Types and Applications of Tungsten Metal

Tungsten Metal: Types and Applications

Introduction

This article will take an in-depth look at Tungsten metal.

The article will look at topics such as:

Principle of Tungsten Metal
Types of Tungsten Alloys
Tungsten vs. Tungsten Carbide
Applications and Advantages of Tungsten Metal
And Much More��

Chapter 1: Understanding Tungsten Metal: Its Principles and Applications

This section delves into the various aspects of Tungsten metal, examining its natural occurrences, manufacturing processes, and notable properties.

What is Tungsten?

Tungsten is a commonly available, silvery-gray metal known for its impressive hardness. It exhibits outstanding tensile strength and can withstand extremely high temperatures, with a melting point of 6191°F (3421.7°C) and a boiling point of 10220°F (5660°C). Tungsten, identified by the atomic number 74, is part of the transition metals group in the periodic table.

Occurrence of Tungsten Metal

Tungsten is naturally found in minerals like wolframite and scheelite. Wolframite, recognized as an iron-manganese tungstate with the formula (FeMn)WO₄, is a solid solution of ferberite (FeWO₄) and hubnerite (MnWO₄). Scheelite, which is calcium tungstate with the formula CaWO₄, is another important source. Various tungsten minerals differ in rarity and economic importance, with some being moderately common and others extremely rare with little economic value.

Tungsten Nomenclature

Below are some critical terms affiliated with tungsten metal, covering its applications and descriptions of tungsten alloys.

Alloy Mixture

An alloy is produced by combining two or more elements to harness the properties of each metal, resulting in optimal performance. Noteworthy tungsten alloys include tungsten carbide (a mixture of tungsten and carbon), Hastelloy (which combines nickel, chrome, molybdenum, and tungsten), and various tungsten nickel alloys, to name a few.

Tungsten’s Brittle Nature

The brittleness of a material indicates its propensity to fracture under stress. Pure tungsten tends to be vulnerable to cracking, leading to its alloying with other metals to boost durability. For instance, combining tungsten with carbon can significantly enhance its strength, making it suitable for applications that would otherwise be impractical for pure tungsten.

Tungsten Filament

A filament is a thin metal wire used in bulbs, adept at converting electricity to light and enduring high temperatures without melting or snapping.

Melting Point

The melting point defines the temperature at which tungsten transitions to a liquid state. It has an exceptionally high melting point of 3,422°C (6,192°F).

Superalloy

Superalloys are metals noted for their high tensile strength, corrosion resistance, and elevated melting points.

Tensile Strength

In engineering contexts, tensile strength refers to the extreme stress level beyond which a metal deforms or breaks.

Wolfram or Tungsten

The alternative name, "wolfram," comes from tungsten's chief ore, wolframite, which is the primary resource for this metal.

Properties of Tungsten

Tungsten displays the following properties:

Tungsten Chemical Properties

Positioned among the transition metals in the periodic table, tungsten exhibits multiple oxidation states: +2, +3, +4, +5, and +6. Its atomic number is 74, and with a relative atomic mass of 183.84, it stays solid at room temperature because of its stable isometric crystal framework, which X-ray analysis can discern.

Tungsten resists corrosion from most acids except nitric and hydrofluoric acids. It can also react with alkaline oxidizers like potassium nitrate or sodium hydroxide but tends to remain generally resistant. However, at high temperatures, tungsten can quickly react with oxygen to form trioxides.

Tungsten exists as a mixture of five stable isotopes: tungsten-180, tungsten-182, tungsten-183, tungsten-184, and tungsten-186. Their respective proportions are approximately 0.12%, 26.5%, 14.3%, 30.6%, and 28.4%.

Tungsten Physical Properties

Tungsten, in its pure form, is a shiny white metal quite easy to handle. However, the presence of minute quantities of oxygen and carbon can make it fragile under severe stress and pressure.

This metal is the densest engineering material, with a density of 19.25 g/cm³ due to its compact crystal arrangement. It boasts a melting point of 3,140°C and a boiling point of 5,700°C. It has the lowest vapor pressure among metals and achieves the highest modulus of elasticity at 400 GPa.

Tungsten has a minimal thermal expansion coefficient of 4.4×10⁻⁶ mm/°C, parallel to that of borosilicate glass, making it ideal for glass-metal seals. Moreover, tungsten is environmentally robust and does not easily break down.

Tungsten Attributes

As a metal, tungsten embodies numerous conventional metallic properties. It efficiently conducts electricity owing to its free electrons and remains an excellent conductor of heat. Tungsten alloys maintain these essential conductive properties, making them invaluable for electrical industries.

Tungsten is known for its corrosion resistance, distinguishing it as a unique metal. Despite its advantageous properties, tungsten can be brittle in its pure form. Therefore, it is generally alloyed with other metals to produce more robust and manageable compounds.

