HardAssetsInvestor

Written by Tom Vulcan  |

December 16, 2008

Tungsten: Heavy Metal (Including Cello)

Details

The once-rosy future of one of Earth's heaviest metals is now uncertain, given the current economic climate.

• General uses
• Supply and demand
• Investing opportunities?

What do all the following contain?

While I'm sure most of you will have been able to work out the answer immediately, for those who have not, the answer is ... tungsten.

In order, these are pictures of:

• General Dynamics' 120mm Terminator (KEW) APFSDS-T (APFSDS: armor-piercing fin-stabilized discarding sabot) tungsten kinetic energy (KE) anti-tank ammunition;
• Scheu Analogue's Scheu Cantus tone arm (for playing vinyl records) that retails for about $1,350 (excluding tax, shipping, etc.);
• NS Design's strings on one of its Bass Cellos (played by the likes of David Darling); and,
• The balls, manufactured by CERATIZIT, in ballpoints.

Why Tungsten?

In the first three instances, it is because tungsten is heavy. In fact, tungsten is one of our heaviest metals.

Approximate density at room temp.

In the last instance, the balls in ballpoint pens (which are made of cemented (tungsten) carbide (WC)), quite apart from being of exacting precision (but also rough), need to be not only extremely hard, but also resistant to corrosion: ink is incredibly corrosive. As carbide compounds (W₂C and WC), tungsten carbides are some of the hardest available.

In addition to its exceptional properties (high thermal and electrical conductivity, very high thermal creep resistance and very high moduli of both compression and elasticity), can be added three surperlatives:

• after carbon, the highest melting point of any element: 3,422°C or 6,192°F (its boiling point, 5,555°C or 10,031°F, is about as hot as the sun's surface);
• the lowest vapor pressure of all metals; and,
• the lowest coefficient of expansion of all metals.

Other, More General, Uses

The four most general uses of tungsten are in:

Hard Metals, or cemented carbides, which are nearly as hard as diamonds and used in a wide range of applications from carpentry tools to hot rolls for rolling mills in the steel industry; and dies, punches and cutting tools for stone, cast iron, nonferrous alloys and steel.

Source: International Tungsten Industry Association (ITIA)

Tiny hard metal "microdrills" are even used in machine-printed circuit boards.