[HN Gopher] How to build a 50k ton forging press
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How to build a 50k ton forging press
Author : chmaynard
Score : 389 points
Date : 2024-08-21 14:00 UTC (1 days ago)
(HTM) web link (www.construction-physics.com)
(TXT) w3m dump (www.construction-physics.com)
| cbsmith wrote:
| ...and now the modern equivalent is the Giga Press:
| https://cleantechnica.com/2024/03/09/teslas-giga-press-has-l...
| mitthrowaway2 wrote:
| Not only is the giga press mentioned in the article, it's very
| far from being an equivalent to the Alcoa 50,000.
| cbsmith wrote:
| Yes, it is mentioned in the article, and it specifically
| says: "We can see a modern, obvious parallel between the Air
| Force Heavy Press Program and Tesla, which has created a
| similar revolution in car manufacturing by using large
| aluminum castings to replace dozens or hundreds of smaller
| parts."
|
| So I didn't think what I said was out of line. Obviously, I
| was mistaken.
| tra3 wrote:
| Super interesting:
|
| > The largest, the 50,000-ton forging presses, were behemoths:
| each was the size of a ten-story building, and could exert enough
| force to lift an entire battleship. The 35,000-ton forging
| presses weren't much smaller.
|
| and then
|
| > Following Germany's surrender, the U.S. and the Soviet Union
| divided up its large press capabilities as well as its rocket
| scientists. The U.S. dismantled four German presses and had them
| shipped back to the states
|
| I wonder what the logistics for moving something like that across
| the ocean was. I know Soviets dismantled a bunch of factories
| during the war and moved them far behind the front lines...wonder
| what that was like.
| dimator wrote:
| There's an excellent video on these presses
| https://youtu.be/hpgK51w6uhk?feature=shared
| hinkley wrote:
| Well when you have military supply vessels just hanging around
| in the area...
| tra3 wrote:
| For context, I work on my car a bit, and the shop manual for
| it is hundreds of pages (thousands?). Now scale it up to a
| factory, maybe without manuals. Disassemble, crate it,
| assemble it 5000 miles away.
|
| Based on my software experience, I can sort of go in blind
| and figure out how a system functions. I suppose that
| translates to real world too..
| hinkley wrote:
| There's a UX school that says that if the user needs the
| manual you fucked up. I mostly subscribe to that school.
| Mostly.
|
| It drives my family nuts that I will assemble a piece of
| furniture without reading the instructions. But the thing
| is with a little mechanical sympathy, and a well designed
| product, there's only one sensible way for the parts to go
| together, and if you organize them right while you
| disassemble it (granted, harder to do when shipping
| overseas) then you're good.
|
| Imagine you had a device where four hardened steel bolts
| held the critical parts together. It would be stupid if the
| handles used the same bolt sizes in mild steel, right?
| Someone will fuck that up and use the wrong spare parts or
| do deep maintenance wrong. You'd use a different size bolt
| so they can't get mixed up.
| WheatMillington wrote:
| Your viewpoint is rather naive in the mechanical world.
| OK it's enough to assemble a coffee table, now try an
| engine with 2,000 parts. Without a manual how can you set
| bearing clearances? How do you know how much thrust
| clearance there should be? How do you know which way up a
| piston ring goes, or how much torque to apply to a head
| bolt?
|
| Machines are extremely complex, and that's before you
| even touch electronics and hydraulics, both of which are
| highly complex systems. Simply moving large machine parts
| safely requires documented procedures, let alone order of
| assembly.
| kragen wrote:
| there's a lot of shade-tree mechanics who have
| successfully rebuilt engines with thousands of parts.
| essentially figuring out how to rebuild an engine is
| similar to figuring out how to build one from scratch,
| which is within human capacity, particularly with
| background knowledge. but the guy rebuilding the engine
| has a lot of hints
|
| granted, he'll probably fuck up his first two or three
| pretty good without haynes or chilton
| hinkley wrote:
| There is a lot of stuff you can do when it's pass fail.
| As a pro you have a time limit and you're bad if you
| can't rebuild in X hours.
|
| My dad will tell you I helped him rebuild a bike coaster
| brake at 14. But the truth is the only decision he made
| was to buy the repair kit. I got rags and laid all the
| parts out like an exploded diagram, we cleaned them or
| swapped them and they went back in the way they came out.
|
| I worked as a bike mechanic for two summers in college.
| Cars have manuals and maybe the mechanic you work for has
| them. Bicycles do not. You're all shade-tree until you've
| seen everything a couple times.
| kragen wrote:
| yeah. thank god for sheldon brown
| hinkley wrote:
| I was more of a Brandt boy myself.
| rlonstein wrote:
| > granted, he'll probably fuck up his first two or three
| pretty good without haynes or chilton
|
| Given the assumptions, inaccuracies, and mistakes I've
| seen in some Haynes and Chilton manuals they'll probably
| fuck up with them. Factory manuals are usually worth the
| price (Honda's are, KTM's not so much).
| kragen wrote:
| i certainly did. haynes is no substitute for clue
| bacon_waffle wrote:
| I've rebuilt several motors, transmissions, various other
| mechanical contrivances. Sometimes with decent
| documentation, sometimes not so much. Also done a bit of
| amateur machining, and worked as an engineer on physical
| products.
|
| Under no circumstances would I claim that rebuilding a
| motor was essentially figuring out how to build one from
| scratch. In software, maybe that's like claiming that
| figuring out how to configure a new Linux box is
| essentially the same thing as figuring out how to write
| an OS.
| kragen wrote:
| yes, i agree. what i was trying to express is that
| rebuilding a motor is _generally strictly easier than_
| building one from scratch, because it 's building a motor
| from something more than scratch. i don't think i
| expressed it very well
|
| (i mean, if all the parts of your engine are trashed, you
| are going to have to machine replacements for them, and
| that might actually take you longer. but it's clearly
| achievable given that people have built internal
| combustion engines without a working example to take
| measurements from)
| bacon_waffle wrote:
| Ah, that helps, thanks.
|
| It's a bit academic, but set theory doesn't really apply
| to such fuzzy human things as knowledge and experience.
| Repairing and designing are different pursuits which
| might have a lot of similarities, but I wouldn't presume
| that a design engineer could competently do the work of a
| technician.
|
| Just consider that any particular field of engineering as
| might be described by a lay person, can be far too broad
| and deep for an individual to be competent in all facets
| of it. I'm reminded of my neighbour asking for some help
| configuring email for her new iPhone, because she knows I
| do computer work. Mainly firmware.
| kragen wrote:
| there's something to that, for sure; there are plenty of
| design engineers who don't know nearly as much as they
| think they do, and who depend heavily on the expertise of
| their technicians to get anything done in the real world.
| they could never build an engine on their own! but there
| are also others who are eminently capable at the
| technical level, and i think their designs benefit from
| that
|
| repair and design have in common that they require a lot
| of hard thought about the causal relationships involved
| in making the artifact work, tracing the causal chains
| through until they break, then patching them up. but they
| both also certainly involve other skills that the other
| does not; design also requires figuring out how to make
| new things happen, which involves imagining things that
| have never happened, while repair also requires knowing
| how not to bust your knuckles or spill the gasoline
| hinkley wrote:
| Does every car mechanic have the entire Chilton's catalog
| or do the mechanics just have to memorize things or look
| them up on the Internet? My understanding is it used to
| be a little A and a lot of B, and now it's a mix of B and
| C
| WheatMillington wrote:
| I was using the engine example as an analogy in an
| apparently failed attempt to help you appreciate the
| complexity involved. Mechanics in general will feel their
| way around an issue, but almost universally have access
| to paid repair databases when non-intuitive and complex
| issues come about.
| hinkley wrote:
| You might recall that we're all talking about
| manufacturing equipment that was exfiltrated as war
| reparations.