Producing Tungsten Metal

Tungsten goes through a multi-step extraction and refining process. Initially, tungsten ore is transformed into tungsten (VI) oxide (WO₃). This oxide is then subjected to heating with hydrogen or carbon to create tungsten powder. Due to its high melting point, forming tungsten ingots is technically challenging and commercially unfeasible.

Tungsten powder is combined with small amounts of nickel or other metals before undergoing sintering, allowing nickel to diffuse and form tungsten alloys.

The powder can also be obtained by reducing tungsten hexafluoride (WF₆) using hydrogen.

WF₆ + 3H₂ → W + 6HF

For manufacturing tungsten products, sintered tungsten alloys are molded into billets, later processed into foils, bars, plates, or sheets by grounding, drawing, die cutting, or molding. Some articles may need additional processing steps.

Tungsten products come in three primary forms: black (with a lubricant layer), oxide, and cleaned (surface stripped with chemicals). The ground form is further refined using diamond or silicon carbide tools for precision and smoothness.

Tungsten Products

Items made from tungsten are adaptable and find usage in manufacturing tungsten electrodes, drilling equipment, light bulbs, industrial machines, tools, military armament, material coatings (such as for boats), X-ray screens, and construction tools.

Tungsten alloys are instrumental in weapon production and developing effective heat sinks for thermal management. They are also essential in turbine blade fabrication and heavy-duty equipment manufacturing, such as weights and ballasts used in fitness applications.

The corrosion resistance of tungsten extends tool lifespan and quality. Tungsten is used for producing electrodes suitable for high-temperature applications, capable of withstanding water without rust or degradation.

Tungsten is integral to welding equipment for transmitting high voltage and currents across metal sheets. Its applications also include electrical discharge machines and tungsten gas arc welding setups.

Chapter 2: What are the different types of tungsten alloys?

Tungsten possesses five primary alloy forms: alloyed tungsten, cemented carbide, tungsten carbide, tungsten-based chemicals, and pure tungsten. These tungsten alloy types are classified based on their nominal tungsten content and the ultimate tensile strength of each alloy. Understanding the different varieties of tungsten alloys is essential when evaluating materials for industrial applications due to their unique mechanical, chemical, and physical properties.

Tungsten Carbide

Tungsten carbide is a specialized alloy produced by combining tungsten and carbon in nearly equal proportions. It initially appears as a fine, gray powder that is further processed into an extensive range of industrial materials and components. Renowned for its exceptional hardness, wear resistance, and extreme durability, tungsten carbide boasts the ability to withstand exposure to harsh chemicals, including acids and alkalis, oxidation, and water. With hardness nearly twice that of high-grade steel and a density surpassing both titanium and steel, tungsten carbide sets an industry benchmark for strength and resilience. More than 20 unique grades of tungsten carbide powder exist, each differing in grain size, tensile strength, hardness, and melting points, making it highly adaptable to diverse application environments.

The manufacturing process of tungsten carbide involves advanced sintering and pressing techniques, shaping the powder into robust, long-lasting products, precision tools, and wear-resistant components. Tungsten carbide’s remarkable strength and abrasion resistance account for its widespread use in mining, oil and gas drilling, construction, metalworking, manufacturing, and machining. In fact, approximately 60% of all tungsten carbide alloys are manufactured specifically for critical applications in these industries, underscoring its dominance in high-performance tooling markets.

Tungsten carbide is a cornerstone material in tool manufacturing. Often referred to simply as “carbide,�� this alloy forms the cutting edges of industrial tools such as saw blades, drill bits, end mills, lathe tools, and reamers—enabling these cutting tools to deliver superior durability and longer service life under extreme working conditions. In CNC machining and precision manufacturing, tungsten carbide remains indispensable, being used to produce complete tooling solutions that withstand the high loads and repetitive stresses of automated machine processes. Unlike conventional hand tools, CNC machining implements often utilize solid tungsten carbide for their entire structure, maximizing wear resistance, temperature stability, and edge retention. The use of tungsten carbide in metal cutting, high-speed machining, and tool grinding offers substantially increased productivity, minimized downtime, and lower replacement costs for manufacturers and machinists.

This advanced alloy stands out for its outstanding strength and impressive resistance to corrosion caused by chemicals such as acids and alkalis, as well as from oxidation and water exposure over time. With more than 20 available powder grades covering a wide spectrum of grain sizes, hardness ratings, tensile strengths, and melting points, tungsten carbide’s versatility ensures that professionals can select the optimal material for each demanding engineering or manufacturing application.

Tungsten carbide is processed through specialized sintering techniques to produce an array of durable products, machine parts, wear plates, and tooling inserts, making the alloy exceptionally prized in mining, construction, oil and gas, aerospace, wood processing, and advanced manufacturing. Its properties, such as high compressive and tensile strength, extreme surface hardness, low coefficient of expansion, and high melting point, guarantee outstanding wear resistance and stability—even in challenging environments with abrasive or corrosive exposures.

