Tungsten electrodes WT-40 orange

The Type WT 40 'orange' consists of 96% tungsten and 4% radiant thorium. WT-40 is a non-standard electrode for DC welding applications and is not suitable for AC welding.
The thorium content causes (like all oxides) a reduction in the electron work function and thus a higher electron emission. With increasing thorium, ignition - durability - current capacity is improved. The main application is the direct current welding of high and stainless steels.

Scope

Because of the radioactivity of thorium used for doping the use of these electrodes should be avoided enables consistently.

The risk of thoriated electrodes (see also the relevant provisions of professional associations) is not in the gamma radiation - it is largely negligible. Dangerous is the alpha radiation (particle radiation), inhaled in the radioactive particles and for all time remain in the lungs and damage the cells continuously, which in the worst case causes lung cancer. If thoriated electrodes are used anyway, the strictest standards for suction of grinding dust and welding smoke have to comply with all official regulations. Please note, that only Extractors Dust Class H (highest dust category) are approved.

Working with thoriated electrodes without these security measures is dangerous and unhealthy with no doubt. Nowadays it is not necessary to use thoriated electrodes since lanthanated (WL) or ceriated (WC) electrodes only offer advantages in all areas. It is expected that in the foreseeable future these thoriated electrodes may no longer be offered.