|
| I'm much less convinced than you are about the
| availability of accurate and detailed manuals. Which is
| why I keep steering the conversation to more murky
| engineering projects.
|
| But I do want to circle back to say that I did at some
| point higher up gloss over the importance of things like
| torque and clearances. I'm not trying to say that those
| are things you can just intuit. Even if we could both
| probably dig up an old mechanic who tightens things by
| feel.
| krisoft wrote:
| I don't understand the problem. You take the equipment,
| the manual, the guy who used to read the manual and
| maintain the equipment and the guy who wrote the manual
| and designed the equipment.
| jessebro wrote:
| Did we mention that the manual was burned, and the guy
| and the guy who wrote the manual died in the explosion
| that burned the manual?
|
| It was at the end of a massively destructive war of
| annihilation.
| tra3 wrote:
| I think everyone has access to full shop manuals in soft
| copy these days. I imagine it's a lot like writing code.
| You remember how to write a for loop (oil change? a
| brakes?) but have to look up API docs for more esoteric
| functions (a clutch job?).
|
| FWIW here are Nissan factory manuals in all their glory:
| https://www.nicoclub.com/nissan-service-manuals
| sushid wrote:
| Sure, but now you have another bolt and nut configuration
| that requires a different drill, maybe a new supplier,
| etc. RTFM!
| hinkley wrote:
| Bolts and nuts in two different materials/grades are
| still two separate pieces of inventory to manage.
| metadat wrote:
| Sometimes the intuitive way is wrong and you end up
| damaging the piece.. ask me how I know.
| jessebro wrote:
| Better hope they done have one set of 50mm bolts which
| are mild steel, and another set that are hardened high
| tensive steel that aren't clearly marked and the same
| length!
|
| Or you're going to have quite an adventure when you go to
| do your thing and a random selection of bolt heads come
| pinging off at you at mach 5.
| bee_rider wrote:
| They talk about machining, casting, and pressing. Mostly with
| casting and pressing in a good light, machining not so good.
|
| As somebody who knows absolutely nothing about this stuff, I
| wonder--casting, I thought, was generally a lower quality option
| (like cast iron doesn't have fantastic high-performance material
| qualities, and I had some crappy cast pewter toys as a kid). Are
| there different, higher quality casting processes, and I've only
| seen the bargain bin results? Is there a general ranking of the
| quality of the result or is it all very complicated and material
| specific?
| debacle wrote:
| Casting isn't necessarily "lower quality," it just has
| different properties. It's also much older (by thousands of
| years) than machining or pressing, but you can't get to the
| pressing or machining step without having an ingot, which comes
| from the casting process.
|
| The main drawbacks of casting are you get a hard, but brittle
| product with (generally) uneven quality. There are processes
| (like annealing, though I don't know how you anneal a massive
| component) that can solve these problems, but all iron/steel is
| "cast" at some point.
| BlueTemplar wrote:
| Until the mid-1800s, basically only the Chinese used cast
| iron, since it's so brittle. Ingots would come from smelting,
| not casting.
| kragen wrote:
| depends on what you mean by 'machining'. grinding is at least
| 7000 years old https://en.wikipedia.org/wiki/Shoe-last_celt
| and roughly contemporary with pottery. casting presumably
| began with pottery but was definitely in full swing by the
| bronze age, a mere few thousand years later
| WJW wrote:
| Machining is fine, but in the context of the article the
| problem is that it usually starts off from plates or otherwise
| block-shaped materials. That means that if you have a weirdly
| shaped part full of holes and/or with many protrusions in weird
| angles (as vehicle parts tend to have), then you either have to
| combine many smaller parts into a final part or have to machine
| away a huge amount of material from a solid block to come to
| the final shape. It would be much better to cast or forge the
| part into roughly the right shape straight away, so you'd need
| only minimal finishing work. That is what these presses
| enabled.
| hwillis wrote:
| > like cast iron doesn't have fantastic high-performance
| material qualities
|
| Cast iron is a material, not a process. It's an unfortunate
| legacy term for very high carbon steel (>2% by weight, or <11
| iron atoms per carbon atom). For reference "standard" steel is
| ~.08-.18% carbon, and high-carbon steel is ~.8% carbon.
|
| The >1% carbon precipitates out into graphite within the steel,
| causing it to behave totally differently. Less rusting, but
| weaker and much more brittle when solid. Less viscous when
| liquid, so you can cast long and thin parts.
|
| > Are there different, higher quality casting processes, and
| I've only seen the bargain bin results?
|
| There are, but it mostly is independent of the material. Some
| turbine blades are cast as single crystals for heat stability;
| you can't really cut a single crystal without introducing
| cracks and issues. There's also vacuum casting and spin casting
| (using a centrifuge to force liquid into the mold), which lets
| you cast metals that react with air or cool too quickly for
| normal methods.
|
| Most of the variation in process is about the final form you
| cast into, though. Engine blocks are sometimes cast into a one-
| off ceramic shell that is sprayed onto a sand form. It's an
| expensive process but it lets you do the whole thing in one
| step.
|
| > is it all very complicated and material specific?
|
| It is very material specific. Fundamentally its all about
| shaping the grains. In many steels you can physically alter
| grains. In others, like precipitation grains (aluminum alloys,
| some steels) the structure is determined by the cooling and you
| can't physically shape them. In that case you may often get a
| better structure by casting since you can choose how to cool
| parts down, while a billet will have a homogenous structure
| that is usually worse towards the center.
| hedgehog wrote:
| Monocrystalline turbine blades are one of those things that
| make me appreciate how deep the state of the art is for a lot
| of "simple" things when you look closely.
| eternauta3k wrote:
| There's nothing simple about jet engines :)
| pfdietz wrote:
| > The >1% carbon precipitates out into graphite within the
| steel, causing it to behave totally differently. Less
| rusting, but weaker and much more brittle when solid.
|
| If one adds some magnesium or cerium to the alloy, the
| graphite precipitates out as spherical nodules rather than
| feathery dendrites. The resulting material, called ductile
| iron, is much less brittle than traditional cast iron.
|
| An advantage of the higher carbon content is a reduction in
| the melting point (by > 300 C), so the material is easier to
| cast than low carbon steel.
| mrob wrote:
| They also talk about forging. Forging can produce higher
| quality parts because metal has a grain structure. Just like
| wood, it's easier to break between grains than across the
| grain. Forging is deforming the metal without melting it. If
| the temperature isn't too high, it will deform the grain
| structure along with it. The grain can be aligned to make the
| metal stronger along the axis where it needs to resist the most
| force.
|
| Wikipedia has a image of an connecting rod that has been etched
| to show the grain:
|
| https://upload.wikimedia.org/wikipedia/commons/5/5c/ForgedCo...
|
| You can see the grain has been stretched along the length of
| the narrow parts. Wrenches are another example of something
| that's commonly forged for this reason.
| colechristensen wrote:
| Cast iron is a material, it's good for what it's good for but
| its material properties don't really come from the casting
| process, just the ratio of iron to carbon.
|
| Casting has problems with thermal expansion, plenty of
| materials shrink significantly as they cool and complex parts
| cool unevenly which can cause them to break or deform.
|
| Casting has problems with microstructure, plenty of materials,
| especially steels develop complex crystal structures with
| multiple phases of materials as they cool from liquids and even
| extensively in hot solid phases. It's hard to control this in a
| cast part.
|
| Casting has problems with precision. The molds just can't be
| all that precise when in machining, a thousandth of an inch can
| be a relatively large distance.
|
| However casting gets a bad reputation because most of the time
| you see it it's because it's actually very cheap, cheap
| materials, cheap process, minimal post processing. Higher cost
| things don't necessarily realize the savings from casting as
| much so they don't use it. And also a lot of higher quality
| materials have higher melting points which require more
| advanced tools to melt and handle.
