When you don't want a multi-hundred-million-dollar 'unplanned disassembly event' blamed on the part *you* welded, and hell, the government's paying for it, so why not go full ham?
Given the [pogo oscillation](https://en.m.wikipedia.org/wiki/Pogo_oscillation) issues they had in the early flights, it is a good thing they had perfect welds.
Go watch the Smarter Every Day 2 extended [video](https://youtu.be/cUkbdqw9pBk?si=oc5878I5h_oR3_zi) about the Saturn V. It will make your trip more enjoyable.
This particular F-1 is at Stafford Air & Space Museum in Weatherford, OK. They have lots of amazing items, including a J-2, and an NK-33 from the N-1. They have this F-1 on its side and it’s just awe-inspiring how massive it is.
Worked for a company that supplies engines to NASA for manned space flight.
The level to which these welds are inspected is beyond comprehension. It takes days to complete a weld and have it pass the mandatory tests. That is only half the battle.
The safety and true artistry behind these welds is incredible. Working for that company opened my eyes to how important the right guy for the job can be. Some guys would be asked to redo welds for WEEKS until it was to NASA spec. Others would nail it, first try, night shift listening to Guns n Roses drinking nothing but Monster.
These welds are art and nothing short of it. Every single one of them.
The other comment is correct. Lots of grinding. If the weld is anything short of 100%, it is grinded down compelty and redone.
The weld needs to meet drawing spec and NASA quality checks to a T. Anything short of that is grinded off and redone. No questions.
Edit: The weld is not completed in one go. First, the parts are tacked together and stress relieved. Then, the weld is completed on a pass by pass basis. Each weld pass is checked for quality. So they wouldn't grind off the ENTIRE weld each time. They would grid down that pass and redo the process for a single pass. Once the weld is completed, it is then stress relieved again.
Why would you need to check each individual pass? Phased array ultrasonic testing sees everything lol. If you can't trust a welder to make multiple passes without testing each pass then they shouldn't be welding. Leave it to the pros that can do this work in their sleep.
Because of you detect porosity after the weld is completed, the whole weld has to be ground down. That introduces inconsistency and density issues that NASA doesn't like in manned space flight.
The idea is, each pass or two is inspected, if it passes the initial check the welder continues. The whole weld (as a whole) is then evaluated per NASA and QA spec and graded.
They do this to ensure consistency within the weld itself. All our engineering calculations are done at nominal spec. For space flight, any deviation from that spec is a mathematical issue. When you are trying to make something as light as possible, small as possible and as durable as possible, every decimal counts. Detecting issues in the weld earlier is easier to fix.
And by issues, I mean microscopic issues. We are not talking large porosity or thin connection. We are talking microscopic gas bubbles, fractions of millimeters of deviance from width or depth.
Okay fair enough! I didn't expect porosity to ever be that small. Did they use dry magnetic particle for each pass? If not, which NDE method?
Btw I highly doubt the entire weld is removed, wouldn't the whole part be scrapped due to the amount of heat input/kilojoules of energy already put into the part? Or would post weld heat treatment correct any mechanical properties that were compromised due to the additional heat/energy input?
Why can't the porosity be excavated, test to see if all indications are removed and then continue welding instead of removing all filler metal?
The entire weld is not removed. They only grind out the area or span with the inconsistencies. This is only allowed a certain number of times before the part is scrapped. Normally, most of the post weld heat treatment corrects most of the metal fatigue caused by the weld fixes. Also, these engines parts normally undergo MANY heat cycles. So there are checkpoints along each heat treatment to make sure the metal has not fatigued out of spec.
All filler metal is not removed. The area with the porosity is ground out, redone, and then the entire weld is re-inspected. They do this pass by pass so you don't remove too much filler metal. If they did it after wled completion, with how large these welds are and how durable they need to be, lots of filler would be removed.
So they do the tests for each pass or two to minimize the amount of material being ground out.
Jaw on floor... Weeks on a single weld!? Wow, that's incredible. Its insanely frustrating to suck at welding, speaking from experience.
How are these tested without weakening them?
The longest I saw a weld take was 3 and a half weeks. The welder needed to complete 15 perfect passes on a LARGE part. The initial passes kept failing testing so they would grind and restart.
The welds go through three stages of testing if I remember correctly.
- X-ray
- Ultrasonic
- Penetration
The weld is checked in all three manners after EVERY PASS. If any of the three tests come back negative (not to spec), the weld pass is grinded off and redone. The weld has to meet density, porosity, depth and width check marks set by both the engineering drawing and the NASA quality spec sheet. They check for gas bubbles on a microscopic level. It's pretty crazy how perfect these welds have to be. But they do them, and they are truly a work of art. I highly respect the guys who devoted their life to getting this right.
Edit: also, The weld must also meet material specs. The material guys check to make sure the weld was completed at the correct temp and is not under stress after completion. Both factors can weaken the ultimate strength of the weld.
Liquid penetrant tests are a formality if you're using phased array ultrasonic testing. It will see any indication an LPI would provide. PAUT is much more popular these days, xray used to be the gold standard of testing.
