Question for hammerfall

Tai Goo

Tai Goo

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I’m curious about precipitation hardening copper. Do you know anything about it?

I think I read somewhere that the alloys are toxic? Is it safe to work with in a traditional metalsmithing scenario?

I’m also interested in temps, times etc..

I haven’t tried it yet and just curious.
 
If anyone else has some info., please chime in. I didn’t mean to put hammerfall on the spot, just that he was talking about precipitation hardening steel on another thread and had some good info.

How practical/safe is it for your average smith?
 
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Oh,... also not for knife blades, but for handle fittings. I wasn't thinking of using it for a blade.
 
Tai Goo said:
I’m curious about precipitation hardening copper. Do you know anything about it?

I think I read somewhere that the alloys are toxic? Is it safe to work with in a traditional metalsmithing scenario?

I’m also interested in temps, times etc..

I haven’t tried it yet and just curious.
Click to expand...

My experience with nonferrous is certainly limited but from my time in a foundry environment I do know that bronze is much safer than brass which would infer that tin is the worse alloying metal of the two as far as fumes go but one must be extra careful with some of the alloys of bronze as well. I would recommend a bit of research time before jumping into any serious work with them.

;)I wouldn't rely on second hand info if it were me.

Gary
 
This isn't related to the precipitation hardening alloys, but it's worth mentioning that some brasses contain lead in the form of little tiny blobs mixed into the brass. It makes machining these alloys much easier. I don't remember the names, but some research is in order for anyone grinding or forging such alloys (any alloys really, but these are particularly bad).

The precipitation hardening Cu alloys I know of are Copper/Beryllium alloys. I do know they can achieve very high strength, comparable to some steels. Polishing them would be problematic, as any dust will contain some beryllium, very bad. The melting temp is lower than steels, and you could run into a "slush" of a liquid phase and a solid phase mixed together. If you're used to forging Cu based stuff, you likely won't have any trouble, though the notion of some inattentive time in the forge and a hammer blow spraying my shop with molten beryllium isn't a good one. My references say these alloys frequently have some Cobalt mixed in too. Ingesting beryllium in any way is very bad for you, whether breathing, eating, or any other way. **Repeated for emphasis**

Standard heat treatment as follows: Solution treat at 1475 F, water quench, age at 600 F for highest strength for 4 hours. Cold working after quenching will increase the strength quite a bit. Typical alloys begin to melt a little below about 1600 F, so good temperature control is required.

I have something here on martensite formation in Aluminum bronzes as well, but the strengths aren't nearly as high as what we're used to for martensite.
 
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Cu can have 2% degree of solution in austenite structure, which is a lot higher than its in martensite matrix. If heat up to above austenitzing temperature then rapid quench it below Ms, will result ovsaturated matrix with Cu being the solute. During the aging Cu will precipitate harden the steel. first start with forming of GP area, then ε-Cu will precipitate. The very finedε-Cu will dispredly locates inside the martensite matrix. Cause increasing strength and hardness. The strengthening result usually pick at 500~550C.

But there is also big down side for Cu. because it often segregate near grainboundry during the high temperature. Cu eutectic with other alloys that segregate near grainboundry, and has a chance futhure decreasing the melting point. Thus cause heat brittlness. This will make hot work very difficult, especially for high carbon tool or ball bearing steel whose ingots is already hard to forge. That's the reason we don’t see much steel with Cu as an alloying elements.
 
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sorry, i misunderstooded it. you were asking Cu based alloy.

i am not formilar with Cu based alloy. but i can ask someone arround and see if they can give any useful information.

oh yeah, talk about poisoning, braze welding Cu sometimes invoved low melting point alloys such like Pb, and Sn. they might gasified during the weld, enough breathed you may get poisoned. small amount usually are not enough to kill, but shits like Pb will decreasing people's sexual ability. it suppose make man impotence, and lower women's pregnancy ability.

so yeah, it definatly something have to be very careful.

but back the days in new york i readed news papper says lead poisoning everything in China. and now i have been here for a very long time. and i am still doing well enough to satisfy ladies. so i am confused lol.
 
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As to the toxicity of copper, it is the ability of copper to bind with other elements and organic compounds that makes it toxic. Some copper is required for life, too much interrupts cellular function.

Most of the problems with copper toxicity are related to the metals that it is alloyed with. Zinc, lead, antimony, arsenic, etc. are regular cohorts of mild mannered copper.

Avoiding inhalation of vapors and dusts, as well as avoiding skin exposure is the normal protocol.


The talk of copper pans being toxic if tomato soup is heated in them, as well as the Alzheimer's reports about copper are mostly an exaggerated risk.

Treat copper as a general toxin, as is most of the stuff we work with, and you should be fine.

The one copper alloy you should NEVER work with is Cu/Be. It can be extremely toxic...as in nerve damage, cancer, and death. Even though the beryllium content is small, the toxicity is extreme.

As to precipitation hardening, like most similar metals, it involves heating to the precipitation range and holding for enough time to allow the change to occur. The range changes from alloy to alloy, but the normal area is 500-900F. The time is 1-3 hours.
 
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That's what I was afraid of... I like the idea of trying to make my knives the best they can be,... but I like myself too much to die early for it. I'd rather just smoke myself to death. LOL
 
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