Hard Aluminums
Hard Aluminums
(OP)
I was curious to find a Hard, Weldable, Machinable Aluminum. I am looking at AL-6019 and AL-6020. I can not find much information on either. Does anyone know anything about these or good sites with information them relative to each other? Also any other suggestions on possible other Aluminums to use. Thanks





RE: Hard Aluminums
Weldability is limited to resistance welding in solution and precipitation hardened alloys. 6xxx series can be heat treated after fusion welding. For hardened surfaces consider Hard Anodizing.
http://www.welding-advisers.com/
RE: Hard Aluminums
RE: Hard Aluminums
RE: Hard Aluminums
RE: Hard Aluminums
RE: Hard Aluminums
RE: Hard Aluminums
RE: Hard Aluminums
RE: Hard Aluminums
RE: Hard Aluminums
RE: Hard Aluminums
check this out...
Tony
RE: Hard Aluminums
and this...
Tony
RE: Hard Aluminums
6061-T6 is one of the hardest aluminium alloys. my metals reference gives 500kg-10mm brinell hardness at 95.
There are a few other 6xxx series alloys with higher hardnesses given: 6066 6070 6262. All of these in the T9 temper will have a hardness of ~120 HB500... The problem is that this hardness is developed by cold work after the aging treatment. By welding you would remove the increased strength and hardness imparted by cold working and aging.
Helicoils are often used to strengthen threads in soft materials. Drill and tap to the helicoil 1 size larger than your thread, then insert the helicoil (I like to use red locktite to assure the helicoil attaches to the base matl') then you will have a harder thread.
You have also been given many suggestions for other ways that your problem might be solved. There isn't much else we can do for you.
Summary: 6xxx alloys are not going to solve your problem.
RE: Hard Aluminums
RE: Hard Aluminums
http://www
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Hard Aluminums
Pipe threads, especially small sizes, are especially prone to pullout. In our case was a worst case as we heated the part to about 280-290?F and thermal expansion, softer material, and repeated assembly all contributed to loss of integrity.
We worked on the problem from several different angles.
First we used a brass reducing bushing that was special made with male straight threads and female NPT to get a better area ratio with the AL. Redesign of the component part reduced our ability to use this bushing, size. After several iterations we end up with a brass insert for metals with internal straight pipe threads with a valve. We used valve with straight pipe threads on AL side and tubing fitting on the other side. We used several different pipe dopes, the best white lead they took away. They are using Teflon paste now.
I think the best approach is the insert route if you have the material thickness and to get away from the NPT threaded valve end if possible.
RE: Hard Aluminums
RE: Hard Aluminums
The obvious answer to your problem has been stated twice before. Helicoils. Yes this is used commonly as a repair procedure but it is also used commonly by OEM's by original design. It is a common solution in the aircraft industry where LOTS of aluminum is used but where a screw or bolt needs to be routinely removed and replaced in the threaded hole.
Give us one good reason why not to use a helicoil. BTW I am fairly certain that Helicoil is a trade name but I do not know the generic term. Yesterday I was in a Fastenal store and they have threaded inserts by another name.
RE: Hard Aluminums
Unclesyd's suggestion of a brass adapter is a good one - I would add the following to his suggestion: make the i.d. thread fit your NPT valve, the o.d. thread should be chosen from whatever size SAE J1926 O-ring boss seal thread that will fit, with preference given to larger sizes (larger thread diameter and more surface area will give lower stresses). Pipe dope on straight threads may seal for awhile, but with any amount of flex or thermal cycling, the joint may/will develop a leak.
OSU, do you not have access to a large enough oven to re-HT your alum. part?