|
| Plenty of things though are cast and then machined, you notice
| this if you look.
| spenczar5 wrote:
| Castings can achieve shapes that are impractical to machine. A
| classic example is a spoked wheel. The spokes are really hard
| to make precisely with machining, but fairly straightforward
| when casting. Bandsaw wheels are virtually always cast, for
| example.
|
| Also, the processes are not really independent. It can be much
| cheaper to do a rough casting, and then machine just the
| critical faces of it, instead of using an "off the shelf" hunk
| of metal and machining it all into shape. So it's not really
| "casting is superior to machining" or vice versa. More that
| machining is high precision but expensive. Casting has some up-
| front cost but once the patterns are made, each item will use
| material quite efficiently.
| IshKebab wrote:
| Spoked wheels aren't cast because it's hard to machine them.
| You can easily CNC them if you really want. But that would be
| insanely expensive and wasteful and not any better.
| spenczar5 wrote:
| Yes, I said "impractical", not "impossible".
| IshKebab wrote:
| You said
|
| > The spokes are really hard to make precisely with
| machining
|
| That is not true.
| jessebro wrote:
| Back in the days of manual machining it was definitely
| true. CNC, especially modern 5+ axis high speed high
| rigidity machines are god level cheating.
| buildsjets wrote:
| I've watched enough Chip Foose on TV to know that in the
| custom car world it is commonplace to start with a solid
| blank wheel and CNC away 90% of the face to achieve any
| particular design. It takes only minutes, and unlike
| casting or forging you do not need to purchase hard tooling
| for each different design.
|
| https://www.youtube.com/watch?v=nqOlM6-YIIs
| bagels wrote:
| Other materials can be cast, such as various aluminum alloy.
| Casting can have a higher cycle time, be cheaper, and require a
| less expensive equipment.
| bluGill wrote:
| Which cast iron? There are many different grades/alloys with
| different properties. Sometimes cast iron (some specific grade)
| is better sometimes it is worse. And of course you can cast
| things other than iron, cast steel does exist (rare outside the
| feed to a press, roll, or some other process, but you can cast
| steel into a specific shape if you want to). There are trade
| offs. The topic is so broad we cannot even start to talk about
| it. Instead we start with what your application needs and then
| look at the options to get that.
|
| Cast iron is fantastic for building machine out of - while it
| isn't as strong, it is stable against vibration. There is a
| reason engine cylinder selves are often cast iron.
|
| > I had some crappy cast pewter toys as a kid
|
| Those were pot metal, not pewter (pester has many definitions
| but implies some qualty control). They are made out of whatever
| melts in a pot - often whatever is cheap at the recycle yard
| (without trying to identify what is in the metal - including
| lead which shouldn't be used in toys). Typically no control of
| the alloy was made and often they start with several different
| things that are great in isolation but when mixed result in bad
| behavior. Then the next time the make the toy they use
| different mix and get different properties. If you spend a
| little extra to get a known alloy pot metal is a high quality
| castings with great properties.
|
| > I've only seen the bargain bin results
|
| You have likely seen a lot of non bargain bin results. However
| since the parts are invisible you never thought about it or the
| alloy used. You see the failures and so casting gets a bad
| reputation because it is obviously used in the cheapest things
| with low quality control. (the door knobs in your house are
| likely cast pot metal plated with brass, but they last for
| decades)
| shiroiushi wrote:
| >Cast iron is fantastic for building machine out of - while
| it isn't as strong, it is stable against vibration. There is
| a reason engine cylinder selves are often cast iron.
|
| I thought it was because cast iron had very high resistance
| to wear.
| Metacelsus wrote:
| Now I want to see one of these on the Hydraulic Press Channel!
| jcgrillo wrote:
| My little 20 ton shop press brake can bend 5/8" plate. Incredible
| to imagine what this behemoth can do...
| kibwen wrote:
| Using advanced math I hereby extrapolate that this 50,000 ton
| press can bend 12,500/8" plate.
| hwillis wrote:
| The second moment of area is quadratic with thickness (t^2),
| so 250/8" plate. But in reality 2-3x more than that, because
| at that scale steel gets a bit... goopy.
| kristjansson wrote:
| I understand very little about machining, expect that _all_
| materials are kinda squishy if one applies enough squish.
| mikewarot wrote:
| Even inconel is bubble gum in a Kurt vise if you're
| chasing tenths, or microns.
| jcgrillo wrote:
| well the next time I need some 130ft thick brackets I'll ask
| them whether I can use it after hours or on the weekend
|
| EDIT: or, according to hwillis' math, 2.5ft thick. I guess
| those could be useful for anchoring a zipline to the moon or
| something.
| hinkley wrote:
| I saw a guy weld 1.5 or 2 inch plate once to repair the
| bucket on a giant bulldozer. That was... interesting. I was
| trying to figure out why he left such a big gap until he
| started welding. He had to fit the head in to lay down
| layer after layer of welding bead to join the pieces at
| full depth.
|
| How would you weld even one foot of steel?
| jcgrillo wrote:
| For a butt joint V it out on both sides and do many, many
| passes. Maybe have a few guys with rosebud torches
| working heat into it as you go. Big rods make it go
| faster (https://youtu.be/j61ezBX-EyA). For a lap joint
| it's the same idea, you're going for a great big fillet.
| But if you have a gigantic press at your disposal there
| are other options. For inspiration:
| https://youtu.be/k_LA_R4ifYk
|
| The idea behind forge welding is you get both parts
| nearly molten (e.g. "welding heat") then your hammer blow
| (or the pressure from a huge press) puts enough energy
| into the weld area to briefly melt it.
|
| Also, hot rivets might be a better option than welding if
| you can get away with it.
| buildbot wrote:
| Explosively?
| https://en.wikipedia.org/wiki/Explosion_welding
| hinkley wrote:
| OMG. Are you required to slap it and say, "That'll hold"
| afterward?
| jessebro wrote:
| A lot of the armor plate on the big battleships like New
| Jersey were welded. Some of those are over a foot thick.
|
| It would take a LOT of passes.
| js2 wrote:
| Letterman being silly with an 80 ton press:
|
| https://youtu.be/0CqCLf4RUUY
| eric_the_read wrote:
| A worthy predecessor to the Hydraulic Press channel:
| https://www.youtube.com/channel/UCcMDMoNu66_1Hwi5-MeiQgw
| PaulHoule wrote:
| Nobody in North America has a press that can make a vessel for a
| nuclear reactor without making it in pieces and welding them
| together (probably adding a year to the schedule if you don't use
| a new welding technique just developed in the UK not to mention
| people being anxious over the welds)
|
| There is a Canadian company that is gearing up to make small
| reactor vessels like the BWRX-300 but so far I haven't seen a
| sign they aren't Nuscale 2.0
| phiiiillll wrote:
| Was curious about what welding technique you meant, looks like
| it is local electron beam welding
| https://www.thefabricator.com/thewelder/blog/assembly/sheffi...
| PaulHoule wrote:
| That's it.
| MisterTea wrote:
| I work in an EB shop doing everything from welding,
| engineering assistance, machine repairs, and complete machine
| rebuilds. It's quite an impressive process and Ive had parts
| in my hands that come from some of the biggest names you can
| think of in aerospace, semiconductor, military, medical and
| more.
| hinkley wrote:
| Are they for prototypes? Or how do you service production
| runs for parts?
|
| If for arguments sake it were a part for an AWACS or an
| aircraft carrier you might only need to make eight or a
| dozen. But even military aircraft tend to run into the
| hundreds.
| MisterTea wrote:
| We do production runs with the rare service run. Most
| parts are one time use as you might imagine. Service work
| is the rare mold repair.
|
| We are part of a few companies just in time manufacturing
| so they pay for expedite processing on orders as small a
| one piece to a few dozen. And we can get production run
| orders in the tens of thousands.
