Metalworking is one of the oldest crafts, going back far beyond recorded history. But until a few thousand years ago, one of the most abundant metals—iron—was virtually unknown. The ancient Egyptians and Sumerians knew iron only from meteors, and considered it heavenly, a gift from the gods. Later civilizations discovered how to smelt it, and their period came to be known as the Iron Age, but they didn’t know how to consistently make it strong, and not brittle. During the Industrial Revolution, we discovered how to make it strong, consistent, and even cheap.

Now high-quality steel is everywhere around us: holding up our buildings (in both girders and reinforced concrete), in our cars and ships, in trains and their rails, in bridges and towers, in electrical infrastructure, in refrigerators and washing machines, in pots and pans, in forks and knives, in hammers and saws, in nails and screws, in tables and chairs.

The wonder of the metal is gone, but the wonder of the process remains. A steel foundry is an amazing sight, with enormous blast furnaces several stories high, raging at thousands of degrees 24/7, attended by a swarm of workers, like a great beast with an insatiable hunger for ore, coke, and lime.

The product they put out is of such purity and consistency that it would be hailed by the ancients as a miracle, a feat of craftsmanship possible only through divine intervention. But in the modern economy, it is a commodity.

What is this material? Why is it so hard to make? And how did it go from mythical to mundane?

Full post with lots of images:

New Comment
8 comments, sorted by Click to highlight new comments since:

In at least some cases, "religious rituals of purification and prayers to invoke the gods," should be classed with "things that work even though we don't know why" instead of "things that do not work." When working metal, time and speed are really important, and specific prayers and rituals can regulate that. You saw the same thing in other areas like baking. "Stir with this spoon while saying this prayer" because that old dirty wooden spoon had lingering yeast on it, and it took 4 times reciting the Lord's prayer or whatever for enough to make it into the dough for it to rise properly.

On another note: I wonder if it mattered much that iron was an element instead of an alloy. Copper and tin aren't mined in the same places, so whenever long distance trade broke down, like in the late bronze age collapse, you had serious issues. Iron, you needed ore and fuel, potentially more resilient?

I really like the 'prayers are just a religious working song' angle.


That reminds me of a story I read about a lambic brewer in Belgium who needed to replace an again brewery roof. They ended up building a roof over the existing, but dilapidated, one because of the wild yeast that was had grown in it over the decades. His concern (legitimate) was removing the old roof and replacing it would cause the flavor of the brew to change.

One can easily see how such an event 2 or 3 hundred years back might produce a more mystical explanation but based on a very empirical observation.

Even more remarkable is the development of aluminum. Aluminum was considered to be as valuable (if not more valuable) than gold. The peak of the Washington Monument is tipped with 100 ounces of pure aluminum, which even as late as the 1880s was considered to be too rare and valuable to be used for anything other than jewelry. And now, aluminum is just as mundane as steel, if not more so.

Yup, aluminum is even more abundant in the Earth's crust than iron; about 8% vs. 5%. But it requires electricity for smelting and so wasn't common until the very late 1800s or so

Note of confusion:

Today, we know that iron with less than about 0.1% carbon is wrought iron, with more than 2.1% it is cast iron

But earlier these were described as different methods of shaping the iron, with wrought iron coming out of the furnace solid and being beaten into shape and cast iron coming out liquid and being moulded.

Is it that these processes (typically?) result in these quantities of carbon?

It's more the other way around: Iron with more than ~2.1% carbon is brittle, and therefore it cannot be worked with tools; it can only be cast—so it's called “cast iron”. The low-carbon iron can be worked with tools, hence “wrought”.

It's the smelting process that results in the carbon content: smelting at temperatures high enough to melt the iron, also causes it to undergo a phase change that causes it to absorb more carbon.

It's always nice to take in a bit of Joy in the Merely Real. I have sometimes found it a useful exercise to consider just which things would or would not be shocking to people in the past. For example, anyone from before 1500 would be utterly shocked and mystified by any page of printed text or any piece of clothing from 1800 or after.