Tungsten, found in wolframite and scheelite ores, is a rare earth metal ideal for high-value manufacturing applications requiring superior wear and impact resistance. This metal is processed under high temperatures through a series of chemical reactions led by a hydrometallurgical extraction. Because of its unique properties, high economic value, and perceived scarcity, tungsten’s global market value is projected to reach $8.8 billion by 2029.
Tungsten is also the hardest metal in the world. Refining and machining this chemical compound requires extensive material knowledge, engineering expertise, and access to advanced technology. If you intend to benefit from tungsten’s superiority in 2024, you need a manufacturing partner with a proven track record of engineering innovative solutions with tungsten according to industry-approved quality standards.
To choose a suitable partner, you need basic knowledge of the following subtopics:
- 7 Key Properties of Tungsten
- How is Tungsten Made: The Tungsten Manufacturing Process
- 4 Core Tungsten Machining Methods to Adopt in 2024
- 4 Tungsten Alloys and Their Primary Industrial Use Case
- 5 Steps in Choosing a Tungsten Manufacturing Partner
7 Key Properties of Tungsten
1. Steel-Gray, Lustrous Metal
One of tungsten’s most obvious physical properties is its luster. This chemical element has a silver or grayish-white coloring. Tungsten has a shiny exterior. Its surface also reflects light and is opaque.
2. High Melting and Boiling Point
Tungsten has the highest melting point among all metals, at 6192 oF or 3422 oC, with a boiling point of 10031 °F or 5555 °C and a low vapor pressure above 2500 °K and below 3200 °K. You’ll find Tungsten in the 6th group of the periodic table with the symbol W and atomic number 74.
You’d need to expend more heat energy to convert tungsten to a molten liquid because it has strong intermolecular forces binding its atoms. These atomic and metallic bonds make tungsten metals resistant to heat and surface wear.
3. High Density
Tungsten is one of the densest metals in the world. It has a density of about 19.3 g/cm3. This property indicates that it has a high mass quantity. Heavy metals like tungsten have a longer shelf life and can withstand harsh environmental conditions, including radiation exposure.
4. High Tensile Strength
Tungsten has high scratch resistance and modulus of elasticity, meaning only an unusual force to crack or expand its surface. Its tensile strength is the highest of any pure metal at 980 MPa. Tungsten’s yield strength is approximately 750 MPa. This feature indicates that tungsten can resist permanent elastic deformation and surface wear when exposed to heavy loads and extreme stress conditions.
5. High Corrosion Resistance
Pure tungsten metals can withstand attack from environmental deterioration sources at room temperature, including corrosion from water, air, gasoline, acid, and other organic solvents. Although pure tungsten has a high corrosion and oxidation resistance, it can show signs of rust and tarnish if combined with chemical elements such as cobalt, nickel, chromium, and iron.
6. High Electrical Resistivity
Tungsten resistivity is 5.6 x 10-8 Ωm (ohms) at 20oC. It has one of the highest electrical resistivities of any metal, indicating its usefulness in applications involving high resistance to the flow of electrical currents. Tungsten is also a good conductor of electrical currents. Its conductivity level is at 0oC, which is 28% of that of silver.
7. High Thermal Conductivity
Tungsten metals are excellent conductors of thermal energy. Tungsten’s thermal conductivity level is approximately 175 W/(m-K) at room temperature. This property indicates that tungsten metals can speedily transfer heat from one material/surrounding to another. Hence, they are perfect for heat sink applications.
How is Tungsten Made? The Tungsten Manufacturing Process
Tungsten is extracted from natural elements such as wolframite and scheelite through mining. These ores are broken into smaller pieces using special tungsten ore crushers and grinders. The tungsten deposits are then separated from the ore through gravity concentration or flotation separation.
The tungsten ore is roasted under oxidizing conditions between 700oC to 1100oC temperatures, based on the quantity of the compound for two or three hours. To obtain ammonium paratungstate (APT), you decompose the tungsten ore by acid leaching or autoclave soda processes. Leaching involves extracting particles from a solid material dissolved in a contacting liquid.
Tungsten extracts are digested with an alkaline pressure solution (soda or concentrated sodium hydroxide) to produce a sodium tungstate solution. The solution is then precipitated and filtered before it’s converted into an ammonium tungstate solution. To obtain ammonium para tungstate (APT), you crystallize the solution. APT can then be calcined, under oxidizing conditions, to its decomposition temperature to create tungsten oxides. To produce tungsten powder, high-purity tungsten oxides go through a hydrogen reduction.