Manufacture of Tungsten Carbide

Tungsten carbide alloy is produced by reacting tungsten metal with carbon at extremely high temperatures, typically in the range of 1,400 to 2,000°C. Alternative methods include a low-temperature fluid bed process, where tungsten metal or blue tungsten oxide (WO₃) is combined with carbon dioxide or carbon monoxide and hydrogen gases at temperatures between 900 and 1,200°C. These optimized production protocols yield high-purity, fine-grain carbide particles essential for advanced industrial and tooling applications.

Further chemical vapor deposition (CVD) techniques have been developed for high-purity carbide formation, including the following reactions:

Tungsten hexachloride is reacted with hydrogen (serving as a reducing agent) and methane (as the carbon source) at a precisely controlled temperature of 670°C.

WCl₆ + H₂ + CH₄ → WC + 6HCl
Tungsten hexafluoride is also reacted with hydrogen as a reducing agent and methanol as a carbon source at a temperature of 350°C.

WF₆ + 2H₂ + CH₃OH → WC + 6HF + H₂O

Properties of Tungsten Carbide

Tungsten carbide features a macrocrystalline structure that imparts unparalleled strength, toughness, and longevity compared to most other metal alloys. The addition of carbon in the structure lowers its melting point to approximately 2,870°C while providing a notable boost in hardness, allowing it to achieve a score of 9 on the Mohs mineral hardness scale—rivaling corundum and surpassed only by diamond and some advanced ceramics. While this alloy demonstrates superior acid resistance, high compressive strength (exceeding 540,000 psi in some grades), and robust corrosion resistance, it can react with oxygen and strong oxidizers when subjected to very high temperatures.

Tungsten carbide is both hard and durable, with excellent performance in tensile and compressive strength and moderate electrical conductivity. Its density (typically around 15 g/cm³) further enhances its performance in applications demanding stability, vibration damping, and dimensional accuracy over long operational lifespans.

Main Uses of Tungsten Carbide

Tungsten carbide is the industry standard for manufacturing high-performance cutting tools, drill bits, milling inserts, saw blades, mining picks, wear-resistant machine parts, and gauge blocks. Its high abrasion resistance and ability to maintain sharp cutting edges at elevated temperatures make it the preferred material for production lines, metal fabrication, CNC machining, casting, and aerospace part manufacturing. Carbide tooling remains sharper and usable much longer than steel-based rivals, offering tremendous value by decreasing tool changeover frequency, reducing production downtime, and improving manufacturing throughput.

Furthermore, tungsten carbide is essential in defense and ammunition manufacturing, where its extreme hardness and density enable it to produce armor-piercing ammunition, kinetic energy penetrators, and other specialized rounds capable of breaching reinforced targets such as tank armor and concrete fortifications. The alloy is foundational in mining and drilling, being commonly used to construct rock drill bits, rotary cutters, plow chisels, tunnel boring heads, and wear plates for earthmoving equipment to maximize penetration and durability in harsh geological conditions.

Beyond traditional industrial uses, tungsten carbide serves as an efficient neutron reflector in the nuclear energy sector, corrosion-resistant material for precision surgical tools, hard-wearing elements in sporting equipment (such as ice spikes, cycling tire studs, and trekking pole tips), and an attractive material in jewelry manufacturing due to its metallic luster and lasting finish. Its versatility and long lifespan lead to a lower cost of ownership, reduced maintenance requirements, and higher total equipment effectiveness in sectors where uptime and reliability are mission critical.

Health Issues Associated With Tungsten

Exposure to tungsten carbide dust can pose significant occupational health risks, including respiratory conditions such as fibrosis and chronic lung disease. Industries using tungsten carbide should institute comprehensive dust control, personal protective equipment measures, and comply with occupational health and safety regulations to safeguard workers from hazardous inhalation and minimize industrial hygiene risks.

Cemented Carbide

Cemented carbide is a widely utilized tungsten alloy, created by combining tungsten carbide grains with a metallic binder—most commonly cobalt. This sintered composite structure adds toughness, reduces brittleness under high pressure, and makes cemented carbide suitable for highly demanding structural and wear-resistant applications. The integration of cobalt ensures improved mechanical durability and impact resistance compared to non-cemented tungsten alloys.

Composition of Cemented Carbide

Cemented carbides generally feature a composite structure composed of hard carbide particles (such as tungsten carbide or sometimes titanium carbide) serving as the aggregate, embedded within a metallic matrix composed of cobalt, nickel, or iron. This engineered composite structure, similar in concept to a grinding wheel’s abrasive grains and binder, yields a material with remarkable toughness and wear resistance.

Key production steps include hot isostatic pressing (HIP), where carbide grains are merged with molten binder metal while maintaining solid carbide phases (due to their significantly higher melting point). This creates a complex microstructure that enables the alloy’s unique properties, including fracture toughness and thermal shock resistance, ideal for high-impact and high-heat manufacturing environments.