| mensetmanusman wrote:
| 50 kW ebeam?
| MisterTea wrote:
| We have 7.5 kW and 15 kW machines. Smaller chambers but
| there's plenty of smaller work out there.
| pfdietz wrote:
| That is, a vessel for a pressurized water reactor. A reactor
| operating at lower pressure (like one using molten salt as a
| coolant) wouldn't need such a vessel, as the salt would not
| become highly pressurized, even in accident conditions.
|
| I saw a link from some government minister in Canada named Don
| Morgan who stated a BWRX-300 would cost $5B (CAN), which comes
| to about $3.6B (US). $12/W (US) is not the worst, but it isn't
| great. Not clear if that was all-in cost or just overnight
| cost.
|
| https://www.deassociation.ca/newsfeed/4-provinces-push-ahead...
| hwillis wrote:
| > Forgings have the added advantage of variable grain direction
| which generally can be tailored to the stress patterns of a
| specific design.
|
| This is a super underappreciated fact! It's often repeated that
| forging is just stronger, but just squishing steel does NOT make
| it stronger. Forging a part is so much more than just smashing it
| into a shape.
|
| Steel cable is made of pretty ordinary steel which is stretched
| 100s of times its original length. That process alone makes it
| _2-4x stronger_ in that direction. You stretch steel and it gets
| stronger in that direction.
|
| Do you see how complicated that optimization process becomes? The
| process steps are not just trying to take it to the final shape.
| Your piston rod needs to be strong lengthwise, so you actually
| want to start with a short fat ingot and stretch it out instead
| of one that is near-final size.
|
| Think of making an I-beam. You could hammer out the middle,
| making it thinner. That would give you a bit of strength there
| but very little on the edges. If you instead pull the edges out,
| you create a long continuous stretch that will be very strong
| against bending. Where, how, and in what order you stretch makes
| all the difference. You may want to leave extra material and cut
| it off later, so that your grains are all oriented together
| instead of tapering to a point.
|
| For any moderately complex part, this process is as complicated
| as modern engineering problems. With poor steel you genuinely
| need to understand how to foster and bring out those continuous
| lines or your corkscrew will unwind like playdough. Blacksmiths
| had a legitimately intellectual job back in the day!
| thaumasiotes wrote:
| > Blacksmiths had a legitimately intellectual job back in the
| day!
|
| ACOUP noted that blacksmiths might be assisted by unskilled
| laborers, strikers, who had the actual job of lifting the
| hammer and hitting the object with it.
| NegativeLatency wrote:
| Unskilled feels unfair, it requires a fair bit of skill, and
| you're also learning how to forge while doing it.
| droopyEyelids wrote:
| This has been such a frustrating culture war definitional
| argument.
| knodi123 wrote:
| Not necessarily a culture war thing. People who aren't
| familiar with the subject might take "unskilled" in the
| plain-english sense, as a pejorative. And who can blame
| them? We're english speakers before we're technical
| speakers.
|
| Make gracious assumptions.
| jessebro wrote:
| Anyone who has worked in a job classified 'unskilled'
| generally doesn't need a pejorative to feel unloved. It's
| the nature of the game.
|
| Digging ditches generally sucks, same as I imagine being
| a striker, but most anyone can do it (until their body
| gives out, anyway, which in some cases is 'immediately').
| bell-cot wrote:
| The reality is that, depending on circumstances, a highly
| skilled craftsman of yesteryear could have any number of
| obviously less-skilled assistants. Some would be "career
| track", some semi-skilled seasonal help, some minimally-
| skilled (whether due to youth, infrequent day labor, poor
| talent, or social status), and some in supporting type of
| skilled work - animal handling, cooking, bookkeeping, etc.
| Terr_ wrote:
| I tried to maintain a certain kind of optimistic humility,
| that almost anything which employs a person full-time is a
| problem-area that has fractal layers of complexity one
| don't have to know from the outside.
|
| The only question is whether someone will pay you for doing
| the fancy skill/science tricks or not.
| thaumasiotes wrote:
| > Unskilled feels unfair, it requires a fair bit of skill,
| and you're also learning how to forge while doing it.
|
| Both of those points are untrue. Strikers are unskilled
| labor and in general are not learning how to forge. The
| smith shows where he wants the hammer to fall, and they let
| it fall there.
|
| https://acoup.blog/2020/10/02/collections-iron-how-did-
| they-...
|
| > Things were worse for the many strikers and other
| laborers who were essentially unskilled hired hands or even
| enslaved laborers (given their depiction in artwork, it
| seems likely many ancient strikers were slaves) of much
| lower status and who could not expect to be trained into
| blacksmiths themselves some day. While some strikers were
| probably apprentices in training, it is quite clear that
| not all of them were! These workers would also have been
| far less richly paid; _indeed, the entire point of strikers
| was to have laborers who could be paid very little but
| still amplify the production ability of the blacksmith
| himself._
|
| (emphasis original)
| HPsquared wrote:
| This effect also applies to polymers! Perhaps even more so.
| Take a polyethylene bag (LDPE) and stretch the material in one
| direction. You might notice the material becomes thinner but
| also stronger. This is due to the polymer chains becoming
| aligned. Eventually you get "drawn fibers" where the molecular
| strands are aligned with the fibers for optimum tensile
| strength.
| 01HNNWZ0MV43FF wrote:
| That makes sense, if I don't rip open a bag on the first try
| it'll just stretch and never open
| myself248 wrote:
| Stretch it in one direction, then grab in the middle of the
| stretched area and pull sideways, and it pops open like
| nothing.
| kragen wrote:
| it varies a lot with polymers, and it's a different effect.
| steel is entirely crystalline; ldpe is mostly amorphous. a
| big part of what's happening in the strain hardening of ldpe,
| aside from making it uniaxially oriented, is that it's
| crystallizing; the crystalline domains become larger, greatly
| reducing the amorphous volume fraction. (there are also other
| ways of achieving this effect, such as annealing, which you
| will notice softens steel rather than hardening it.) ldpe's
| strength isn't determined by crystal dislocation density in
| the same way as steel's, and of course steel doesn't have
| polymer chains to align
| wizardforhire wrote:
| This is exactly what dyneema is only with hdpe.
| kragen wrote:
| no, dyneema is not hdpe; it's uhmwpe, and it isn't just
| strain-hardened, it's gelspun
| libria wrote:
| Assuming these terms are all correctly spelled, this has
| to be the shortest sentence I've understood the least of
| on HN.
|
| Guess I've got some googling to do.
| kragen wrote:
| they are! sorry to be telegraphic
| NavinF wrote:
| UHMW = ultra high molecular weight. Each molecule is
| literally heavy because they have a lot of atoms.
|
| PE = polyethylene. The most popular plastic on this
| planet.
|
| HDPE = high-density polyethylene. One of the most common
| plastics. Milk jugs, glue bottles, etc.
|
| Stick some UHMW tape on anything that needs to slide
| easier. Its surface is quite slippery
| jessebro wrote:
| HDPE is also what Nalgenes and the like are made of (or
| used to be anyway), and is very popular for storing
| chemicals as well. It is very nearly completely inert.
| kragen wrote:
| you cunninghammed me: nalgenes are polycarbonate, which
| is a lot less inert
|
| all the polyethylenes are relatively inert, because
| polyethylenes are in some sense just heavy paraffins.
| paraffin is germanized latin for 'relatively inert'
| PuffinBlue wrote:
| And you have Cunninghammed me :-)
|
| _Some_ Nalgene 's are polycarbonate, like those commonly
| drunk from. But not all, some are HDPE[0,1,2].
|
| Some are Polypropylene co-polymer[3] but those are more
| for specialist things I guess.
