Of course that proved true - we call it steel - and if you go by the date of Bessemer's patent (after which steel became cheap enough to use on structures), they only had to wait 9 years.
ductile cast iron does now exist but bessemer didn't invent it
it is true that some castings are now indeed made of steel, but bridge girders are not among them, and the casting steels used today postdate the bessemer process by generations. chrome wasn't used in steel until 01865 (except, to everyone's great surprise three years ago, in medieval persia), nickel until 01889
(you can roll them as much as you want without cracking, and in fact they're dramatically more ductile than actual structural steel alloys like a36, but generally people don't because they're far too expensive and not at all easy to roll)
this is not, as you falsely claim, a quibble about nomenclature, in which bridge girders are made of mostly iron and are made by casting but are just not called 'cast iron'. they aren't cast at all
as for 'improvements', bessemer's steel was not an improvement over cast iron in every way (it's softer, has a higher thermal coefficient, and can't be practically cast) but in any case brunel did not make the claim you falsely imply he does:
> At present cast iron is looked upon, to a certain extent, as a friable, treacherous, and uncertain material; castings of a limited size only can be safely depended upon; wrought iron is considered comparatively trustworthy, and by riveting, or welding, there is no limit to the size of the parts to be used. Yet, who will venture to say, if the direction of improvement is left free, that means may not be found of ensuring sound castings of almost any form, and of twenty or thirty tons weight, and of a perfectly homogeneous mixture of the best metal? Who will say that beams of great size of such a material, either in single pieces or built, may not prove stronger, safer, less exposed to change of texture or to injury from vibration, than wrought-iron, which in large masses cannot be so homogeneous as a fused mass may be made and which when welded is liable to sudden fracture at the welds?
(https://ia801404.us.archive.org/3/items/brunel-isambard.-the... p. 192 (224/603), letter of 01848-03-13)
this is clearly not at all what happened. i don't fault brunel for failing to predict the future; i fault you for claiming he did
you're wrong, you made a mistake, what you said isn't true, it's false, and by continuing to dance around that and play word games instead of admitting it, not to mention flagging my rebuttals so people can't see them, you're leaving traps for people in the future who read this thread to try to understand the historical development of metallurgy
and please leave the 'my dude' shit (https://news.ycombinator.com/item?id=35664138) on twitter or wherever you picked it up, that kind of bullshit isn't welcome here. likewise the claim to be an authority on a subject because you took a class on it in college. a degree is not a substitute for knowing what you're talking about
in fact that is much of brunel's point in these letters
And is steel mostly iron, or isn't it?
How many different ways can you ignore the obvious? I would think we could dispense with all this, see the big picture, talk in broad terms, but apparently not.
It's not me flagging your posts, it's someone or someones else. Sounds like you have a different and inaccurate idea of what's "welcome here" - who exactly do you think you're speaking for? I'm perfectly welcome here. YOU leave. And I'm not wrong either, hell I'm barely even stating anything; even the thing you contradicted, I never said, so it's rather tragicomic.
"Rebuttals" is a generous term indeed for your childish rage my dude. And shallow wordplay is exactly the thing you've been doing from the getgo with "no, steel is not cast iron," which, again, I never said in the first place, although I see why you thought I meant that, and again, there is an ironic, no pun intended, and mostly unrelated fact here, which is that steel is mostly iron and goes through casting as part of its process. No dancing needed, I'm just repeating the same thing.
Never been on Twitter, for the record, my dude, but from what I hear, you would fit right in. My dude.
The initial disconnect here seems to be that I'm deliberately eliding a lot of details in order to see all iron products as part of a unified whole, with improvements on a continuum over time. Whereas you seem to see this as an egregious violation of terminology and facts. It's really just a question of which level of detail you want to work at. That kind of objection wouldn't be a problem, except... The problem I have with it, and the reason I will now most likely never be won over to anything you have to say, is because while missing my point (which mind you is small and not that interesting), you jumped right into not only correcting details I left out intentionally, but also asserting that that must mean I'm ignorant of them. Do we need to always say everything we know about metallurgy? I guess it's a dick-waving contest... shoot, I would've brought my whole dick if I'd known. Saying I studied it in college - that wasn't an appeal to authority, it was a hint to you that your lecturing about basics is unneeded, in the hope of changing the context back away from the minutiae.
All iron products are made of iron and are cast at some point. Cast iron is the only one we call "cast iron," and that is an arbitrary, happenstance artifact of history. Terminology is arbitrary symbology, always, and deserves the appropriate skepticism or at least the ability to imagine a world with different symbols. Not even a world... go to a country where they speak another language. They might not even have separate words for "sky" and "heaven." If that feels like a "word game" you need to realize all words are games and are non-deterministic. I don't need to dance around to evade your amazing laserlike prowess at calling out my errors because again, you're arguing minutiae while missing my pretty modest point.
RE Bessemer I left you a giant implicit 'else' clause by saying IF you want to take his patent as a milestone, then it's 9 years. Obviously there are reasons not to particularly take it as a relevant milestone.
You know what, I'll go all the way and actually say the thing you accused me of saying: steel is cast iron. With a bunch of ingredients and processing steps added. I know, I know, it's ridiculous, and bordering on meaningless, because look, a microprocessor is just a rock with a bunch of ingredients and steps added. The point is not to take it to extremes of ridiculousness, the point is to see the similarities and see how processes were added and changed to improve and transform the final product.