Properties of Cemented Carbide

The thermal expansion of cemented carbide is influenced by the metallic binder content, most commonly cobalt. Generally, increasing the proportion of cobalt increases the thermal expansion coefficients, affecting the alloy’s dimensional stability under temperature fluctuation. Cemented carbides retain high compressive strength, exceptional hardness, and superior resistance to deformation and impact, making them especially effective in high-speed machining and industrial cutting operations. Tailoring the binder composition allows manufacturers to optimize the alloy for specific wear, hardness, and toughness requirements.

Main Uses of Cemented Carbide

Cemented carbide is the material of choice for indexable inserts, cutting tool inserts, metal cutting tools, mill rolls, boring and threading equipment, die-casting molds, and progressive stamping dies. Its reinforced structure ensures reduced vibration susceptibility and enhanced precision in critical machining and toolroom applications. To prolong tool lifespan and boost surface finish, cutting tools often receive specialized coatings such as titanium aluminum nitride (TiAlN), titanium carbide (TiC), titanium nitride (TiN), and aluminum titanium nitride (AlTiN)—as well as tungsten-based coatings—to provide even greater abrasion and oxidation resistance.

Heavy-duty mining and tunneling equipment are typically outfitted with cemented carbide-tipped cutting elements, known as bottom bits, which deliver unparalleled drilling and excavation capability in the world’s toughest geotechnical conditions. The alloy further finds use in hot and cold rolling mill rolls, high-performance industrial pump pistons, valve seats, wire drawing dies, and specialized components for nuclear power applications due to its high thermal and mechanical stability.

Alloyed Tungsten

Alloyed tungsten encompasses a broad class of high-performance tungsten alloys produced by combining tungsten with various metals such as copper, nickel, and iron. These alloys are valued in specialized engineering, electronics, and industrial applications where a customized balance of density, machinability, electrical conductivity, or magnetic properties is required. For example, tungsten-nickel-iron alloys benefit from nickel’s enhancement of density, strength, and ductility, making them ideal for counterweights, defense projectiles, and high-mass components. Tungsten-nickel-copper alloys, with added copper content, are non-magnetic—critical for applications in medical imaging (such as oncology systems), electrical contact shielding, and non-magnetic sensor housings.

Properties of Alloyed Tungsten

Alloys of tungsten containing copper or nickel exhibit lower tensile strengths (typically ranging from 500 to 700 MPa) and reduced ductility relative to steel; however, they provide unique characteristics such as high thermal and electrical conductivity (in tungsten-copper blends) or non-magnetic behavior (in tungsten-nickel-copper alloys). Their mass density and electrical properties make these alloys highly desirable in the manufacture of electrical contacts, EDM electrodes, thermal management systems, and heavy-metal shielding.

Uses of Alloyed Tungsten

Tungsten-copper alloys are primarily used in high-temperature heating elements and electrical resistance heating coils, due to their outstanding stability and low thermal expansion. You’ll find these alloys in products such as water heaters, industrial furnaces, kettles, ovens, specialty resistors, and advanced stove plates. Their performance in environments with rapid temperature cycling, high electrical loads, and corrosive atmospheres makes them indispensable in both consumer appliances and advanced manufacturing facilities.

Heavy Metal Tungsten Alloys

Heavy metal tungsten alloys feature exceptionally high tungsten content (up to 90% or higher), with a minor proportion of additional elements. Incorporating 2% thorium oxide into tungsten alloys, for instance, significantly enhances thermionic electron emission properties, making these high-density, heavy metal alloys essential for a variety of specialized electronics, aerospace, medical, and nuclear applications, such as radiation shielding and electrical contacts.

Pure Tungsten

In its pure metallic state, tungsten displays exceptional electrical conductivity and is primarily employed in electrical, electronic, and semiconductor applications. Due to its remarkable melting point (the highest of all metals at 3,422°C), pure tungsten is indispensable for fabricating filaments in lighting, electrical contacts, heater elements, and as a crucial interconnect material in circuit boards and microelectronics.

Tungsten Based Chemicals

Tungsten chemistry plays a crucial role in the production of pigment phosphors, organic dyes, catalysts, X-ray screens, lubricants, and fire-resistant coatings. Tungsten compounds and salts contribute to a diverse range of chemical and industrial processes, offering unique properties for electronic, catalytic, and material science applications.

TA-1 Tungstic Acid

Tungstic acid is a yellow, fine-grained powder with an ultra-small particle size and excellent chemical purity. It is highly reactive and primarily used as a sintering enhancer in the fabrication of ultra-high-temperature ceramics, advanced catalysts, and certain specialty glass coatings.

ST-0 Sodium Tungstate Dihydrate

Sodium tungstate dihydrate is a high-purity, water-soluble white crystalline powder, used extensively in the synthesis of other tungsten compounds, corrosion inhibitors, catalysts, and as a starting material for electronic-grade tungsten processing. Its ability to dissolve completely in water makes it valuable for chemical and industrial manufacturing requiring high purity and low residue.

AMT-0 Ammonium Metatungstate

Ammonium metatungstate is a tungsten salt appearing as a water-soluble white crystalline powder and is favored in catalyst production, reactive media for electronic components, and advanced ceramics. Its complete solubility in water ensures its suitability in high-purity, precision chemical synthesis and material preparation.