|
| [0]
| https://ultralightoutdoorgear.co.uk/ultralite-1-litre-
| wide-m... [1] https://www.cotswoldoutdoor.com/p/nalgene-
| hdpe-125ml-wide-mo... [2]
| https://www.elitemountainsupplies.co.uk/camping-
| trekking-c4/... [3]
| https://www.thelabwarehouse.com/products/bottle-nalgene-
| ppco...
| wizardforhire wrote:
| I stand corrected! Thanks for the headsup <3s
| pfdietz wrote:
| I wonder if it's possible to do additive manufacturing with
| pre-elongated snippets of wire.
| hwillis wrote:
| annealing, which resets the grain structure, happens at a
| lower temperature than melting or sintering.
| kragen wrote:
| true, conventional welding or sintering would be a bad
| idea. but you can connect them together with brazing,
| laser-welding, explosive welding, ultrasonic welding, self-
| propagating high-temperature synthesis of an intermetallic
| like nickel aluminide, electrodeposition, lashing, or globs
| of glue
| pfdietz wrote:
| Doesn't annealing take hours, particularly at the lower
| range of temperatures? Perhaps the additive process can
| keep the metal hot for a much shorter time. Granted, this
| also means stresses from the manufacturing process will not
| be removed.
| kragen wrote:
| > _just squishing steel does NOT make it stronger_
|
| just squishing steel does actually make it stronger, because it
| increases the number of dislocations in its crystal structure.
| smaller grains mean higher strength even without the variable
| grain direction. also, peening, which is not exactly the same
| as forging but is also just squishing steel, can give you
| higher strength for a third reason: areas with residual
| compressive stress can't initiate cracks until you overcome
| that stress, which increases strength. even more, though, it
| increases fatigue resistance
| samstave wrote:
| I have had this question in my mind for decades:
|
| > _" Can you forge metals in a highly controlled and directed
| magnetic field where you can orient the grain/alignment of
| atoms/fields in whatever direction you want. Further, if true,
| what happens when you make damascus from varying plated that
| have particular alignments/grains - and what are the features
| of this material?_
| hwillis wrote:
| > Can you forge metals in a highly controlled and directed
| magnetic field where you can orient the grain/alignment of
| atoms/fields in whatever direction you want.
|
| This is how you make magnets. "Soft" ferromagnets have small,
| round grains that rotate to reinforce outside fields. "Hard"
| ferromagnets have permanent fields of their own and long
| grains that can't reorient.
|
| Forging with a field has a very low impact on the material
| properties because of how weak a magnetic field is compared
| to the forces moving atoms- same reason steel loses its
| magnetic properties when it gets hot.
|
| > what happens when you make damascus from varying plated
| that have particular alignments/grains
|
| "Damascene" is the layered look most often made from acid
| etching sandwiched and forge-welded layers of different
| steels. Damascus is a single alloy for which the pattern is
| named.
|
| Since in both cases the material is melted together, it's far
| too hot for any magnetic properties to have any impact.
| samstave wrote:
| Thanks for that.
|
| Though I was thinking of super intense magnetic fields
| (like in CERN), however, Ill leave it to my Comic Book
| Science collection, then :-)
| abe_m wrote:
| I'd really like to see some backing of these claims. I've seen
| "grain flow" claiming big gains for years in various enthusiast
| magazines (bike, motorcycles, cars, etc) as to why components
| are forged.
|
| Then I started working in engineering, and I can't find any
| support for these claims. For sure when a steel bar is worked
| down to become wire for a steel rope, it cannot be pulled to an
| elongation of 100x increasing strength. A36 steel which is a
| basic structural steel has an elongation at break of 23% in a
| 2" gauge length [1]. In every rolling mill I've been in, there
| is a limited amount of reduction per pass through the mill,
| after which the metal needs to go for thermal treatment to be
| annealed to remove all the cold work. Every time you anneal the
| material, you completely resets the elongation (internal
| plastic strain) and strengthening due to work hardening. If
| they do too much reduction in one pass or at too low of a
| temperature, it cracks the material and makes it weaker.
|
| For sheet metal, there is lore about the material being
| stronger in the rolling direction as that is the direction of
| grain flow. I have yet to find a source that can point to any
| large difference. In papers like this [2] there are claims of
| certain orientations of samples relative to rolling direction
| have different tensile properties, but when you look at the
| tensile charts, there is minimal difference. The yield strength
| in these charts isn't reported, but all three orientations look
| to yield at the same point. In this test the across the grain
| (90 degree to rolling direction) orientation had the highest
| tensile strength which is the opposite of the expectation of
| the forging "grain flow" promoters. But the magnitude of the
| difference isn't large, and is small relative to normal factors
| of safety in a reasonable design.
|
| When designing automotive components, I've only ever seen
| forging methods selected for efficiency of production. If a
| part mostly fills the envelope of a bar or plate, it is cut
| from bar or plate in all cases. If there is a lot of void
| volume in the part, the calculation will be made to determine
| if the cost of developing forging tooling and development will
| get paid back in reduced material and machining cost. I have
| yet to see the dimensions of the part change with manufacturing
| method, which would be needed if the non-forged part was
| significantly weaker.
|
| And finally, a lot of forged parts are subsequently heat
| treated. When heat treating steel all of the grains in the
| steel have to be destroyed and recrystallized. That is the
| mechanism by which heat treatment works. Depending on the exact
| process and part geometry, this process removes or reduces the
| grain flow in the finished parts.
|
| Having said that, the claim of superiority of forging persists,
| and I'd love to see a technical reference that shows the
| magnitude of the change from someone who has plausibly actually
| tested the effect.
|
| [1]
| https://matweb.com/search/DataSheet.aspx?MatGUID=d1844977c5c...
| [2]
| https://www.researchgate.net/publication/283447700_The_effec...
| hwillis wrote:
| It's plenty real, and it matters for more than just strength.
| Cold rolled grain oriented electrical steel has better
| magnetic properties than non-oriented steel and is used in
| some applications where the field is in a straight line.
| kragen wrote:
| your comment is an extremely valuable contribution!
|
| disclaimer: i don't have a relevant technical reference
| handy, and i'm far from an expert on the area, which is vast,
| and i recognize you know things i don't about it. still, i do
| spend a lot of time reading papers with metallurgical
| micrographs in them+, and i think i figured out the answer to
| your question many years ago, so i will explain my
| understanding
|
| except for the part about grain orientation, anyway
|
| > _In every rolling mill I 've been in, there is a limited
| amount of reduction per pass through the mill, after which
| the metal needs to go for thermal treatment to be annealed to
| remove all the cold work. Every time you anneal the material,
| you completely resets the elongation (internal plastic
| strain) and strengthening due to work hardening. If they do
| too much reduction in one pass or at too low of a
| temperature, it cracks the material and makes it weaker._
|
| as i understand it, this is exactly right, but you say it as
| if it's contradictory. strain hardening increases the yield
| strength of metal (by making it yield). it can also change
| the tensile strength, but to a much smaller degree. when the
| metal can no longer handle stress by yielding, in particular
| by yielding in a way that produces further work hardening, so
| that the yield is distributed over the metal rather than
| being concentrated wherever it starts, it cracks. that's why
| strain hardening metal makes it more prone to cracking. in
| general, a given metal is more prone to cracking when you
| harden it, whether you harden it by cold forging, case
| hardening, or quenching. (peening is the exception; it
| inhibits crack initiation by a different method.)
|
| https://en.wikipedia.org/wiki/Work_hardening has an overview
| that talks about how this phenomenon can be either desirable
| or undesirable
|
| the change in yield strength from cold working can be quite
| large, a factor of 4 or so. it doesn't change the ultimate
| tensile strength much (or at all in the case of your wire
| rope), but there are a lot of cases where what you care about
| is the yield strength, not the uts, because if the part
| yields by more than a tiny amount, it is out of tolerance and
| has therefore failed
|
| (with respect to a36 steel, elongation at break, and wire
| rope, this is a minor detail, but it's possible to elongate
| it somewhat more through rolling than you can through wire-
| drawing. but you are certainly correct that you cannot
| elongate it 100x, and wire rope is mostly made by drawing,
| not by rolling.)
