The race is on to use tricky metal in weight-bearing applications

OEMs press Alcoa to share aluminum-bonding process

The race is on to use tricky metal in weight-bearing applications

When the Alcoa 951 process is used on the surface of aluminum, it allows an adhesive — the reddish substance in the photo at left — to bond more effectively. Below, sheets of aluminum are treated with Alcoa 951 before shipment to automakers.
Related Topics

At the request of automakers, Alcoa Inc. is making its patented Alcoa 951 bonding process available to competitors who also supply aluminum to the auto industry.

Alcoa 951 coats aluminum to prevent corrosion and prepare the surface for adhesives. It will help automakers produce more structural load-bearing parts made of aluminum.

Novelis Inc., another major aluminum supplier, says it can use Alcoa 951 but has its own coating.

Automakers are counting on aluminum to help boost fuel economy to meet the government-mandated 54.5-mpg fleet average by 2025. Alcoa expects demand for aluminum parts to double in the next decade.

In January, at the North American International Auto Show in Detroit, Ford Motor Co. is expected to introduce the next-generation F-150 pickup with extensive use of aluminum in the body. Several vehicles, such as Land Rover's Range Rover, the Jaguar XKF and Audi A8, already use complete bodies -- including doors -- made of aluminum.

The 2014 Chevrolet Corvette Stingray has a lightweight aluminum frame held together by welds, bonding and special screws.

The 2014 Chevrolet Corvette has a lightweight aluminum frame held together with glue, screws and welds.

Virtually all vehicles with aluminum body parts use some type of adhesive to join the parts, often in conjunction with screws or rivets and, in some cases, welds.

Most aluminum panels on today's vehicles are hoods, trunks and parts that don't bear a load. Automakers want strong bonds so aluminum can be used in more structural parts that carry loads.

Steel car bodies are constructed with electric welds, but welds are tricky with aluminum because oxides on the surface of the metal can prevent a strong bond. General Motors says it has solved that problem with a new type of dome-shaped electrode that is used to conduct current to fuse two pieces together.

Alcoa spokesman Kevin Lowery said the company rarely shares its proprietary technology with competitors but is doing so with 951 "at the request of automakers." He declined to name the automakers that applied the pressure.

"Alcoa 951 is the enabler to move from those 'hang-on' applications to the true structural body-in-white applications," said Randall Scheps, Alcoa's director for automotive sheet business.

Automakers loathe having a single supplier for a component and usually can bargain for lower prices when multiple suppliers are competing.

Alcoa has licensed the 951 process to Chemetall, a German company that specializes in chemicals that treat metals and plastics. Chemetall will produce and sell the Alcoa 951 to aluminum suppliers and pay Alcoa a fee.

Neil Hirsch, a spokesman for Novelis, says his company can supply aluminum with Alcoa 951 as well as other pretreatments. Novelis, he said, offers its own pretreatment coating and is working on an advanced version.

When the Alcoa 951 process is used on the surface of aluminum, it allows an adhesive — the reddish substance in the photo at left — to bond more effectively. Below, sheets of aluminum are treated with Alcoa 951 before shipment to automakers.

Bonding with oxides


Alcoa 951 is applied by either spraying it on aluminum or dipping the metal in the substance. Alcoa says the 951 bonds at the molecular level with the oxides on the surface of aluminum. Scheps says 951 is not affected by stamping or welding.

"We take the coil of aluminum after we fabricate it then we run it through a series of tanks that apply the coating as well as wash, and then recoil the material. Then we ship to car company's stamping plant," said Scheps.

Alcoa already has aluminum treated with 951 on the road in one vehicle, and more on the way, said Lowery, the Alcoa spokesman. Alcoa wouldn't identify the vehicle that's on the road.

GM's top materials expert, Susan Smyth, said GM has evaluated Alcoa 951, but she would not say whether there are plans to use it.

"We are looking at a lot of different variants. That's one specific company with one specific solution," said Smyth, GM's chief scientist for global manufacturing. "Looking at the pretreated material, it definitely has some major advantages. And it could be a real enabler for automotive use. A number of companies are looking at similar end goals with slightly different chemistries."

Ford mum on F-150


While GM has increased aluminum content on some vehicles, the company is not abandoning steel, Smyth said. "What we are seeing is the shift to more and more aluminum-intensive vehicles. I really hesitate to use the terms 'absolutely' and 'all'. I really think it is going to be mixed material solutions."

Ford isn't saying whether Alcoa 951 will be used in the next F-150. Said Ford spokeswoman Kristina Adamski: "It's not Ford policy to discuss who our suppliers are, and it's premature to discuss future products."

You can reach Richard Truett at rtruett@crain.com.


advertising
Have an opinion about this story? Click here to submit a Letter to the Editor, and we may publish it in print.

Or submit an online comment below. (Terms and Conditions)




Rocket Fuel