High tech is achievable. (no magic required)
However, there are plenty of problems to solve, a good collection in Gary Walker's answer, on those it can be depicted how it's done differently, and presence of magic aka "free" energy definitely helps in that.
History of development may differ significantly, not necessarily the speed, however. Meaning it not necessarily adds another thousand years between a steam engine and an iphone29, but may or may not add a hundred years.
Some solutions may not look like we know them today, railroads mentioned in comments as an example, but there are other variations of those. So as honorable mentioning of the current state of usa transportation system, as an example of good roads system and weak railroad system, or more ancient times developed road system in Rome empire, water channels of medieval time so as of today, maglev, and low tech exotics from '50-'70s, airships.
All sorts of inefficiencies of alternatives, when we compare it with modern solutions, are not stoping factors for development, again an honorable mentioning is steam engines of a steam-era when they were 5-10 percent efficiency at their relatively mature state which is few times less efficient than any combustion engine of today. And that inefficient solution did manage to propel us through an industrial era of the development of our technologies just fine. And when u do not have alternatives, as of today's example no unobtanium which is 50 times stronger than
iron, one will use that solution just fine.
Fundamentals and differences
Fundamentals of our technological development weren't the iron and iron age by itself, but discovering\development of means to convert energy to mechanical work to amplify our strength(free labor force), so as energy sources to produce that energy as wind-hydro-wood-coal-oil. people were quite happy burning wood for energy production, but yeah it grows too slow, and then eureka moment - we have coal, a lot of it, let's burn it, and then comes oil and it even easier to burn especially in specific applications.
So a question to be answered can be means of energy conversion be build without iron. The answer is yes, windmills were mostly woods - wooden gears, wooden shafts etc.
First steam engine application for industrial purposes, not sure they used iron at all, for main components, someone more curious may add it here.
Another question to address is the scalability of solutions. iron has certain advantages, and no it isn't its abundance which is helpful but not the main factor, but that iron is a strong metal and it isn't brittle it has plenty of alloys etc. And that strong metal can be relatively easily machinable - u can cut it, u can grind it, so as u can cast it, etc.
This set of advantages in one package is hard to beat, so overcoming should be done with different materials and in different ways depending on application demands.
Despite those hurdles, industrial steam era applications (mean up to ends of the steam era) replacements are relatively easy in many cases.
- let's illustrate some of the possible alternatives
At the start efficiency of engines was close to zero, it just worked, but down the road, it got better and took the shape of the engines we may depict in our mind as soon as we hear words steam engine. But it started like:
A newspaper in March 1702 announced that Savery's pumps were ready for use and might be seen on Wednesday and Saturday afternoons at his workhouse in Salisbury Court, London, over against the Old Playhouse.
Mind u, 17xx, no moving parts at all. So as this comparison is quite interesting even if not that reliable wiki/Thomas Savery
The Savery steam pump was much lower in capital cost than the Newcomen steam engine, with a 2 to 4 horsepower Savery pump costing from 150-200 GBP. It was also available in small sizes, down to one horsepower. Newcomen steam engines were larger and much more expensive. The larger size was due to the fact that piston steam engines became very inefficient in small sizes, at least until around 1900 when 2 horsepower piston engines were available. Savery type pumps continued to be produced well into the late 18th century.
so it about 200 years of development until it was full steam, quite a time to wrap the brain around different alternative solutions.
u may laugh, but the stone is a decent alternative, not every stone but some basalt and diabase, in stationary cases even a good alternative to make a steam engine, with pistons and all that, for engine blocks, for valves.
And here is not so well known technology, basalt and diabase casting. Here is some marketing advertisement from the link
Basalt casting was originally developed in the Czech Republic to be used as a replacement for iron and steel which was in short supply after WWII – the crushed natural basalt is heated back to molten lava and then poured into moulds to make components such as pipes and floor tiles, which are incredibly hard wearing and abrasion resistant
originally developed by czech's is a marketing, it was started in a good old place where all good stuff comes from revolutions and fashion - by french in 18xx if i'm not mistaken, google brings plenty of links by keywords "basalt casting". in early 19xx some people toyed with the ideas of replacing iron with basalt and diabase casting, but it ended mostly on the primitive side of things pipes where abrasion factor and chemical resistance are important factors, different slabs - this technology still alive.
But for early steam the abrasion resistance is a good thing, there are no combustion explosions in a steam engine, there will be no corrosion, almost the same tensile strength with half the mass as cast iron, rocks are abundant enough. So your typical factory steam engine or its marine counterparts can be made out of those casts. there are specific nuances and problems, but no without advantages.
Cast iron in most cases, especially simple alloys, most basic stuff is similar in properties with those possible stone castings, except thermal conductivity. And there are limited thermal cycles on a stone block, so u may invent 3 shifts working earlier, or keep it idle under minimal power over nigth.
