Heavy Tungsten Alloys
EAGLE High Density Metals are made possible by Powder Metallurgy techniques. The process is a mixture of tungsten powder with nickel, iron, and/or copper and molybdenum powder, compacted and liquid phase sintered, giving a homogeneous structure with no grain direction. The result is a very high density, machinable material with unique physical properties.
Weights and Counterbalances for aircraft control surfaces and rotor blades, guidance platforms, balancing of flywheels and turbines, vibration damping governors, fuse masses, and weights for self-winding watches. Because of the physical properties of EAGLE high density metal, it is often used as both a weight and structural member.
CRANKSHAFT BALANCING — Used extensively to balance crankshafts in high performance engines. Individual weights are stocked. See our weight chart for formulas and information to solve balancing problems.
RADIATION SHIELDlNG — Tungsten alloys are used for radioactive source containers, gamma radiography, shields and source holders for oil well logging and industrial instrumentation; for collimators and shielding in cancer therapy machines and syringe protection for radioaotive injections, There is no licensing required for tungsten alloy materials. It is stable at high temperatures and 1/3 less material than lead can be used for the same energy absorption effectiveness. EAGLE high density tungsten alloys are used wherever radioactivity has to be controlled mid directed.
ROTATING INERTIA MEMBERS — Material Is used for gyro rotors, fly wheels, and rotating members for governors. Because of its unique physical properties, this material can be rotated at extremely high speeds.
ORDNANCE COMPONENTS — In spheres, cubes. and projectile shapes. these materials are used for hypervelocity armor penetratng applications. Properties such as elongation, ultimate tensile strength, arid hardness can be varied by manufacturing technique and additives.
BORING BARS AND GRINDING QUILLS — The standard for vibration free machining and grinding has been established by EAGLE Chatter Free and EAGLE Super Chatter Free materIals. It’s used where rigidity and minimum vibration are critical Heavier cuts, Ionger tool life, end a better finish result when using EAGLE Chatter Free materials. Tool extensions of up to 9-1 are possible depending on the diameter. Tools run cooler because of the high thermal conductivity, and you can braze directly to material without affecting its physical properties.
These mñteriais are often used in place of tungsten carbide boring bars because it has a higher density, is readily machinable, less prone to chipping and breakage, and both material and finishing casts are less. See our technical brochure Chatter Free and Super Chatter Free materials.
HIGH TEMPERATURE TOOLING — for die castIng and extrusion dies, hot upsetting and electro brazing. EAGLE has developed a special tungsten alloy for this type application called DIEMETAL. It’s a tungsten, molybdenum, nickel, iron based material, It has good thermal conductivity and maintains excellent physical properties at high working temperatures. It resists errosion and scaling, minimizes soldering and heat checking and basically eliminates the need for heat treatment. See our technical bulletin on DIEMETAL
DESIGN CONSIDERATIONS -Because EAGLE High Density Metals are produced by powder metallurgy, parts often can be tooled and produced to net or near net shape, minimizing material and machining costs, Normally, medium to small sized parts can be pressed and sintered to a (plus or minus) 1%, both dimensionally, and by weight. As the part gets larger, this percentage increases, Finish for “as sinterd” parts is normally 63 or better. When designing parts to be used "as sintered,” deep splines, re-entrant angles, and feather edges should be avoided.
While EAGLE high density metals are relatively noncorrosive, plating Is recommended if used in a corrosive atmosphere. Standard plating procedures for cadmium, nickel, and chromium are used. A copper flash Is sometimes used for better adherence. Plating is suggested if used with aluminum to prevent galvanic reaction,
Oxidation starts at approximately 400C (752F), and in high humidities at approximately 66C (150F) showing a blue-black film. To minimize oxidation at high temperatures and high humidity, plating is recommended.
MACHINING AND FINISHING
EAGLE high density metal is similar to machining gray cast iron. A coolant is optional and carbide tools are recommended in most cases.
TURNING & BORING — Roughing — use C-2 carbide with cutting depth of .030” to 125’ and .008” to .015 feed, at 200 to 300 SFM. Finishing — .010" to .015" cutting depth and 004" to .010" feed at 250 to 400 SFM.
DRILLING— Use high speed steel surface treated drills with plain points. Increased clearance angles and automatic feeds are often used to avoid binding and seizing. Carbide drills will give better tool life. A chlorinated oil Is sometimes used as a coolant.
TAPPING — Use high speed steel or carbide, two flute plug spiral point taps. Chlorinated oil or a tapping compound is recommended.
GRINDlNG - Use aluminum oxide or silicon carbide wheels of medium hardness.
MILLiNG - Use M-2 high speed steel for light cuts and M-42 high speed steel for deep cuts. Carbide cutter inserts will extend tool life. We recommend when using carbide, feeds .007” to .015” per tooth at speeds of 200 to 400 SFM for roughing, and when finished, feeds .003” to .010 per tooth at speeds of 300 to 700 SFM.
EAGLE high density tungsten alloys are not heat treatable; however, stress relieving is sometimes done on machined parts. We suggest heating at 600F in air for two hours and cool in air or in a protective atmosphere at 900F for 30 minutes.
SAWING OR CUTTING — When sawing, use a bi-metai coarse blade at high speeds, or a high speed steel coarse blade at low speeds. Coolant can be used. Material also can be cut using high speed abrasive cutoff wheels.
As a result of the materials’ characteristics and especially its low thermal expansion. very close tolerances and fine finishes can be held.
COPPER BRAZING Is a very good method of joining high density tungsten materials to itself or other materials. Joint strength Is close to that of parent material. One disadvantage is that it should be done in a controlled atmosphere, which is not too practical for most users.
DIFFUSION BONDING is an ideal way of joining tungsten alloy material to itself, but It has to be done by the material manufacturer. If parts are finished, there may be some distortion from the process.
SILVER SOLDERING for most companies is a practical and efficient method of joining these types of material either to themselves or to steel.
SUGGESTIONS: Typically .002 clearance between parts to be joined is required, As the part gets larger, more clearance is required. Parts should be as clean as possible, sand blasting is sometimes used, both parts are fluxed, carefully heated until solder flows. Easy flow 45 is commonly used. A slow uniform cooling is recommended, Uneven cooling could set up stress in the joint and the material.
SHRINK FITTING is another good method of joining high density tungsten material to steel. Depending on the size, .0005/.0007 interference fit per side is recommended. The tungsten alloy is chilled In dry ice or nitrogen while the steel is heated. When assembled, a slow cool is necessary, while parts are held by a locating pin or fixture.
EAGLE high density tungsten material is stocked in the following sizes:
1/8" to 1" dia. in 8" & 12" lengths
1 1/8" to 2" dia. in 12" lengths
1/4" to 1" square in 8" & 12" lengths
1 1/8" to 2" square in 12" lengths
Rectangles, discs, and rings are also available.
Larger sizes up to 6" dia. or 41/2" square x 30" long, and depending on cross section, longer lengths and sizes can be supplied.
All round bars up to 2" diameter are centerless ground, while all larger diameters are lathe finished.
If material is not in stock, delivery is normally 10-14 days, or sooner for emergency requirements.
Because we make our own toooling, special shapes and sizes can be made quickly and competively— finished machined to your requirements or as a near net shaped blank.
COPPER TUNGSTEN AND SILVER TUNGSTEN
Refractory metal composites produced by EAGLE which are. used for:
Resistance Welding Die Inserts and Electrode Facings
EDM and ECM Electrodes
Semi-Conductor Heat Sinks and Thermal Bases
Wear Surfaces Requiring High Electrical and Thermal Conductivity