08 nov 2019
Tungsten helped the manufacturing age to reach its apex.
Exclusive
6
image
default
white
60
Stuff of Progress, Pt. 3: Tungsten
By Tony Morley
|


First isolated as a metal in 1783, tungsten has had a substantial impact on human progress. Starting in 1904, tungsten provided a metallic medium for incandescent lighting. Such was the advantage of using tungsten in electric lightbulbs that the metal is only now being phased out globally by more efficient lighting solutions. The value of inexpensive and clean lighting can scarcely be exaggerated. In 1900, four years prior to the advent of tungsten lighting, the cost of a million lumen hours of artificial light hovered around $285 (in today’s money). By the mid-2000s, the cost had dropped to less than $3. Tungsten’s unique properties make the metal of immense practical application, both as a tool and as an incorporated material. 

 

Tungsten (or wolfram – hence its chemical symbol “W”) has an astonishingly high melting point of 3414°C (6177°F). It is also extremely dense. These properties have allowed tungsten to be deployed in a broad range of high-performance industrial and commercial applications including in the aerospace industry, and in laboratory and military equipment. Tungsten carbide (a chemical compound containing equal parts tungsten and carbon atoms) reinforced inserts are essential in rotary and percussion drilling and crushing, thus helping to furnish human civilization with oil, gas, and mined metals and minerals. However, perhaps the most critical service that tungsten provides pertains to machine tooling. 

 

The history of manufactured goods is a history of machines and the quest for more precise and efficient methods of manufacture. 

 

Humans have long been capable of advanced mathematics and theoretical engineering. Unfortunately, we lacked the capacity to translate many of our forward-thinking concepts into reality. The age of precision machining started in earnest in 1776, when the English industrialist John Wilkinson helped James Watt to develop a steam engine cylinder. Wilkinson possessed unequaled knowledge in the production of iron goods - especially cannons. Using a hardened steel cutting tool, Wilkinson was able to bore out a cylinder cavity from an enormous iron block with such precision as to preclude the escape of steam from the engine’s piston. That allowed Watt to increase tremendously the efficiency of his steam engine, thus helping to give birth to the Industrial Revolution. 

 

As the Industrial Revolution advanced, so did human ability to produce stronger and harder-wearing iron, steel and other high strength metals and alloys. These advances created both opportunity and technical challenge. Harder and more abrasive materials, as well as faster production methods and cutting speeds, required machine tools of maximum hardness, strength and durability. The first tungsten carbide compounds were developed towards the end of the 1800s and continued to be refined through the 20th and 21st centuries. Tungsten carbide tools allow for faster cutting of harder materials with reduced tool replacement, downtime and associated costs.  

 

Tungsten carbide machine tools and tooling inserts are created by combining finely powdered tungsten carbide and (often) cobalt with a proprietary organic binder, and then finalized via sintering - a process of curing the tungsten carbide and cobalt powder under high heat for an extended duration. Modern tungsten carbide cutting tools are formed via the compaction, under enormous pressure, of tungsten, cobalt and other trace materials. The compacted cutting forms are then heated to such a temperature as to incinerate the organic binder, leaving behind an ultra-hard cutting tool. After diamond grinding to achieve the appropriate dimensions, the finished cutting tools are utilized in the high speed cutting and manufacturing of performance parts in factories and laboratories around the globe.  

 

When combined with Computer Numerical Control (i.e., the automated control of machining tools such as drills, boring tools and lathes), tungsten carbide cutting inserts form the mechanical basis of nearly all of the world’s precision manufacturing - from internal combustion engines to electric vehicle motors, from aircraft landing gear to the electrical turbines that power our civilization. In fact, no other metal has had a greater impact on general manufacturing processes. Today, tungsten carbide cutting tools are used in advanced metal manufacture in every developed country across the globe. The most exacting CNC machining systems can regularly reproduce parts with precision tolerance requirements of just +/- 2 microns or 0.000001 inches. While tungsten may not have kicked off the age of precision machine manufacturing, it did help the manufacturing age to reach its apex.  

Tony Morley is a freelance science writer, and human progress and economic growth exponent. He is based in Australia.
81|273|262|184|204