Background
200 million tungsten bullets a year, using an ounce of tungsten each. That makes more than 5,500 t, or one eighth of existing annual tungsten consumption in the world.
 
Green Bullets
In 1999 the US Army began manufacturing "green" bullets. The bullets - which are used primarily for shooting practice during peace time - are as deadly to humans as their predecessors but less deadly to the Earth.

Lead bullets, which the Army currently uses, tend to bioaccumulate in the environment, often ending up in sediments, surface water, and groundwater, according to A Multimedia Strategy for the Management and Reduction of Lead Hazards released by the US Environmental Protection Agency Region 5. Accumulated lead can adversely affect wildlife and people who get their drinking water from a contaminated source, according to the report. Lead slugs are such a water quality hazard that the federal district court in New York ruled that spent lead shot is a "pollutant" as defined by the Clean Water Act.

The lead slugs the Army uses in traditional 5.56 mm bullets have been bioaccumulating at shooting ranges, forcing several to close. These slugs will be replaced with environmentally friendly tungsten-based slugs, according to Wade Bunting, project manager for environmental armament technologies at the Picatinny Arsenal in New Jersey. Not only is tungsten more environmentally "benign" than lead, but ozone depleting chemicals and volatile organic compounds have been eliminated from the bullet manufacturing process - resulting in pollution prevention and money savings, he says. Although tungsten is more expensive than lead, the cleanup of the manufacturing process actually will result in savings of $0.01 to $0.05 per round, or $5 million to $20 million per year, he explains.

The bullets also will allow several indoor and outdoor shooting ranges that closed because lead concentrations became a human health or environmental hazard to reopen, cutting down the costs of transporting troops to far away, still-operational shooting ranges and eliminating associated pollution he adds.

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Catalysts
In chemical processes, catalysts are used to modify the mechanisms of chemical reactions. By providing an energetically favourable pathway, catalysts accelerate reactions which would normally be too slow or would not even take place. After the reaction, the catalyst remains essentially unchanged.

The main chemical application of tungsten is in the form of catalysts.

•         DeNOx catalysts for the removal of nitrogen oxides from combustion power plant stack gases by selective catalytic reduction with ammonia; the products are harmless nitrogen and water vapour. Typical DeNOx catalysts are honeycomb-shaped TiO2WO3V2O5 ceramics.

•         Catalysts for hydrocracking, hydrodesulphuration and hydrodenitrification of mineral oil products, where tungsten and nickel oxides on ceramic carriers are used. These catalysts help to increase the yield of gasoline and other light hydrocarbons in crude oil processing and to make the products more environmentally friendly by reducing the contents of aromatic hydrocarbons, sulphur and nitrogen compounds.

•         Other tungsten containing catalysts for various applications in the chemical industry, for example dehydrogenation, isomerisation, polymerization, reforming, hydration and dehydration, hydroxylation, epoxidation, etc

Catalyst production usually starts with the very water soluble ammonium metatungstate [(NH4)6H2W12O40 . x H2O], tungstic acid [H2WO4] or ammonium paratungstate. In the finished catalyst, tungsten is mostly present in the form of tungsten oxide or sulphide, or in the form of phosphotungstic acid (a "superacid" in the organic chemist’s terms).

Another example of catalytically active tungsten compounds is superfine tungsten carbide, mostly prepared by thermal decomposition of organic substances in the presence of a suitable tungsten compound.

Chemical Products
For the manufacture of chemical products, commercially available tungsten compounds such as sodium tungstate, ammonium tungstates, tungstic oxide or tungstic acid are commonly used as raw materials. The following list gives a few examples.

•         Inorganic pigments for ceramic glazes and enamels. Tungstic acid or tungsten oxide is used for bright yellow glazes. Tungsten bronzes, i.e. partly reduced alkali and alkaline earth tungstates, are available in many bright colours.

•         Barium and zinc tungstate are examples for bright white pigments. Coloured organic dyes and pigments based on phosphotungstic acid and phosphotungsto-molybdic acid are made for paints, printing inks, plastic, rubber and other materials.

•         Tungsten disulphide is a lubricant for temperatures above the application range of molybdenum disulphide. It has also been used to form a self-lubricating surface on razor blades.

•         Organic tungsten compounds have been patented as viscosity stabilisers in lubricant oils.

Laboratory ApplicationsIn laboratories, tungsten is used in several applications, for example

•         High purity sodium tungstate as a reagent in biochemical analysis

•         Sodium metatungstate for the preparation of heavy liquids to be used for the separation of minerals by density in mineralogy or for density gradient centrifugation in biochemical analysis

•         High purity tungsten granules as an accelerator in the determination of carbon and sulphur in metals by combustion in an induction furnace.
 

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Background
Tungsten was among the first alloying elements systematically used - as early as the middle of the 19th century - to improve steel properties. It has been one of the most important alloying constituents in tool steels and constructional steels and was added to enhance the properties of hardness, cutting efficiency and speed of tools.

These highly alloyed steels are used primarily in working, cutting and forming of metal components. They must thus possess high hardness and strength, combined with good toughness, over a broad temperature range.
 