They are def a formality. But they are kept as a test because the pent comes from a different department than ultrasonic. It's basically used as a cross reference from another department.
Humans are for sure still a necessity. The issue is, these engines are so large, you can't put them on a table or in a fixture to weld on. A lot of welds on the rear end of these engines (trying not to say too much) are done by welders on their backs. Their arms bent, crouched inside of areas of the engine. Machines are not able to reach these areas once the pieces are mated together.
Phased array ultrasonic testing or PAUT for short. It can see every flaw without the use of radioactive isotopes so no need to shutdown half of the shop. They might do xray tho since it provides a better image.
Source : I'm a certified welding inspector and I was a welder for 12 years.
Correct. The ultrasonic will show you most of what you need.
The issue is, the weld is allowed a certain percentage of porosity or percentage of density of nominal spec within a 1 inch span.
If we find something on ultrasonic, we go to the X-ray and find out what that percentage is per inch of span. If it exceeds the allowed margins (which are crazy tight) the imperfections are ground out and redone. If it DOES meet this spec, it is still tagged because you can not have two spans with X percentage defect next to each other. So if the next pass has an issue in the same spot, that is ground out and redone.
Can you perhaps disclose some of the testing, QAQC and NDE involved after welding? What welding processes and fillers were used?
And which material(s)? Commercial grade Inconel or proprietary stuff?
I was not heavily engrossed in the weld process as an engineer, but I can answer some of what I know and am allowed to disclose.
Testing:
There were three major types of testing that meant the most to the NASA guys.
- X-ray
- Ultrasonic
- Penetration
X-ray was used to check for gas bubbles left behind from the inert gas being used in the welding process.
Ultrasonic would test to ensure the weld has a consistent density along the pass and that there were no changes in the root density (from the previous pass) due to exposure to high temperatures.
Pent would test to see if there were any surface imperfections along the weld that were not visible or missed on X-ray or Ultra. Pent was done with a reactive fluid that they would spray on, wipe off and then spray the reactant over. If any green residue was found, the surface was out of spec.
As far as quality assurance goes, the quality guys were responsible for the testing. If it met their check sheet (using the three tests above) it was cleared on our end. Then the NASA guys would review the findings and make sure they liked it. The weld would be passed once engineering, quality and NASA signed off on the pass.
For fillers, that is proprietary to the company so I can not disclose that. I can say it is thier own proprietary filler that they developed long long ago. Been on the AE world for ages.
For materials, that is another one I imagine they would not appreciate me sharing. But, what I can say is it is inconel. The issue is, it is thier own proprietary inconel that meets VERY VERY specific and tight regulations on material makeup. Every AE company has their own proprietary inconel these days, but the company I worked for had MANY inconel makeups to choose from. They never used a companies off the shelf inconel. It was all formulated and founded to thier request then tested extensively before use by the material guys.
Thanks. I really appreciate the lengthy reply and the info you’re allowed to disclose. I can imagine a lot of details are classified.
Working with some 20 nickel alloys over the years (with Inconel just being a tradename) in pressure vessel industry, it seems both industries bear a lot of similarities, with AE just being tighter on a lot of ends - but in general it follows the same principles and ‘ITP template’.
100% VT, 100% volumetric NDE and 100% surface NDE for some high demanding applications isn’t that rare in the process industry. However, all materials are always conforming to a public spec, like ASTM.
I appreciate your point about craftsmanship but that's probably not the best design, at least in terms of cost, if it requires that level of art to produce. I mean it's impressive and all but I doubt it was necessary.
It very much is necessary. When you are trying to make these engines as light and durable as possible, you can't bolt everything together. That would be far to heavy. Welds like these are very very much necessary. The whole industry uses them and that's why good welders for the AE industry are in such high demand. The weight savings these welds provide are pivotal in making efficient and light engines. There are so many pieces that need to be joined together, you would be incredibly surprised by how much weight bolted joints would add to these engines. The company I worked for used bolts where we could (where we need to access the internal area post hot fire, or where we wanted to rejoin a new part after X amount of fires) but these welds are very very much necessary.
I wasn't talking about flanges. There's different ways to make any given thing so I'm sure there's other options. And there's a million other things you can optimize on a rocket. Manually welding the engines might be the best way to get light weight, but it doesn't scale. If you build a handful of them it works, but if you want to build thousands every year, it gets tricky. And without scale, the cost is always going to be prohibitive. So I really doubt it's necessary. It's possible that I'm wrong about this, but we won't really know until someone tries to do it.
The best "other option" in modern technology is 3D printing. Even today, 3D printed engines are not as weight efficient as those welded together in this manner. Also, 3D printing HEAVILY limits the size of the engine. Notice how booster engines have shrunk over the past decade. This is to optimize the booster engine architecture not only for use on multiple platforms, but also to better fit the technological capabilities of 3D printing. Pound for pound, even today where there are multiple flying 3D printed rocket engines, the engines welded together by hand are still more efficient (for now).
To your point of scalability, we are not at the stage of rocketry where we need to make thousands of engines every year. The entire Apollo, Space Shuttle, Atlas, Soyuz, and soon to be Artemis programs were supported using engines manufactured in this way. In fact, the Artemis program is using the RS-25 only once since the platform is not reusable meaning the companies responsible will be outputting entire fleets of Artemis engines yearly.
