U.S. Steel's last large open hearth furnace

450-ton open hearth installed in the 1970s when everyone else had moved to BOFs. Probably world's largest steel furnace ever made. Symbol of US Steel conservatism.

That wasn't very efficient. Then came the basic open hearth — what Andrew Carnegie used — where you just had a big furnace with a layer of liquid iron about three feet thick. You start figuring out the density of that iron. We used open hearths from the 1880s to the 1970s. When everyone else was going to the basic oxygen furnace, U.S. Steel — being the conservative people they were — in the 1970s put in the world's last open hearth furnace at 450 tons, probably the world's largest steel furnace ever made. They were going bigger and bigger in scale.

Early 1970s — U.S. Steel builds the world's largest open hearth at 450 tons while every other producer is installing BOFs. Within a few years they have to convert anyway. Emblematic of management failure.

It forms a froth, and you can now refine that steel in thirty minutes — what used to take twenty-four hours — because you've got lots of surface-to-volume ratio. U.S. Steel, in all their great wisdom, in the early 1970s built the world's largest open hearth, 450 tons. Everyone else in the world was putting in BOFs. They ran their hundreds-of-millions-of-dollars open hearth, the last one in the world, largest one in the world, for a few years, and then they realized they had to put in a BOF. U.S. Steel did come up with the Q-BOP — "basic oxygen process" — where they inject the air from underneath, which has certain advantages. So it wasn't as if they didn't develop something. But you look at the productivity gains here, and you're seeing factors of ten or twenty or fifty by these process changes.

Tom's central indictment of US Steel management: in the early 1970s, after BOF had been proven for a decade, US Steel built the last large open hearths (450-ton capacity) at ~$1B cost. "Billion-dollar dinosaurs."

US Steel built the last open hearth in the early 70s. They were about 450-ton capacity, huge. In this whole thing, you tap it by the whole thing lifts up, so you're lifting up this thousand-ton vessel that has 450 tons of steel in it. What replaced it — we're going to talk productivity here — was the basic oxygen furnace, after World War Two.

U.S. Steel built a 450-ton open hearth in the 1970s while the rest of the world was moving to BOF. Cited as case of competitive misreading.

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.

U.S. Steel built a 400-ton basic open hearth in the early 1970s — the last of its scale — at the moment the BOF was displacing the technology globally.

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.

Built in the early 1970s when the BOF had already won; Tom's verdict: "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.