Tungsten (W) is a metallic element known for its high value across numerous industries. It possesses the highest melting point of all known metals, reaching 3,422 degrees Celsius. This refractory metal also exhibits a high density, approximately 19.3 grams per cubic centimeter, nearly the same as gold. The element is inherently hard, a characteristic amplified when chemically combined with other substances.
Applications Exploiting High Heat Resistance
Tungsten is suited for applications operating under intense heat. Its primary historical use is as the filament in traditional incandescent light bulbs. The tungsten wire can be heated to around 2,500 degrees Celsius, causing it to glow brightly without melting or deforming its structure.
This property is leveraged in high-temperature industrial settings, particularly in vacuum and hydrogen-atmosphere furnaces. Tungsten is utilized for heating elements, heat shields, and structural components within these furnaces, which can operate at sustained temperatures up to 2,800 degrees Celsius. Its low vapor pressure minimizes material loss through evaporation and prevents contamination of the furnace contents.
In welding, tungsten is the preferred material for the non-consumable electrode used in Gas Tungsten Arc Welding (GTAW), also known as TIG welding. The electrode must withstand the extreme heat of the electric arc without melting or eroding quickly. High electrical conductivity at elevated temperatures allows it to maintain a stable, focused arc for precise welding operations.
Applications Exploiting Extreme Hardness
While pure tungsten is hard, its most commercially significant application is found in tungsten carbide (WC), a compound rivaled only by diamond in hardness. Tungsten carbide is manufactured by combining tungsten and carbon powder, then sintering it with a metallic binder, typically cobalt or nickel, to form cemented carbide. The resulting material combines the ceramic-like hardness of WC grains with the metallic toughness provided by the binder.
This extreme hardness gives cemented carbide exceptional resistance to abrasion and wear, making it indispensable for industrial cutting and drilling tools. It is widely used in inserts and tips for machining steel and other hard alloys on lathes and milling machines.
The mining and construction industries rely heavily on tungsten carbide-tipped tools for drilling rock and earth. Applications include rotary drill bits, picks, and road planing tools, where the material must maintain a sharp edge and structural integrity under constant, high-impact friction. Beyond cutting, tungsten carbide is also fabricated into wear-resistant parts like nozzles, valve seats, and bearings, where its ability to resist surface erosion ensures a longer service life than conventional steel components.
Applications Exploiting High Density
Tungsten’s high density, approximately 60 percent greater than lead, is the primary factor in applications focused on mass and weight manipulation. When maximum weight must be contained within a small volume, tungsten alloys are the material of choice for counterweights and ballast. This is frequently seen in aerospace and racing, where high-density alloys are used in aircraft control surfaces, helicopter rotor blades, and engine parts to manage vibration and balance rotating assemblies.
The sheer mass of the element also makes it an effective material for radiation shielding against X-rays and gamma rays. Because the effectiveness of shielding is directly proportional to a material’s density, a tungsten alloy shield can be made thinner and smaller than an equivalent lead shield. This is a considerable advantage in medical imaging and radiotherapy equipment where space is limited.
The combination of high density and hardness is utilized in kinetic energy penetrators for military applications, requiring a dense, fast-moving projectile to transfer maximum energy upon impact. In non-military contexts, this density is used in vibration dampening tools, such as heavy-metal boring bars. The high mass of the tungsten alloy absorbs machine vibrations to improve the precision and finish of machining operations.