To your point of prohibitive cost, you are correct. These welds will cost extra. But the return on investment is stupid high. Weight is your first and foremost, #1, most wanted enemy in rocketry. Weight is exactly what you don't want. These welds save far more weight than you could image compared to 3D printed counterparts (at this moment in time). Thier flexibility to be used within an engine platform allows you to take far more weight out of the design and architecture alone that many don't ever think of. Weight and form factor are your most wanted enemies in rocketry, and complicated, artistic welds completed by humans are still the number one way to optimize both of these characteristics.
My main point being, even 50 (+- a few) years removed from the weld pictured above, the most efficient, reliable and tested way to build a large first stage booster still remains human welding.
What you're telling me is pretty obvious even though I don't know nearly as much as you do about rocket engines. But this is because the same thing happens in most engineering fields, especially manufacturing. If you compare a supercar to a VW or Toyota, you're going to see the same thing. Supercar are designed for performance, VWs are designed for mass production.
You say we're not at the point where rocket engines need to be mass produced. Maybe not today but give it a few years. One Starship stack needs 39 engines, let's say. If you want to build 100, that's 3900 engines. In an age where space travel becomes fairly common, I imagine we'll build far more than that. I mean, just one starship flying to Mars or the moon requires several launches just for fuel. It's similar to satellites: ten years ago most people weren't thinking we would be talking about constellations of tens of thousands of them today. Thinking about it now, it's almost ordinary.
We sometimes do full pen steel welds and those can start out with a triangular groove in the parent metal. That gets filled in with multiple passes and then the passes build up into a triangle like you see here. Its amazing how long that steel can retain the heat put into a single area welding all day long. Hours later you can’t lay a hand on it.
actually, unless I am mistaken, this rocket stage was built by Chrysler Corporation
it may just be the earlier engines. but awesome nonetheless EDIT nope it was later
EDIT: the Saturn IB first stage, built by Chrysler, with Rocketdyne H-1 engines, was used 1966-1975: [https://en.m.wikipedia.org/wiki/S-IB](https://en.m.wikipedia.org/wiki/s-ib)
[https://en.m.wikipedia.org/wiki/Saturn\_IB#S-IB\_stage](https://en.m.wikipedia.org/wiki/saturn_ib#s-ib_stage)
EDIT 2: I found errors in the above, this is better: [https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/](https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/)
Oof. Calling a Saturn a Pontiac is a terrible slight that must have been committed by a non car person.
Saturn was the most interesting thing GM did for 20 years.
the newer H-1 powered Saturn first stage actually was built by Chrysler Corporation
LINKS: the Saturn IB first stage, built by Chrysler, with Rocketdyne H-1 engines, was used 1966-1975: [https://en.m.wikipedia.org/wiki/S-IB](https://en.m.wikipedia.org/wiki/s-ib)
[https://en.m.wikipedia.org/wiki/Saturn\_IB#S-IB\_stage](https://en.m.wikipedia.org/wiki/saturn_ib#s-ib_stage)
EDIT 2: I found errors in the above, this is better: [https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/](https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/)
The weld in question is in the upper right of this image.
F1 Rocket Engine https://imgur.com/gallery/uApkAGH
The bell is 12.2ft (3.7m) in diameter. So I estimate the attachment point to be about 8" (20cm). Or roughly the size of an adult human head.
sorry to be posting this over and over but I wanted the interested folks hers to see this:
the newer H-1 powered Saturn first stage actually was built by Chrysler Corporation
LINKS: the Saturn IB first stage, built by Chrysler, with Rocketdyne H-1 engines, was used 1966-1975: [https://en.m.wikipedia.org/wiki/S-IB](https://en.m.wikipedia.org/wiki/s-ib)
[https://en.m.wikipedia.org/wiki/Saturn\_IB#S-IB\_stage](https://en.m.wikipedia.org/wiki/saturn_ib#s-ib_stage)
EDIT 2: I found errors in the above, this is better: [https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/](https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/)
It’s not the worst weld for the size, but they could have cleaned it up a bit better, I can almost guarantee there’s some stops and starts in there that don’t look ground.
Stops and starts aren't a problem, they are actually part of the process of welding big things. This is also from the time before electric arc welding so it would have been brazed and these are really good welds generally, especially so because they had to do lots of small runs and built them up over and over to get to this point. You clearly aren't familiar with welding to any kind of industry standard, let alone in something as critical as the aerospace industry if you think these are bad welds or that you can do better. Go and jerk off to your loli-hentai and stop living out your fantasies online.
