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How to build a 50k ton forging press

construction-physics.com

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Re: How to build a 50k ton forging press

#101

Post by tra3 »

hinkley wrote: post #96
WheatMillington wrote: post #78

Earlier quoted context omitted.

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…

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

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

Re: How to build a 50k ton forging press

#102

Post by kragen »

debacle wrote: post #8
bee_rider wrote: post #4

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 pr…

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…

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

Re: How to build a 50k ton forging press

#103

Post by kragen »

hinkley wrote: post #92
kragen wrote: post #81

Earlier quoted context omitted.

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 c…

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 wo…

yeah. thank god for sheldon brown

Re: How to build a 50k ton forging press

#104

Post by dekhn »

chasil wrote: post #70
a2tech wrote: post #67

Earlier quoted context omitted.

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 PI…

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...

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.

Re: How to build a 50k ton forging press

#106

Post by kragen »

retzkek wrote: post #89
kragen wrote: post #83

Earlier quoted context omitted.

many people in the usa say 'the world' when they mean 'usa'

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.

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 Verkhniaïa 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...

Re: How to build a 50k ton forging press

#107

Post by infogulch »

azalemeth wrote: post #100

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 det…

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?).

Re: How to build a 50k ton forging press

#108

Post by nntwozz »

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.

Re: How to build a 50k ton forging press

#109

Post by rlonstein »

kragen wrote: post #81
WheatMillington wrote: post #78

Earlier quoted context omitted.

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…

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 c…

> 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).

Re: How to build a 50k ton forging press

#110

Post by abe_m »

hwillis wrote: post #20

> 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 o…

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...

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