Tungsten is a rare natural metal found in minerals such as wolframite.
Pure tungsten is grey to silver in color and has a lustrous appearance.
Tungsten is located on the periodic table under the symbol “W” with the atomic number of 74 (atomic numbers are based on number of protons an element contains).
Tungsten is extremely strong, dense, and hard to melt, making it perfect for use in industrial applications and everyday products.
Table of Contents
- Melting Point
- Tensile Strength and Ductility
- Interesting Facts
- How is tungsten used?
History and interesting facts about tungsten
Tungsten is a versatile metal with a rich 240 year history.
The following sections cover the history of tungsten and provide facts such as tungsten’s melting point, strength, and other interesting tidbits.
In 1781 Carl Wilhelm Scheele, a German Swedish chemist discovered a new kind of acid named tungstic acid could be obtained from scheelite (this was the name for tungsten back then).
Two Spanish chemists Juan José Elhuyar and Fausto Elhuyar (brothers) came along a couple years later and were the first to isolate tungsten in 1783.
The Elhuyar brothers utilized an acid made from wolframite that was nearly identical to tungstic acid.
They isolated tungsten by reducing this acid with charcoal and originally called the element “wolfram” or “volfram”.
The name tungsten came from the Swedish word tung sten which means “heavy stone” and is commonly used in English and French languages.
European languages often refer to tungsten as “wolfram” or “volfram”, just like the Spanish chemist brothers that originally isolated tungsten back in the 1700’s.
Where did the name wolfram come from?
Wolfram comes from the German language and means “wolf’s soot” or “wolf’s froth”.
The origin of the name wolfram is not well known.
Some believe the name wolfram came from the large amounts of tin consumed by the mineral during its extraction, as the process would “devour tin like wolves devour a sheep”.
Tungsten melting point
Tungsten melts at 6177 °F (3414 °C or 3687 kelvin), making it the metal with the highest melting point.
Carbon wins first place, but tungsten comes in second for the highest melting point of all elements on earth.
To provide perspective, steel melts between 2500 – 2800°F, gold melts at 1,948°F, and aluminum melts at 1221°F.
Tensile strength and ductility
Tensile strength is the maximum load or pressure a material can withstand without breaking.
This is often referred to as pounds per square inch or psi.
Tungsten has a tensile strength of 100,000 – 500,000 psi at room temperature
It’s strength is reduced as heat is applied.
For example, the tungsten tensile strength at 932°F is 75,000 – 200,000 psi, and that reduces to 50,000 – 75,000 psi at 1832°F.
Tungsten is not ductile at room temperature, meaning it is nearly impossible to to stretch, spread, or bend it in without breaking.
The poor ductility of tungsten makes it a challenge to work with unless it is heavily alloyed with other metals.
Tungsten is extremely dense at 19.25 g/cm³.
This becomes apparent when comparing density to other metals.
|Tungsten vs Lead Density
|Lead 11.29 gram/cm3
|Tungsten Density vs Gold
|Gold 19.30 g/cm³
|Steel vs Tungsten Density
|Steel 8.05 g/cm3
|Tungsten Density vs Iron
|Iron 7.86 g/cm3
|Aluminum vs Tungsten Density
|Aluminum 2.70 g/cm3
|Tungsten Density vs Silver
|Silver 10.50 g/cm3
Using the chart above, gold is slightly more dense than tungsten, but iron and silver are nearly half as dense.
The density of water is 1 gram/cm3, so tungsten is about 19 times more dense than water.
The only elements more dense than tungsten are: plutonium, neptunium, rhenium, platinum, iridium, and osmium.
There are multiple processes used to test how hard a material is including the Mohs, Rockwell, Brinell, Vickers, and Knoop hardness tests.
The following table shows where tungsten compares on each hardness test:
|Tungsten Hardness Rating
|Tungsten Mohs Hardness
|Tungsten Rockwell Hardness
|66 (Rockwell A), 31 (Rockwell C)
|Tungsten Brinell Hardness
|Tungsten Vickers Hardness
|Tungsten Knoop Hardness
To provide a comparison, the hardness of tungsten is rated at 9 on the Mohs scale whereas the notoriously hard diamond is rated at 10.
- Tungsten is found in nature alongside other elements in ores and is not found in a pure form.
- Tungsten is similar in density to gold, scammers will coat tungsten bars in a thin layer of gold to create counterfeit gold bars. This trick is still used today and the scam can remain unobserved when thorough tests are not performed.
- As of 2020, China had the world’s largest tungsten reserves at 1.9 million metric tons followed by Russia (400,000) and Vietnam (95,000). The USA has its own natural tungsten deposits, however they are not being mined due to a number of social and political concerns.
- Tungsten rings are incredibly strong and cannot be safely cut off a finger during an emergency. First responders use vice groups to apply pressure in order to fracture and remove the ring safely from the finger.
- Tungsten is considered vital and is stockpiled by the United States military for national defense. The US does not mine their own tungsten directly.
Questions and answers about tungsten
It is impossible to cover every aspect of this metal as tungsten is a diverse metal that has nearly unlimited uses.
The below Q&A covers the most commonly asked questions about tungsten.
How is tungsten used and what type of products are made from tungsten?
The use of tungsten is very diverse and is incorporated in everything from military equipment and munitions to jewelry and golf balls.