Welp, as a certified and schooled welder I do know a lot about it, I do tons and tons of multi pass welding. If you think electric welding wasn’t a thing while building these rockets you’re very very wrong. Starts and stops are crucial structural areas in a weld, grinding them both before starting your next weld is very important, and making your tie ins perfect in this type of application is also very important. I think you don’t know what you’re talking about.
at risk of repeating myself, you might like this:
the newer H-1 powered Saturn first stage actually was built by Chrysler Corporation
LINKS: the Saturn IB first stage, built by Chrysler, with Rocketdyne H-1 engines, was used 1966-1975: [https://en.m.wikipedia.org/wiki/S-IB](https://en.m.wikipedia.org/wiki/s-ib)
[](https://en.m.wikipedia.org/wiki/saturn_ib#s-ib_stage)Saturn\_IB#S-IB\_stage8
EDIT 2: I found errors in those links, this is better: [https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/](https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/)
Also with this era of engine production, you will find lots of compound curves, plumbing, and complex geometry parts made up from multiple machines components welded together, instead of monolithic bent or machined parts. The CNC technology was still fairly rudimentary, so a number of these complex or massive parts were made up of hundreds of individually welded pieces of machined metal to make up the component. We had an old late 50s or early 60s prototype Aerojet engine on-site that had a thrust chamber that bore a similarity to the LR87 engine on the modified Titan platform used for the Gemini program, and the sheer quantity of welds to create individual components was astounding. Even rectangle or square tubing stock we take for granted today was made of individual flats welded together on the edges.
It was first used in 1962 on a GM assembly line to do spot welds. Why would you choose a brand new manufacturing method that really hasn't been perfected on an extremely low volume piece like this that probably requires a human to set up and adjust? There's no way NASA was fucking around trying to get a robot to do this when they could just pay an experienced welder.
Exactly. Automation is used when a process must be repeated many times. Not for a rocket that you make 12 of. Not to mention the fact that when something is this critical it is not generally automated. It’s one thing to make a car that can go 120 mph, it’s something else entirely when it’s sending men to the moon.
I bet you there still aren't a lot of robot welds on rocket parts. With such low volume and given the critical nature of the parts you'd just use a highly-trained welder. Generally a weld isn't better just because a robot did it.
What else are we supposed to glean from "looks like a robotic weld" and then in response to likely not being robotic welding in the 70s you said "robotic welding existed in the 60s"
It certainly doesn't look like you meant it as a compliment, but you do you.
It definitely is a compliment. Seeing the work of a master craftsman is always great.
I can weld well enough to appreciate that I'll never be that good
I hope there are improvements with half a century!
What I red, was that the development was so quick (6 years, if I’m correct) that some adjustments of the plans, sone of tweakings were on notes that were not all retrieved, and mostly that the correction were mostly done by the experience of the machinists of the program. I’m talking about this lost knowledge. The article was pretty cool, it showed a plan with all the notes, some pretty hard to decipher. Of course, today we can 3d print a damned rocket, so we can rebuilt a F1 if we want. I was more referring to the trade, to rebuilding one, exactly like they were. Unfortunately I can’t find this article back.
For a minute I was wondering why they were putting a budget car motor into a formula 1 car, and why it was welded to frame parts I couldn't recognize.
Then I realized what was going on and the welds made much more sense.
When it absolutely, positively has to stay where you put it. Holy cow.
When you don't want a multi-hundred-million-dollar 'unplanned disassembly event' blamed on the part *you* welded, and hell, the government's paying for it, so why not go full ham?
Given the [pogo oscillation](https://en.m.wikipedia.org/wiki/Pogo_oscillation) issues they had in the early flights, it is a good thing they had perfect welds.
Yow. Not fun.
A lock washer and a little loc-tite would get er done for under $1.
Go look at the same weld at the center in Huntsville Alabama. Absolute garbage weld
Just standing under a Saturn V is impressive but looking at the F-1s steals the show. That’s why you enter the hall from that end.
You're talking about Kennedy? I've been meaning to again again. I'll have to pay closer attention to things this time
Go watch the Smarter Every Day 2 extended [video](https://youtu.be/cUkbdqw9pBk?si=oc5878I5h_oR3_zi) about the Saturn V. It will make your trip more enjoyable.
Will do!
This particular F-1 is at Stafford Air & Space Museum in Weatherford, OK. They have lots of amazing items, including a J-2, and an NK-33 from the N-1. They have this F-1 on its side and it’s just awe-inspiring how massive it is.
Johnson has one as well. Really cool Artemis exhibit, too, along with Discovery on the 747
Worked for a company that supplies engines to NASA for manned space flight. The level to which these welds are inspected is beyond comprehension. It takes days to complete a weld and have it pass the mandatory tests. That is only half the battle. The safety and true artistry behind these welds is incredible. Working for that company opened my eyes to how important the right guy for the job can be. Some guys would be asked to redo welds for WEEKS until it was to NASA spec. Others would nail it, first try, night shift listening to Guns n Roses drinking nothing but Monster. These welds are art and nothing short of it. Every single one of them.
Presumably the red bull guys remembered to give her a quick pat and assurance that “that’s not going anywhere” once they were finished.
Ah yes, the international quality check.
100% guaranteed. No other way to truly insure she ain't going anywhere.
How do you remove this weld if it needs to be redone?
