Mission accomplished: advancement in military castings. (Casting Market Focus).

Men have fought with one another ever since the day that Cain struck down his brother Abel. Simply put, it is a fact of the human condition. As long as tyrants and madmen continue to create injustices, weaponry and other such combat equipment will remain necessary. In fact, after 11 years of decline, world military expenditures have been increasing since 1998.

Castings have been used for this purpose since 3200 B.C., when men discovered they could pour molten bronze into stone-carved molds to produce weapons. Castings have played an integral part in military and defense ever since, from arrowheads, swords and cannons to the modern-day missiles, jets and tanks.

Castings are meeting the military's needs for speed, agility and lightweight equipment, which was evident in Operation Iraqi Freedom. In addition to improving the distance and accuracy of weapon systems, castings are helping vehicles move quicker and faster to ensure the safe return of the men and women who are putting their lives on the line in the field of battle.

The Briefing

According to Garry Kosteck, systems engineer at the U.S. Army Armament Research Development & Engineering Center, Picatinny Arsenal, New Jersey, the casting industry is essential to national defense. The U.S. Dept. of Defense, he said, spends $2.3 billion annually on castings for military applications, second only to the auto industry in terms of casting purchases.

"Castings are the most cost-effective and direct way to obtain a complex metal shape--saving 50-80% compared to other manufacturing processes," said Dan Gearing, program manager for the Defense Logistics Agency's metalcasting program in Fort Belvoir, Virginia. "In some cases, casting may be the only economic method to employ some lightweight metals.

"In order to exploit the advantages of casting, there are two necessary attributes--a sophisticated design capability that understands how metal flows and solidifies in the mold, and a sophisticated procurement operation that knows how to buy castings using the best value source selection. To do both takes a conscious decision."

Driving Farces

Both the conflicts themselves and military responses have changed dramatically over the years. "Today's military deployments are radically different than the conventional approach of deploying a large unit with integral capabilities in all areas," said Gearing. "Today's specifically configured units require equipment that is lighter, more mobile in cross-country terrain or in an urban environment, and more easily transportable by air. Component parts for weapons systems or individual combatant equipment requires a greater level of sophistication in manufacturing."

Because of that need to air-drop equipment into the area of conflict, weight is of great importance today. "Strength-to-weight ratios are very important in engineering decisions," said Dick Farrara, a retired Benet Laboratory process engineer now working as a contractor. As an example, he noted the Crusader self-propelled 38-ton self-propelled artillery gun. After reducing the total weight of this system from 55 to 38 tons, it was sent back to the drawing board for another order of magnitude weight reduction. This is part of the transformation to a lighter, faster fighting force.

Enlisted Suppliers

The nature of casting supply to the military sector is quite different than in years past. Today's metalcasters cannot survive solely on military work, and the industry's pressures at large (including imports and regulation) have continued to whittle away the supply base.

While the days of big spending once allowed military-focused foundries, said Sivyer Steel's Hal Davis, military is typically just one of many other markets served today for most surviving foundries. Rigid testing is also a way of life for today's military casting supplier, he said, "Because of the utmost importance placed on equipment reliability, there are tremendous requirements in the way of inspections. Perhaps it's carried too far, but that's what they feel they need. In effect, they're 'buying' testing and documentation."

A key for today's casting supplier, Davis said, is to follow the programs. "This is not like other industry sectors where the customer is making thousands of machines per year for extended periods of time. There's a beginning and end to every program. But there are opportunities to be involved in the next generation developments that will take its place."

Using information provided by the American Metalcasting Consortium (see sidebar p. 29), following is a sampling of recent examples of how castings are being applied in key military equipment.

Advanced Amphibious Assault Vehicle 

The AAAV is used by the Marines for ship-to-shore and in-land combat to transport troops and equipment. A tracked vehicle, it moves inland once on the beach.

The steering deflector is used on the AAAV to steer the direction of the water jet (and therefore the vehicle) under 10,000 psi of thrust. Initially conceptualized as a weldment, the part was converted to a casting to reduce weight and cost, A201-T7 was chosen for mechanical properties, and the 61 lb part was cast in dry sand.

LW155 Lightweight Howitzer 

Now in low-rate initial production, the LW155 is a 155 mm lightweight towed howitzer designed to improve ground and air mobility for quick battlefield response. This 10,000-lb machine can be emplaced in 3 min and is described as "harder to find, harder to hit and harder to kill." The LW155 is a joint Marine Corps-Army program, with the Marines leading the development.

One of many casting successes was the single casting replacement of a six-piece welded towing eye bracket. Each bracket required 52.65 hr of weld time. When the Army converted to a single low-alloy steel casting, a per unit savings of $6989 was realized--a $4.2 million savings over 600 quantities. The 40-lb investment casting is welded to the system's muzzle brake.

This project resulted in the presentation of the White House's "Hammer Award" to the AMC-led engineering and design acquisition team based at New York's Watervliet Arsenal. It was awarded for "enabling the Army to decrease weapon system development leadtimes and costs while improving component quality."