TO-0 Tungsten Trioxide

Tungsten trioxide, found as either yellow or green ultra-fine powder, is highly pure and features an advanced crystal structure. It is deployed in the manufacturing of smart window coatings, gas sensors, pigment formulations, and as a precursor for producing metallic tungsten and tungsten oxide-based catalysts.

TC-1 Tungsten Carbide

TC-1 tungsten carbide chemical is a black, fine-grained powder, commonly used in manufacturing high-density suspensions and enhancements for SPT-3, as well as in the production of strong, dense composites, abrasives, and advanced coatings designed for extreme service environments.

Leading Manufacturers and Suppliers

Chapter 3: What are the differences between tungsten and tungsten carbide?

Tungsten was first identified in 1783 through the charcoal reduction of the oxide extracted from wolframite. It has been utilized for centuries, notably in the production of porcelain for pottery. In various countries, tungsten is known as wolfram, a term derived from the German words "wolf rahm," meaning "wolf's foam." The name tungsten originates from Swedish, meaning "heavy stone."

Tungsten serves as a base and alloying element, with tungsten carbide being one of its most common alloys. Key tungsten minerals include scheelite and wolframite. Tungsten's first major modern application was as a filament material in light bulbs, a use that remains widespread today.

Tungsten carbide is a compound composed of equal amounts of tungsten and carbide atoms. It appears as a gray powder that is compressed and shaped through sintering for various applications, including equipment, cutting tools, abrasives, armor-piercing shells, and jewelry. Like tungsten, tungsten carbide has a high melting point of 5,200°F (2,870°C) and a boiling point of 10,830°F (6,000°C).

There are two main types of tungsten carbide compounds: tungsten carbide (WC) and tungsten semicarbazide (W₂C). Additionally, tungsten carbide is categorized into two forms: α-WC, which has a hexagonal structure, and β-WC, which has a cubic structure that is stable at high temperatures.

Tungsten

Throughout the centuries, tungsten's popularity has increased due to its exceptional resistance to high temperatures, low vapor pressure, high melting point, stiffness, conductivity, and density. It is often alloyed with metals such as nickel, copper, and iron to create a more malleable microstructure that improves machinability and ductility while preserving tungsten's superior properties. Adding tungsten to any metal enhances the alloy's quality, leveraging tungsten's strength and rigidity.

Tungsten is the second hardest material on Earth but is naturally brittle, making it challenging to work with. While pure crystalline tungsten is more ductile and easier to cut, it is costly and typically reserved for specialized applications. To enhance its ductility and workability, tungsten is usually heated during processing.

The powder form of tungsten is the raw material for processing tungsten products and alloys. It is made into wire, rods, tubes, plates, and various shapes. Tungsten powder is mixed with other metal powders, such as molybdenum, rhenium, copper, and high density tungsten. When it is produced as tungsten carbide powder, it is used to produce hard alloy tools. Although tungsten powder has many uses, it has to be handled with care since it can spontaneously ignite in the open air.

Tungsten Carbide

Tungsten carbide is produced by combining tungsten powder with carbon powder through various methods. One approach involves heating the powders to temperatures above 2,200°C to initiate a chemical reaction. This high-temperature carburization results in a stoichiometric ratio of one tungsten atom to one carbon atom, forming crystals that are 100 µm or larger.

The resulting WC alloy from the combination process is more rigid than steel and boasts superior compression strength. Tungsten carbide (WC) is a highly stable alloy that resists deformation under extreme temperatures, whether hot or cold. In its monocarbide form, WC's hardness is comparable to that of diamonds and it offers excellent resistance to galling, abrasion, and impact. Its ability to withstand thermal shock makes it up to 100 times more durable than steel in extreme conditions.

When tungsten carbide is combined with a binder like nickel or cobalt, it creates a "cermet," or ceramic metal. This composite material is highly durable, capable of enduring cutting, oxidation, high temperatures, and severe wear, with a density of 15.7 g/cm³. Its exceptional toughness makes it challenging to machine, typically requiring diamond-coated tools, as most conventional bits are made from tungsten carbide itself.

Tungsten Carbide vs Tungsten

The elastic modulus, or Young's modulus, measures a metal's stiffness or rigidity. For comparison, magnesium has an elastic modulus of 45 gigapascals (GPa), while tungsten has an elastic modulus of 407 GPa. When tungsten is combined with carbon to form tungsten carbide, the alloy achieves an elastic modulus of 600 GPa, making it nearly as hard as diamonds, which have an elastic modulus of 1,000 GPa.

The shear modulus, also known as the modulus of rigidity, measures a material's resistance to shearing or torsion forces, defined as the ratio of shear stress to shear strain. Tungsten has a shear modulus of 161 GPa, which is twice that of steel, which has a shear modulus of 80 GPa. Tungsten carbide, however, exhibits an even higher shear modulus of 274 GPa, surpassing both steel and tungsten.