Tungsten Alternatives
During World War II, a shortage of tungsten and an increasing demand for tools forced US and European steel makers to find a substitute, and molybdenum was chosen to replace tungsten in varying percentages. This was also cost efficient as the price was lower and the atomic weight is only half that of tungsten (1% Mo is roughly equivalent to 2% of W).

Tool Steels
Tool steels are usually classified in four groups:

•         Ledeburitic Cr-steels with less than 1% W - normally used for producing thread rolls and dies

•         Cold work steels with 0.5 - 3% W, of which cutting tools for instance are made

•         Hot work steels with 1.5 - 9% W, for dies and extrusion tools working up to 500°C and more

•         Steels for plastic moulding which does not include W-bearing steel grades

High Speed Steels
When tool steels contain a combination of more than 7 % tungsten, molybdenum and vanadium, along with more than 0.60% carbon, they are referred to as high speed steels (HSS).

This term is descriptive of their ability to cut metals at the "high speeds" in use through the 1940’s.

The T-1 type with 18% W has not changed its composition since 1910 and was the main type used up to 1940, when substitution by molybdenum took place. Nowadays, only 5-10% of the HSS in Europe is of this type and only 2% in the USA.

The addition of about 10% of tungsten and molybdenum in total maximises efficiently the hardness and toughness of high speed steels and maintains these properties at the high temperatures generated when cutting metals.

The main use of high speed steels continues to be in the manufacture of various cutting tools: drills, taps, milling cutters, gear cutters, saw blades, etc., although usage for punches and dies is increasing.

Coating
In 1979, the Western World’s production of HSS reached 120,000 tons/year, which has never been achieved again. The production in 1996 was 70,000 tons. One important reason for this is the world-wide rapid spread of coating techniques like the PVD procedure, e.g. the coating of HSS tools with a thin layer of TiN and other types of coating.

Coating increases the life of drills by up to 10 times, or it enables the cutting speed (productivity) to be doubled while the lifetime remains the same as for uncoated.

Another reason for declining consumption in HSS is the increasing switch-over to cemented carbide tools.

Heat Resisting Steels
In certain cases, where corrosion resistant steels are used in higher temperature ranges, tungsten is added. Heat resisting steels are chromium/nickel steels with up to 6% tungsten. The main use is as valve steels for combustion engines, containing around 2% W. Such steels are, for instance, used for the valves on the outlet side of automotive engines, where the red-hot hardness has to be combined with high temperature corrosion resistance.

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Its benefits come from the fact that it is denser than any other shot material, including lead, steel or bismuth. To understand how the density factors into performance, let’s look at two spheres about the same size, a golf ball and a ping-pong ball. The golf ball is far denser and will fly farther and hit harder. Now reduce that size down to two single No. 4 pellets, one steel and the other a tungsten alloy. Get the picture? The tungsten will fly farther, hit harder and penetrate deeper. That means more birds, farther out, with fewer cripples.

The beauty of tungsten is you also can reduce shot size and retain all the benefits of the larger lead or steel, with a lot more shot in the pattern. If you normally use No. 4 shot, switch to No. 6 in a tungsten load for a bigger pattern, more range and more forgiveness.

A few years ago, I decided to see just how good this stuff was. I took a mallard I killed that morning, tacked it up over a Shoot-N-See target and shot at it with a tungsten load at 70 yards. Every pellet totally penetrated the duck and left a mark on the target. Neither steel nor lead gave me that result — not even close.

Today, all shotshell manufacturers offer tungsten-alloy loads. The original, Hevi-Shot, is irregularly shaped and mixed in size, yet patterns better than it has any right to. Winchester, Federal, Remington and Kent offer tungsten-based loads that are more uniform in size and, like the Hevi, pattern very well.

Choosing the Correct Choke for Tungsten

We can manhandle lead and, to a lesser degree, steel, by simply forcing it through varying choke restrictions until we get it to behave the way we want it to. Not so with tungsten. Tungsten has a mind of its own and doesn’t play by the rules when it comes to choke.

For most tungsten loads I’ve tested (and I’ve put a small fortune into the pattern board), a modified choke delivers the overall best results in most guns, including over/unders and semi-autos. There have been rare instances where a full choke showed some improvement over a modified — one 12-gauge Spartan o/u and one Franchi semi-auto — but I attribute that to barrel quirks. We don’t know why it’s so, but the densest, most uniform patterns with tungsten most commonly come from modified or improved modified chokes. My tungsten guns always are choked that way.

Can you shoot tungsten in a normal barrel?

Tungsten is definitely harder than steel, and as such, there have been a flood of warnings about not shooting it in ultra-high-end guns or through standard chokes. It will leave marks in a choke tube, but as of yet, I’ve not seen any adverse effects in a barrel.

I wasn’t aware of the concern when I first began testing the then-new Hevi-Shot, and ultimately marred some tubes, but, and this is curious, those marred tubes don’t diminish the patterns in any way, even when I go back to lead or steel shot. My guns are tools, not works of art, so a bit of streaking or scratching in the tube doesn’t bother me. If you have concerns, just switch to a hardened choke tube made for tungsten or steel.

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