Powder metallurgy is the ideal method for processing tungsten powder. Powder metallurgy is a green manufacturing method for producing simple or complex-shaped parts of ferrous and non-ferrous materials. It begins with mixing and blending the refined tungsten powder with other materials (binders and lubricants) to form new alloys, then compacting the loose powder into defined shapes and sizes in a die cavity to create the desired shape.
The compacted parts in the die are then heated below the sintering temperature to strengthen and remove the binders and lubricants added earlier. After which, the compacted parts are sintered below the melting temperature in a controlled environment to allow the particles to bond or fuse.
4 Core Tungsten Machining Methods to Adopt in 2024
Powder Extrusion
Powder extrusion allows you to continuously manufacture complex-shaped parts in large volumes by forcing the tungsten material through a series of dies. Powder extrusion can be heated or introduced at room temperature. In cold extrusion, the tungsten powder or billet is fed through the orifice of the die into an enclosed die cavity at room temperature, and high pressure is applied to the billet or powder using a punch to deform the raw material and ensure it fills out the die cavities.
In hot extrusion, the billet or powder is heated before it is introduced to the extrusion press. Based on the material flow and the direction of the punch, you can classify this process into forward, backward, and lateral extrusion.
Powder Injection Molding
This advanced metalworking process combines metal injection molding (MIM) and powder metallurgy and is used to produce large quantities of complex parts. In powder injection molding, the sintered particles in the form of finely ground metal powder are heated in the barrel under elevated temperature and mixed with a screw until it becomes molten liquid.
The melted metal is injected into the mold cavity—bearing the desired shape—through a gate and runner system to cool and solidify into the final parts as soon as the molten material fills the mold.
Additive Manufacturing
Unlike the formative or subtractive manufacturing methods that require material to be cut out or forced through a machine, the additive manufacturing method minimizes material waste. It also allows you to validate the viability of a product design. 3D printing or additive manufacturing is mostly used in rapid prototyping because it’s cost-effective. It involves heating the metal powder or billet using a laser beam so it consolidates to form the desired final part.
In the additive manufacturing method, layers of tungsten materials are added to a base layer to create a three-dimensional object based on the data from the computer-aided design (CAD) model.
CNC Machining
The tungsten powder goes through a series of machining processes—forging, rolling, and annealing— under heat or room temperature after sintering at a temperature less than that of melting. The data from the CAD model controls the operations performed by the machine. Since tungsten is a brittle metal, it is prone to cracking or splitting under machining operations. It can also damage the edges of the machining tools.
Cutting and foaming fluids may be applied to the material to improve its machinability by reducing heat and friction and improving foamability before or during the process. In CNC machining of tungsten metal, the turning technique is used to rotate the material against a cutting tool to remove unwanted blocks of metals.
During milling, a rotating cutter is used to remove the material blocks. Grinding is used to achieve fine surface finishes and tight tolerance. Electrical discharge machines use electrical sparks to remove materials from the workpiece to form complex shapes. Another machining operation done on tungsten is drilling, where holes are inserted into the workpiece.
4 Tungsten Alloys and Their Primary Industrial Use Cases
Tungsten can be combined with other metals, such as nickel, cobalt, copper, and iron, to improve its tensile strength, corrosion resistance, malleability, density, and machinability. Tungsten alloys are called heavy alloys because they comprise 90-97% of tungsten and 3-10% of a matrix of other metals. We have outlined the most common tungsten alloys in use below.
1. Tungsten Carbide
Tungsten carbide is produced during the sintering phase. It involves mixing carbon powder with tungsten powder under high temperature or pressure to form a bonded material once cooled. Tungsten carbide is one of the strongest engineering metals capable of resisting impact from acid, alkali, air, water, and other chemicals. It’s used across industries to produce specialty cutting and drilling tools, medical devices and surgical tools, jewelry, and heavy-grade ammunition.
Due to the high consumption of tungsten carbide, the global tungsten carbide industry is projected to grow by 7.40%, from $17.7 billion in 2023 to $31.3 billion in 2032.
2. Tungsten Nickel Iron Alloy
Tungsten nickel-iron alloy is expected to experience an increase in demand and market value because of the growing adoption in the medical, aerospace, military/defense, and automotive industries. Tungsten nickel-iron alloy is a high-density alloy produced by adding nickel and iron to a tungsten compound in a liquid-phase sintering process.