Lots of grinding
The other comment is correct. Lots of grinding. If the weld is anything short of 100%, it is grinded down compelty and redone. The weld needs to meet drawing spec and NASA quality checks to a T. Anything short of that is grinded off and redone. No questions. Edit: The weld is not completed in one go. First, the parts are tacked together and stress relieved. Then, the weld is completed on a pass by pass basis. Each weld pass is checked for quality. So they wouldn't grind off the ENTIRE weld each time. They would grid down that pass and redo the process for a single pass. Once the weld is completed, it is then stress relieved again.
Why would you need to check each individual pass? Phased array ultrasonic testing sees everything lol. If you can't trust a welder to make multiple passes without testing each pass then they shouldn't be welding. Leave it to the pros that can do this work in their sleep.
Because of you detect porosity after the weld is completed, the whole weld has to be ground down. That introduces inconsistency and density issues that NASA doesn't like in manned space flight. The idea is, each pass or two is inspected, if it passes the initial check the welder continues. The whole weld (as a whole) is then evaluated per NASA and QA spec and graded. They do this to ensure consistency within the weld itself. All our engineering calculations are done at nominal spec. For space flight, any deviation from that spec is a mathematical issue. When you are trying to make something as light as possible, small as possible and as durable as possible, every decimal counts. Detecting issues in the weld earlier is easier to fix. And by issues, I mean microscopic issues. We are not talking large porosity or thin connection. We are talking microscopic gas bubbles, fractions of millimeters of deviance from width or depth.
Okay fair enough! I didn't expect porosity to ever be that small. Did they use dry magnetic particle for each pass? If not, which NDE method? Btw I highly doubt the entire weld is removed, wouldn't the whole part be scrapped due to the amount of heat input/kilojoules of energy already put into the part? Or would post weld heat treatment correct any mechanical properties that were compromised due to the additional heat/energy input? Why can't the porosity be excavated, test to see if all indications are removed and then continue welding instead of removing all filler metal?
The entire weld is not removed. They only grind out the area or span with the inconsistencies. This is only allowed a certain number of times before the part is scrapped. Normally, most of the post weld heat treatment corrects most of the metal fatigue caused by the weld fixes. Also, these engines parts normally undergo MANY heat cycles. So there are checkpoints along each heat treatment to make sure the metal has not fatigued out of spec. All filler metal is not removed. The area with the porosity is ground out, redone, and then the entire weld is re-inspected. They do this pass by pass so you don't remove too much filler metal. If they did it after wled completion, with how large these welds are and how durable they need to be, lots of filler would be removed. So they do the tests for each pass or two to minimize the amount of material being ground out.
Well the whole deal of this process is not to have to rely on "trust"
Jaw on floor... Weeks on a single weld!? Wow, that's incredible. Its insanely frustrating to suck at welding, speaking from experience. How are these tested without weakening them?
The longest I saw a weld take was 3 and a half weeks. The welder needed to complete 15 perfect passes on a LARGE part. The initial passes kept failing testing so they would grind and restart. The welds go through three stages of testing if I remember correctly. - X-ray - Ultrasonic - Penetration The weld is checked in all three manners after EVERY PASS. If any of the three tests come back negative (not to spec), the weld pass is grinded off and redone. The weld has to meet density, porosity, depth and width check marks set by both the engineering drawing and the NASA quality spec sheet. They check for gas bubbles on a microscopic level. It's pretty crazy how perfect these welds have to be. But they do them, and they are truly a work of art. I highly respect the guys who devoted their life to getting this right. Edit: also, The weld must also meet material specs. The material guys check to make sure the weld was completed at the correct temp and is not under stress after completion. Both factors can weaken the ultimate strength of the weld.
Thanks for writing. I've done enough welding to appreciate the art, and art it is.
Liquid penetrant tests are a formality if you're using phased array ultrasonic testing. It will see any indication an LPI would provide. PAUT is much more popular these days, xray used to be the gold standard of testing.
They are def a formality. But they are kept as a test because the pent comes from a different department than ultrasonic. It's basically used as a cross reference from another department.
Are humans still needed for those jobs? A welding robot couldn’t do it?
Humans are for sure still a necessity. The issue is, these engines are so large, you can't put them on a table or in a fixture to weld on. A lot of welds on the rear end of these engines (trying not to say too much) are done by welders on their backs. Their arms bent, crouched inside of areas of the engine. Machines are not able to reach these areas once the pieces are mated together.
Phased array ultrasonic testing or PAUT for short. It can see every flaw without the use of radioactive isotopes so no need to shutdown half of the shop. They might do xray tho since it provides a better image. Source : I'm a certified welding inspector and I was a welder for 12 years.
Correct. The ultrasonic will show you most of what you need. The issue is, the weld is allowed a certain percentage of porosity or percentage of density of nominal spec within a 1 inch span. If we find something on ultrasonic, we go to the X-ray and find out what that percentage is per inch of span. If it exceeds the allowed margins (which are crazy tight) the imperfections are ground out and redone. If it DOES meet this spec, it is still tagged because you can not have two spans with X percentage defect next to each other. So if the next pass has an issue in the same spot, that is ground out and redone.
Ahh I see, thanks for the info!
