Basic oxygen furnace introduction in Austria

Another increase in productivity in the steel industry: they went from open-hearth furnaces, where to make 3 or 400 tons of steel it took 24 hours to refine the steel, to burn all that carbon out of the cast iron. In the late '50s, in Linz, Austria, someone found they could blow pure oxygen into the steel bath, and pure oxygen will burn carbon faster than air. To do it in a 300-ton bath is a little more exciting. Now they can burn the carbon out of iron not in 24 hours in an open hearth, but in a basic oxygen furnace they can do it in 20 minutes with a supersonic jet of oxygen. The vast majority of the pure oxygen in the world is used to make steel. They just blow a super jet, about this big around, of pure oxygen into the steel bath of 300 tons of steel. Really exciting. Anyone ever been to a steel plant and seen a BOF in operation? You want to see fireworks, it's really neat.

Voest-Alpine in Austria as the developer of continuous casting for steel in the 1950s and 1960s. (Note: Tom is using Voest-Alpine here specifically for the continuous-caster story; the canonical cluster for the BOF process is the closest match in the aggregate.)

There were also some big changes in the industry. They used to make steel — and you'll find this when I talk about casting — by pouring it into an ingot mold. Then in the 1960s some people, Voest-Alpine I think it was, in Austria, decided to see if they could continuously cast steel. People had been continuously casting gold and silver and copper for several decades, but steel melts at a higher temperature, and Voest-Alpine decided in the '50s and '60s to try to develop a continuous caster for steel — much bigger market. In the '60s they actually would sell you a unit. But the "rocket scientists" as I used to call them, who were hired into the steel industry after World War II — remember I told you, after World War II the United States had bombed out all the competition, that's one of those externalities — and we had seventy-five percent of the world's steel market in the mid '60s. When these guys were the middle-level managers, they and the upper managers decided not to put in continuous casting in most US steel mills when they were building a new casting shop.

Linz, Austria, 1958 commercial trial; mid-60s commercialization. Part of the productivity-revolution catalog.

I said it was the basic oxygen furnace, continuous casting, mini-mills. There's a lot of process technology. The basic oxygen furnace was first tried out in Linz, Austria around 1958, went commercial by the mid-60s. Continuous casting — the Japanese were doing it in the late 60s. By 1975, if you didn't have a continuous caster, you were a dinosaur.

1956 Austrian innovation after Allied bombing destroyed open-hearth capacity. Origin story of the BOF.

In 1956 in Austria — remember, we had bombed out their steel making. They didn't have any open-hearth furnaces, and these things cost a fortune. You go to an open-hearth site — I've only seen one or two in my life, but they're huge, and they cost a fortune in capital equipment. Some people in Austria got the idea: let's build something that looks like the Bessemer converter, but let's blow pure oxygen on it. They made a small one of five or ten tons. Nowadays we make them at 300 tons, and they're about six stories tall.

Post-WWII Austrians, lacking capital to compete with US Big Steel, innovate the BOF using liquefied oxygen (a German WWI-era process); make 300 tons in 20 minutes vs. open-hearth 450 tons in 24 hours.

Some people in Linz, Austria — remember, I told you seventy-five percent of the world's capacity was in the United States, and US Steel and Bethlehem had forty percent of the world's capacity between themselves. They thought they were fantastic managers, just the best in the world. The real reason they were so good is because they had bombed out the competition — well, they hadn't done that, someone had done it for them. Some people in Austria wanted to find a way to get into the steel business, but they didn't have the equivalent of 20 billion dollars in today's dollars. Frankly, 20 billion today is sort of a magic number — that's what it takes for a huge corporation to be able to invest without some help. Bethlehem Steel almost went bankrupt, and they were the second largest steel company in the world. If Boeing wants to design a new aircraft, we're talking 20 billion dollars, and when Boeing designs a 787 or 777, it's a bet-the-company proposition. Intel, if they want to build a new fab, is twenty billion dollars. People were projecting fifteen years ago that a new fab was going to cost 30 or 40 billion dollars, and no company in the world, not even Intel, could have afforded it. They were talking about how anybody could build the next-generation fab. Well, people innovated and came up with more efficient ways to do it, and that's essentially what happened in the steel industry.

1958 Austrian innovation: supersonic oxygen jet replaces 24-hour Open Hearth cycle with 45-minute cycle for the same 300-ton heat. Productivity revolution between 1965 and 1980.

