softening copper

[arther dailey]

watching a you tube with well know motorcycle builder of multi extra cylinder bikes and was suprised to see him heat then quench a copper washer to temper it , I thought to soften you let it slowly air cool, to harden you quench ?

 

[Seadog]

Either way works.

 

[mtt.tr]

Material dependent, yes this aneals copper.

It's how I reuse copper washers in a pinch

 

[hermetic]

it does work if you heat to red and allow to cool, but works much better if you heat and then quench!
Phil

 

[Seadog]

The only difference that I've noticed is that most of the scale tends to fall off when quenched.

 

[arther dailey]

Thanks , thought it strange to quench to soften

 

[Dee J]

Thanks , thought it strange to quench to soften

Confusing steel with copper. Copper work-hardens rather than heat hardening. And quenching does descale the copper nicely without impairing the softening.

 

[hermetic]

Copper work hardens, if you beat it into a shape crystals form in the metal which will eventually cause it to fracture, quenching shatters the chrystals and return it to full malleability. air cooling will partially soften it.
Phil

 

[reb78]

When I heat and quench copper, I always find the surface looks black and dirty. Should one clean this up or is it ok to use like that? Often, its copper washers that are on brake systems and I dont have an appropriate sized new one handy but need the vehicle working.

(screwfix do a decent quality copper washer kit with a mix of sizes that is really useful and relatively well priced so I have one of these on the shelf now which is handy as I always prefer to replace)

 

[Kram]

Should one clean this up or is it ok to use like that? Often, its copper washers that are on brake systems and I dont have an appropriate sized new one handy but need the vehicle working.

Brake systems need cleanliness.

A citric dip also removes scale very nicely.

 

[arther dailey]

ok, not confusing with steel, just didnt know you quenched copper to temper it ,interesting thanks...so how if you wanted to would you harden copper ?

 

[Seadog]

Ultrasonic hardening seems to be a method. Not something you'd likely do in the home environment.

 

[Agroshield]

...copper to temper it, interesting thanks...so how if you wanted to would you harden copper ?

Please, I am not intending to be rude, but if you want to talk about these things, it is good to use the correct words. In metallurgy, every term has quite a specialised meaning and they cannot really be used interchangably.

Your original question would be called 'annealing'. It is the process of taking something from a not-necessarily-known state of hardness to a 'dead soft' condition. 'Tempering' (letting down/drawing down) is something you do after hardening, to reduce the hardness to a known level while at the same time reducing the brittleness. The degree of temper depends on what the tool will be used for - a cold chisel will be different to a wood chisel will be different to a scriber.

Again, for different metals, the way you harden them differs. Most engineering steels (i.e. carbon steels) can be hardened by heat treatment. Get them hot and quench them. The quenching medium differs - water, air or oil. For pure copper, as said above, heat treatment will not work, you have to work harden it. Brass is similar. I think pure/soft aluminium is the same (work harden only), but clearly aluminium alloys are amenable to heat treatment.

It is not something I have ever considered, but can you work harden mild (non-carbon) steel?

---

Seadog's post on ultrasonic hardening has just popped up - if you think about it, bombarding it with sound waves is just like hitting it with millions of tiny hammers, so it kind of fits with the work hardening mechanism.

 

[arther dailey]

Please, I am not intending to be rude, but if you want to talk about these things, it is good to use the correct words. In metallurgy, every term has quite a specialised meaning and they cannot really be used interchangably.

Your original question would be called 'annealing'. It is the process of taking something from a not-necessarily-known state of hardness to a 'dead soft' condition. 'Tempering' (letting down/drawing down) is something you do after hardening, to reduce the hardness to a known level while at the same time reducing the brittleness. The degree of temper depends on what the tool will be used for - a cold chisel will be different to a wood chisel will be different to a scriber.

Again, for different metals, the way you harden them differs. Most engineering steels (i.e. carbon steels) can be hardened by heat treatment. Get them hot and quench them. The quenching medium differs - water, air or oil. For pure copper, as said above, heat treatment will not work, you have to work harden it. Brass is similar. I think pure/soft aluminium is the same (work harden only), but clearly aluminium alloys are amenable to heat treatment.

It is not something I have ever considered, but can you work harden mild (non-carbon) steel?

---

Seadog's post on ultrasonic hardening has just popped up - if you think about it, bombarding it with sound waves is just like hitting it with millions of tiny hammers, so it kind of fits with the work hardening mechanism.

 

[arther dailey]

absolutly no offence taken, long time since I was involved in annealing copper (for re use on rewinding a large water cooled spot welder , primaries were approx 1" by 3/32" where as secondary was 7/8 of a turn solid probably again one inch thick bored for water cooling, at a rewind firm) so getting tempered and anealing mixed is an age thing , my apolagies . thanks for your reply.appreciated

 

[arther dailey]

You are annealing, not hardening!

Copper softens on heating. It hardens with work done on it.

Allen Millyard is a clever chap. Very good with a hacksaw, too!

yes realise that , but I was took back that you quench copper , hadnt heard that before , I anealed a tractor diesel pump washer but just heated and let air cool. it worked fine , but now I know to quench copper and it will not only soft but clean , the hardening was just a secondary question out of interest , I have no current need to harden anything copper ...well as yet anyways !
the man is beyond clever , demi god would be a better description

 

[optima21]

maybe they are just quenching it so they can do the next process faster rather than waiting for it to cool.....remember time is money

 

[Cobbler]

When I was at school, in metalwork we made some copper bowls, we quenched them in sulphuric acid to anneal & clean the copper, then buffed them on an industrial buffer. This was in 1962ish, can you imagine that being allowed for 12 year olds today! Still got the bowl.

 

[Seadog]

A brass tea caddy spoon for me. Beat it, anneal it, planish it, silver solder the handle, polish it. Fantastic! I still have it somewhere.

 

[outofthefire]

It is not something I have ever considered, but can you work harden mild (non-carbon) steel?

Yes mild steel work hardens, pretty much the same as copper in my experience.