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Radiation Shields & Weights

heavy metal 1 higher resHeavy metal alloy composed primarily of tungsten. Heavy metals manufactured by our advanced powder metallurgy feature very high density and excellent radiation shielding as well as mechanical strength and machining/processing characteristics. These metals have been well accepted as alternative materials of lead that has adverse impact on environment. They are also used for various weights and rotors and for their excellent shielding performance, in a variety of fields including medical equipment and nuclear power plants.

Features of heavy metal

High Density

Material having a density about two times that of copper and iron and is suitable for rotors and weights. In particular, it is very suitable for applications where a certain weight is required in a limited space and is well accepted to replace lead.

Radiation Shielding Properties

Compared with other metals, our heavy metals are far superior in terms of absorption of high-energy beams and radiation. They have extremely low gas emissions in high vacuum and are superior in mechanical strength and processing workability. They are ideal materials for such applications as medical equipment, nuclear power plants and other radiation shielding applications.

Environmental Properties

Alloys with a small amount of nickel, iron, copper, etc. added to tungsten that is the main component are highly evaluated as environment-friendly material. Unlike lead, they are not resolved in water and have high oxidation performance.

Mechanical Strength

Our heavy metals have high mechanical strength to make these metals suitable for various shapes of weights and shafts that require specially high strength. For their high rigidity, our heavy metals work well in preventing chattering of holders and chucks of tools.

Machining/Processing Characteristics

While pure tungsten is very difficult to machine or process, our heavy metals, while primarily composed of tungsten, are easy to machine with cemented carbide tools. Machining by milling machines and end mills and tapping are also possible. As their melting point is high, these heavy metals are also employed as high-temperature furnace members.

Corrosion Resistance/Nonmagnetic Property

You can select one from a wide variety of products that is most suitable for your application. ST Series featuring high corrosion resistance at high temperatures and high humidity and a type that is not magnetic. We offer most suitable materials according to needs of customers.

Typical properties of heavy metal
Properties       Material        
★HM-12 HM-1 HM-2 HM-5 HM-7 HM-7S ☆HM-7ST ☆HM-8ST HM-185
Tungsten
Composition(%) 
53 90 90 95 95 95 95 97 97
Density  12 17 17 18 18 18 18 18.5 18.5
Mechanical
Properties       
Hardness(HRC) 24 26 26 28 28 28 28 29 29
Compression Strength
(Warpage 0.2%)(MPa)
- 690 690 780 560 560 690 690 780
Tensile strength(MPa) 880 590 600 880 780 780 780 780 880
Yield Strength
(Warpage 0.2%)(MPa)
650 510 510 650 560 560 650 650 650
Elongation(%) 40 0.4 0.4 25 5 5 5 5 10
Young’s Modulus(GPa) - 280 - 350 300 300 350 300 370
Traverse Rupture
Strength(GPa)
- 1.4 - 2.2 2.1 2.1 - - 2.2
Impact Strength(J/cm2 40 2 - 4.9 2.9 2.9 - - 2.9
Thermal
Properties 
Thermal Conductivity
(W/(m・K))
- 88 - 84 92 92 75 - 100
Coefficient of Linear
Expansion(ppm/K)
- 6 - 5.2 5.6 5.6 5.2 - 5
Electrical  Electrical Conductivity
(%I.A.C.S)
- 15 - - 16 - - - -
Specific
Resistance(Ωm)
- - - 110 - - - - 81
Magnetic
Properties  
Magnetism Exist None Weak Exist Weak None None None Exist
Magnetic
Permeability(Km)
- 1.00022 - 4.723 - 1.00013 1.00028 - 4~4.5
Magnetic
Susceptibility(Xm)
- 0.00022 - 3.723 - 0.00013 0.00028 - 3~3.5

※The above values may vary depending on production conditions.

★ Plastic heavy metal (HM-12)

A new material type that allows not only cutting, but plastic processing such as forging and rolling has been added.
Products of complicated shapes can be made at lower cost. The specific gravity is close to that of lead to make this type most suitable as environment-friendly material to replace lead.

 heavy metal 2

☆ Corrosion resistant heavy metal (ST Series)

A new type of heavy metal having excellent corrosion resistance at high temperatures and high humidity while maintaining excellent characteristics of heavy metal has been developed. It maintains this excellent corrosion resistance not only on the surface but also inside of alloys, exhibiting this performance on processed products. The use of this material can eliminate rust preventive treatment such as Ni plating.

Radiation Shielding Application

heavy metal 3Heavy metal exhibits a very high performance in shielding proton beams, electron beams and radiation due to its high density. The shielding performance equivalent to lead can be achieved with 60% of the thickness. Also since this metal can be processed to complicated shapes, it is an ideal material to make a variety of radiation shield equipment more compact. It is employed as shielding material used inside nuclear power plants and cancer treatment equipment.

Examples of application
  Shield material in nuclear power plant
  Medical leaf-collimator
  Shield capsule for isotope
  Shield products for high energy

Shielding Effect of Heavy Metal
Isotope γ Ray Energy
(MeV)
Absorption Coefficient
(cm-1)
1/2 Damping Thickness
(cm)
1/10 Damping Thickness
(cm)
60Co 1.17
1.33
Ave. 1.25
0.93 0.75 2.05
131I  0.364 3.69 0.188 0.64
0.638 1.74 0.4 1.32
Ra 2.2 0.72 0.97 3.2
24Na  1.38 0.97 0.72 2.36
2.76 0.66 1.05 3.5
187W 0.68 1.43 0.49 1.6

 Weight and Rotor Applications

heavy metal 4Heavy metal primarily composed of tungsten has a high density property, excels in mechanical strength and good machinability. These features make the heavy metal suitable for balancers used to control weights. Also since the high density provides a high moment of inertia, it is suitable to make rotors more compact.

 

 

 Examples of application
  Weight for watches
  Weight for golf clubs
  Balancer for speed meters
  Weight for darts and lures
  Vibration-isolating material for cutting tools

 

 

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