Tungsten Alloy

Tungsten alloy contains 80%-98% tungsten along with small amounts of molybdenum, nickel, iron and copper elements. After going through the compacting and sintering process, tungsten is alloyed with other metals, all beginning as a form of powder.

High density tungsten alloy is sintered by powder metallurgy for 60 – 90 minutes at working temperatures ranging from 1500 to 1525 °C. The sintering temperatures and atmospheres are critical factors for attaining certain expected engineering properties, such as high tensile strength and elongation.

W-Ni-Fe alloy has comparatively higher strength and ductility than W-Ni-Cu alloy. However, W-Ni-Fe alloy belongs to magnetic alloy and might slightly interrupt or divert the surrounding magnetic field. Therefore, it isn’t always the preferable tungsten alloy material in applications such as aerospace and electronic devices. W-Ni–Cu alloy is non-magnetic and has a better electronic and thermal conductivity so it is more suitable for components that are required to work under a magnetic environment, such as the contact of high voltage devices and electrodes.

Tungsten Alloy Materials

As an ISO Certified tungsten alloy products manufacturer, CHEMETAL USA is capable of offering various types of W Ni Fe, W Ni Cu and Copper Tungsten Alloy Product that all meet a consistently high standard of flatness, roughness and machinability. We are also able to provide a fast lead time and handle large-volume contracts. CONTACT US and download our PRODUCT CATALOG to learn more about our Tungsten products.

Tungsten Heavy Alloy Application And Properties

Tungsten heavy alloy is excellent in applications requiring high performance in corrosion resistance, density, machinability and radiation shielding. Therefore, this makes it ideal for use in specified steelmaking, mining, aerospace and medical industries.

 

High Density

16.5-19.0 g/cm3 density of tungsten heavy alloy is the most important industrial property. The density of tungsten is two times higher than steel and 1.5 times higher than lead. Although, many other metals such as gold, platinum and tantalum, have a comparable density to heavy tungsten alloy. However, they are either over expensive to obtain or exotic to the environment. Combined with the high machinability and high module elasticity, the density property makes the tungsten heavy alloy to be capable of being machined into a variety of density needed components in many industrial fields. Given an example of counterweight. In a very limited space, counterweight made of tungsten heavy alloy is the most preferred material to offset the gravity change caused by off balance, vibration and swinging.

 

Radiation Absorption

Another considerable advantage of tungsten heavy alloy is radiation shielding which is also associated with the high-density property of tungsten alloy.
The radiation shielding effect of one material will go up along with a rising of its density. Due to this property, tungsten heavy alloy has been widely used in radiation shielding application.  The radiation absorption capacity is one time higher than the lead-based material.
Tungsten alloy shield has one time higher radiation absorption capacity than the lead shield. On the other hand, tungsten heavy alloy is nontoxic to the environment. For radiation shielding application, the absorbing capacity to gamma radiation and X-ray radiation is 30% to 40% higher than lead materials. The component is 25% to 50% less weight than lead. Meanwhile, it relieves the concern of cost caused by waste processing and toxic threaten.

 

Hardness and Wear Resistance

Besides the high density and radiation absorption, many valuable properties associated with the high hardness and resistance have been used in a large number of applications. Tungsten heavy alloy belongs to refractory metal alloys which are extraordinarily resistant to heat and wear. Tungsten heavy alloy has been primarily used to make components required high wearing resistance such as machining tools including lathes and dices.
It gets a little reduction of their characteristics even at high temperature and has excellent wear resistance. Therefore, Tungsten alloys are used for the machining tools such as lathes, milling machines etc. and manufacturing automobile parts such as engines, transmissions, steering etc., which contribute to an improvement of machining accuracy.

  • Low thermal expansion
  • High thermal and electrical conductivity
  • High arc resistance
  • Low consumption

 

Tungsten Heavy Alloy Standards

ASTM B 777Class 1Class 2Class 3Class 4
Tungsten Nominal %9092.59597
Density (g/cc)16.85-17.25
17.15-17.85
17.75-18.35
18.25-18.85
Hardeness (HRC)32333435
Utimate Tensile Strengthksi110110105100
Mpa758758724689
Yield Strength at 0.2% off-setksi75757575
Mpa517517517517
Elongation (%)5532

AMS-T-21014
Class 1
Class 1
Class 2
Class 2
Class 3
Class 3
Class 4
Composition90W7Ni3Fe
91W6Ni3Fe
92W5Ni3Fe
93W4Ni3Fe95W3Ni2Fe
96W3Ni1Fe
97W2Ni1Fe
Density (g/cm3)17.1±0.15
17.25±0.15
17.50±0.15
17.60±0.15
18.10±0.15
18.30±0.15
18.50±0.15
Heat TreatmentSinteringSinteringSinteringSinteringSinteringSinteringSintering
Tensile Strength (Mpa)900-1000
900-1000
900-1000
900-1000
920-1100
920-1100
920-1100
Elongation (%)18-29
17-27
16-26
16-24
10-22
8-20
6-13
Hardness (HRC)24-2825-2925-2926-3027-3228-34
28-36

Mil-T-21014Class1Class1Class 2
Class 3
Class 3
Class 4
Composition90%W,
6%Ni4%Cu
90%W,
7%Ni3%Fe
92.5%W,
5.25%Ni
2.25%Fe
95%W,
3.5%Ni
1.5% Cu
95%W,
3.5%Ni
1.5%Fe
97%W,
2.1%Ni
0.9%Fe
Density (gm/cc; lbs/in3)17;0.61417;0.614
17.5;0.632
18;0.65
18;0.65
18.5;0.668
Hardness (RC)242526
272728
Ultimate Tensile Strength (PSI)110,000
120,000
114,000
110,000
120,000
123,000
Yield Strength, . 2% Offset (PSI)80,000
88,000
84,000
85,000
90,000
85,000
Elongation (% In 1“)6107775
Proportional Elastic Limit (PSI)45,000
52,00046,000
45,000
44,00045,000
Magnetic ProperitiesNilSlightly
Magnetic
Slightly
Magnetic
NilSlightly
Magnetic
Slightly
Magnetic
ASTM-B-459-67
Grade1
Type Ⅱ && Ⅲ
Grade1
Type Ⅱ && Ⅲ
Grade2
Type Ⅱ && Ⅲ
Grade3
Type Ⅱ && Ⅲ
Grade3
Type Ⅱ && Ⅲ
Grade4
Type Ⅱ && Ⅲ

Effects of Heat Treatments on Tungsten Alloy

Heat treatments to the tungsten alloy will follow after the sintering process, which includes quenching, dehydrogenizing and surface hardening. The heating process is also a dehydrogenizing process to the tungsten alloy. It decreases the hydrogen embrittlement and segregation of impurities including P and S. As a result, the tensile strength and ductility of tungsten alloy are dramatically improved by heating treatments. In addition, tungsten alloy attains a fine grain size and a homogenous crystallized structure.

The heat treatment to tungsten alloy can significantly enhance the engineering properties. Take the example of heating W 95 tungsten alloy in a medium-frequency induction furnace. The strength and impact toughness will be markedly increased on the condition that the working temperature ranges from 850 to 900 °C  and the heating lasts for 40 minutes.

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