While most products are made from tungsten alloys, there are specific applications and use cases for products to be made from pure tungsten as well.
Products made from pure tungsten
Pure tungsten is found in everything from smelting furnace heating elements, to metalworking plants and rocket engine nozzles.
A common use for pure tungsten is in the fabrication of filament wiring such as:
- tungsten filaments in incandescent light bulbs
- starter filaments of fluorescent light bulbs
- filaments of cathode ray tubes
Since pure tungsten is brittle, it is commonly mixed with other materials to create tungsten alloys.
Products made from tungsten alloys
Metal alloys are man-made materials in which metals are combined with other metals, non-metals, or both.
Common types of tungsten alloy include tungsten nickel iron, tungsten carbide, niobium tungsten, and molybdenum tungsten.
You will find tungsten alloys in metal bearings, cutting tools, and surgical instruments.
Even common everyday products like lead-free fishing weights, shotgun pellets, weighted throwing darts, and jewelry are made from tungsten alloys.
Products made from tungsten you can buy
Products that contain tungsten include knives, jewelry, light bulbs, and home electronics.
The following are interesting tungsten related items you can buy:
- Different shapes of tungsten items. A 2″ tungsten sphere weighs 3lbs, whereas a 4″ tungsten cube weighs over 41lbs. Both items are a great way to decorate your desk, start a conversation, or teach others about density.
- Tungsten powder is used to add weight to your DIY projects. For example, rather than using lead you can use non toxic tungsten powder can be used to add weight to golf clubs.
- Professional throwing darts are often times weighted with tungsten.
Industries using tungsten
Some of the most common industries benefiting from the use of tungsten are:
- Military and Personal Defense (weapons, body armor)
- Aerospace (rotor blades, propellers, trim weights, prototyping)
- Medical (radiation shielding, producing isotopes, x-rays)
- Oil and Natural Gas (protection of sensitive equipment)
- Machine Shops (high temperature tooling, boring bars)
These are just a few, but tungsten can really be used in any industry that requires an extremely hard metal, especially since it can be alloyed with other metals for specific requirements.
What is tungsten carbide?
Tungsten carbide is an incredibly hard material made from equal parts of carbon atoms and tungsten.
Due to its hardness, tungsten carbide surfaces will rarely suffer from scratches or abrasions.
The hardness, availability of textures, and shapeable form makes tungsten carbide highly desirable for the fabrication of items such as golf clubs and drill bits.
How do you cut tungsten? Is breaking better?
Due to its strength, tungsten can only be cut using specific tools and methods.
The most common ways to cut tungsten include using an angle grinder or a dremel with a diamond tipped wheel.
Use a heavy vice grip to secure the piece of tungsten as any vibration will affect the quality of the cut and cause your diamond cutting wheel excessive wear.
It is also suggested to cut tungsten at a slow to medium speed as higher speeds will also wear out and cause chipping in your cutting wheel.
Forum discussions indicate people prefer to break tungsten rods as pure tungsten is quite brittle.
They break tungsten rods with special machinery that causes the tungsten to fracture, and then use a belt sander to smooth out and remove rough edges from the end points.
Welders use similar methods listed above to cut their tungsten electrodes.
They also use tungsten electrode sharpener rotary tools that are specifically designed to cut and sharpen tungsten with ease.
Is tungsten magnetic?
Pure Tungsten is paramagnetic, meaning it has a weak attraction to magnetic fields.
If you were to wave a magnet in front of a piece of tungsten, the tungsten would not react to the magnet in any way because tungsten is a non-ferrous metal.
While pure tungsten is not magnetic, tungsten alloys can be magnetic depending on the other metals mixed into the metal alloy.
Does tungsten conduct electricity?
Tungsten is a good conductor of electricity when compared to other metals like iron.
While metals like copper are more electrically conductive, tungsten is preferred for specific applications because it does not erode or evaporate under pressure or heat like other metals.
Tungsten carbide also conducts electricity when compared to metals such as steel and is frequently used in electrical components.
However, there is no need to worry if you own a tungsten carbide wedding ring because they become ceramic as they are formed and lose their electrically conductive metallic properties.
This means tungsten carbide wedding rings do not conduct electricity very well and are generally considered safe when compared to traditional gold and silver rings.
Does tungsten conduct heat?
Tungsten is a good conductor of heat with a thermal conductivity rating of 170 W/(mK).
Let’s take a look at the thermal conductivity of common metals.
|Thermal conductivity (W/m-K)
As demonstrated in the table above, tungsten thermal conductivity is in the mid-tier range when compared to other common metals.
For example, tungsten is more heat conductive than steel and brass, but less heat conductive than silver and copper.
What is the price of tungsten?
The price of Tungsten fluctuates from year to year, depending on a number of variables including the geographical location of the buyer.
For example, in 2020 the price of tungsten trioxide averaged around $270 per metric ton in the United States.
Tungsten’s price is not tracked on exchanges.
Companies that use tungsten in their products utilize independent sources such as the metal bulletin to confirm the latest price of tungsten.
Tungsten’s strength, density, melting point, and other attributes give it key advantages over other metals.
This is why tungsten has a diverse range of uses from industrial applications to common everyday products.
Seeing how much of a role tungsten plays in our lives, one can only wonder if there are other metals waiting to be discovered and how they will contribute to improving our everyday life.
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