Moisture in 7018

When this popped up in my video feed I immediately thought of Richard's posts about water running off of 7018 rod.

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Reply to
Bob La Londe
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I kind of like his, "People say... well lets try it" attitude. He did a neat series of videos on gasless flux core as well.

Reply to
Bob La Londe

Most of the properties will be due to the metallurgy - no relation to hydrogen.

The "nnn8's" are CaCO3 based flux - very refining and with a clean microstructure they can got for the fine strong-AND-tough "acicular ferrite microstructure" (whatever the discussions; when you see it under an optical microscope at 500X you immediately know it's "it").

The "nnn3's" and "nnn4's" are based on rutile (Titanium Oxide) and have inclusions which look like boulders at 500X. Coping strategy - do not form acicular ferrite, the avoid the high strength would would be inappropriate here - would work against you. Problem - get a coarse ferrite structure. soft (not strong) and not tough...

I suspect a lot of his "problem" weld is that it just welded so rough. It sounded so wrong as the rod was burning.

There are problems asserting what is contrary to orthodoxy... That can be sidestepped by coming at the same point from a different direction. Structural steels you can weld with cellulosics (typically 6010's and

6011's). No problem. At all "normal" temperatures" (you might have to take precautions at Arctic temperatures). And cellulosics give a way higher hydrogen than you can ever induce with a 7018.

Hydrogen levels in ml of H2 per 100g of weld metal

7018's - baked - about 5 7018's from lying on a damp concrete floor - about 30 6013's always about 30 (you mustn't dry them) 6010's - reputed to be about 70

6010's / cellulosics - that stiff thin rod-like arc which roars and will punch a keyhole - apparently that's the hydrogen - the "physics" effect on the arc.

I would like to do tests like this guy has done. But I would be most interested in leaving fillet welds stationary in a high state of stress - maybe with bags of melting ice-cubes on the welds to keep the potential vulnerability long enough for the potential effect to be seen. Freezing termperature - the weld hydrogen moves a lot slower and the vulnerability will last a lot longer. Plus the hydrogen will be more able to concentrate where it shouldn't. What I'd be looking for is the weld bursting after some standing time

- one aspect to "cold-cracking" is that it can be delayed. The reason is well-known - one hydrogen concentration mechanism is to flow uphill against an apparent concentration gradient to a region in a high state of triaxial stress. Which for a fillet weld in tension you'd expect to be near the fillet toe...

Rich Smith

Reply to
Richard Smith

What I'd be looking for is the weld bursting after some standing time

- one aspect to "cold-cracking" is that it can be delayed. The reason is well-known - one hydrogen concentration mechanism is to flow uphill against an apparent concentration gradient to a region in a high state of triaxial stress. Which for a fillet weld in tension you'd expect to be near the fillet toe...

Rich Smith

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More spaces for it in a deformed lattice?

Reply to
Jim Wilkins

That is a model you could have in your mind.

When you are ready, look further. I am no "Einstein", but I think you have to have a vision of the metallic bond and energy levels.

I came up with an explanation for the metallic bond relating to a human likeness - but it is unrepeatable in polite company... They were falling-about at the miners group I was at. Okay - the ends of the periodic table are like monogamy. Then there is a midband where you get the "flexible social arrangements" which is the metallic bond. The electrons are not unique to any one atom. Explaining the characteristics of a metal

- lustre to light / mirror

- conductivity

- ductility

So when you introduce a region of triaxial strain there must be some effect on energy levels of the bonds. You could imagine that a strained region could find itself less strained by making welcome a hydrogen. Now I never got a chance to talk with a theoretical physicist, but I suspect hydrogen, with a proton as a nucleus and just one electron - if that were to get involved in the sea-of-electrons then we would be talking about just a proton wondering around. If there were right, that would explain the extraordinarily high diffusivity of hydrogen in steel. The initial millimetres is in minutes.

Alexander Troiano of Cleveland was the first to recognise the behaviour of sharp notches under stress in the presence of hydrogen being where after a delay for the hydrogen to accumulate there the hydrogen cracking starts. We visited him - myself and a professor - and he described aircraft on the Pacific islands would be stood there nothing going on and there would be a "bang" and the undercarriage would snap. Clean in two. No warning. Thinking through it, he "got it" with his tests on notched pieces of metal hydrogenated. Back in the 1940's. There in the early 2000's we were seeing him, unbeknownst to us this connection, about aircraft undercarriages...

I will go suggest to fellow doing those tests about trying a fillet weld in static stress.