This alloy is known for its superior wear resistance, density, melting point, tensile strength, radiation absorption capacity, and thermal stability. Tungsten nickel-iron alloy is used to make filaments of x-ray tubes, vibration dampers, bearing assembly, casting, and ballast tanks.
3. Tungsten Nickel Copper Alloy
Tungsten nickel-copper alloy is also produced during the sintering phase by adding a matrix of nickel (6%), copper (4%), and small quantities of other components such as molybdenum, and chromium to the tungsten powder to improve its gravity, tensile strength, melting point, radiation absorption capacity, elongation capacity, and thermal conductivity.
This alloy is also used in the aerospace, defense, medical, and oil drilling fields for high-weight and precision applications involving balancing and radiation shielding. Some of the products made from this mixture include ammunition, heat sinks, and missile components.
4. Cemented Carbide
Cemented carbide is an extension of tungsten carbide. It involves adding cobalt as a metal binder to the tungsten and carbon mixture to form the cement. Cemented carbides are known for their enhanced flexural and compressive strength, hardness, and longer lifespans.
Cemented carbides have high wear and abrasion resistance. You can use these alloys to produce high-precision cutting tools, including drills, lathes, milling cutters, mining tools, measuring tools, and dies.
5 Steps in Choosing A Tungsten Manufacturing Partner
1. Define Your Project Scope
The first step to choosing a tungsten manufacturing partner is understanding what you plan to achieve with tungsten. Research the broad industry to know tungsten’s manufacturing capability and potential. Knowing this will allow you to build an idea bank for your next innovation. Once you have a product idea, the next step is creating a proposal and researching tungsten manufacturers in your state or region.
There are online directories that help you discover and recommend providers in your niche and geographical territory. Then, you can shortlist a couple of companies to visit based on their value offerings and expertise.
2. Review Services and Areas of Expertise
Tungsten production is an arduous process involving several steps, and finding a company that offers all the services you need can be difficult. As such, working with experts in defined areas increases your chances of achieving commercial success. Specialization breeds excellence. You can start by scouting tungsten manufacturing companies specializing in material selection, rapid prototyping, and mass production of final parts using one or more major manufacturing methods.
In addition to the listed services, some companies offer or provide access to vendors that offer tungsten engineering design and specialty tooling services. Suppose you’d like to invest in tungsten extraction. In that case, you should contact a tungsten mining company.
3. Check for Industry Certifications
Quality assurance is an essential step in ascertaining the suitability of a tungsten manufacturing partner. Ensure that the partner you choose can back up their quality claims. Start by reviewing the quality certifications on their website and comparing them with the industry quality standards and requirements for tungsten manufacturing companies.
The required certifications must be complete and up-to-date. You should also be able to review the company’s in-house quality assurance processes and management practices from their website information.
4. Review Track Records
Knowing what past clients think of your potential partner can help with decision-making. You’ll find client reviews on the company’s social media platforms. Find out if anyone from your professional network has a history with your intending partner. If they worked with the company in the past, what can they say about them now? Find out if it was a one-time affair or if they have an ongoing relationship.
Are there case studies and achievement banners on their websites? This information tells you how many high-value projects the company has worked on. Scan through online media platforms to review their public engagement and accountability. Knowing the company’s founding date also allows you to gauge their experience level.
5. Set Up a Meeting to Decide Compatibility
If you’re satisfied with your findings, you can schedule a meeting with the company to determine your compatibility. You should create a project checklist and establish guidelines for forming a new partnership. One of the factors to look out for in a new partner is the quality of their customer service. You also need to know the cost of doing business with them. Ask questions about their tungsten manufacturing costs and compare them with your budget.
Finding a tungsten fabrication company that can tailor their services to fit your budget and specifications will save you a lot of stress in the long run. If they make it easy to keep in touch and provide access to complimentary vendors, you’ll find it easier to manage the outcome of your project.
Final Thoughts
Are you looking for a tungsten manufacturing partner? We’d love to have a chat. At PTI Tech, we take pride in providing customized services to clients who need specialty tooling and metal injection molding for tungsten. Whether it’s a one-time project or a long-term relationship, we have the experience, talent, and infrastructure to make either a success.
For over three decades, we’ve helped clients across the medical, aerospace, defense, and electronics industries create cost-efficient, high-precision, net-shaped tungsten products using selected tungsten alloys and formulations. Our clients rely on us for quality assurance, market research and design validation, material selection, and product development.