Due to their high rigidity and stiffness, tungsten and tungsten carbide are brittle and not suited for high-tension applications. Brittle materials excel in compression. Tungsten carbide, for instance, has a compressive strength of 2,683 MPa at room temperature and maintains this strength despite temperature changes. In contrast, steel has lower compressive strength and its performance varies with temperature fluctuations.

In applications involving heat from friction or electricity, metals often experience changes in thermal conductivity due to temperature variations. Tungsten, however, maintains its thermal conductivity stability and is unaffected by temperature changes. This stability makes tungsten ideal for use in filaments, tubes, and heating coils. It retains its properties under thermal stress, making it suitable for a diverse array of applications.

Among the various properties of tungsten carbide, its hardness stands out as the most remarkable. High hardness indicates that a material is resistant to surface damage from scrapes, pitting, scratches, and abrasions. Hardness is typically measured using an indentation test, where a small sphere or indenter is pressed into the material's surface.

Among the various hardness scales, the Rockwell scale is the most commonly used. For measuring tungsten carbide, the Rockwell A scale is employed, specifically designed for very hard metals. In this test, a diamond indenter is pressed into the material. Tungsten carbide has a Rockwell A hardness rating of 94 HRA, which enables it to cut through hardened steel effectively.

Chapter 4: What are the different forms of tungsten?

Tungsten, like other metals, is available in various forms and shapes to facilitate shipping and meet customer needs. These forms include bars, sheets, and foil, which are produced from the extraction of tungsten ore. Tungsten also comes in different alloys, each tailored for specific applications and processes.

Bars

Tungsten bars are composed of 99.9% pure tungsten powder that has been shaped into various forms. These bars retain all of tungsten's properties, including its high density and resistance to high temperatures. When alloyed with other metals, tungsten bars can be produced in six different alloys and customized for specific applications.

As one of the rare metals found in the Earth's crust, tungsten has a density comparable to gold and is 1.7 times denser than lead. Working with pure tungsten bars can be challenging due to their extremely high melting point of 3,422°C (6,191.6°F). However, tungsten bars are known for their stability under various conditions, including exposure to water, air, and sulfuric acid. They do oxidize when exposed to the atmosphere.

Tungsten bars are produced through powder metallurgy. In this process, tungsten ore is first reduced to a fine powder and then chemically processed to create tungsten oxide. The tungsten is extracted from the oxide through heating, forming pure tungsten, which is then pressed into molds. After shaping, the bars are sintered to further consolidate and bind the metal powder.

Once processed, tungsten bars are sent to manufacturers for the production of various components such as cathodes, wire, pins, electrodes, stainless steel additives, and heating elements. Producers aim to supply tungsten in the appropriate form to meet the specific requirements of their customers.

Foil

Tungsten foil is a thin, smooth metal sheet with a black metallic sheen, produced by rolling tungsten sheets through cold or hot processes to achieve the desired thickness. The manufacturing of tungsten foil starts with tungsten bars that are rolled into flat sheets, which are then further processed to create the foil. The process includes vacuum annealing furnaces to strengthen the tungsten.

Stamped and drawn tungsten foil is utilized in high-temperature applications such as heat shielding, heating elements, and furnaces. It is also used in semiconductors due to its low thermal expansion coefficient and low electrical resistivity. Tungsten foil typically ranges in thickness from 0.05 mm (0.002 in) to 1 mm (0.04 in) and has a purity of 99.9%. It is available in widths from 100 mm to 400 mm (4 in to 16 in) and lengths from 400 mm to 1500 mm (16 in to 59 in).

Tungsten foil is silver gray with a metallic luster, a melting point of 3410o C (6170o F), and density of 19.35g/cm3. It is used to manufacture electric light source parts, medical shields, current collectors for aluminum ion batteries, heating elements, and heat shields. Additionally, tungsten foil is used to make tungsten evaporation boat.

Plate

Similar to tungsten sheets and foil, tungsten plates are flat pieces made from tungsten powder. The manufacturing process involves extracting tungsten from its ore, grinding it into pure tungsten powder, and then molding it into plates using heat and pressure. After shaping, the plates are annealed to improve their strength. While tungsten plates and sheets are similar, they are distinguished by their thicknesses.

Processing pure tungsten plates is challenging due to tungsten's exceptionally high melting point. Every step in the process must be carefully controlled to prevent damaging the plates. During the rolling process, manufacturers must precisely heat the rollers to match the specific rolling conditions.

Tungsten plates are available in a range of sizes and thicknesses, with most being cast. The standard thicknesses start at 6.35 mm (0.25 in), though custom thicknesses can be produced for specific applications. Tungsten plates are commonly used for shipping due to their manageable size and ease of handling.

Tungsten plates are utilized across various industries, including aerospace, construction, and electronics. They are used to manufacture turbine blades for generators and aircraft engine components because of their high melting point and exceptional strength. Additionally, tungsten plates are processed into radiation protection materials due to their density, radiation absorption properties, and resistance to corrosion.

