Tungsten heavy alloy (tungsten nickel iron and tungsten nickel copper) contains 80%-98% tungsten along with small amounts of 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.
Tungsten nickel iron (WNiFe) has comparatively higher strength and ductility than tungsten nickel copper (WNiCu). 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. Tungsten nickel copper 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.
WNiFe/WNiCu Rod | |
| Diameter | 0.029″ (0.75mm) – 5″ (127 mm) |
| Length | 0.15″ (3.81mm) – 40″ (1000mm) |
| Surface | Ground, Polished, Chemical Cleaned |
WNiFe/WNiCu Plate | |
| Thickness | 0.240″ (6 mm) to 3.15″ (80 mm) |
| Width | Maximum 22″ (558mm) |
| Length | Maximum 80″ (2000mm) |
WNiFe/WNiCu Sheet | |
| Thickness | 0.004″ (0.1 mm) to 0.240″ (6 mm) |
| Width | Maximum 26″ (660mm) |
| Length | Maximum 80″ (2000mm) |
Tungsten Alloy Machining Service
As an ISO-certified refractory metal manufacturer with advanced machining facilities, CHEMETAL USA is capable of offering various tungsten machined parts that all meet a consistently high standard. With years of experience in handling tungsten materials, our highly-trained technicians are skilled in offering the following machining services.
- Turning
- Milling
- Drilling
- Cutting
- Joining
- Forming
- Grinding
- Stamping
- EDM Machining
Tungsten Heavy Alloy Standards
| ASTM B 777 | Class 1 | Class 2 | Class 3 | Class 4 | |
| Tungsten Nominal % | 90 | 92.5 | 95 | 97 | |
| Density (g/cc) | 16.85-17.25 | 17.15-17.85 | 17.75-18.35 | 18.25-18.85 | |
| Hardeness (HRC) | 32 | 33 | 34 | 35 | |
| Utimate Tensile Strength | ksi | 110 | 110 | 105 | 100 |
| Mpa | 758 | 758 | 724 | 689 | |
| Yield Strength at 0.2% off-set | ksi | 75 | 75 | 75 | 75 |
| Mpa | 517 | 517 | 517 | 517 | |
| Elongation (%) | 5 | 5 | 3 | 2 | |
| AMS-T-21014 | Class 1 | Class 1 | Class 2 | Class 2 | Class 3 | Class 3 | Class 4 |
| Composition | 90W7Ni3Fe | 91W6Ni3Fe | 92W5Ni3Fe | 93W4Ni3Fe | 95W3Ni2Fe | 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 Treatment | Sintering | Sintering | Sintering | Sintering | Sintering | Sintering | Sintering |
| 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) | 24-28 | 25-29 | 25-29 | 26-30 | 27-32 | 28-34 | 28-36 |
| Mil-T-21014 | Class1 | Class1 | Class 2 | Class 3 | Class 3 | Class 4 |
| Composition | 90%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;0.614 | 17;0.614 | 17.5;0.632 | 18;0.65 | 18;0.65 | 18.5;0.668 |
| Hardness (RC) | 24 | 25 | 26 | 27 | 27 | 28 |
| 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“) | 6 | 10 | 7 | 7 | 7 | 5 |
| Proportional Elastic Limit (PSI) | 45,000 | 52,000 | 46,000 | 45,000 | 44,000 | 45,000 |
| Magnetic Properities | Nil | Slightly Magnetic | Slightly Magnetic | Nil | Slightly 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 |
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 alloys (tungsten nickel copper and tungsten nickel iron) are 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, 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, a counterweight made of tungsten nickel copper and tungsten nickel iron 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 in its density. Due to this property, tungsten nickel copper has been widely used in radiation shielding applications. 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 non-toxic 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 that required high wearing resistance such as machining tools including lathes and dices.
It gets a little reduction in its characteristics even at high temperatures 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
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 of 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.