Elsewhere on the howitzer, a total of 23 welded titanium fabrications on the gun's upper carriage and saddle were converted to castings. These changes reduced welding time by 50%, part count by 51%, improved manufacturing variability and allowed for targeted strengthening of structures.

"Our evaluation was all based on FEA testing and validated by live-fire testing, so we knew the high stress areas where we had sharp radii and corners anti improved them during casting to put the metal where it was needed," explained Chris Hatch, production engineer for the Marine Corps at Picatinny Arsenal, New Jersey.

As one example, the 75-piece saddle base fabrication required complex fixturing and high rework due to distortion. Plus, it required 416 man-hours to complete. All this was eliminated upon the conversion to a single titanium investment casting.

Based on that success, several more castings were implemented in the lower carriage area. Hatch said these changes have further reduced the number of welds by 80%, with a 77% reduction in weld inches, "The titanium casting conversions have resulted in major improvements to the producibility, quality and cost of the LW155," he said. "Cast titanium's use in future ground combat systems is very likely."

Crusader Self-Propelled Howitzer

With the objective of improving indirect fire support capability at a reduced weight, the Army's recent Crusader development program consisted of an automated 155 mm self-propelled howitzer and a resupply vehicle.

None of the 700 components on the original Crusader design were cast. The AMC team, however, identified 60 parts and/or combined parts for casting that provided a component cost reduction of 25%. These lower weight, lower cost parts would have provided a $40 million savings over 480 Crusader systems.

Two examples of how castings improved this system are the load arm and the gun mount cradle.

The load arm is a large, complex, highly loaded component that is an integral part of the ammunition handling system. The 1900 mm x 1000 mm x 400 mm part consisted of a 30-piece aluminum weldment, with sections ranging from 6-70 mm. Producing the weldment in production quantities, however, required numerous holding fixtures and production setups.

As the Crusader was being redesigned to reduce vehicle weights from 55 to 38 tons, the load arm structure had been weight-reduced to where material mechanical properties were critical. Due to its size, complexity and mechanical and fatigue strength requirements, it had not previously been considered for casting.

The structural, reliability and weight requirements of the load arm are demanding and, as the centerpiece of the ammunition handling system, it must operate flawlessly throughout the vehicle's lifecycle, loading tens of thousands of 45-47 kg projectiles into the gun.

With the support of AMC, however, the product design team revised the design to reduce the loads and fatigue stresses by 50%, providing a robust sand-cast design that was more cost-effective than other manufacturing methods.

A206-T4 was selected for the cast load arm based on the strength, ductility and availability of experienced vendors. Special sculpting and lightening fixtures were added to the casting to minimize machining. The price savings for using a single casting vs. the weldment was estimated at $9674 each ($4643 million in total). Potential exists for other alloys that could provide acceptable properties at an even lower cost, and a part redesign could further reduce both weight and cost.

Another example is the gun mount cradle. Previously, the cradle weldment consisted of 43 piece parts, requiring many holding fixtures and several setups. A titanium (alloy Ti 6-4) cast cradle could be manufactured using two castings (front and rear) with a formed ballistic skin. Using castings instead of wrought products is estimated to save $34,000 per unit, or $16 million.

Despite reducing the total system weight by 30%, U.S. Defense Secretary Donald Rumsfeld canceled the Crusader program in favor of his plans for even lighter, faster and more lethal precision weapons in the field, Regardless, engineers proved that castings offer significant lightweight opportunities that can still be improved upon. The design approaches realized for the Crusader System are being transitioned to the Future Combat System.

F-22 Raptor Fighter

The F-22 program is the next-generation air superiority fighter for the Air Force to counter emerging worldwide threats. It is designed to penetrate enemy airspace and achieve a first-look, first-kill capability against multiple targets.

The fuel duct component for the jet's propulsion system/fuel interface was originally fabricated from welded aluminum at a cost of $500. Due to a 25% scrap rate on the welded sections, costs escalated to $750.

A design team was formed to consolidate the fabrication into a one-piece aluminum investment casting. A356 aluminum alloy was selected based on required properties and investment casting was chosen based on required tolerances and surface finish. Based on prototype configurations of the casting, a scrap rate of just 2-5% was estimated.

Accounting for design and prototype costs, the redesign saved $160,000 over two-year production life. While such a conversion might no longer reach fruition clue to higher AMC thresholds of $250,000 and 40% savings, it demonstrates the type of savings that can be found in such equipment.

LA Class Submarine

An accumulator cylinder component (part of the submarine's hydraulic system) on the Navy's LA Class Submarine fleet was causing difficulties in manufacturing, required chrome plating and had a limited service life, in fact, causing the entire submarine to be dry-docked for repair. As a solution, these parts were transitioned to a duplex-alloy stainless steel design that was cast centrifugally. Not only did this reduce manufacturing costs and eliminate secondary plating operations, but more importantly, it extended accumulator life for greater in-duty performance of the sub.

According to Ken Urtel, Defense Logistics Agency, this new design also eliminates the time, risk and expense associated with the critical pressure hull of the submarine.