|
| there are different kinds of heat treatment, but the most
| common kind for steel involves a phase transition to
| austenite and back, which does indeed destroy the entire
| grain structure of the steel, losing any potential advantage
| of forging, precisely as you say. i'd think this would also
| be mostly true for hot-forging, where steel is forged while
| still austenitic; the relevant grain structure for strength
| will be the one that the steel acquires when it leaves the
| austenite phase. there are other kinds of heat treatment
| (more commonly used with things like aluminum) that don't
| involve fully recrystallizing the metal, and i would expect
| some grain structure to survive those
|
| probably none of that is telling you anything you don't
| already know, but perhaps it's a different way of thinking
| about the things you know that explains the apparent
| contradictions
|
| as for which direction i would expect grain orientation to
| make things strongest in, i really have no idea at all
|
| ______
|
| + last night, for example, i read
| https://www.mdpi.com/2075-4701/8/2/91/pdf and https://www.jst
| age.jst.go.jp/article/jjspm/63/7/63_15-00089/..., but also
| parts of
| https://pure.tue.nl/ws/portalfiles/portal/1584410/617544.pdf,
| http://www.diva-
| portal.se/smash/get/diva2:1352113/FULLTEXT01..., https://yadd
| a.icm.edu.pl/baztech/element/bwmeta1.element.baz...,
| https://www.imerys.com/public/2022-03/Specialty-Carbons-
| for-..., and https://backend.orbit.dtu.dk/ws/portalfiles/port
| al/200743982..., but i was maybe on a bit of an atypical
| metallurgy bender. none of these are more than marginally
| relevant to the questions at hand of forging, strain-
| hardening/work-hardening, and grain structure orientation
| bobeboph wrote:
| MIL-HDBK-5 [1] is a good publically-available source for
| strength allowables for several aerospace alloys, including
| multiple directions relative to the grain for some of them.
|
| The first relevant example I found was on page 3-86, extruded
| 2024, 2.250 - 2.499 inch cross-section. For ultimate tensile
| strength, F_tu, the L (in the direction of extrusion)
| allowable is 57 ksi, while the LT (perpendicular to the
| direction of extrusion) allowable is 39 ksi. That's a 30%
| drop in strength.
|
| [1] http://everyspec.com/MIL-HDBK/MIL-
| HDBK-0001-0099/MIL_HDBK_5J...
| kragen wrote:
| this is a fantastic find, thanks!
| buildsjets wrote:
| Thanks for posting that as I was about to! I will note that
| MIL-HDBK-5 is no longer valid for actual aerospace design,
| as it has been superseded by Battelle Institute's MMPDS
| Handbook, which is locked behind a very very tall paywall.
| The MIL-HDBK is still all perfectly good data.
|
| https://www.mmpds.org/
| azalemeth wrote:
| The best evidence for grain flow on a really atomic scale
| comes from what is called texture analysis in X-ray or
| electron-beam crystallography (or related techniques): you
| get a deviation in the distribution of Bragg peaks due to the
| fact that you have a non uniform distribution over the
| orientation of the unit cells within the crystallites in the
| bulk material. You can fit this in a spherical harmonic basis
| and quite accurately work out the excess or defect of the
| distribution, typically quantified in units of 'multiple of a
| random distribution' or mrd, again either in crystallographic
| axes or traditionally in three orthonormal axes - parallel to
| the surface of the workpiece ("rolling direction"), axially
| transverse to it, and normal to it. The phrase to search for
| is 'pole plot'. They're rotationally symmetric and an inverse
| projection over all space, and so usually only a quarter of a
| hemisphere is shown.
|
| A very good example of the affect of annealing tungsten wire
| is here [1] - note that (a) there is a very clear orientation
| dependence that some difficult geometric transformations will
| undoubtedly show means that they are aligned in the wire
| drawing dimension; and (b) after annealing at 1600 oC for an
| hour the preference is slightly reduced but still about 15
| sigma away from random...
|
| [1] https://www.researchgate.net/figure/001-110-and-111-pole-
| fig...
| kragen wrote:
| but 1600deg for tungsten is still barely above its ductile-
| to-brittle transition, isn't it? because that can be up to
| 967deg
| mywacaday wrote:
| I studied construction for a year, always remember being
| totally baffled why this makes a beam stronger in certain
| cases, https://www.grunbauer.nl/eng/waarom.htm
| https://www.sciencedirect.com/science/article/pii/S004579491...
| Yenrabbit wrote:
| For a program started in the 50s, it's impressive that "Six of
| the ten presses are still operational today."!
| barryp wrote:
| I got curious as what happened to the other 4. Wikipedia lists
| them as extrusion presses being scrapped in the 90's and 2021
| in Maryland and Torrence CA.
| https://en.wikipedia.org/wiki/Heavy_Press_Program
|
| I wonder if they wore out?, something better came along?, or
| just no demand?
| SoftTalker wrote:
| They've been maintained, wear parts such as bearings and
| seals can be replaced. You can keep well-made machinery
| running almost indefinitely if you take care of it.
| bhouston wrote:
| More details in this video:
| https://www.youtube.com/watch?v=iZ50nZU3oG8
| chasil wrote:
| I understand that this press, and the Cleveland site, is now
| owned by Howmet Aerospace, which is a "daughter company" of Alcoa
| (along with Arconic) after its 2020 separation.
|
| https://en.wikipedia.org/wiki/Howmet_Aerospace
|
| The big Cleveland press has its own wiki.
|
| https://en.wikipedia.org/wiki/Alcoa_50,000_ton_forging_press
| a2tech wrote:
| Howmet is an interesting company. My dad worked for them his
| entire life (it was called MISCO, then Howmet bought them, then
| Alcoa). He worked specifically in titanium injection molding--
| they would heat titanium until it was liquid and then force it
| under pressure into intricate molds they made onsite.
|
| Most of the time they made turbine blades for jet engines, but
| if it was slow they would make golf club heads for PING and
| companies like that. In all the years he worked there, the golf
| club heads were the only tangible product of his work that I
| saw because everything else was tightly controlled in the
| facility.
| chasil wrote:
| The blades were actually perfect crystals, with either all
| the grain boundaries aligned, or no grain boundaries. This
| lets them run at higher temperatures without melting,
| increasing efficiency.
|
| Pratt & Whitney appears to have developed most of the
| technology.
|
| https://www.americanscientist.org/article/each-blade-a-
| singl...
| dekhn wrote:
| Oh, so that's what they were doing in the facility in my
| hometown. It was always pretty secretive and now I can see
| why.
| baking wrote:
| There is no "H" in "Worcester."
| mhb wrote:
| And it's odd to see one there, since, from the pronunciation,
| you'd expect it to be spelled "Wooster".
| mauvehaus wrote:
| The Wooster in Ohio is spelled "Wooster".
| shepherdjerred wrote:
| What strikes me is how great of an investment this turned out to
| be. Does the US invest in manufacturing like this anymore?
|
| Tangentially, if there were a war today would the US be able to
| produce as much as it did in WW2?
| bradford wrote:
| > Does the US invest in manufacturing like this anymore?
|
| It might be easy to argue over the exact degree of similiarity,
| but I'd argue that the US has repeatedly made manufacturing
| investments since the 1950s. Buried in bills signed into law,
| you'll find such investments.
|
| Recent examples include the Recovery Act of 2009 or the
| American CHIPS act of 2022.
|
| https://en.wikipedia.org/wiki/American_Recovery_and_Reinvest...
|
| https://www.cfr.org/in-brief/what-chips-act
| waythenewsgoes wrote:
| In terms of raw output, the answer is likely no.