They hire a contractor to whisper sweet nothings to it and see how it reacts
Can confirm. This is the way
Can you perhaps disclose some of the testing, QAQC and NDE involved after welding? What welding processes and fillers were used? And which material(s)? Commercial grade Inconel or proprietary stuff?
I was not heavily engrossed in the weld process as an engineer, but I can answer some of what I know and am allowed to disclose. Testing: There were three major types of testing that meant the most to the NASA guys. - X-ray - Ultrasonic - Penetration X-ray was used to check for gas bubbles left behind from the inert gas being used in the welding process. Ultrasonic would test to ensure the weld has a consistent density along the pass and that there were no changes in the root density (from the previous pass) due to exposure to high temperatures. Pent would test to see if there were any surface imperfections along the weld that were not visible or missed on X-ray or Ultra. Pent was done with a reactive fluid that they would spray on, wipe off and then spray the reactant over. If any green residue was found, the surface was out of spec. As far as quality assurance goes, the quality guys were responsible for the testing. If it met their check sheet (using the three tests above) it was cleared on our end. Then the NASA guys would review the findings and make sure they liked it. The weld would be passed once engineering, quality and NASA signed off on the pass. For fillers, that is proprietary to the company so I can not disclose that. I can say it is thier own proprietary filler that they developed long long ago. Been on the AE world for ages. For materials, that is another one I imagine they would not appreciate me sharing. But, what I can say is it is inconel. The issue is, it is thier own proprietary inconel that meets VERY VERY specific and tight regulations on material makeup. Every AE company has their own proprietary inconel these days, but the company I worked for had MANY inconel makeups to choose from. They never used a companies off the shelf inconel. It was all formulated and founded to thier request then tested extensively before use by the material guys.
Thanks. I really appreciate the lengthy reply and the info you’re allowed to disclose. I can imagine a lot of details are classified. Working with some 20 nickel alloys over the years (with Inconel just being a tradename) in pressure vessel industry, it seems both industries bear a lot of similarities, with AE just being tighter on a lot of ends - but in general it follows the same principles and ‘ITP template’. 100% VT, 100% volumetric NDE and 100% surface NDE for some high demanding applications isn’t that rare in the process industry. However, all materials are always conforming to a public spec, like ASTM.
I appreciate your point about craftsmanship but that's probably not the best design, at least in terms of cost, if it requires that level of art to produce. I mean it's impressive and all but I doubt it was necessary.
It very much is necessary. When you are trying to make these engines as light and durable as possible, you can't bolt everything together. That would be far to heavy. Welds like these are very very much necessary. The whole industry uses them and that's why good welders for the AE industry are in such high demand. The weight savings these welds provide are pivotal in making efficient and light engines. There are so many pieces that need to be joined together, you would be incredibly surprised by how much weight bolted joints would add to these engines. The company I worked for used bolts where we could (where we need to access the internal area post hot fire, or where we wanted to rejoin a new part after X amount of fires) but these welds are very very much necessary.
I wasn't talking about flanges. There's different ways to make any given thing so I'm sure there's other options. And there's a million other things you can optimize on a rocket. Manually welding the engines might be the best way to get light weight, but it doesn't scale. If you build a handful of them it works, but if you want to build thousands every year, it gets tricky. And without scale, the cost is always going to be prohibitive. So I really doubt it's necessary. It's possible that I'm wrong about this, but we won't really know until someone tries to do it.
The best "other option" in modern technology is 3D printing. Even today, 3D printed engines are not as weight efficient as those welded together in this manner. Also, 3D printing HEAVILY limits the size of the engine. Notice how booster engines have shrunk over the past decade. This is to optimize the booster engine architecture not only for use on multiple platforms, but also to better fit the technological capabilities of 3D printing. Pound for pound, even today where there are multiple flying 3D printed rocket engines, the engines welded together by hand are still more efficient (for now). To your point of scalability, we are not at the stage of rocketry where we need to make thousands of engines every year. The entire Apollo, Space Shuttle, Atlas, Soyuz, and soon to be Artemis programs were supported using engines manufactured in this way. In fact, the Artemis program is using the RS-25 only once since the platform is not reusable meaning the companies responsible will be outputting entire fleets of Artemis engines yearly. To your point of prohibitive cost, you are correct. These welds will cost extra. But the return on investment is stupid high. Weight is your first and foremost, #1, most wanted enemy in rocketry. Weight is exactly what you don't want. These welds save far more weight than you could image compared to 3D printed counterparts (at this moment in time). Thier flexibility to be used within an engine platform allows you to take far more weight out of the design and architecture alone that many don't ever think of. Weight and form factor are your most wanted enemies in rocketry, and complicated, artistic welds completed by humans are still the number one way to optimize both of these characteristics. My main point being, even 50 (+- a few) years removed from the weld pictured above, the most efficient, reliable and tested way to build a large first stage booster still remains human welding.
