1850s steel technology advance before the Bessemer converter

Question

The Bessemer converter is often cited as the critical invention causing a breakout in the production of cheap steel and enabling the industrial revolution. However, I just put together this chart today from data in "The Chemistry of Iron & Steel Making" by Williams which suggests another cause:

So, if this chart is right we see the Bessemer converter being invented in the middle of the breakout, not at the beginning. In the 1851 data point we see a large increase in the production of steel, yet the Bessemer converter had not come into use yet.

Is there some key technology advance that preceded the Bessemer converter that could have enabled this increase in production?

Note that I am just guessing that there was some key advance that led to the increase in production. It is entirely possible that there was no technological advance, and that the number of factories and workers simply increased.

(Just as an aside, some may wonder why there was a decline in the 1870s. The reason for that is a scrap effect. Much of the iron produced in the boom of the 1850s rusted and turned into scrap by the 1870s. By recycling all this scrap, the need for new production declined. A secondary cause was an increase in American production at that time.)

Answer 1

I had to do a lot of research into industrialization, and Bessemer, for my end of year project. How it relates to your question is that I found out that most machine equipment (along with military uses) needed steel in certain parts, which made those parts impractical for most of the 18th century. Luckily, the steam engine was invented, and then improved by Robert Fulton, which allowed more coal to be mined.

Coal, and then later coke, is one of the parts needed for making steel; because before Bessemer you had to heat iron to an extreme heat, take out the slag and then get the wrought carbon filled iron you made out of the regular iron with low carbon content.

So the start of your graph's rise in steel is when they could finally get enough heat to make steel and use the puddling process. Your rise between 1820-1840 was from the amount of steel needed still using traditional methods. Steel would be the metal gun chambers, high pressure engine parts, knife edges, and other industrial equipment needed.

After Bessemer, rather than your theory of rust (Damascus steel rusts much more slowly than regular iron and most of the steel made from before wasn't in places that should have gotten wet). Two Sheds idea of steel railroads seems to pop out as a major cause but that was also the time of steel skyscrapers, steel bridges, steel ships and artillery... So all of that would account for the major increases.

EDIT: before the OP edited his question to make it more precise what he was asking, I didn't clear up what my answer to what technology came before Bessemer that enabled the increase in production. The answer is the puddling process; it was the process that purified iron, and by using coal and coke, it gave the iron strength. But, as others have pointed out, they didn't need a new technology to be able to make more steel. They just needed better resources and the want to make it. Before the industrial revolution, they could not get enough high quality hematite and charcoal and coal, to want to use steel for items that they made just as well with easier alloys to mix. They had to use steel by the later industrial revolution for high quality parts that could stand up to stress that bronze and normal iron could not.