|
| However, this might not matter as much now as it did in the
| past due to nuclear weapons being the primary deterrent in war
| these days, and the fact that our standing fleet of aircraft,
| aircraft carriers, nuke subs, tanks, etc... is essentially
| second to none. Additionally what we do have is highly capable
| and extremely specialized, in my opinion, leading to not really
| needing as many (quality over quantity). Take for example, an
| F35, which doesn't really have an equal in the skies, we have
| over 630 of them, with the goal of having around 2500. China
| only has 300 J-20s which are basically a copy of the older F22.
| Russia only has 22 non-test Su-57s. Would we have a realistic
| need to build 1000 of them within a year?
|
| Due to many factors, but primarily free trade and
| globalization, it's unlikely that we ever see that non-
| automated manufacturing capacity return, though if needed we
| could probably mobilize the economy via the defense act to
| force more manufacturing capacity, though it's hard to imagine
| we would currently need to.
| bluGill wrote:
| > Does the US invest in manufacturing like this anymore?
|
| No, but that is different from not investing. Today the US
| invests more in automation and engineering and less in manual
| labor.
|
| > if there were a war today would the US be able to produce as
| much as it did in WW2?
|
| It took several years to ramp up to WW2 level production. We
| would see the same, a couple years of trouble on the fronts
| while building industry at home, then when the industry is
| built up massive production.
|
| Historians (amateur so I'm not sure if they are right) tell me
| Hitler was ready for WW2 first and Italy begged him to not
| start the war as their industry wasn't ready. However France
| and Briton saw the war coming and were building their industry
| and so waiting might have made things worse.
| shiroiushi wrote:
| I wonder how history would be different if Hitler had told
| France and UK to f** off with the WWI reparations stuff,
| threatening a war if they tried military action to force
| payment, but then didn't invade anyone and concentrated on
| developing their economy and becoming a technological and
| manufacturing power.
| margalabargala wrote:
| We didn't have _any_ of these presses in WWII. We have several
| of the article 's presses still operating today.
|
| Furthermore, all presses mentioned in the article have been
| surpassed by a 60,000 ton press that opened in Los Angeles, in
| 2018.
|
| People with agendas will happily feed others narratives about
| the US not investing in manufacturing anymore, but it isn't
| true.
|
| US manufacturing output has been steadily increasing since
| always, with the occasional 1-3 year dip during recessions.
| However, manufacturing does represent a lower percentage of our
| GDP with each passing year, despite the absolute value
| increasing.
| shiroiushi wrote:
| >People with agendas will happily feed others narratives
| about the US not investing in manufacturing anymore, but it
| isn't true.
|
| It's a matter of perception. Most people don't directly see
| (or buy) the stuff manufactured in the US these days. Normal
| people don't buy nuclear power plants, aircraft engines,
| commercial aircraft, etc., and certainly not military
| hardware which the US makes a lot of. They do buy clothes and
| various consumer electronics, and they see "Made in China"
| (or for some clothes, places like Bangladesh or Vietnam or
| Cambodia) printed on all those, when 50 years ago all that
| stuff had "Made in USA" printed on it, or for the nicer
| consumer electronics 30-40 years ago, "Made in Japan". People
| still might be getting a CPU for their laptop computer
| manufactured in the USA, but the chip will probably say "Made
| in Malaysia" because only the silicon was made in the US, and
| was then shipped somewhere else for packaging.
|
| >However, manufacturing does represent a lower percentage of
| our GDP with each passing year, despite the absolute value
| increasing.
|
| I'd say that's probably a bad sign: what other sectors are
| increasing? Likely they're things that aren't actually
| productive, such as healthcare (the value received does not
| represent the price paid in the US by a long shot, compared
| to other advanced economies; most of the money goes to
| insurance companies and waste), legal services, ever-
| increasing real estate valuations, etc.
| wyck wrote:
| Some machine porn I found about the the biggest(?) press in the
| world in L.A. by Weber metals, I think it's 60k tons.
| https://www.youtube.com/watch?v=mOe8KYZXGeg
| gffrd wrote:
| > By the early 2000s, parts from the heavy presses were in every
| U.S. military aircraft in service, and every airplane built by
| Airbus and Boeing.
|
| >The savings on a heavy bomber was estimated to be even greater,
| around 5-10% of its total cost; savings on the B-52 alone were
| estimated to be greater than the entire cost of the Heavy Press
| Program.
|
| These are wild stats.
|
| Great article! I was fascinated to learn about the Heavy Press
| program for the first time, here on HN[1] a month ago, and am
| glad more about it is being posted.
|
| It makes me think: what other processes could redefine an
| industry or way of thinking/designing if taken a step further? We
| had forging and extrusion presses ... but huge, high pressure
| ones changed the game entirely.
| westurner wrote:
| > _It makes me think: what other processes could redefine an
| industry or way of thinking /designing if taken a step further_
|
| Pressure-injection molded hemp plastic certainly meets spec for
| automotive and aerospace applications.
|
| "Plant-based epoxy enables recyclable carbon fiber" (2022)
| [that's stronger than steel and lighter than fiberglass]
| https://news.ycombinator.com/item?id=30138954 ...
| https://news.ycombinator.com/item?id=37560244
|
| Silica aerogels are dermally abrasive. Applications for non-
| silica aerogels - for example hemp aerogels - include thermal
| insulation, packaging, maybe upholstery fill.
|
| There's a new method to remove oxygen from Titanium: "Cheap yet
| ultrapure titanium metal might enable widespread use in
| industry" (2024) https://news.ycombinator.com/item?id=40768549
|
| "Electric recycling of Portland cement at scale" (2024)
| https://www.nature.com/articles/s41586-024-07338-8 ...
| "Combined cement and steel recycling could cut CO2 emissions"
| https://news.ycombinator.com/item?id=40452946
|
| "Researchers create green steel from toxic [aluminum production
| waste] red mud in 10 minutes" (2024)
| https://newatlas.com/materials/toxic-baulxite-residue-alumin...
|
| There are many new imaging methods for quality inspection of
| steel and other metals and alloys, and biocomposites.
|
| "Seeding steel frames brings destroyed coral reefs back to
| life" (2024) https://news.ycombinator.com/item?id=39735205
| twic wrote:
| Electrolytic refining of iron, all the way from ore. Gets rid
| of blast furnaces, allows far more precise control over
| metallurgy.
| nickdothutton wrote:
| These massive presses are/were of strategic importance. Something
| politicians, most of whom seem to be lawyers these days,
| completely fail to grasp. I am not in general a fan of government
| subsidy, but I was very disappointed when the government of the
| UK declined to fund a large press in Sheffield, which would have
| been used to build the next generation of nuclear reactors. June
| 2010 timeframe. Luckily natural gas is cheap and has no
| geopolitical supply chain problems eh?
| Dennip wrote:
| Sheffield Forgemasters?
|
| They are actually now directly govt owned as of 2020, with
| future investment for a new heavy forge.
| pjc50 wrote:
| We're not going to build the nuclear reactors either. The
| problem will finally be solved by re-permitting onshore wind
| and a lot of batteries imported from China.
|
| (The "local supply chain is vulnerable to political uncertainty
| over long term project funding" problem is much worse in regard
| to trains, and has resulted in losing most of our train
| building capacity. See HS2 fiasco.)
| ckemere wrote:
| Was reading this NYT op ed -
| https://www.nytimes.com/2024/08/19/opinion/chris-murphy-demo... -
| and reflecting that the people talking don't get that the secret
| sauce for meaningful labor is not just that it pays, but also the
| sense that it is "special" somehow, in the sense that
| manufacturing parts with 50000 ton press is manual labor but also
| remarkable because of the uniqueness of the machine being used.