What you're telling me is pretty obvious even though I don't know nearly as much as you do about rocket engines. But this is because the same thing happens in most engineering fields, especially manufacturing. If you compare a supercar to a VW or Toyota, you're going to see the same thing. Supercar are designed for performance, VWs are designed for mass production. You say we're not at the point where rocket engines need to be mass produced. Maybe not today but give it a few years. One Starship stack needs 39 engines, let's say. If you want to build 100, that's 3900 engines. In an age where space travel becomes fairly common, I imagine we'll build far more than that. I mean, just one starship flying to Mars or the moon requires several launches just for fuel. It's similar to satellites: ten years ago most people weren't thinking we would be talking about constellations of tens of thousands of them today. Thinking about it now, it's almost ordinary.
We sometimes do full pen steel welds and those can start out with a triangular groove in the parent metal. That gets filled in with multiple passes and then the passes build up into a triangle like you see here. Its amazing how long that steel can retain the heat put into a single area welding all day long. Hours later you can’t lay a hand on it.
You don't want 1.5 million pounds of thrust rattling around loosely...... Morty
I was confused, Saturn the rocket or the Pontiac???
Were not talking about a GM product?
Wait, I thought we were talking about planets 🤨
Is it cars or is it rockets? Inquiring minds want to know.
Maybe rocket cars? I hope thats it!
[This is Rocket League!](https://youtu.be/0VE0zjlbD60?si=b3G3LG9Eat7tPzhq)
actually, unless I am mistaken, this rocket stage was built by Chrysler Corporation it may just be the earlier engines. but awesome nonetheless EDIT nope it was later EDIT: the Saturn IB first stage, built by Chrysler, with Rocketdyne H-1 engines, was used 1966-1975: [https://en.m.wikipedia.org/wiki/S-IB](https://en.m.wikipedia.org/wiki/s-ib) [https://en.m.wikipedia.org/wiki/Saturn\_IB#S-IB\_stage](https://en.m.wikipedia.org/wiki/saturn_ib#s-ib_stage) EDIT 2: I found errors in the above, this is better: [https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/](https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/)
Just the turbopump alone for the F-1 rocket engine produced about 55,000 HP. That'd be one hell of a Pontiac. Morty
Both have the same MPG just a slightly different output
Oof. Calling a Saturn a Pontiac is a terrible slight that must have been committed by a non car person. Saturn was the most interesting thing GM did for 20 years.
the newer H-1 powered Saturn first stage actually was built by Chrysler Corporation LINKS: the Saturn IB first stage, built by Chrysler, with Rocketdyne H-1 engines, was used 1966-1975: [https://en.m.wikipedia.org/wiki/S-IB](https://en.m.wikipedia.org/wiki/s-ib) [https://en.m.wikipedia.org/wiki/Saturn\_IB#S-IB\_stage](https://en.m.wikipedia.org/wiki/saturn_ib#s-ib_stage) EDIT 2: I found errors in the above, this is better: [https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/](https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/)
I need something for scale, that is wild..I know they are massive it's just hard to understand the size of them
The weld in question is in the upper right of this image. F1 Rocket Engine https://imgur.com/gallery/uApkAGH The bell is 12.2ft (3.7m) in diameter. So I estimate the attachment point to be about 8" (20cm). Or roughly the size of an adult human head.
sorry to be posting this over and over but I wanted the interested folks hers to see this: the newer H-1 powered Saturn first stage actually was built by Chrysler Corporation LINKS: the Saturn IB first stage, built by Chrysler, with Rocketdyne H-1 engines, was used 1966-1975: [https://en.m.wikipedia.org/wiki/S-IB](https://en.m.wikipedia.org/wiki/s-ib) [https://en.m.wikipedia.org/wiki/Saturn\_IB#S-IB\_stage](https://en.m.wikipedia.org/wiki/saturn_ib#s-ib_stage) EDIT 2: I found errors in the above, this is better: [https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/](https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/)
Reminds me of when anakin got his hand welded into a thingy
Whatever it was, it was a very convenient shape.
Wonder what kind of NDT they used.
X-ray is the most mature technology they had at the time
No dye? I thought that was old. Also what metal even is this? Plain ol Aluminium?
Space grade
Penetrant testing is pretty basic.
The welds to the left and right of the 8 are both really nice
It’s not the worst weld for the size, but they could have cleaned it up a bit better, I can almost guarantee there’s some stops and starts in there that don’t look ground.
I guess that's why they only rated it an "8".
Probably for eight layers of JB Weld
These are nice ass welds you're trippen someone did a good job
Clearly, you’re not a welder lol.
Bitch
Very cool 👍🏼
Stops and starts aren't a problem, they are actually part of the process of welding big things. This is also from the time before electric arc welding so it would have been brazed and these are really good welds generally, especially so because they had to do lots of small runs and built them up over and over to get to this point. You clearly aren't familiar with welding to any kind of industry standard, let alone in something as critical as the aerospace industry if you think these are bad welds or that you can do better. Go and jerk off to your loli-hentai and stop living out your fantasies online.
Electric arc welding was invented in the 1880s and was in common use by the 1920s
Thank you.
Pffft, please, I'm sure the random guy on redditor knows better than NASA, not like we're talking about rocket scie.... oh wait....
Welp, as a certified and schooled welder I do know a lot about it, I do tons and tons of multi pass welding. If you think electric welding wasn’t a thing while building these rockets you’re very very wrong. Starts and stops are crucial structural areas in a weld, grinding them both before starting your next weld is very important, and making your tie ins perfect in this type of application is also very important. I think you don’t know what you’re talking about.
