日本在50年代修建的普通水电站和抽水蓄能电站,容量都比较小,水头也比较低,故其压力钢管的H(钢管最大设计水头,米)×D(钢管主管内径,米)值仅在500～600米~2之间。使用的钢种为SS41、SB42或SM41等普通低碳钢,焊接方法采用手工电弧焊。到60年代,新建的水电站和抽水蓄能电站的容量增大,水头也提高了,压力钢管 The average hydropower station and pumped storage power station constructed by Japan in the 1950s are relatively small in capacity and relatively low in water head so that the value of H (the maximum design head of the steel pipe, m) × D 500 ~ 600 meters ~ 2 between. The steel used is SS41, SB42 or SM41 and other ordinary low carbon steel, the welding method using manual arc welding. By the 1960s, capacity of new hydropower plants and pumped-storage power plants had increased, and water heads also increased. Pressure pipes