With friction welding?

I know of a process where copper is bonded to aluminum to make battery plates using an explosive charge.  that's two non ferrous metals.  never heard of steel being welded to aluminum, glued or bonded through some other means maybe. 

I heard this, watching a video on the building of the huge cruise ships. The hulls are steel for strength but after the 5th floor or so, they switch to aluminum. They want to be bottom heavy because some have 15 or more floors.

 

So they said they use a process where they meld a sheet of aluminum to a sheet of steel by causing an explosion  between them. They then end up with a sheet that can be welded to steel on one side and aluminum on the other. There was a name for the explosion but I forget it. They didn't go into that part in detail but I envisioned some kind of thin dynamite sheet sandwitched between the two and ignited.

 

 

Hinterlands what's what.

 

I know, I know some will say it's called something other than welding. but I got your attention

-- Edited by MANCAVER on Friday 11th of April 2014 11:24:51 PM

Friction welding is one method.....

Q: Can I weld aluminum to steel with the GMAW or GTAW welding process?

A: While aluminum can be joined to most other metals relatively easily by adhesive bonding or mechanical fastening, special techniques are required if it is to be arc welded to other metals such as steel. Very brittle intermetallic compounds are formed when metals such as steel, copper, magnesium or titanium are directly arc welded to aluminum. To avoid these brittle compounds, some special techniques have been developed to isolate the other metal from the molten aluminum during the arc welding process. The two most common methods of facilitating arc welding of aluminum to steel are bimetallic transition inserts and coating the dissimilar material prior to welding.

Bimetallic Transition Inserts: Bimetallic transition materials are available commercially in combinations of aluminum to such other materials as steel, stainless steel and copper. These inserts are best described as sections of material that are comprised of one part aluminum with another material already bonded to the aluminum. The method used for bonding these dissimilar materials together, and thus forming the bimetallic transition, are usually rolling, explosion welding, friction welding, flash welding or hot pressure welding, and not arc welding. The arc welding of these steel aluminum transition inserts can be performed by the normal arc welding methods such as GMAW or GTAW. One side of the insert is welded steel-to-steel and the other aluminum-to-aluminum. Care should be taken to avoid overheating the inserts during welding, which may cause growth of brittle intermetallic compounds at the steel-aluminum interface of the transition insert. It is good practice to perform the aluminum-to-aluminum weld first. In this way, we can provide a larger heat sink when the steel-to-steel welding is performed and help prevent the steel aluminum interface from overheating. The bimetallic transition insert is a popular method of joining aluminum to steel and is often used for producing welded connections of excellent quality within structural applications. Such applications as attaching aluminum deckhouses to steel decks on ships, for tube sheets in heat exchangers that have aluminum tubing with steel or stainless steel tube sheets, and for producing arc welded joints between aluminum and steel pipe lines.

Just waiting for slim to give us the real deal,,