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Old 01-28-2015, 02:58 PM
elavir elavir is offline
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Default 1050A h14 weldable with?

For a while I've been practising gas welding aluminum and the last days it's going in the right direction. So my next step is making a gas tank. The sheet I want to use is 1050A h14 but besides that I need some tubing(fillercap vent) and some rod(to weld on the bottom of the tank, with thread inside the rod to fasten the tank) I'm not sure if this is available in 1050A and if not what kind of alu is the best to use. It is my intention to gasweld the whole tank.
Has any of you guys some ideas?

Cheers Richard.
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Old 01-28-2015, 03:13 PM
TRAMP TRAMP is offline
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For filler rod I would just use strips cut from the sheet.
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Old 01-28-2015, 03:27 PM
elavir elavir is offline
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Hi Lee,

I use strips cut from the sheet as filler rod, but what I meant with the rod is an attachment to fasten the tank( to the cilinderhead in this case, it's for an old outboard, Seagull)
My idea is to weld a threaded rod eg.12mm inside the tank.
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Old 01-28-2015, 05:42 PM
crystallographic crystallographic is offline
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Hi Richard,
While it is common to use strips of the parent metal to weld with, and that will be fine with your tank seams all being the 1045 alloy, the neck, fittings and possibly the threaded rod could likely be a stronger machinable alloy. I would be looking for a 6000 series alloy for those products, and the 6000 can be fairly easily brazed to the 1045 with good strength, and less distortion than welding would involve.

Here in the US we have 6153, 6063, and 6061 as available 6000 series, with the 6061 very available in rod, bar and sheet products, including machined fittings. Many aircraft and auto racing tanks use 6061 machined aluminum bungs that are readily available from common sources.
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Old 01-28-2015, 07:23 PM
AllyBill AllyBill is offline
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Hi Richard,

1000 series aluminium is essentially pure and very soft. Easy to work with as you can push it around with your fingers and it has great corrosion resistance if you're making a gas tank for an outboard but not so good if you want to put threads in it so either get some 6000 (2000 is even better but not so good corrosion resistance) for your threaded parts or, even better, use helicoils for your threads. Don't worry about welding one grade to another as they will all stick together perfectly satisfactorily just be aware which are the softer or harder grades when planning what you want them to do.

Will
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Old 01-29-2015, 02:42 AM
elavir elavir is offline
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Hi Kent,

I have no experience with brazing aluminum( I am really a newby here) so if I want to braze 1000 series to 6000 which brand is good(and for sale in Holland) and further is it strong enough to withstand heavy vibrations?

Hi Will,

Is the 2000 series gasweldable with the 1000 series?
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Old 01-29-2015, 02:54 AM
elavir elavir is offline
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Kent,

What I forgot to mention is that I want to polish the tank, so is the "colour"match of the brazing and the parent material almost the same?
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Old 01-29-2015, 04:16 AM
AllyBill AllyBill is offline
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Hi Richard,

No reason why you can't weld 2000 to 1000, I do it all the time, but I'd avoid 2000 in a seawater environment as it's a copper alloy and doesn't have good corrosion resistance. I'd avoid brazing too if there's a lot of vibration going on due to lower joint strength, unless you can design joins with a lot of area but it involves pretty close tolerances and extreme surface preparation if you're going to do it right.

Will
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Old 01-29-2015, 09:39 AM
Marc Bourget Marc Bourget is offline
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Will,

My mentor, a legendary Aeronautical Engineer, recommended against welding 2XXX series because of the copper alloy, which will precipitate out at those temperature and, IIRC, lead to intergranular corrosion. Bad thing one would wonder for a fuel tank mounted on an engine, like an outboard engine.

But that was long ago and new technology arrives every day. What practices do you employ to successfully weld 2XXX series aluminum?

Thanks in advance.

mjb
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Old 01-29-2015, 08:06 PM
AllyBill AllyBill is offline
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Quote:
Originally Posted by Marc Bourget View Post
Will,

My mentor, a legendary Aeronautical Engineer, recommended against welding 2XXX series because of the copper alloy, which will precipitate out at those temperature and, IIRC, lead to intergranular corrosion. Bad thing one would wonder for a fuel tank mounted on an engine, like an outboard engine.

