U. S. Army Cooperative Development of Armor
Cast steel armorplate
Since 1985, NETL has cooperated with U. S. Army Tank and Automotive Command (TACOM) through an Interagency Agreement to develop cast steel and titanium armor. Office scientists currently are working with the Army Research Laboratory (ARL) to develop titanium armor applications. Initially, the program focused upon the production of cast steel armor prototypes using the lost foam, loose sand casting process developed by NETL. Evaporative pattern casting is a process that uses polystyrene patterns in unbonded sand molds where the polystyrene vaporizes as molten metal is poured into the patterns and is replaced by metal. The process allows the design of more complex shapes with better surface finish than conventional casting practices. NETL's Albany , OR site was recognized by the industry as the world leader in the development of this process using steel alloys. The largest steel casting in existence using this technology was produced at the Albany site in 1989. These prototype castings consisted of very complex shapes, both in size and shape, but also because they utilized the Army's P-900 pattern consisting of hundreds of rows of angled slots. The angled slots in the armor are designed to fracture incoming projectiles into numerous pieces, none of which has enough energy to penetrate the vehicle. The cast armor plates were 10 pct lighter than the rolled, forged, and machined production bustle. In addition, the ballistic results indicated that the cast armor was superior.
The cast steel armor program culminated in the production of three different prototype armors: the first being a three piece bustle to protect the rear of the turret and the commander's hatch on the Army's Bradley Fighting Vehicle, shown above. The armor was an upgrade that provided additional protection for new ballistic threats. The second set of prototype steel armor was developed to counter a threat to the M-113 armored personnel carrier and consisted of a set of 14 pieces of flat P-900 armor to completely cover the sides of the M-113. The third type of steel armor was a complex cast hatch for the Bradley Fighting Vehicle developed in an NETL-TACOM-Lanxide-DARPA macro-composite structural armor (hatch) program. Applique armor, developed as a spin off from this program, was fielded on a number of U. S. Army and Marine Corps vehicles during the first Gulf War.
In the 1990s, emphasis was focused on the production of titanium armorplate chosen because of its lighter weight, higher corrosion resistance, and superior ballistic properties. Initially, a number of titanium targets for an NETL-designed statistically valid, ballistic and mechanical property evaluation program using Ti-6Al-4V aerospace-grade alloy were produced with physical, chemical and mechanical properties of the targets evaluated. This series of tests yielded unclassified and publishable results. Ballistic testing on the targets was then performed. In the ballistic testing of materials, in thicknesses not previously evaluated or with rounds of a new nature, the test results were classified and the results could only be released into a secure storage environment. Some of the results obtained from this program fell into this category, but arrangements were made to obtain the data in a "sanitized" form that allowed the Center to complete the statistical evaluation.
Next the first titanium hatch for a tank was fabricated at NETL. It consisted of a complex titanium machining for use as prototype blow-off hatch for use on the M-1A1 Abrams Main Battle Tank. The hatch, weighing 195-lb with dimensions of 1-in by 30-in by 44-in, was made at the request of the U. S. Army Tank/Automotive Command (TACOM) and the General Dynamics Corporation, the prime contractor for the Abrams.
The NETL Albany site then hosted a symposium on low-cost titanium that was attended by over 50 industry and government personnel. Industry representatives included personnel from the three primary titanium producers; a cross-section of the industry's top titanium fabricators, forgers, and casters; and representatives from 5 defense contractors. Representatives from 9 other government agencies also attended the meeting. The meeting covered the Ti industry's new, low-cost Ti alloys and the properties of these alloys.
Scientists worked with personnel from the three major titanium producers, TACOM, and FMC, then the prime contractor for the Bradley Fighting Vehicle, to produce titanium hatches for the Bradley and other armored vehicles that are still in use today.
NETL also participated in programs to make titanium hatches for all of the armored vehicles, titanium skirts for the Abrams main battle tank, titanium tracks for the Crusader, improve titanium welding techniques, and other, classified portions of armored vehicles.
Since 2000, NETL scientists have been working with their counterparts at the Army Research Laboratory to develop beta-titanium alloys for use as armor components. In addition, work is currently on-going to develop hardfacing surfaces to increase the properties of titanium for use as body armor. In late 2004, NETL participated in a significant program to develop prototype armor and other parts for ARL using a new, low cost powder provided by International Titanium Powder, LLC, a start up company that utilizes a new, proprietary process to produce titanium and titanium alloy powders at a substantially reduced cost.
Main Accomplishments of the Program:
- The largest steel casting in existence, 300 lb, using loose bonded, lost foam technology, was produced at the Center in 1989.
- Prototype armor to protect the rear of the turret and the commander's hatch on the Army's Bradley Fighting Vehicle and the sides of the M-113 Armored Personnel Carrier were produced using 4340 carbon steel that was 10 pct lighter than the rolled, forged, and machined production bustle with ballistic results that indicated that this cast armor proved to be far superior to the previous armor at a lower cost.
- A complex cast hatch using 17-4 PH stainless steel for the Bradley Fighting Vehicle was developed for an NETL-U. S. Tank/Automotive (TACOM)-Lanxide-DARPA macro-composite structural armor (hatch) program. Applique (appliqué) armor developed as a spin off from this program, was fielded on a number of U. S. Army and Marine Corps vehicles during the Gulf War. Non-classified reports stated that the armor "behaved magnificently."
- The first titanium hatch for a tank was fabricated at NETL consisting of a complex titanium machining for use as prototype blow-off hatch for use on the M-1A1 Abrams Main Battle Tank at the request of the U. S. Army Tank/Automotive Command (TACOM) and General Dynamics Corporation, then the prime contractor for the Abrams.
- NETL scientists worked with personnel from the three major titanium producers, TACOM, the Army Research Laboratory (ARL) and FMC, then the prime contractor for the Bradley Fighting Vehicle to produce titanium hatches for the Bradley and other armored vehicles that are still in use today.
- NETL scientists developed a process that increased the ductility of a beta-titanium alloy by 16 pct while maintaining the same level of strength.
- NETL scientists have developed a patented process for hardfacing titanium alloys that significantly increases the alloys' properties.
- NETL scientists have been selected to produce the first prototype parts using the newly introduced ITP low cost titanium and titanium alloy powders.
For more information, contact Paul C. Turner, Director, Process Development, 541-967-5863.