Rod

Tungsten rods are cylindrical extrusions available in various lengths to suit different applications. They come in a range of diameters, shapes, sizes, and tungsten grades. Their widespread use is attributed to their remarkable strength, durability, and corrosion resistance. Tungsten rods can be machined, ground, and shaped to create a diverse range of parts and products.

Tungsten rods are available in various shapes such as round, square, rectangular, octagonal, hexagonal, and oval, depending on the manufacturer and intended use. However, a notable challenge with tungsten rods as raw materials is the difficulty in fabricating them into finished products due to tungsten's high melting point.

Tungsten rods have many uses and are a critical part of engineering designs and industrial manufacturing. A common use for tungsten rods is as cutting tools, which is superior to cutting tools made of aluminum or steel. In medicine, tungsten has been perfected to be used as implants and in medical procedures that require exposure to extreme temperatures due to sterilization. The factor that makes tungsten rods the first choice for manufacturing, production, and industrial applications is its exceptional wear resistance, which makes it perfect for operations that require repeated use of a tool.

Sheet

Tungsten sheet is a flat form of tungsten that is thicker than foil but thinner than tungsten plate. It is produced from tungsten slabs refined during processing. Tungsten sheets are distinguished from foil and bars by their thickness, which ranges from 1.5 mm to 2.2 mm (0.06 in to 0.09 in). Tungsten material thicker than 0.25 mm (0.1 in) is categorized as tungsten plate.

The surface of tungsten sheets can vary, including finishes such as shiny, matte, satin, or rolled, depending on their thickness. The sheets are produced by isostatically pressing and sintering high-purity tungsten powder into ingots using powder metallurgy techniques. Before reaching the final finish, the ingots are deformed and heat-treated. The resulting blanks are then further processed by hot or cold rolling into sheets.

Tungsten sheets, like tungsten plates and foils, are prized for their radiation shielding properties and are used in manufacturing electronics, cables, and shipbuilding materials. They are particularly valuable for specialty applications that leverage their unique attributes. Tungsten sheets are often preferred over other high-density metals such as lead, tantalum, and uranium. Lead and uranium are avoided due to their toxicity, while tantalum, though a viable alternative, is very costly compared to tungsten.

Chapter 5: What are the key applications and benefits of using tungsten metal?

This section will explore the uses and benefits of Tungsten metal.

Applications of Tungsten Metal

Tungsten is commonly employed in making filaments for incandescent light bulbs. However, these bulbs are being gradually replaced in many places because they are not energy-efficient and convert more energy into heat than into light. When an electric current flows through the filament, it heats up and emits light. Tungsten’s ability to endure high temperatures allows the filament to remain functional and continue glowing despite the intense heat.

Tungsten is frequently used in the production of cutting tools. It can be fashioned into blades or combined with other elements such as nickel, copper, or carbon to enhance its properties. Tools made from tungsten or its alloys are exceptionally hard and can endure high temperatures, allowing them to operate for extended periods without melting or deteriorating.

Tungsten is also utilized in drilling and boring equipment. The metal’s exceptional hardness makes it ideal for drill bits and heavy-duty earth-boring machinery. Additionally, tungsten is used in dental drills. Cemented carbide, a tungsten-based material, is commonly employed in high-speed tools for mining refineries and other demanding applications. Due to its durability, tungsten is also popular in the creation of jewelry.

Calcium and magnesium tungstate are employed in fluorescent lighting applications. Tungsten is also utilized as a catalyst in the reduction of certain complex compounds. Additionally, tungsten plays a role in the production of magnetrons used in microwave ovens. Old television sets with cathode ray tubes incorporate tungsten due to its ability to endure the high temperatures generated over time.

Tungsten is employed in applications where high density is essential. Common uses include producing counterweights, ship anchors, and tail ballasts for engines in rockets, airplanes, and other vehicles.

Tungsten finds several important military uses. Its strength and hardness make it suitable for producing armor-piercing ammunition. Tungsten or its alloys are sometimes used in the manufacture of missiles, grenades, shells, and large rounds designed to penetrate heavily fortified targets such as tanks or bunkers.

Tungsten (IV) sulfide serves as a lubricant capable of enduring extremely high temperatures, making it ideal for use in high-speed tools.

Advantages of Using Tungsten

Advantages of utilizing tungsten metal include:

Resistance to High Temperature

Among all pure metals, tungsten boasts the highest melting point at 3,244°C. This exceptional property allows it to be utilized in environments with extremely high temperatures where other metals would fail.

High Density

Tungsten has a high density of 19 g/cm³, attributed to its microcrystalline structure. This characteristic makes it valuable in applications that need substantial mass within compact dimensions.

Low Thermal Expansion

Among all pure metals, tungsten has the lowest coefficient of thermal expansion. Unlike steel, tungsten remains highly stable at elevated temperatures and does not change in form or size.

