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Up Topic Welding Industry / General Welding Discussion / fusing mild steel to aluminum
- - By stickwelder (*) Date 09-02-2009 19:44
I have an application where i need to weld aluminum to mild steel.
I was unable to locate info on lincoln or millers website.
Anyone have experience with this? Process, consumable, polarity etc.?
Parent - By rlitman (***) Date 09-02-2009 19:57
You mean, like JB-Weld?
Parent - - By OBEWAN (***) Date 09-02-2009 20:01
Tread lightly on this one.  Also, walk softly and carry a big stick.  It is like mixing oil and water.

Your only hope would be friction welding, explosion welding and/or MAYBE MAYBE brazing.

We have a part that is an aluminum to stainless joint that was friction welded. Good yields ran 85% and yields on bad lots were in the 15%-25% range.  The welds are extremely brittle and a slight thermal stress will fracture them like dropped glass.  We had better results with explosion welding (about 85%) but the welds were still brittle.  My research turned up some brazing with a secondary titanium interlayer, but even that warned of brittle joints and bad intermetallic compounds.

My fear is that regular carbon steel would behave the same way as our stainless did.
Parent - By DaveBoyer (*****) Date 09-03-2009 02:24
   A friend of Mine who participates on a blacksmithing website was trying to explosion FORM aluminum into a stainless die. He used to much charge and welded the aluminum to the die. :-( He had to machine it off to try again.

   When someone asked about welding aluminum to steel on the blacksmithing site I posted that it was so easy that Rich Waugh did it by accident. :-)
Parent - - By BryonLewis (****) Date 09-02-2009 20:09
Get some bolts!!!  :-)
Parent - - By stickwelder (*) Date 09-02-2009 20:23
Thanks for the info.
I think you are right. Bolting is not what we want, but it is what we will have to do.
It sounds as though any fusion process, is likely to be failure prone.

Parent - By jffluxcore (**) Date 09-02-2009 21:36
i think the govenment can do it by exploding in to assemble it.
Parent - - By F-17 (**) Date 09-02-2009 23:43
Ummm if you want a seamless type construction with no boltheads or nuts sticking out.Drill holes for flush rivets(the same kind used in airplanes,called "Buck" rivets,counter sink both sides and  air hammer the rivets flat.One side of the flush rivet has a chamfered head that will end flush in the hole,If the rivet is countersunk properly on the backside and is the right length it will fill up that hole as well.And I guarantee it won't come apart if the right alloy rivet is used.Some are hard and some are soft depending on the alloy.Proper length for the rivets should be the thickness of the material + the size of the hole.Wear earplugs......It's LOUD.
Parent - By pypLynr (***) Date 09-03-2009 01:01
Pardner , I don't think you can 'fuse' aluminum alloy to  carbon steel . I do alot of aluminum and alot of carbon ... and those don't mix , buddy .  I read above and I totatlly agree with the popular vote ... bolts or carriage bolts.
Parent - By DaveBoyer (*****) Date 09-03-2009 02:17
In ship building, they use a strip that has been explosive welded giving steel to weld to steel on 1 side and aluminum to weld to aluminum on the other.
Parent - By bozaktwo1 (***) Date 09-03-2009 02:05
Explosion welding.  Saw it on History channel last year.  Take a sheet of steel, a sheet of aluminum and a bucket of ammonium nitrate.  Boom.  Welded.

"MODERN MARVELS® goes from skyscrapers in Las Vegas to oil platforms beneath the sea to see different welders in action. Learn about the first welds, and how they have evolved to include robotic welding and explosion welds. See how the process is still a combination of science and artistry, and what the future holds for the welding industry."
Parent - - By Stephan (***) Date 09-03-2009 07:08

the others may know I am not going to advertise within the forum, but as I read your topic I felt committed to give another hint:

It is definitely possible meanwhile to join steel to aluminium using e.g. controlled GMAW or Laser but some special precautions have to be considered.

Parent - - By DaveBoyer (*****) Date 09-04-2009 03:28
Does the zink coating on the steel mentioned in the link play any part in the process, or does it work the same with bare steel?
Parent - - By Stephan (***) Date 09-04-2009 11:27 Edited 09-04-2009 11:39

You will get 'full marks'! :-)

You have recognised it absolutely correct!

Yes, the zinc coating plays a crucial part at all. The main problem with joining steel to aluminium and its alloys is the most restricted solubility of iron into aluminium.

As a well-known this leads to those brittle constituents referred to as 'intermetallic phases'. The more energy transferred to the material while joining, the higher the fraction of those compounds. In other words one has to reduce the 'heat input' as much as even possible. 'Conventional' GMAW processes are rather non suitable thus for joining both materials due to the intermetallics' growth arises as a function of the thermal energy input. There was plenty of investigations on this in Germany and - in particular - in Austria either. Here also 'conventional' GMAW-P welding in combination with a low melting 4000 Al-Alloy was used. The results weren't that bad but rather non reproducible, with respect to a calculable amount of intermetallics. Using a special controlled process, makes it possible to reduce the 'heat input' drastically the growth may be reduced.

However, even though the exact metallurgical causes aren't fully understood yet, the zinc is assumed to being a kind of additional 'inhibitor' against the intermetallic phase growth. Also it improves the filler metal's wetting behaviour. That's exactly the reason for using zinc coated sheet metals when it comes to joining steel to aluminium.

Like I mentioned already. Also the Laser is an excellent tool for joining steel to aluminium, due to its excellent thermal input controllability. It has to be considered however, that the Laser does not activate the metal's surface as being done by an arc. Therefore one has to use particluar fluxes to enable both wetting and joining. There have some awesome papers and PhD Theses been written. In Germany especially the BIAS (Bremer Institut für Angewandte Strahltechnik) in Bremen, see also:


is specialised in the investigations of steel-aluminium hybrid structures. They have a most outstanding expert team with the BIAS.

In Austria, the company FRONIUS International has accomplished groundbreaking investigations whereas in regard to developing a controlled process referred to as 'Cold Metal Transfer' or abbreviated 'CMT' to be used for highly reproducible results (+ calculable amounts of intermetallic phases) in steel to aluminium joints. You know, there was one single man with the company who has researched for years on this topic and he has never lost the belief in that it will work someday. And it does, that's a fact. This process is by now - at least to the best of my knowledge - the only one which is suitable for joining steel to aluminium under serial production conditions. Always considering however the precautions to be considered.

Anyway, to shortly reply  the second part of your question. Bare sheet steels or plates to aluminium joints are undergoing a dramatic growth of intermetallic phases what's the reason for the brittleness of the joint. You may almost rupture the joint by bending it over your knees.

Thanks Dave!


EDIT: Have deleted a dispensable word ;-)
Parent - - By DaveBoyer (*****) Date 09-05-2009 03:26
Stephan, that is a lot of interesting information. Thanks.
Parent - By Stephan (***) Date 09-05-2009 08:44
I thank YOU for asking, Dave!
Up Topic Welding Industry / General Welding Discussion / fusing mild steel to aluminum

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