RE: Welding Aluminum and Steel - Exhaust Manifold Question

[ToMoyer@xxxxxxx]

Ok, exhaust manifolds are not made from aluminum.  That is a true
statement, at least as of this time.  In the near future, that may be
another story as different alloys of aluminum are made.  It was not too
many years ago that you could not weld aluminum by any method, but alloys
were developed that are weld able by flame brazing using special flux and
fill rod, by electric-arc using special fill rod and the right type of
welding machine, mig using special wire and inert gas and by tig using
platinum electrodes.

It is not a true statement any more that you can not weld steel and
aluminum.  The Russians have developed the process and have been suing it
in their aero-space and military programs for years.  The major
international OEM for which I used to work, purchased the technology from
the Russians back in 1999 and I worked on developing the process so that it

could be combined with Hydro-Forming to make vehicular structures (frame
and sub-frames and frame parts).  It is done with special equipment and is
done with a combination of electrical and magnetic pulses.  The final weld
seam between the steel and aluminum is just as strong as that of 2 pieces
of steel welded together by any method and actual pull tests document that
the joint is stronger for the steel-aluminum.  But even for starting this
development back in early 2000, on full sized Chivy and Caddy rear side
members, which were 2 pieces butt welded together to make one, the one
piece was aluminized steel and the other just steel.  Normal butt welding
methods were used to weld them together.  In fact, the company that I
worked for has several patents on the process based on the Russian
methods.  It will not be long before you see this in some upper end
vehicles to held reduce weight and make the structure more rigid.

And to go another step, anyone with alloy wheels (which are made from
aluminum) has found that they have been "welded" to their hubs if not
removed for some time and nothing was "painted" on the wheel mounting
surface of both the wheel and hub such as NeverSeize compound.  Galvanic
corrosion is a type of welding as electrons are shared by the steel and the

aluminum making a bond, though not as strong as a weld.

Just thought I'd clear the air about welding steel and aluminum together.

Happy motoring,

tom
BMWCCA Member
former ASE Certified Tech
former Prototype and Tooling Developer for DANA/Parish Structures Division
(22 plus years)
Journeyman Tool & Die Maker
ISCET Certified Electronics Engineer
'84 318i
'85 318i
'89 325ix
'91 318is

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