Electronic Structure

Due to its excellent conductivity and general inertness, tungsten is commonly employed in electrical devices that operate under high levels of radiation. It also serves as an ideal material for electrodes in the electrolysis of various substances.

Corrosion Resistance

Tungsten's exceptional resistance to corrosion allows it to be used in diverse applications where corrosion is a concern. It performs well in outdoor environments exposed to water and acids. Typical uses of tungsten include fishing lures, ship construction, and certain types of jewelry.

Fabrication Strengthening

Despite its strength, tungsten can be drawn into extremely thin wires without breaking. For example, the filaments in light bulbs are made from tungsten, allowing them to endure high temperatures while remaining functional.

Disadvantages of Tungsten

Brittle Metal

In its pure form, tungsten is quite brittle and can easily fracture. It cannot withstand stretching, compression, or twisting without losing its shape. This fragility is due to its rigid structure, which limits its ability to be manipulated without failure.

Health Concern

Inhaling tungsten can irritate the mucous membranes and the lungs. It is considered highly toxic, and uncontrolled exposure could pose significant risks to both human health and the environment.

Tungsten Costs

Tungsten is a valuable metal with a high cost due to its unique properties. Its rarity and the growing demand contribute to its continued high price.

Weight of Tungsten

Tungsten is a dense metal, which makes it challenging to work with. For example, tungsten jewelry can be quite heavy, often causing discomfort for the wearer. Similarly, in the production of earth-boring equipment, the metal's weight results in high transportation costs due to the difficulty of moving such heavy machinery.

Economic Value

Although tungsten is expensive, it does not retain its value upon resale. Unlike gold, which can be fashioned into various jewelry pieces and resold at a value close to its original purchase price, tungsten does not hold the same resale value.

Comparing Tungsten with other Metals

Compared to other metals, tungsten has the following specific applications and uses:

Manufacturing Heavy-Duty Tools

Tungsten and its alloys are used to manufacture durable tools for cutting and crushing. Unlike steel, which can wear out and break when used on tougher materials, tungsten offers superior longevity and strength, making it the ideal choice for heavy-duty applications.

Electrical Conductivity

While tungsten is a good conductor of electricity, its high cost, weight, and brittleness make it less favorable compared to other metals. Copper, aluminum, and steel are generally preferred for electrical conduction due to their more advantageous properties.

Building Material

Although tungsten is a hard and tough metal, it is not ideal for use in the construction industry. Its brittleness makes it unsuitable for large structural applications. Instead, lightweight and strong materials such as reinforced steel are more appropriate for building projects.

Chapter 6: Who are the leading manufacturers of tungsten?

ATI - Allegheny Technologies Incorporated

ATI offers a wide range of metals, including various types of tungsten, known for their high performance and superior quality. In addition to standard metals, ATI manufactures specialty metals to fulfill specific customer requirements and industrial demands. With over 25 years of experience, the company processes tungsten in the Dallas, Texas area.

Betek GmbH & Co.

Betek specializes in manufacturing tungsten carbide tools, systems, and wear protection. The company produces high-quality tools tailored to specific industrial applications, ensuring a longer lifespan and reducing the need for frequent tool replacements. While focusing on current needs, Betek is also committed to future innovations to address evolving demands and requirements.

Buffalo Tungsten Inc.

Buffalo Tungsten produces tungsten and tungsten carbide powders of the highest quality. They offer a range of powders including fine, coarse, crystalline, ultra-high purity, high density, low grade, and granulated tungsten. Their powders boast a purity of 99% with particle sizes ranging from 10 microns (µ) to 50 µ. The company also provides ultra-high purity 5N tungsten metal powder, with a purity level of 99.999%. Buffalo Tungsten enhances the density, particle size, and flow characteristics of their powders through additional processing.

H. C. Starck Solutions

Starck Solutions manufactures high-quality tungsten chemicals, metal, and tungsten carbide. Their product range includes various tungsten forms, from tungstate to tungsten carbide, available in both ultrafine and coarse grain sizes. The company is committed to adhering to the highest standards in tungsten production and works closely with customers to develop innovative, customized solutions that meet and exceed their requirements.

Federal Carbide Co.

Federal Carbide produces a variety of tungsten products, including tungsten heavy alloy, tungsten carbide, tungsten carbide seal rings, and tungsten heavy metal alloy radiation shields. Their tungsten heavy alloy items are available as machinable blanks or custom parts tailored to specific customer requirements. Their product range spans the full spectrum of the tungsten market, including components for engines, helicopter rotors, firearms, and golf club weights. Federal Carbide emphasizes providing the hardest man-made metal, tungsten carbide, at the lowest cost with fast and efficient delivery. The company's commitment to hard work and quick responses to customer needs underpins its goals.

Conclusion

In summary, tungsten is a naturally occurring metal found on earth. It is a very unique metal as it has a very substantial chemical structure. It has a very high melting and boiling point and is a very dense metal with an over the top weight and density. Despite all these excellent characteristics, tungsten is a very brittle metal and cannot be used as would other metals like copper and iron.