|
| Most discussions about trying to build industrial capacity in the
| US seem to focus on either our high labor costs or on the
| disinterest in capital to invest in low margin places. I would
| love to understand what time frame of guaranteed business the
| government provided these companies to convince them to
| participate, and also what other industrial processes the
| government invested in which failed to take off. Specifically,
| why didn't this sort of thing work for the solar industry a few
| years back?
| Animats wrote:
| Progress continues. The biggest press in the world today was
| built in 2018, is rated for 60,000 tons, and is in Los Angeles
| County, California.[1][2]
|
| [1] https://www.lightmetalage.com/news/industry-
| news/forging/web...
|
| [2] https://www.youtube.com/watch?v=jNFIMy8BuHc
| doormatt wrote:
| The article says there's an 80,000 ton press in China.
| kragen wrote:
| many people in the usa say 'the world' when they mean 'usa'
| retzkek wrote:
| That's pretty ungenerous. The press release says "The press
| is the world's strongest hydraulic pull-down die forging
| press in pit-mounted design" so it's easy for a layman to
| read "world's strongest ... press" and take that at face
| value.
| kragen wrote:
| i admit i don't know what 'pull-down' and 'in pit-mounted
| design' mean, and i'm not sure my understanding of 'die
| forging' is correct, but that seems likely
|
| on the other hand, the press release might be written by
| the same sort of people who say things like 'the world
| series', which is a baseball tournament between teams
| from the usa (and canada)
|
| https://www.gasparini.com/en/the-worlds-largest-
| hydraulic-pr... says
|
| > _The United States leadership only lasted two years: in
| 1957 the Ukrainian company Novokramatorsky
| Mashinostroitelny Zavod (NKMZ), specialized in steelworks
| equipment, built two 75,000-ton presses. The first one,
| destined for a plant in Samara, is now owned by Alcoa's
| Russian branch. The second was installed in Verkhniaia
| Salda and is used by VSMPO-AVISMA, the world's leading
| producer of titanium and other specialty alloys._
|
| > _Outside the two superpowers, France was the third
| country to equip itself with a hydraulic press of this
| size: also built by the Ukrainian NKMZ, this 65,000 ton_
| presse hydraulique* was installed in Issoire between 1974
| and 1976. Owned by Interforge, the machine is 36 metres
| high and manufactures components for Airbus, Boeing, the
| space and transport industries.*
|
| ...
|
| > _After 60 years, the USA has added a new 60,000-ton
| hydraulic forging press. Built by SMS Group and managed
| by Weber Metals in California, it started operations in
| October 2018._
|
| > _The heavyweight champion, of course, is Chinese: a
| machine with the incredible power [sic] of 80,000 tons is
| in operation since 2013 for the giant Erzhong Group in
| the province of Sichuan. As tall as a 10-storey building,
| its use is very confidential: it seems to be used to
| build parts for military aircraft, like its titanic
| sisters. To give an idea of the power of this machine,
| with its 780,000 kN it could easily lift an entire cruise
| ship. As often happens, larger does not mean better: it
| is not the most technologically advanced press in the
| world. It was built by adapting old USSR projects from
| the 1980s, and is currently underused due to competition
| from the other giants we mentioned._
|
| either this derives from this longer post from 02022, or
| they both derive from a common source:
| https://www.linkedin.com/pulse/worlds-largest-hydraulic-
| pres...
|
| the owner was at risk of bankruptcy in 02015: https://web
| .archive.org/web/20160809080032/http://www.france...
| brcmthrowaway wrote:
| Is this how the SR71 was made?
| advisedwang wrote:
| This should be a lesson for free-market advocates, especially
| those who see the US economic boom as a result of laissez-faire
| economics. In reality there are opportunities the free market
| doesn't take, and wise government intervention can yield enormous
| benefit to the public.
| mannyv wrote:
| In reality what we call 'capitalism' is unstable and requires
| continual intervention to survive.
| hackit2 wrote:
| That is a very simplistic perspective of 'capitalism', it is
| a bit more nuance than that. It typically requires
| intervention to prevent it from destroying the economy
| because of insider trading, liquidity, and monopolist
| practices. The only criticism you say about it mirror aspect
| of our-selves that we don't like to admit. It isn't perfect
| but people are not perfect how-ever based on how fast we're
| pull people out poverty, you have to admit its pretty good!
| refurb wrote:
| Do you feel that the free market wouldn't have adopted it at
| some future point in time?
| eternauta3k wrote:
| You may be right, but your conclusion doesn't follow from the
| article.
| azalemeth wrote:
| If you're reading this article, you may wish to know that
| arguably a "counterpart" to heavy press forging is explosive
| forming [1] in which a chemical high explosive is used to force a
| template material against a template. The overpressure generated
| by the explosive can be equivalent or maybe even greater than
| heavy press forgings (a 50,000 US short ton force press exerts
| [?]500 MN force; peak overpressure close to detonating TNT or
| PETN explosives can be MPa or higher [2] so depending on the
| geometry of the part they may be comparable) and it has the added
| "fun" fact that complex cylindrical or spherical shapes can be
| made very easily and accurately.
|
| The only people I know who have worked with this have used it to
| make superconducting magnets, explosively forming either titanium
| or high grades of nonmagnetic stainless (A4, which has ur [?] 1)
| without causing marsenite formation due to machining. This
| includes a major international MRI scanner manufacturer, for one
| relatively niche product. It's like the "extreme" version of
| metal spinning [3] - forcing a rotating chunk of metal against a
| rotationally symmetric mandrel.
|
| [1] https://en.wikipedia.org/wiki/Explosive_forming [2]
| https://www.researchgate.net/figure/Variation-of-peak-over-p...
| [3] https://en.wikipedia.org/wiki/Metal_spinning
| infogulch wrote:
| There are some popular videos making spheres using explosive
| hydroforming, which is quite fun, and much lower tech than
| explosively forming magnets to avoid the formation of marsenite
| (sp?).
| kragen wrote:
| *martensite
| Animats wrote:
| Explosive forming has been used to make aluminum boat hulls.[1]
| It's a useful way to form very large sheet metal parts.
|
| [1] https://www.youtube.com/watch?v=CbS6rS0seuk
| urbandw311er wrote:
| Anybody know: Do these large presses still exist usefully today
| or have they been obsoleted by larger ones / by newer
| manufacturing techniques?
| ggm wrote:
| TFA says some of these are still in operation.
| nntwozz wrote:
| The workers in those pics have no hearing protection, no eye
| protection; no helmets.
|
| Yeah, must be the 50s.
|
| My 75 years old carpenter is half deaf, his grandfather fell from
| a roof and died.
|
| He himself fell off a roof in 1981 but was lucky and survived.
|
| Just some thoughts seeing those men working in those conditions.
| asib wrote:
| Recently watched this great video on the USAF Heavy Press
| Program: https://www.youtube.com/watch?v=iZ50nZU3oG8
| Simon_ORourke wrote:
| I'm not sure it's rose-tinted glasses or some sense of nostalgia
| for the "good old days", but it does feel that our manufacturing
| processes have taken a step backwards since then.
| sidcool wrote:
| Love them or hate them. Tesla's manufacturing prowess is
| unmatched.
| humansareok1 wrote:
| Given their seeming lack of proper quality control I find this
| statement highly suspect.
| twic wrote:
| > Partly this broad range of uses for the heavy presses came from
| expanding the range of materials used in them. Originally the
| presses were designed to make parts from aluminum and magnesium,
| but by the 1960s they were not only pressing aluminum and
| magnesium but steel, titanium, nickel, copper, columbium,
| beryllium, and a variety of other metals.
|
| Columbium is apparently an old name for niobium, and one perhaps
| still in use by American metallurgists.
|
| There's no way anyone was making huge niobium forgings, though.
| Or nickel? Surely this is a reference to the use of those
| elements in superalloys.
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