Rich Smith

(photon thinking "I'll not entering that pit of iniquity") (one gets in one side of the bed while another gets out of the other side of the bed)

It is maybe crude and can fail However the "space" model can brea

Reply to
Richard Smith

When you are ready, look further. I am no "Einstein", but I think you have to have a vision of the metallic bond and energy levels.

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I had that hammered into my head as part of the Chemistry degree. At the time I don't believe there was much experimental verification of the models, for lack of instruments rather than lack of interest. I received a summer research grant to explore Deuterium as a trackable substitute for Hydrogen, though not in solid metals. Their magnetic spin resonances are different.

The instrument that measured it was called an NMR, Nuclear Magnetic Resonance. When it entered the medical field the name had to be changed to MRI, Magnetic Resonance Imaging, to avoid scaring people. It was in high demand and my time on it was 11PM to 5AM, meaning I saw hardly a soul all summer. The next June they told me I needed 4 more credits to graduate. I signed up for Summer Theatre as a carpenter and grip for 6 pass/fail credits and saw enough of "interesting" people to last me for years. It wasn't a party, those people worked 12-14 hours a day and slept the rest. I attended all the classes to help balance the M/F ratio and was in dance rehearsal when Armstrong landed on the moon.

Reply to
Jim Wilkins

You got the opportunities. There in the US

Here in the UK, I "busted a gut" and got nothing. Reality calibration

- I have never - ever - been asked what I would do for the Company's bottom-line - which I would gladly answer. No no no - over here there are so many important candidate selection criteria that whether you'd earn a Company money is disappearingly far down the list. As ever I have experienced it. Did I get something wrong, I ask myself?!

I once had some damn' idiot try to "CBIF" me when I'd gone for a welder job. CBIF = the very "In" "Competency Based Interview Format". To manage recruitment to objective criteria they formulate a list of questions. Then ask each candidate the same list of questions - non-interactively on the part of the interviewer.

That was where their welder welded outside no workshop - so knew it could not be MIG/GMAW for doing these structural steels - inferred that. He was hovering try to show me the setup. Which the boss wouldn't have. I pointed out he was leaving to Australia in three days and she needed to act now to do a handover and she went - well whatever someone like this is categorised as going - generally concept was it was angry / furious. He muttered as I passed that yes they have to do structural steels with SMAW given welding is in a lean-to outdoors.

You want to know how it is that we've gone to war and had our asses kicked - correction politely catapulted by these calm-thinking people

- into the middle of the next century? Yup it's right here to see in this microcosm - delusional reality substitution through-and-through. As I understand it...

My fatigue-resistant welds investigation - I could get 2Million cycles over the weekend. Special protocol was I came in each day of the weekend to simply see all seemed well and strictly if anything wasn't right press the "Stop" button and leave. Right aptitudes and abilities. No entrepreneurialism. I found "the discovery of the century" for welding - mass-produced welds with a fatigue resistance matching that of the rolled steel sections you are joining - which is unheard-of.

Reply to
Richard Smith

You got the opportunities. There in the US

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I knew that a BS couldn't be the end, I'd need at least a Masters to become more than a lab tech. However the grad school draft deferment had been dropped, ending that path. When I returned from the Army the EPA had almost killed chemistry in the US and my Army training was far short of a BS in electronics, so I started as a factory assembler. They were kind enough to apprentice me as a machine designer/builder and cycle me through most of the support positions. The Drafting I learned in 7th grade (age 13) was suddenly very valuable. At that time, the mid 70's, the data sheets for new electronic components were more informative and useful than an electronics degree that covered older tech. I found that out when a newly hired EE told me to use a transistor in a way that satisfied the theoretical model but blatantly ignored its real-world operation. You can't put 5V on the base if it's just a diode to the grounded emitter. Poof!

Reply to
Jim Wilkins

Things do change don't they. In 1980 (maybe 81) I went on a high school chemistry class field trip to a DuPont facility in Ohio where they bragged about all kinds of things. I think they were mostly trying to impress (and snow) us with their electron microscope, but they did also talk about various plastic and polymers with all kinds of properties. This century I called them once looking for the trade name for one of the polymers they had talked about so I could find a vendor. After much bullshit I finally talked to somebody who's sneer was audible over the phone that they were working on environmental science more now. Huh?

Reply to
Bob La Londe

I came up with an explanation for the metallic bond relating to a human likeness - but it is unrepeatable in polite company... They were falling-about at the miners group I was at. Okay - the ends of the periodic table are like monogamy. Then there is a midband where you get the "flexible social arrangements" which is the metallic bond. The electrons are not unique to any one atom.

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When I studied Thermodynamics I was struck by how closely the statistical laws concerning interactions describe collective human behavior.

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Reply to
Jim Wilkins

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