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Ultrasound hardening of copper

and improved pickle?

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pgk pgk09/07/2020 18:23:39
1849 forum posts
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Has anyone tried chucking a silver-soldered copper fabrication into a standard ultrasonic cleaner to harden it before a further operation on it? And does it shift flux quicker than just a citric acid pickle?

pgk

peter smith 509/07/2020 21:33:29
25 forum posts

Machine dro used to sell cleaning fluid to go into ultrasonic cleaners. I used it often when fabricating boiler fittings and fittings in copper and brass. Add citric acid crystals plus a touch of the fluid that the fairies use for the best results. Copper can only be hardened by working it and the silversoldering would have annealedit anyway.

pete

pgk pgk09/07/2020 22:31:38
1849 forum posts
288 photos

As I understand it ultrasonics can be used to harden copper... but whether an 'ordinary' unit would do it was my question....

If pickle in a cleaner works quicker (as one would expect) then a bonus..

pgk

Michael Gilligan09/07/2020 23:32:02
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210 page PhD thesis, dated 1974

Sorry, haven’t had time to read it

**LINK**

http://epubs.surrey.ac.uk/848536/1/10804105.pdf

... You may want to jump-in at 4.14

MichaelG.

Nigel Graham 210/07/2020 00:37:01
667 forum posts
15 photos

I suspect you'd need rather more than an ordinary ultrasonic cleaning-tank to work-harden copper.

Adding citric acid ... if the detergent is alkaline won't they simply neutralise each other in a haze of precipitated something-citrate?

Machine-DRO might have stocked ultrasonic cleaners and the detergents, but not now. Instead you need their fellow Allendale Group company, called Allendale Ultrasonics. (allendale ultrasonics. co.uk).

I have just looked on their inviting site - the only thing that worries me a bit is the rather odd mains voltage quoted, of 220V. Ours is 240V (the EU standard is actually 230V but with a tolerance that allows 240).

pgk pgk10/07/2020 04:49:07
1849 forum posts
288 photos

MichaelG:

That article discusses copper plating in an ultrasonic bath as a ' beter' deposit and comments on hardening and cavitation of the foil electrodes from prolonged use. So it does support the idea but doesnt really answer the practical question here.

Nigel Graham

I meant using pickle as the ultrasound solution 'in a cleaner' was the machine rather than the solution.

Perhaps someone wth an ultrasonic cleaner would care to cut two small strips of copper... anneal them and drop one in an ultrasonic cleaner for say 30 mins (sans pickle) and do a simple bend test on the two samples?

pgk

Michael Gilligan10/07/2020 08:21:53
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Posted by pgk pgk on 10/07/2020 04:49:07:

MichaelG:

That article discusses copper plating in an ultrasonic bath as a ' beter' deposit and comments on hardening and cavitation of the foil electrodes from prolonged use. So it does support the idea but doesnt really answer the practical question here.

[…]

Perhaps someone wth an ultrasonic cleaner would care to cut two small strips of copper... anneal them and drop one in an ultrasonic cleaner for say 30 mins (sans pickle) and do a simple bend test on the two samples?

pgk

.

I am well aware of that ... which is why I pointed you to 4.14

MichaelG.

Andrew Johnston10/07/2020 09:28:11
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5556 forum posts
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Posted by Nigel Graham 2 on 10/07/2020 00:37:01:
......... the rather odd mains voltage quoted, of 220V. Ours is 240V (the EU standard is actually 230V but with a tolerance that allows 240).

The European standard is 220VAC, while the UK is 240VAC. All the EU did was "standardise" at 230VAC and widen the tolerances to include both 220VAC and 240VAC. The voltage on my mains monitor is reading 240.2V at the moment.

The first time we flew in the French Alps nobody's battery charger worked; except my home made one. We measured the mains at 202VAC.

Andrew

pgk pgk10/07/2020 09:42:55
1849 forum posts
288 photos
Posted by Michael Gilligan on 10/07/2020 08:21:53

.

I am well aware of that ... which is why I pointed you to 4.14

MichaelG.

T'was 4.14 I read a lot of until it wasn't going anywhere helpful ( a few pages past the high mag images). Typical PHD thesis of the era... volume, volume, volume

pgk

Michael Gilligan10/07/2020 10:06:20
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Posted by pgk pgk on 10/07/2020 09:42:55:
Posted by Michael Gilligan on 10/07/2020 08:21:53

.

