Electrodes
THE CHOICE OF tungsten electrode depends upon the type of welding current selected for the application. With conventional ac, better arc action is obtained when the electrode has a hemispherical-shaped tip, as shown in Figure 1.8. AWS classifications EWP (pure tungsten) and EWZr (tungsten-zirconia) electrodes retain this tip shape weL4 Fine tungsten inclusions result when using thoria-tungsten electrodes with ac power. Classifications EWTh-i or EWTh-2 (tungsten-thoria)
electrodes are suitable with direct current only. Both classifications have higher electron emissivity, better current-carrying capacity, and longer life than do EWP electrodes. Consequently, arc starting is easier and the arc is more stable,Pure or zirconiated tungsten electrodes are satisfactory for ac welding. The zirconiated electrode is less prone to electrode contamination by base or filler metal and has a slightly higher current rating. Thoriated tungsten electrodes are not generally recommended for welding with ac.
ElectrodesTHE CHOICE OF tungsten electrode depends upon the type of welding current selected for the application. With conventional ac, better arc action is obtained when the electrode has a hemispherical-shaped tip, as shown in Figure 1.8. AWS classifications EWP (pure tungsten) and EWZr (tungsten-zirconia) electrodes retain this tip shape weL4 Fine tungsten inclusions result when using thoria-tungsten electrodes with ac power. Classifications EWTh-i or EWTh-2 (tungsten-thoria)electrodes are suitable with direct current only. Both classifications have higher electron emissivity, better current-carrying capacity, and longer life than do EWP electrodes. Consequently, arc starting is easier and the arc is more stable,Pure or zirconiated tungsten electrodes are satisfactory for ac welding. The zirconiated electrode is less prone to electrode contamination by base or filler metal and has a slightly higher current rating. Thoriated tungsten electrodes are not generally recommended for welding with ac.
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