Underwater Welding Arc Temperature Spectral Diagnostic Studies

The temperature of underwater welding arc is studied systematically by means of spectral diagnostics of plasma in this dissertation. The collection of underwater welding arc signal . spectral analysis and two lands of calculating method areinvestigated in details, and on the basis of which several main factors that influence the temperature of underwater welding arc are discussed in three aspects as follows:The comparison of arc temperature between underwater wet and dry welding is made and the influences of water cooling and pressure to arc temperature are considered. The results show that the temperature of underwater wet welding arc is lower than that of dry welding and the difference between them gets greater with the increase of the welding water-depth. Furthermore, both arc temperatures of wet welding and dry welding increase with the welding water-depth increasing.Next, some possible effects of iron powder or thermit mixture content in coating on the temperature of underwater welding arc are analyzed. The experimental evidence shows that adding iron powder of low ionization voltage in coating causes the temperature of underwater welding arc to decrease. However, arc temperature increase with thermit mixture increase in coating because of its great chemical heat effect.The factor of welding current that plays an active role on influence arc temperature is also investigated. The result indicates that the temperature of underwater welding arc increases with the increase of welding current within the experimental conditions.The works is significant and valuable to the study of underwater welding arc physics and welding metallurgic.