Tuesday, February 10, 2015

A Welding Breakthrough?

Wall Street Journal:
Austrian welder Alois Leitner fuses strips of steel and aluminum alloys in what could be part of a historic breakthrough.
“They taught us in engineering school this was impossible,” said Mr. Leitner, who works for Linz-based Voestalpine AG , Europe’s third-biggest steelmaker.
Mr. Leitner’s work in a small lab on the outskirts of this industrial town near the Czech border seems simple enough—but these two basic 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.
Voestalpine’s process is neither easy nor cheap. The company uses a 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.
“You need to hit all the parameters in the right way to achieve the right properties,” said Voestalpine spokesman Peter Felsbach. The 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....
For decades, steel and aluminum makers have competed for car parts—from hoods to engine blocks—touting their metal as stronger, cheaper and lighter, and the other as inferior. Being able to readily combine the two would increase auto makers’ portfolio of parts, adding a palette that benefits from steel’s strength and aluminum’s lightness.
Luxury-car maker Audi AG first contacted Voestalpine to help it join “materials like steel and aluminum or fiber-reinforced plastics,” according to the auto maker. “Welding aluminum and steel is a very promising technology development,” it said.
“We had always said it can’t be done,” said Dick Evans, chairman of Constellium NV, a major producer of aluminum sheet for the auto industry that doesn’t currently have a hybrid product on the market....
On a recent day, Mr. Leitner, whose services also are used by a welding company called Fronius International GmbH, a partner in the development, applies a special solder to two car parts—one zinc-coated steel and one aluminum—and fires up his torch. Slowly running down 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 once piece. “We could use this for exposed, outside parts of the car,” said Voestalpine’s Mr. Eder. “You could exchange today’s laser-welded steel parts with steel-aluminum parts.”
Interesting.  The place I work is all about welding, but I'm not sure how much use this technology would be to us.  Usually, our weldments are all steel, aluminum, stainless or fiberglass, depending on what atmosphere they will operate in.  I'm not sure how much benefit we would see from being able to weld hybrid parts. 

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