehem steel plant, American steel mills adopted basic oxygen processes. Within few years, the United States became the fourth ranked steel producer in the world as per the World Steel Association, and still continues to follow the league.
Future of steel
Today, most stainless steel made in mini mills. Unlike ancient times, metalworkers do not make steel scratch. Instead, it is melted and used for various purposes. William Siemens invented Electric Arc Furnace. This furnace is the most common type used in mini mills which uses carbon- electrodes to create an electric charge for metal melting.
Iron and Steel in today’s century can be found in a variety of types. Speaking exclusively of iron, the most common types used in industries are —
• Gray Iron
• Cast Iron
• Wrought Iron
• Ductile Iron
• Maalleable iron
• Compacted Graphite Iron
• White Iron
There are over 3,500 different types of steel that are now separated into different categories depending on their metal alloy content and chemical content. The most common types of steel ruling the metal industries are —
• High Carbon Steel
• Mild Steel
• Medium Carbon Steel
• Stainless Steel
• Cobalt Steel
• High Speed Steel
• Nickel Chromium Steel
• Aluminum Steel
However, the usage and purpose of each type depends on specific project requirements.
Metallurgists, in the current era; are working developing eco-friendly steel production methods that have the potential to demolish greenhouse gas emissions. It’s believed researchers at MIT are currently testing electricity-based technologies for smelting metals.
Researchers with innovative ideas are working on ways to limit car emissions which lead to harmful gas emissions in our climate. In February 2018, Voestalpine initiated the construction of a mill specifically designed to replace coal with hydrogen fuel technology. Many countries have now enforced limits on their own steel outputs in the past few years.
Even though steel has evolved in the 21* century, the question remains the same: how do we get better technology to make steel without putting our climate at stake?