There are two non-radioactive tungsten materials have been developed. The first one, introduced in the 1980's, is most commonly available as 2% ceriated tungsten. This material is commonly used for lower amperage DC welding applications. In fact, it holds a very high market share in sales for the orbital welding process.

More recently, 1½% lanthanated tungsten has emerged as what could be the future standard for tungsten electrodes. The 1½% by weight content (as opposed to 2%) was chosen by three of the largest manufacturers as the optimum content amount based on scientific studies which showed that this content amount most closely mirrors the conductivity characteristics of 2% thoriated tungsten. Therefore, welders can usually easily replace their radioactive 2% thoriated material with this tungsten and not have to make any welding program changes. In addition, since the lanthanum oxide material is less dense that thorium oxide, a stick of 1½% (by weight) lanthanated tungsten actually contains 15% more oxides by volume than a stick of 2% (by weight) thoriated tungsten. This aids in arc starting and stability, as well as longevity, because the additional volume of oxides keep the tip cooler.

Finally, 1½% lanthanated tungsten is suitable for both AC and DC welding applications. Therefore, facilities that stock both 2% thoriated tungsten for DC welding and another tungsten type (usually pure or zirconiated tungsten) for AC welding, could stock only one tungsten type.

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The International Institute of Welding Health and Safety Commission VIII states that there are no specific hazards regarding storage, handling or welding but dust extraction equipment should be used on the grindstone and respiratory protection should be worn by the operator during grinding. This is covered by the Health and Safety Executive Guidance note HS(6) 53 The selection, use and maintenance of respiratory protective equipment.

In the UK the use of thoriated tungsten electrodes is subject to the Ionising Radiations Regulations 1999. Exposure must be kept as low as is reasonably practicable, and the guidelines in the previous sections are designed to achieve this.

Local rules and adequate supervision are required. The employer must appoint a Radiation Protection Supervisor (RPS), who should be responsible for

Firs,the implementation and monitoring of all health and safety procedures for the storage, grinding, use and disposal of thoriated tungsten electrodes and all by-products.
Second, keeping records of the amount of thoriated tungsten in store, and the numbers of electrodes issued to each welder.
Third, giving instruction in the correct use and grinding procedures to the welders. These procedures should be in the form of written instructions, in addition to verbal presentations. The welders must know the name to the RPS.
Fourth, monitoring to check that the welders are carrying out the grinding procedures correctly, and that the dust extraction system is working effectively.

 

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Tungsten heavy alloy is increasingly adopted in tungsten alloy defense as the raw material to make parts of military products, such as bullet, armor and shells, shrapnel head, grenade, hunting gun, bullet warheads, bulletproof vehicles, tank panzers, cannons, firearms, etc. A major use for tungsten heavy alloy is in kinetic energy penetrators, where they are in direct competition with depleted uranium (DU).

The Army uses of powder metallurgy (P/M) extend from the conventional press and sinter to the more exotic processes of liquid phase sintering of tungsten heavy alloys (WHA) and powder injection molding (PIM). The Navy has taken great advantage of WHA by employing them iii the phalanx close-in weapon system (CIWS). The Army intends that research will lead to an alloy or composite of tungsten that, when used as a long rod penetrator, will perform as well as, or better than, current depleted uranium (DU) penetrators. Tungsten Heavy Alloys (WHAs) are the best choice when Designers in defense industries, WHAs are the ideal material which combines high density, good mechanical strength and which is easily machined, tungsten alloy for mlilitary defense is very important

Probably the most well known application for tungsten alloy is the aerospace industry, where weights and counterweights are often required to be housed in restricted areas. With significant reductions in size possible, this in turn, leads to greater control of weight distribution. These components can increase the sensitivity of control mechanisms and keep the forces required to operate flight controls within acceptable limits.

Vibrations in the dynamic components of aircraft engines and propeller systems are highly undesirable. Vibration, caused by mass imbalance of externally rotating components, can be reduced or eliminated by using mass trim weights. Additionally, counterweights are incorporated into the pitch control systems of many propeller designs as a failsafe mechanism. During flight the propellers are kept at the correct angle by hydraulic pressure counterbalances to optimize performance. Tungsten alloy offer designers several advantages over conventional balance materials such as lead or steel. The higher density of the alloys permits smaller components to be used, reducing overall system weight. Unlike lead, which can exhibit creep at ambient temperatures, these alloys are stable and so may be used in mechanically stressed positions without the need for additional fabrication and encasement.


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