And then, in a little place in Austria — actually I think it's 1958 — they decided to try pure oxygen and burning off the carbon. Steel is basically burning the carbon off the blast furnace iron. Blast furnace iron has 3 or 4% carbon. You've got to get it down to a tenth of that value to have steel. You've got to burn off the carbon. In an Open Hearth you just use air flowing over the furnace to slowly burn off the carbon. Here you blow a supersonic jet of liquid oxygen into a molten steel bath, and you burn off — not in 24 hours but in 10 minutes — all the carbon. So now every 45 minutes for the whole cycle you're producing 300 tons of steel, as opposed to 3 or 400 tons in a day. Pretty big productivity increase. It all occurred between 1965 and 1980.

Supersonic-velocity pure-oxygen lance creates froth of steel; 300 tons of cast iron converted to steel in 20 minutes vs. 24 hours in basic open hearth. The shaving-cream-vs-surface-diffusion analogy.

Then some guys in Europe, in Austria, decided to go back to something similar to the Bessemer converter. They would have a huge vessel four or five stories tall, steel lined with ceramic so you can melt steel in it without melting the steel shell. You have a massive steel pot maybe three or four feet deep. You pour the hot cast iron in here, and then you bring in a lance, a water-cooled copper lance, maybe about three-quarters of a foot in diameter, and you blow at supersonic velocity pure liquid oxygen down. That creates a froth of steel. They will fill up a 700-ton vessel — and in 20 minutes you can do what took 24 hours in a basic open hearth. The basic open hearth was surface diffusion. It was air going across the surface. You had to transport that carbon to oxygen one way, the carbon dioxide the other way — slow process, low area of contact, a surface reaction. Over here it's like shaving cream. You've got lots of surface area. And it's pure oxygen — you don't have to add any heat, you're burning carbon in there. In 20 minutes, 300 tons of cast iron becomes 300 tons of steel.

LD firm in Austria, 1950s. Switched from air to pure oxygen blowing. Cycle time fell from 24 hours / 400 tons (open hearth) to 1 hour, now 20 minutes / 300 tons. Tom's productivity-revolution headline example.

I'm giving you the long-winded answer, which is actually in one of my other modules, but you asked the question, so I'll answer it. What happened is, in the 1960s and 1970s we developed two processes. One was an improvement on the old basic open hearth. The basic open hearth took 24 hours to make 400 tons of steel by blowing air over it to oxidize away the carbon. Some guys in Austria — the LD firm in Austria in the 1950s — said, hey, why don't we blow pure oxygen on this steel rather than air, and we can oxidize it faster. They got the time down from 24 hours to one hour, and now it's down to about 20 minutes to make 300 tons of steel as opposed to the old open hearth's 24 hours. U.S. Steel built a huge open hearth in the 1970s with 450 tons. Everybody else was going to the basic oxygen process, which was pure oxygen. That was a tremendous increase in productivity.

Post-WWII Austrian innovation: water-cooled copper lance, supersonic oxygen jet, 20–30 minute refining vs. 24 hours for open hearth. The productivity revolution that displaced Andrew Carnegie's basic open-hearth furnaces.

After World War II, some guys in Austria decided there was another way to do it if they used pure oxygen. So today we have what's called the basic oxygen furnace. The basic open hearth got as large as 400 tons — U.S. Steel built one in the early 1970s. Meanwhile, in the 1950s, this little firm in Austria decided to build a water-cooled copper lance and a vessel that looked not all that different from Bessemer's. You put 50 tons — today it's about 300 tons — of cast iron that comes out of the blast furnace, and you blow a supersonic jet of liquid oxygen. You're blowing liquid oxygen in, but by the time it heats up and comes out, it's a supersonic jet of pure oxygen. And you can burn all the carbon out of that cast iron.

1950s Linz, Austria — replaced air-blown Bessemer with pure-oxygen blow using Linde liquefaction. 300 tons of steel in 20 minutes vs. 24–48 hours in open hearth. By the 1970s had taken over the global industry. U.S. Steel built the last open hearth in the early 70s — "they were stupid to build that one."

In the 1950s, there was a guy at Linz in Austria who decided, all you're doing in the open hearth and the other furnace is basically the Bessemer process of passing hot air over cast iron to burn the carbon off, to turn it into a lower-carbon version, which is basically steel. He decided, why don't we just use pure oxygen? The Germans had developed the Linde process for liquefying air, and you could get pure oxygen. So they built a basic oxygen furnace. In the old open hearth process, it would be 400 tons of steel in the furnace, and it used to take anywhere from 24 to 48 hours to process those 400 tons of steel. The BOF furnace, which they started building around 1960, by the 1970s had taken over the entire industry. The last basic open hearth was built by U.S. Steel in the early 70s, and they were stupid to build that one. The BOF process is 300 tons of steel in 20 minutes.