Copper was used as an alternative for pipes under pressure - an advanced example of that is a car Doble Model E, some can see it in here as an example 1925 Doble E-20 Steam Car - Jay Leno's Garage nice piece of engineering, which uses copper pipes as its boiler, and 58bar pressure which is way more than early steam engines can handle.
for mobile applications replacing iron in boilers can be a bit challenging, but for stationary not impossible with mortar and stone may do the job, the main problem here is a poor thermal conductivity of stone, which is good for a shell and bad heat exchange, so even if u put stone pipes inside the boiler, as it was done with steam locomotives, it will be less responsible on changing the power until u improve on that, and Doble Model E is a showcase how it is can be done and that it may be as responsible as your typical car.
shafts and gears
it is pity that nobody mentioned composite materials as some of the replacements. But with stone, it is one of the ways to overcome one of its disadvantages namely brittleness of it. Chemistry in times of stem engines was on its rise in 18-19xx, and at the beginning of 19hundreds, there was already a good variety of plastics available. So as making glass fiber. And those were used for gears, bearings (friction bearings) etc.
composite materials are not only your typical fiberglass, metal + fiber also a composite material, metal metal etc. it all needs their own development, and coincidently they are all about replacing metals|iron improving its qualities, and compared to our history in the environment of inaccessibility of iron all that development will start early on and it will bring its fruits early, as simple cases are simple and what one needs is mostly incentive, which we got when "iron" become not good enough.
gear boxes - there are more than two alternatives for making gearboxes - different hydraulic solutions(more than one), different variable speed solutions which can be done out of plywood for machines at 1-2-3kw power, different belt solutions, hydraulic transmissions etc - there are solutions which can avoid problems of lack of strength in gear teeth or brittleness of them by not using them. For lower power solutions plastic gears, composite gears, aluminum gears, etc work fine.
Energy, after steam.
what caught my attention in Gary Walker's answer is the oil extraction problem, it begins to be a problem at times when high-density power sources are in demand, and it comes at a time of more advanced technology.
So as chemistry vessels and high-pressure vessels for mass chemistry production, which again is a sign of more advanced technology and so as more advanced technological competencies to solve those problems.
So as agriculture plows etc will need solutions.
As space rockets - there are different solutions to approach the problem of high volume high-stress vessels - that are different composite materials, aluminum alloys. So as with other space technologies to solve corrosion resistance, heat resistance - and iron isn't used that much(exclude engine) - so space technologies is our top-notch benchmark for some cases and it sort of shows to us iron isn't a winner here.
however, a transition from steam to that, in which combustion engines played their role, may come in a different way, maybe even somewhat skipping it. The same way as electric-powered cars didn't fly in 1900's, because of the convenience of alternatives of combustion engines, so as Doble Model E died for the same reason. in case of the absence of iron - electric powered solutions are the convenience and Doble Model E fights not internal combustion engines but electric-powered vehicles and probably wins over at some applications.
u probably won't see those high powered airplane engines of wwii, sea ships engines as those low rpm monsters will also have certain problems.
So there will be a plethora of problems, but it does not differ that much in the complexity of problems we solved to get us where we are today.
A characteristical difference maybe that u may work with less powerful or less compact solutions, jump additional hops be more creative, which will take its toll but not impossible.
- in time of wwii there were ship hulls made out of cement
- helicopters maybe not a thing, but airships may still be a thing (airships can be quite efficient, better than trucks, and a 1.5 times worse than railroads)
- precise manufacturing won't suffer that much, but there can be certain limitations on a big size, which is not that critical for making semiconductors as an example.
- big big machines monster trucks, excavators - pretty much kiss it goodbye, until u set a firm food at composition material and nanocarbon.
- jet engines, fighter jets, etc, probably arrivederci too.
- turbines do not necessarily suffer the same fate, but it needs a redesign.
- rotary combustion engines may be more popular than as of today
- fiber optics and a broadband connection - no problems
- electricity generation - doable but less efficient, preferably direct mechanical energy usage where it is possible (in production, as the backbone of tech development it is possible almost everywhere)
- springs will have a hard time and they are used a lot, but in some cases, there are alternatives(pneumatics as an example) in others u may need to avoid them by means of design and find other alternatives (chemically tampered glass, Compliant mechanis)
- cutting tools - more synthetic diamonds will do, I think it worth the change, lol
- bearings - more friction bearings, hydrodynamic bearings, hydro and aerostatic bearings, ceramic bearings which in many cases just are a better alternative to your typical one.
- structure elements more plastic, more aluminum, more composite materials.
- connections more glue use and epoxy and adhesives
- higher focus on chemistry
- firearms will have a problem, particularly powerful and rapid-fire ones. However, there are rifles with composite barrels.
where it is a problem in need to solve it will be solved directly or by going around. some technologies which didn't fly in our tech tree can fly in an iron-absent tech tree, some solutions can meet its nerfing, some won't fly.
the key technology of today - microelectronics and all the electronics can be achieved and be not affected that much.
Things that will be harder
- resource gathering, large scale mining operations will be harder
- deep hard to get oil extraction
- high tech wars
- getting down to 3% population in the agrocultural sector will be hard
if u can improve upon of brittleness of stone and limited heat cooling cycles which is the same problem, then it can be used everywhere where cast iron was and is used.
in absence of an alternative it pointless to refer to economic incentives as we see them today, as we do have options, but they don't - it is done or doesn't. And expenses are defined by widespread technology - the meaning amount of supply, amount of energy put in the refinement of technologies. Ceramic bearings are exotics to us, but for them, it can be a get-go from the very start when they needed them with decades of refinement of technologies and establishing production chains and capacities.
ferromagnetic materials can be a problem for electric engines, so as generators - but it is not one which can't be solved by an excess of wires, so it is not a fundamental one. So as nickel and cobalt will play a more significant role where u have to have them. one does not have to have those metals more, u just use them less and only in places where they bring u the most, power plants as an example.
okay, those are my two cents on the topic