Tungsten heavy 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.
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 | 0.120”(3 mm) to 2”(50 mm) |
| Width | Maximum 12”(300mm) |
| Length | Maximum 40”(1000mm) |
WNiFe/WNiCu Sheet | |
| Thickness | 0.004”(0.1 mm) to 0.012”(3 mm) |
| Width | Maximum 14”(350mm) |
| Length | Maximum 60”(1500mm) |
Tungsten Heavy 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 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 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 |
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.