Reducing tungsten demand.

Author:Stover, Mark
Position:Tooling around

In September, we explored the stranglehold that China has on the worldwide supply for the main raw material of tungsten carbide. (See "The hidden monopoly among cutting tools.") A significant supply risk, not to mention price risk, is present when any single entity has this type of monopoly--80 percent. This risk can result in a complete distortion of supply and demand. While altering the supply side of the equation is not possible, let's look at a solution to exert better control on the demand side.

Using alternatives

Maybe it's possible to use alternatives other than tungsten carbide so that metalworking is not so dependent on one supply source. Let's look at the alternative cutting-tool materials. High speed steel (which also normally contains some small amounts of tungsten). Yes, HSS cuts metal, as long as you are willing to accept that your cycle times will at least triple compared with what they are with carbide--because of the slower cutting speed for HSS. There are also PCD and CBN tools right? Yes, except PCD cannot be used on any type of ferrous materials, and CBN costs in the range of five to 10 times more than carbide and generally must be used during rather favorable setup conditions. Cermets might be an answer--except that cermets are based on titanium, which has its own supply constraints and high-cost issues, and cermets lack the bulk toughness required for at least 70 percent of the metalcutting operations that are performed today with carbide. What about ceramics--where the base material (most often aluminum oxide) is very plentiful? Unfortunately, materials engineers have yet to find a way to impart enough toughness to ceramic cutting tools to make them successful, or cost effective, for the vast majority of cutting-tool applications. Conclusion: For metalworking, tungsten carbide is a very critical material without viable substitutes.

Reducing consumption

Consider this: For practically all carbide cutting tools, more than 97 percent of the volume weight is simply a vehicle to carry the cutting edge. Think about that for a moment. Here we have this rather costly base material. In "consuming" it, we actually have deployed only a very small fraction of the material. And then after using this small fraction, we render the material as no longer useful? Why not instead implement a simple way to directly reduce...

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