The Holy Grail of Welding: Steel + Aluminum

This process sounds more like brazing than welding, at least as seen by the steel.
Joe Gwinn
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..<http://www.wsj.com/articles/the-holy-grail-of-welding-steel-aluminum- 1423528185>
John W. Miller Feb. 9, 2015 7:29 p.m. ET (Wall Street Journal)
aluminum alloys in what could be part of a historic breakthrough.
third-biggest steelmaker.
metals are famously incompatible. Solving the riddle of how to combine them has long been considered a Holy Grail for big metals and auto companies.
special solder and torches just hot enough to melt aluminum but not steel. The process, called cold metal transfer, employs an argon gas to avoid oxidation. Finally, the steel is coated with zinc to bind the steel, solder and aluminum.
company said its technique is two to three times as expensive as the riveting and gluing techniques now used. It hopes to shave costs by a third to make the process suitable for high-end autos. Welder Alois Leitner shows a weld between steel and aluminum pieces that used a cold metal transfer technique that has piqued the interest of auto makers now shifting to lighter weight materials for improved fuel economy. ENLARGE Welder Alois Leitner shows a weld between steel and aluminum pieces that used a cold metal transfer technique that has piqued the interest of auto makers now shifting to lighter weight materials for improved fuel economy. Photo: John W. Miller/The Wall Street Journal
To make it commercially feasible, the company said it would need more customers, which would help pay for the tinkering necessary to refine the process and make it less expensive. Advertisement
The payoff is potentially huge.
lighter, and the other as inferior. Being able to readily combine the
Luxury-car maker Audi AG first contacted Voestalpine to help it join
Constellium NV, a major producer of aluminum sheet for the auto
The interest is rising as mass-market auto makers, led by Ford Motor Co. with its 2015 F-150 pickup truck, embrace lighter but more expensive aluminum to meet new fuel standards. Honda Motor Co. uses another technique to fuse steel and aluminum, but its application so far has been limited. A handful of other top metal and auto firms have explored how to make hybrid parts.
Steelmakers are fighting back by developing lighter, harder steels that can lessen the weight difference with aluminum. They even can weld together steel pieces of different weight and thickness, to piece together a part that is only as thick as it needs to be throughout its surface.
Under Chief Executive Wolfgang Eder, Voestalpine has developed an
The quest to weld the two metals is important enough for the U.S. government to be involved in research. Its scientists say success could make cars lighter and streamline car making. Zhili Feng, who researches
Ridge, Tenn., said a compact car can have as many as 6,000 spot welds.
part, the welds have to be made with high quality and
the best technology to weld aluminum to steel. Right now, it is a wide
Todd Summe, director of automotive technology for Novelis Inc., the largest global producer of automotive sheet aluminum.
Novelis said its researchers are testing new technologies for mixed-material solutions, such as aluminum-steel hybrids. The company has no commercial products specifically designed for hybrid aluminum-steel structures, but Mr. Summe said its products have been successfully paired with steel using adhesives and mechanical fasteners for quite some time.
On a recent day, Mr. Leitner, whose services also are used by a welding company called Fronius International GmbH, a partner in the
joint, the 1,000 degree Fahrenheit flames melted the two pieces together.
What resulted was a part so cohesive it can be stamped as if it were
Audi and other customers say they are interested if costs can be brought down, according to Voestalpine. It is working on doing that by, for example, trying to make the welding process faster and tinkering with the alloy of the film between the two metals.
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On 16-Feb-15 6:51 AM, Joe Gwinn wrote:


Seems to be behind a pay wall.
Sounds interesting.
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wrote:


Try this:
http://www.digitalweldingsolutions.com/CMT.pdf
Fronius has been doing it for a while. It's welding on the aluminum side, and brazing on the steel side.
To get at a WSJ article, or an Economist article (both behind pay walls) copy the exact title and paste it into Google. Then click on the hit that links to the publication.
For the WSJ article, try:
The Holy Grail of Welding: Steel + Aluminum
It usually works.
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The ignorance of the news media is astounding.
Steel welded to aluminum was achieved on a commercially successful basis years (probably decades) ago by the high energy materials folks - ie, explosive welding. As far as I recall they simply made long strips of interface welded explosively, and those were welded by normal means to put aluminum superstructures on top of steel hulls.
Here's one, there are others: http://triplate.com
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On Sun, 15 Feb 2015 21:55:46 -0500, Ecnerwal

Yeah, but this is different. Fronius has been doing it. It really could be important in car manufacturing.
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All-Clad pots, pans and skillets are also layers of bonded steel and aluminum. Somewhere there was a video of how the fuse everything into a sheet. It's fascinating that this material can then be made into deep pots.
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On Mon, 16 Feb 2015 17:49:57 +0000 (UTC), Cydrome Leader

Bonding aluminum and steel (including stainless) has been around since the '60s. In the late '70s, roll bonding became a high-volume process used to make automobile trim, including bumpers.
They get a strong bond that way, but it's not like these weld/braze methods that are being used to make hybrid parts. This is fairly new.
The language used to describe it is all over the map, which is not made clearer by the people trying to market it, nor by the general-press writers trying to write about it.
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