aluminum rivets

[skittish]

I have a few thousand 17-T4 alum rivets and would like to know if anyone has experience on how to normalize the rivets to use with 5052 al in non aircraft use. they are extremely hard and even heated retain their hardness. Is there any way of using them , or softening them?

 

[BBerson]

For non-aircraft I heat them in my home oven to 500° for about 15 minutes and let them cool slow.
Not fully annealed, but about half hard.

 

[skittish]

For non-aircraft I heat them in my home oven to 500° for about 15 minutes and let them cool slow.
Not fully annealed, but about half hard.

Thanks for the info - tried this and it did soften them, did two batches, one quenched and one set cooled slowly then put both sets it in the freezer. Both sets still hard, but at least compressible. Appreciate your reply.

 

[gtae07]

I would just use them as-is unless you've demonstrated that they just can't be used that way.

 

[Marc Bourget]

There are two ways, actual annealing and the second, frequently called annealing, is technically bringing the material to "W" Temper - which takes more than 500 deg F.

You really want to have the rivets as soft as possible. Some may recall my addressing this point in my sheet metal forums at Sun'nFun and OSH. The reasons could last 1/2 hour.

Wil Taylor has shown me the best knowledge in this area. His posts on the Eng-Tips forum are comprehensive and detailed. I defer further comment to him.

Onward and Upward

 

[BBerson]

Full anneal is 775° F. But a home oven only goes to about 550° even on broil.
Solution Heat treatment at 940°F (+ or -10°) requires proper equipment.

 

[skittish]

Full anneal is 775° F. But a home oven only goes to about 550° even on broil.
Solution Heat treatment at 940°F (+ or -10°) requires proper equipment.

Thanks for your help. "As is" is not possible to use or compress. I do have a kiln and can bring them to 775 F. Will check out Wil Taylor 's posts as well. Been solid riveting for 30 years on non aircraft parts, but not using these rivets. These came from 1950 military aircraft rebuilds. All rivets are coated in purple die and have the raised center dimple. I have hopefully identified them correctly using Fletcher Aircraft Std workers Manual (9th edition).

 

[BBerson]

Raised dot is D rivets. Too hard (38k) for your 5052 sheet. AD rivets are 30k. (AC43.13)

 

[Angusnofangus]

. All rivets are coated in purple die and have the raised center dimple. I have hopefully identified them correctly using Fletcher Aircraft Std workers Manual (9th edition).

The raised dimple (tit) identifies them as 'D' rivets, which can be driven as received, but they certainly benefit from being heat-treated.

 

[Matt G.]

Instead of trying to use the wrong strength rivet for your application, "B" rivets (5056 alloy) would likely give you a lot better results.

 

[BBerson]

"B" rivets are not easy to find unless you are buying like Boeing.

 

[pictsidhe]

I found 5 current listings for ms20470b in eBay. It's a good place to find Boeing surplus. I bought some A10 oil nozzles last week, for 1/8 the current industrial price. Lord knows what the military paid for them.

 

[Yellowhammer]

I found 5 current listings for ms20470b in eBay. It's a good place to find Boeing surplus. I bought some A10 oil nozzles last week, for 1/8 the current industrial price. Lord knows what the military paid for them.

Check Government liquidation.com. I purchased some fuel tank sealant that was Boeing surplus. They have rivets all the time on there for sale. Even pull rivets.

 

[Victor Bravo]

Nobody loves to use free or bargain stuff more than I do (nobody), but please take a moment to compare the cost of a few thousand "normal" AD or B rivets to what you would have to do to safely and properly use the free "D" rivets you have.

I cannot guarantee it but you may find that ten or twenty bucks' worth of 470AD rivets from Spruce or Hanson Rivet will get your project completed faster and more easily than going to a heat treat shop and having them soften the ones you have.

 

[Have-Purple]

Full anneal is 775° F. But a home oven only goes to about 550° even on broil.
Solution Heat treatment at 940°F (+ or -10°) requires proper equipment.

I don't know anything about rivets, but if you need ~950F for annealing purposes look into salt bath annealing. There are even cheap kits you can buy that use lead melting pots to heat the salts. Its a ridiculously easy and repeatable process. My use case is brass annealing.

 

[BBerson]

Interesting, factories use salt bath. Heat treating at 940° needs accurate temperature control thermostats. Do they have that in kits? Or is it all self design?

 

[Richard Roller]

From personal experience salt bath annealing is very critical in the temperature and quench. Aluminum alloys with copper content can experience intergranular corrosion easily.

 

[BrianW]

I don't know anything about rivets, but if you need ~950F for annealing purposes look into salt bath annealing. There are even cheap kits you can buy that use lead melting pots to heat the salts. Its a ridiculously easy and repeatable process. My use case is brass annealing.

Your mention of salt bath annealing - including that simple idea of using a lead melting pot [perhaps with a thermocouple thermostat] bring back to memory an early experience of seeing hot molten sodium/potassium cyanide pots used for case hardening....

 

[skittish]

Well, for something that was going to be simple, this has turned into not so simple. The 117 military rivets I have are extremely hard (almost impossible to upset- 70 plus years of aging have hardened them well). I have 117 rivets that I have purchased recently and they are hard, but useable "as is", not so with the military rivets. Because I am using 5052 sheet in a salt water environment, the 117 rivets will have an electrolytic reaction with the 5052. 5052 rivets are not available through Hansen. 5056 are available, but they are used for magnesium alloys. What is available is soft 1100 rivets. Have not found any supplier with 6053 either. Well, maybe it is time to have my second cup of coffee before a decision can be made....

 

[BBerson]

I got some 6053 at rivetsinstock.com
Limited selection. They are almost as hard as "AD"
The 1100 are really too soft, but apparently the only choice for soft rivets. I was looking for something half between "AD" and "A".