The independent German Federal Institute for Materials Research and Testing (BAM) has compared the thorium-free WL15 welding electrode with the earlier WT20 standard and has confirmed: WL15 is the high-performance, environmentally-friendly alternative.
With their red marking, WT20 electrodes with thorium content were the long-established standard for TIG welding. However, legal requirements have made the production, packaging, shipment and disposal of thorium-containing materials increasingly expensive for manufacturers and users alike. So we recommend you to change to the gold-colored WL15 electrode.
The independent German Federal Institute for Materials Research and Testing (BAM) in Berlin has also confirmed the quality of the golden WL15. Its ignition time is just as fast as that of the red WT20 electrode. When used with high-alloy steels, the WL15 ignites even faster.
The continuous ignition tests performed by the BAM also identified a clear difference in the external appearance of the TIG electrodes. Electrodes of the type WT20 show a greater tendency towards oxidation and more extensive signs of wear than the WL15 electrodes.