随着锅炉作周期运行次数的增加,已引起不同金属之间的焊缝大量发生事故;经研究已发现其原因,同时改进了的无损探伤技术也使得有可能早日确定问题的范围。 As the number of boiler cycles has increased, a significant number of accidents have occurred in welds between different metals; the causes have been found to have been studied and improved non-destructive flaw detection techniques have made it possible to determine the extent of the problem at an early date.