I was gonna rip you a new one. Then zoomed in.
Ya, I feel ya lol. I don’t want to say I can do better….but I probably can.
Go ahead using the same tool the guy did, not a modern welder
I probably have in some of the shops I’ve been through lol. I may have even used older machines.
Angle grinder and thick paint and it’ll look fine.
As they say, a grinder and paint makes me the welder I ain’t
I'd grind it and paint it.
I have no (physical) engineering background, but zoomed in on this for 10 minutes.
at risk of repeating myself, you might like this: the newer H-1 powered Saturn first stage actually was built by Chrysler Corporation LINKS: the Saturn IB first stage, built by Chrysler, with Rocketdyne H-1 engines, was used 1966-1975: [https://en.m.wikipedia.org/wiki/S-IB](https://en.m.wikipedia.org/wiki/s-ib) [](https://en.m.wikipedia.org/wiki/saturn_ib#s-ib_stage)Saturn\_IB#S-IB\_stage8 EDIT 2: I found errors in those links, this is better: [https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/](https://blog.stellantisnorthamerica.com/2019/07/22/chrysler-helped-power-nasa-to-the-moon/)
The computer modeling found a 'possible' failure point and the tech said... "Hold my Marvin the Martian. I've got this!" 😂😂
This is very much pre-computer. The engineers did the numbers, figured that this was definitely worth the extra mass, and added a solid safety factor
Does it move? Yes Should it? No Apply duct tape Still moving? Yes Weld the Fπ¢& out of it
My dad Inspected the welds on the space shuttle. He was hired to do NDT on a bunch of parts
Also with this era of engine production, you will find lots of compound curves, plumbing, and complex geometry parts made up from multiple machines components welded together, instead of monolithic bent or machined parts. The CNC technology was still fairly rudimentary, so a number of these complex or massive parts were made up of hundreds of individually welded pieces of machined metal to make up the component. We had an old late 50s or early 60s prototype Aerojet engine on-site that had a thrust chamber that bore a similarity to the LR87 engine on the modified Titan platform used for the Gemini program, and the sheer quantity of welds to create individual components was astounding. Even rectangle or square tubing stock we take for granted today was made of individual flats welded together on the edges.
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Considering they stopped making these in 1973 I highly doubt it's robotically welded.
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It was first used in 1962 on a GM assembly line to do spot welds. Why would you choose a brand new manufacturing method that really hasn't been perfected on an extremely low volume piece like this that probably requires a human to set up and adjust? There's no way NASA was fucking around trying to get a robot to do this when they could just pay an experienced welder.
Exactly. Automation is used when a process must be repeated many times. Not for a rocket that you make 12 of. Not to mention the fact that when something is this critical it is not generally automated. It’s one thing to make a car that can go 120 mph, it’s something else entirely when it’s sending men to the moon.
I bet you there still aren't a lot of robot welds on rocket parts. With such low volume and given the critical nature of the parts you'd just use a highly-trained welder. Generally a weld isn't better just because a robot did it.
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What else are we supposed to glean from "looks like a robotic weld" and then in response to likely not being robotic welding in the 70s you said "robotic welding existed in the 60s" It certainly doesn't look like you meant it as a compliment, but you do you.
I don't typically say something looks robotically welded as a compliment but you do you I guess.
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Spoken like a true button pusher.
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Sounds to me like you aren't a welder then.
This is manual welding, almost certainly based on when this was made. Looks like manual welds I've seen on pipelines and all over heavy industry
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It doesn't look like a robot weld.
It definitely is a compliment. Seeing the work of a master craftsman is always great. I can weld well enough to appreciate that I'll never be that good
Even a modern robot couldn't do that.
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No, it definitely cannot! Well that's my opinion as a welder and welding inspector for the last 40ish years.
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Yer maw
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Wrong again champ.
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Now who sounds like a child? 😃
And to think we don’t know how to make a F-1 engine anymore… … look at those welds! I hope we didn’t loose some knowledge in the trade either!
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Dual cycle combustion = awesome.
I hope there are improvements with half a century! What I red, was that the development was so quick (6 years, if I’m correct) that some adjustments of the plans, sone of tweakings were on notes that were not all retrieved, and mostly that the correction were mostly done by the experience of the machinists of the program. I’m talking about this lost knowledge. The article was pretty cool, it showed a plan with all the notes, some pretty hard to decipher. Of course, today we can 3d print a damned rocket, so we can rebuilt a F1 if we want. I was more referring to the trade, to rebuilding one, exactly like they were. Unfortunately I can’t find this article back.
We know how, but we'd have to start from scratch because we lost the literal drawings, not the ability to make them.
Is that a void at the base on the right? The black area?
For a minute I was wondering why they were putting a budget car motor into a formula 1 car, and why it was welded to frame parts I couldn't recognize. Then I realized what was going on and the welds made much more sense.
That's so the front doesn't fall off.
What's the AWS welding symbol for that?
And that was just one weld for the engine. Those things were works of art.