But that was long ago and new technology arrives every day. What practices do you employ to successfully weld 2XXX series aluminum?

Thanks in advance.

mjb
Marc, how long do you have?

Some basic metallurgy for those unfamiliar with what we're talking about. 2000 ally is a aluminium/copper (Al/Cu) alloy where the Cu is in solution in the Al same as sugar is in solution in your coffee. This makes it heat-treatable, i.e. its mechanical properties can be determined by various thermal processes.
Put simply, to make it soft, the material is heated to a temperature where the Cu goes into solution then cooled slowly to make sure the Cu stays in solution.
To make it hard, it's heated to solution temperature then cooled rapidly by quenching to make a saturated solution that causes the Cu to precipitate out and form a crystalline structure that resists deformation. Different levels of precipitation mean different properties with a trade off between strength and crack resistance. The properties are expressed as a 'temper' so typically you'll see 2XXX-TX with T typically having a value between 0 and 9 with 0 being the softest.

So, let us consider what happens when it's welded. If you weld the metal from cold what happens is that you heat the weld pool but it's almost instantly quenched by the surrounding, cold material so a proportion of the material is heated above the solution temp then rapidly cooled causing Cu to precipitate at the weld boundaries. But if you carry on welding the heat-soak means that an increasing amount of material is taken over the solution temp then left to cool slowly producing the exact opposite effect in that it puts the Cu that was deliberately precipitated to give the metal its desired temper back into solution making it softer (annealing).
This material loves to corrode. For aircraft applications it is often clad with a thin layer of pure Al to prevent it from corroding, known by the proprietary name of Alclad
Suspend an aircraft for display and it will develop stress corrosion where some material is stretched and other is in compression. Scratch it and it will develop differential aeration corrosion. In fact, look at it for too long and it will corrode for fun so it's hardly surprising that your aeronautical engineer didn't like the idea of welding it - he was absolutely right, but it's a long-term concern and not something that will affect you overnight and we've not even mentioned the residual stresses left in the material by welding.

2024A-T3.jpg

A couple scraps of 2024A-T3 welded with 2000 filler.

You asked about welding it and it welds like any other aluminium alloy but here is why people think it's a difficult material to work with. As it's a high-duty alloy used for aircraft skins and forgings and is about as far as you can go when seeking strength with minimum weight you are unlikely to come across it in its T-0 condition and that puts you up against another of its properties, its elongation value, or,put another way, how far it will stretch before snapping. In its tempered states that is not a big value so if you introduce a weld with opposing forces as the welds contract it will literally pull itself apart.
If all you want to do is weld two pieces together it's no problem but if you want to insert a patch into the middle of a panel it will often just crack behind the weld pool as you go around in circles. Eventually it will anneal as you go and some sort of cure can be effected but it's not the way to go.

Why weld this material in the first place? Old aircraft, is the answer, and this brings with it another problem. Age hardening. Over time the Cu precipitates out naturally forming an increasingly hard and brittle material until it snaps if you try to bend it and that really will not weld.

So, without going on forever, and to answer the original question about welding processes for 2000 ally, there are several simple options.

You can dilute down using soft rods with a high Si content and use a large weld pool so that the elongation is taken up by the weld and not the native metal. This will work in most cases but not with severely age hardened material or harder tempers because the piece will break at the weld boundaries.

You can locally anneal the edges then use soft rods and use pre/post heat to avoid cracking but these are both workaround answers.

What you really need is to have the material annealed and furnace cooled. I always ask for my jobs to go into the furnace last thing on a Friday so that they get the staged cool and then an extra cool over the weekend after the furnace is shut down. The heat treatment plant will reduce even the most age hardened material back to its T-0 condition and make it as soft as pure aluminium and just as easy to work and weld. You can then leave it that way if you want.

If you really want to do the job right then all the material should be annealed and furnace cooled to T-0 and beyond, welded with 2000 filler then stress relieved and heat treated back to the desired temper.

Actually arcing-up and welding 2000 ally is the least of the problems.

Will
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Last edited by AllyBill; 01-29-2015 at 09:07 PM.
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