TUNGSTEN
Abundance, Extraction, and Refining
Tungsten (W) is an element with atomic number 74 and belongs to the transition metals group. It is relatively scarce in the Earth’s crust, with an abundance of 1.25 ppm. In 2023, the leading producers of tungsten were China, Vietnam, and Russia*.
Tungsten oxide is extracted from various ores, with wolframite being the primary source. The tungsten is isolated as a powder through reduction processes using elements such as carbon or hydrogen. Due to its high melting point (3422°C), tungsten is produced by sintering the powder obtained during the refining process.
Properties
Tungsten is extremely hard and offers the highest tensile strength among metals. It resists corrosion very effectively and has a density similar to gold (19.3 g/cm³). Additionally, its thermal expansion coefficient is remarkably low.
Alloys
Pure tungsten is seldom used. Instead, it is commonly found in various alloys where it is utilized to enhance mechanical and thermal resistance.
Tungsten was isolated, identified, and discovered in 1783. The metal saw significant growth during the industrial revolution and the advent of metallurgy at the beginning of the 20th century. Initially, it was used to manufacture filaments for incandescent light bulbs. Soon after, its alloys were employed in the production of cutting tools (chisels, drills, milling cutters, etc.). Tungsten became a key component in the segments of oscillating weights with the widespread adoption of automatic watches, where it is often preferred over gold or platinum due to its lower cost and similar density.
In horology, tungsten is predominantly used in alloy form for the production of cutting tools. However, it is also commonly found in automatic watches, where it is often chosen over gold or platinum for the creation of oscillating weight segments due to its lower cost and comparable density.