大岗山水电站水轮机蜗壳与压力钢管采用凑合节方式连接，因蜗壳、压力钢管和凑合节钢板均采用B610CF高强钢板，致使安装焊控制难度大，焊接工艺要求高，极易出现裂纹。介绍了凑合节安装时机的选择，以及凑合节安装和焊接的工艺方法，包括焊接顺序、焊接材料、焊后热处理等。经检测，依据上述工艺安装焊接的凑合节经无损探伤检验一次合格率达98.81%。其成功经验可供国内同类工程参考。%The turbine spiral case and steel penstock are connected with expansion joints in Dagangshan Hydropower Station. The spiral case, steel penstock and expansion joints are all forged by B610CF steel, and the welding technology is complicated and higher demands should be fulfilled so as to avoid fissure. In this paper, the choice of installation time, installation process and welding control of expansion joints are introduced, including welding sequence, welding materials and heat treatment after welding. Through non-destructive tests, the qualified rate of expansion joints reached to 98. 81% by applying the above meas-ures.
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