Multiple Launch Rocket System

A derivative of the Bradley vehicle, the M270 Multiple Launch Rocket System (MLRS) rapidly delivers large volumes of firepower against critical, time-sensitive targets. The warhead contains 644 M77 grenades, which reportedly obliterates everything unprotected by armor over an area as wide as 0.23 sq km. These weapons met and, in most cases, exceeded levels for readiness, reliability and maintainability.

Due to an unacceptable dud rate because of deformation of a 6061-T6 stamped aluminum fuze housing (the mechanical switch that activates the grenades launched from the MLRS rocket), a diecast fuze housing design was evaluated. Using the power of casting geometry and varying wall sections to enhance the strength of the housing, this 0.01 Ib, A380 aluminum diecasting proved to be significantly stronger than the stamping.

Reengineering the housing enables the Army to avoid electronic fuzes and housings, which cost nearly $10/unit. The mechanical fuze system allows the Army to purchase fuzes at less than $2.50/unit. The fuze housing also benefits from a stiffer, robust design that prevents the part from deformation, therefore dramatically decreasing the "dud" rates.

M1-A1 Tank

The Abrams tank (pictured on p. 25) is the backbone of the U.S. Armored Force, with about 8000 fielded M1 tanks in service. The M1-A1 is equipped with the M256 cannon, and the breech handle is an integral component for initial loading of the cannon. This handle assists the soldier in initiating and terminating firing.

The original handle design consisted of three separate components mechanically fastened together at a cost of $1180 per handle. Due to handles lost in service and those not returned with the tank upon arrival for maintenance, Watervliet Arsenal currently procures about 15 handles per month.

In order to drive out cost, the handle was evaluated for conversion to a single-piece investment casting. The investment casting configuration is net shape to the final geometric tolerances with a smooth as-cast surface finish, eliminating the need for any additional machining or finishing processes.

The prototype 4140 steel investment casting design cost $150 per handle, and will remain an accurate production price for the design. Considering an annual procurement volume of 204 handles and amortizing the hard tool at this volume, the projected annual savings is $210,000.

RELATED ARTICLE: Losing our Edge? Shrinking Manufacturing Base Raises Readiness Questions

Debates about the size of the armed forces and overall defense spending are nearly as old as the casting process itself. Beyond that, however, is a much larger concern that cannot be remedied as easily as the next budget proposal. It is the question of the U.S.' ability to manufacture what is needed to provide the armed forces with what they need to protect and defend.

Historians remember that Japan's surprise attack on Pearl Harbor in 1941 took out a sizable piece of the U.S.' existing military force. Following the declaration of war, American manufacturing's ability to quickly build up the capacity to produce military goods was a key to winning the war. What has transpired in manufacturing's relative place in the U.S. since that time, however, leaves many with concerns about domestic capacity and the reliance on other nations to produce these goods.

This issue applies across many manufacturing industries. As just one example, Farrara noted that 100% of the forged gun tubes for the howitzer must be brought in from France because no domestic suppliers exist. With only seven nations eligible to supply the military, peacetime alone affords few choices, with far fewer reliable ones in times of conflict.

Following are some additional thoughts on this issue:

"With the end of the Cold War, many foundries left the military aerospace sector forever or simply went out of business. The consolidation of this sector and the loss of work to other countries could contribute to capacity constraints in the event of massive rate increases in wartime."

--Tim Scaville, associate technical Fellow, Boeing Commercial Aircraft Group Product Development, Seattle

"Domestic control of this basic industry [metalcasting] is critical for national security in regard to military vehicles, ordnance, and ship components. There is a dynamic juxtaposition of the increasing need for improved, technically advanced weapon systems and the shrinking ability of the domestic U.S. industrial base to supply the needed castings for the manufacture of these systems. The average citizen should be aware of a potentially critical inability within the U.S. to produce needed war-fighting equipment in a timely, efficient, and cost-effective manner in order to assure an appropriate level of industrial readiness and military preparedness."

--Garry Kosteck.. systems engineer at the U.S. Army Armament Research Development & Engineering Center, Picatinny Arsenal, New Jersey

"To rely on overseas source for logistics, development and time is not a wise thing. There is a great advantage to having production capability with tooling in place, and the continued expertise and knowledge needed to manufacture of components and parts."

--Hal Davis, director of new business development, Sivyer Steel Corp., Bettendorf, Iowa

AMC Helps Military, Casting Industry

Launched in 1992 by the Defense Logistics Agency, the American Metalcasting Consortium (AMC) is working to identify cost and time benefits available to the Dept. of Defense engineered cast components. Its Procurement Readiness Optimization-Advanced Casting Technology (PRO-ACT) is focused on harnessing castings for lighter, higher performing, less costly and readily available parts for weapon systems. AMC's PRO-ACT program is sponsored by the Defense Supply Center Philadelphia, Philadelphia, and the Defense Logistics Agency, Ft. Belvoir, Virginia.

Included among AMC's partners are the AFS, SFSA, NFFS and NADCA. Working with 245 metalcasters, AMC to date has evaluated 18,000 parts, worked up 500-plus business cases and has developed supply chains impacting more than 100 components. In addition, it has trained more than 1100 military and commercial personnel in casting design and procurement. For more information, visit http://amc.aticorp.org.