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News | April 20, 2016

New Technology, Ancient Industry

By Chris Erbe

Research and development programs are normally considered incubators for the newest cutting-edge technology. But the Defense Logistics Agency manages two R&D programs devoted to advances in manufacturing technologies that are truly ancient.

Metal forging and casting have been around thousands of years. The world’s oldest known casting dates from 3200 B.C., and forging may be even older. The Romans worshipped Vulcan — the Greeks, Hephaestus — both gods of fire and the forge and mythical inventors of smithing and metalworking. Through the ages, man has used casting and forging to advance the human condition and to produce weapons of war.

Today’s warfighters still depend on metal for almost everything — from enormous ships to the smallest engine parts. To help meet this need, DLA’s casting and forging R&D programs invest where industry can’t or won’t invest in new technology to help industry create the parts that the military requires. The programs are part of the DoD’s Manufacturing Technology Program, or ManTech, designed to improve the quality, productivity, technology and business practices of industries providing goods and services to the DoD.

Consider DLA’s challenges. Many items the military requires are so specialized, they are not suitable for mass production and thus are not attractive for industry to manufacture. Also, DLA needs domestic manufacturers to produce military parts in an era when much of the industry is overseas. Added to that, the military often needs a small number of very critical parts for legacy aircraft and ships — parts that manufacturers have long since stopped producing.

“If we don’t have people to make the parts we need, we’re in trouble,” said Dean Hutchins, manager of DLA R&D’s casting and forging programs. “It’s a competitive industry with a lot of pressure from overseas. We have a mandate to make certain things in the United States, but it’s difficult to get domestic manufacturers to start projects because of the heavy capital investment needed.”

DLA’s forging and casting R&D programs work with industry to help them produce the parts that the military needs. Part of the program’s purpose is to help industry fund startup projects. The programs also acts as a bridge, bringing together established manufacturers with military and university R&D programs to develop new technologies and processes that will help improve the production of military parts.

“We’re looking to improve the process to make it less costly and more efficient,” Hutchins said. “To work new ideas, we create consortiums that bring together industry associations and research universities like the University of Iowa, Case Western Reserve and the Colorado School of Mines. Foundries and forge shops help us experiment with whatever is being developed.”

Casting and forging are equally vital to the military because of the advantages that are inherent to each process.

Forging involves heating metal so that it is malleable, then pounding it with high pressure into the required shape sometimes using a metal form, called a die, to shape the metal. Think of the iconic blacksmith using a hammer to pound hot metal against an anvil. The advantages of forging are strength and durability.

“If you have a piece of metal the size of a loaf of bread and want to make it stronger, you would use forging techniques to compress it down to the size of a metal tube,” Hutchins said. “You’re closing gaps between molecules, creating grain flow and giving that metal a lot of strength and durability.”

To say the military needs high-strength metal parts would be an understatement. Bulkheads, hinges, engine mounts, brackets, beams, shafts, landing gear, wheels, brake discs and arresting hooks are examples of forged items on which the military depends. A heavy tank contains more than 550 separate forgings while an armored personnel carrier employs more than 250.

Casting, which pours molten metal into a pre-shaped mold, is a good way to make complex parts. Motor parts are cast because of the curved internal passages.

“One casting method, die casting, starts with a metal mold from which we make a wax pattern,” Hutchins said. “The wax pattern is dipped into a ceramic slurry, so the ceramic can surround that wax. The reason we do this is because ceramic can hold and withstand the heat of molten metal. The wax is then melted out of the mold. When metal is poured in, wherever the wax was, the metal will takes its place and create a part.”

A short list of examples of military parts created from casting include cross bleed valves for the F-5 Jet Fighter; the transmission case for the Advanced Amphibious Assault Vehicle; ice cleats on the M1 Abrams tank; and hydraulic accumulator cylinders for Navy submarines.

Manufacturers choose casting as the most appropriate forming method for certain parts because no other method can meet the complexity, shape and tolerance requirements as efficiently and cost-effectively as casting. Creating the molds, called tooling, is the most expensive part of the casting process.

“Once you make the tooling, which could cost very little or as much as $1 million for a large item, you can pump the parts out quickly,” Hutchins said. “Casting is most cost-effective when you make parts in large quantities.”

With many weapon systems being extended and used decades beyond their initial expected life, the Department of Defense faces a big challenge in finding new cast or forged parts to keep this older equipment in use. It’s possible that the military can go for decades before needing to order certain parts, by which time the manufacturers have stopped producing them and possibly even gone out of business

“When procuring a part for a legacy aircraft when we haven’t bought one in 10 or 20 years, now we have to go back and either recreate the tooling or try to find it,” Hutchins said. “When that happens, we have a challenge on our hands filling that order. We have consistently found that cast and forged items make up a disproportionate share of the oldest back orders.”

A 2013 study showed that 13 percent of  backorders and 20 percent of the oldest backorders are items that contain a  casting or a forging.

To help meet the challenge, one of the casting program’s early projects was to create the Metalcasting Procurement Solutions Network, an online database of manufacturers that have the materials, tools and processes to make needed parts for DLA. The result was an increased number of bids from capable suppliers and a reduction in lead time and cost to the DoD.

In a current project, casting program participants are working to reduce or eliminate the need for lubricants during production of aluminum die-cast parts, which could result in reduced cost and environmental impact for the die casting industry.

Normally, die casters use a liquid lubricant to coat the die so that the metal part will slip out easily. The lubricant is messy and can be hazardous  to the manufacturing environment. The project involves developing a coating for the die surface  that will allow metal to separate from the die without sticking — much like Teflon is used in a frying pan to keep food from sticking.

“We’ve just completed successful trials in January,” Hutchins said. “The Colorado School of Mines is doing the research, and Mercury Marine, a manufacturer of marine propulsion systems with their own aluminum-die-casting foundry based in Wisconsin, is testing the technology.”

The forging program is also seeking to improve its process through experiments like intensive quenching. Once hot metal is formed into the required shape, it is then “quenched,” or cooled quickly, which freezes the properties in its current state. Depending on how a part is cooled can influence the properties that the part exhibits, Hutchins said.

“It’s like the blacksmith heating up a sword red hot, beating it with a hammer and then putting it in cold water,” he said. “That’s quenching. It’s used to obtain specific  mechanical properties. For some things you want the part to be ductile — to bend a little bit without breaking. Other things you want to be very strong and inflexible. Quenching at the right time can keep the properties of the metal in a desired state.”

DLA’s forging and casting R&D programs have several other projects under way.

Currently, casting R&D program participants are working on a project to make improvements in casting modeling software that will identify and predict potential problems areas in mold designs; developing and testing high-fluidity aluminum and magnesium alloys that can be used in die-cast molds; and developing improved heat treatment procedures of cast high-strength steel that improve the mechanical properties of the welded areas (a project that received the 2015 Defense ManTech Achievement Award); and more.

Forging R&D program projects include cutting down forging processes by using parts that are cast nearly to the final shape, then finished through forging; using simulation software to identify the optimum design and forging process for the manufacture of a part; developing new welding technology for repairing and upgrading forging dies; and others.

Will new technology like additive manufacturing ever take the place of casting or forging? According to Hutchins, 3D printing has a lot of work to be done before it can replace these ancient metalworking processes. For now, each method occupies a unique niche that makes it the manufacturing choice for certain parts.

In the meantime, DLA’s Forging and Casting R&D Program continues to develop new ways to cut costs, increase efficiency, improve manufacturing processes and promote innovations so that our nation’s warfighters will have the parts they need to complete their most critical mission.