Effects of Welding Heat and Travel Speed on the Impact Property and Microstructure of FC Welds

摘要

This paper is concerned with the effects of welding heat (current x voltage = W) and travel speed (v) on the impact property and microstructure of FC (flux cored) welds. Two sets of plate were welded under different welding conditions such as higher W, v and lower W, v, while maintaining identical heat input. We evaluated the effects of each factor by Charpy impact test and observation of the microstructure, and then compared these data with the results of the numerical temperature analysis. The size of the re-heated zone was increased as the v value decreased, and the results of numerical analysis also revealed the same tendency. Cooling rate of welds (both of as-welded and re-heated zones) decreased as the W value increased. Despite identical heat input conditions, the use of lower W and v made the microstructure finer and increased the volume fraction of AF, thereby leading to a substantial improvement of the impact property.