Steel was not invented on a single date. The oldest known pieces are carbon steel fragments from central Turkey dated to about 1800 BCE, but steel only became cheap enough for beams, rails and bridges after Henry Bessemer patented his converter process in 1856.
Between those two dates, smiths made steel in small batches by hand. After 1856 it was made in tons per heat, and today the US alone produces more than 80 million metric tons a year. This timeline walks through the main steps, what each one changed, and how they lead to the structural shapes on this site.
First, What Counts as Steel?
Steel is iron with a controlled amount of carbon, usually well under 2 percent, plus other elements for particular grades. Too little carbon gives soft wrought iron; too much gives brittle cast iron. The hard part of steelmaking has always been hitting that middle range on purpose. Our guides to what steel is made of and iron vs steel explain the chemistry. Because of that narrow window, “when was steel invented” really asks two questions: when people first made it at all, and when they learned to make it reliably and in bulk.
Steel in the Ancient World
The oldest known steel: Kaman-Kalehöyük, about 1800 BCE
The earliest steel identified so far comes from Kaman-Kalehöyük, an archaeological site in central Anatolia (modern Turkey). Iron fragments excavated there and dated to around 1800 BCE were found in a 2005 analysis to include carbon steel. A 2023 study of the site’s Bronze Age iron artifacts by Kucukarslan and colleagues, “Early Efforts to Smelt Iron in Central Anatolia,” backed this up and found the carbon content varied widely from piece to piece. That pattern points to smiths experimenting, not to a controlled recipe.
Bloomery iron and carburizing
For most of history, iron was smelted in a bloomery: a small furnace that never got hot enough to melt the metal, leaving a spongy lump of iron and slag that smiths hammered into wrought iron. Steel came from heating that iron in contact with charcoal so the surface picked up carbon, then folding and forging it. The results could be excellent, but the carbon level was uneven and each piece depended on the smith’s skill.
Crucible steel in South and Central Asia
Smiths in South and Central Asia developed crucible methods long before industrial Europe. Iron and carbon-bearing material were sealed in clay crucibles and heated until the steel melted, giving a more uniform metal. Ingots of this steel, often called wootz, were traded widely and forged into the patterned blades Europeans later called Damascus steel.
The 1740s: Huntsman’s Crucible Steel in Sheffield
In Britain the turning point came from a clockmaker. Benjamin Huntsman wanted more consistent steel for clock springs and parts, so he experimented with melting steel in crucibles. Sheffield Museums describes a 1740s longcase clock at Kelham Island Museum as the first object to contain Huntsman’s crucible cast steel, and credits his process as the foundation of Sheffield’s steel industry. Crucible steel was high quality but made in small pots, so it went into tools, cutlery and springs, not buildings.
1856: Bessemer Makes Steel Cheap
Until the 1850s, large structures were built from cast iron and wrought iron because steel cost too much to use in bulk. Henry Bessemer changed that by blowing air through molten pig iron. Oxygen in the air burned off excess carbon, and the reaction released enough heat to keep the metal liquid without extra fuel. According to the Lemelson-MIT profile of Henry Bessemer, he patented the process in 1856, his converter could make 30 tons of steel in about half an hour, and in 1860 he patented a tilting converter that worked more efficiently than the original fixed design. The same profile notes that American William Kelly had worked on a similar air-blowing method.
The first Bessemer steel had problems. The process did not remove phosphorus, which makes steel brittle, so it only worked well with low-phosphorus iron ores. A later version with a “basic” furnace lining solved that and opened up phosphorus-rich ores. The open-hearth furnace, which allowed slower and better-controlled refining, eventually overtook the Bessemer converter.
From Rails to Rolled Beams
Once steel could be made by the ton, rolling mills turned it into rails, plate, and eventually standard structural shapes. Steel’s higher strength and toughness compared with wrought iron allowed taller frames and longer spans. The I-shaped beam, which places most of the steel in the flanges where bending stress is highest, became the standard member. Our explainer on what an I-beam is covers why that shape works so well. Most of those shapes are formed hot, a process compared with cold forming in hot rolled vs cold rolled steel.
1952: Oxygen Steelmaking
Bessemer used air, which is mostly nitrogen. Once pure oxygen became available in industrial quantities, steelmakers could blow oxygen instead and refine iron faster and more cleanly. The first industrial oxygen converter ran in Austria: voestalpine’s history of the Linz-Donawitz (LD) process records that the first 30 tons of LD steel were tapped in Linz on 27 November 1952. The basic oxygen furnace (BOF) used in integrated mills today descends directly from that converter.
Today: Electric Arc Furnaces and Minimills
Modern US steel comes from two routes. Integrated mills smelt iron ore in a blast furnace and refine it in a basic oxygen furnace. Minimills melt mostly recycled scrap in an electric arc furnace (EAF). The arc furnace route now dominates in the US. The USGS Mineral Commodity Summaries 2026, Iron and Steel (published February 2026, checked November 2026) reports:
- US raw steel production of about 82 million metric tons in 2025 (estimated).
- Electric arc furnace steel made by 47 companies at 102 minimills.
- Integrated mills accounting for roughly 28% of domestic steel production.
- Construction taking an estimated 31% of net steel shipments, the largest single market.
- World raw steel production of about 1,900 million metric tons in 2025 (estimated).
Wide flange beams are a good example of the shift. They are now widely rolled from scrap-based EAF steel, and the standard US grade for them is covered in our page on ASTM A992 steel.
Steelmaking Methods Compared
| Method | When | How carbon is controlled | What it changed |
|---|---|---|---|
| Bloomery and carburizing | Ancient world onward | Iron heated with charcoal, then forged | Steel possible, but uneven and made one piece at a time |
| Crucible steel | Ancient Asia; Sheffield from the 1740s | Steel fully melted in sealed clay pots | Uniform, high-quality steel in small batches |
| Bessemer converter | Patented 1856 | Air blown through molten pig iron | First cheap bulk steel |
| Open hearth | Later 19th century | Slow refining in a large heated hearth | Better control, overtook Bessemer |
| Basic oxygen (LD) | From 1952 | Pure oxygen blown into hot metal | Fast, clean refining in integrated mills |
| Electric arc furnace | Majority of US output today | Scrap melted by electric arcs, then refined | Scrap-based minimills, most US steel |
When Was Steel Invented? FAQ
Who invented steel?
No single person. Early smiths made steel thousands of years ago without written records. Henry Bessemer is the name most linked to steel because his 1856 process made it cheap enough for large-scale use.
What is the oldest steel ever found?
Carbon steel fragments from Kaman-Kalehöyük in central Turkey, dated to about 1800 BCE, are the earliest reported so far.
When did steel replace iron in construction?
Gradually, in the decades after the Bessemer and open-hearth processes made bulk steel affordable in the second half of the 1800s. Wrought and cast iron were used alongside steel for a time before rolled steel shapes took over.
How is most steel made today?
In the US, mostly in electric arc furnaces that melt recycled scrap. USGS data put integrated blast furnace and oxygen mills at roughly 28% of domestic production, with minimills making the rest.
Is Damascus steel the same as modern steel?
Not exactly. Historic Damascus blades were forged from crucible (wootz) steel with a distinctive pattern. Modern “Damascus” knives are usually layers of different steels forge-welded together to imitate the look.
Reference information only, not engineering advice. Disclaimer.