I am well aware of that ... which is why I pointed you to 4.14

MichaelG.

T'was 4.14 I read a lot of until it wasn't going anywhere helpful ( a few pages past the high mag images). Typical PHD thesis of the era... volume, volume, volume

pgk

.

dont know Funny, that ...

What I read in 4.14 was about sample dimensions, depth of immersion, ultrasonic power, and duration [and more] ... all packed into less than one page.

That, together with the documented results was sufficient to convince me that you would be wasting your time [and that of anyone who steps forward to do a 30 min test for you].

MichaelG.

secret

Andrew Johnston10/07/2020 11:05:08
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5556 forum posts
650 photos

Posted by pgk pgk on 10/07/2020 09:42:55:

Typical PHD thesis of the era... volume, volume, volume

At least mine was nearly 10 years later, although somewhat longer. I had to get permission from the Board of Graduate Studies to exceed the 250 page limit. embarrassed

Andrew

pgk pgk10/07/2020 12:46:05
1849 forum posts
288 photos
Posted by Michael Gilligan on 10/07/2020 10:06:20:

dont know Funny, that ...

What I read in 4.14 was about sample dimensions, depth of immersion, ultrasonic power, and duration [and more] ... all packed into less than one page.

That, together with the documented results was sufficient to convince me that you would be wasting your time [and that of anyone who steps forward to do a 30 min test for you].

MichaelG.

secret

4,14 describes the method

I'll admit i gave up reading at the section covered in electron micrographs so i missed further down at table XI ? and I'm a novice at uderstanding their ultrasonic power compared to a contemporary machine. Table I still seems to be related to use of electrolysis within the ultarsound bath for grain hardness. Presumably I;m not findgn the table results or 4.14 method itself. Ah! found it table XIX p 88... no bloody wonder!
..shows it works but takes longer than 30 mins....

Any clue how those numbers relate to work-hardened copper??

pgk

pgk pgk10/07/2020 12:49:23
1849 forum posts
288 photos
Posted by Andrew Johnston on 10/07/2020 11:05:08:

Posted by pgk pgk on 10/07/2020 09:42:55:

Typical PHD thesis of the era... volume, volume, volume

At least mine was nearly 10 years later, although somewhat longer. I had to get permission from the Board of Graduate Studies to exceed the 250 page limit. embarrassed

Andrew

I recall helping a mate prepare his thesis circa '68 - a whole bunch of us carefully fixing 'letraset' down to make all the headings, tables and graphs. It's got to be a whole lot easier with computer printers now.

pgk

SillyOldDuffer10/07/2020 13:43:45
5932 forum posts
1282 photos

Is pgk's question related to Ultrasonic Impact Treatment? As described on Wikipedia it makes sense, ie a hammer head, maybe consisting of several pins, is vibrated at 200Hz, with an ultrasonic component superimposed on top.

The strength of metal depends on surface condition because even microscopic flaws act as stress raisers. Roughly finished bars break in a tensile testing machine before their highly polished twins. As a souped-up mechanical hammer, UIT improves surfaces by removing flaws caused by corrosion, closing micro-cracks, and smoothing the surface to reduce stress-raisers. It also hardens by mechanically altering the metal's grain structure. I guess this form of ultrasonic hardening is only effective close to the surface, but still very useful.

In contrast ultrasonic cleaners work by pressuring a liquid into the surface of an object, mostly dirt, and then rapidly releasing the pressure causing a vacuum. Anything loose is broken away. It must also have a hardening effect, but my guess is cavitation as the wave reverses causes more damage by digging out soft spots that UIT would seal and harden. Maybe the result is a hard but spongy surface.

If the notion that an Ultrasonic Cleaner digs holes in metal is right, it should be possible to see microscopic damage appear first on the matt side of a piece of Aluminium Cooking Foil, because the other side is highly polished.

I'm not suggesting that ultrasonic cleaning is dangerous to metal! In practice ultrasound cleaning is applied in short bursts and has dirt to work on. Doing significant damage to clean metal would need plenty of power and long exposure. After all, the bowl is made of stainless steel...

Dave

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