Study of closure welded joint between penstock and spiral case

In this paper, the closure-welded joint is studied through experiment after canceling telescopic joint of penstock in the hydropower station at dam toe. The closure-welded joint includes butt joint and lap joint and each has its own characteristics. According to calculation and experiment, these two joints can meet the requirements of design. There are little axial contraction and low restraint stress in the lap joint. Using some technologies, the restraint stress in butt joint can be reduced and cracks can be prevented. The lap joint has more complex stress distribution and higher stress concentration factor than butt joint. It is advantageous for safe running of penstock to use butt joint.

水电站合拢焊缝接头形式研究

坝后式引水压力钢管取消伸缩节后合拢焊缝接头形式有对接和搭接两种接头形式。对两种接头形式进行了试验研究,结果表明:对接和搭接两种接头形式都有各自的特点,对接接头形式优点较为明显,采用一些工艺措施可以减少焊接拘束应力和防止裂纹的产生,采用对接接头形式有利于引水压力钢管安全运行。

压力钢管合拢焊缝接头形式试验研究

通过模拟合拢焊缝现场施焊的实际工况条件，了解和掌握合拢焊缝采用对接接头或搭接接头形式时的拘束应力和焊接残余应力状况，为三峡左岸电站#1～#6机压力钢管合拢焊缝选择合适的接头形式提供依据。

某水电厂蝶阀安装合拢焊缝拘束应力施工监测

水电厂蝶阀安装焊缝实际就是压力钢管与金属蜗壳端的合拢焊缝。蝶阀安装时,金属蜗壳与压力钢管均已经与锚筋固定、并已浇筑混凝土。此时蝶阀安装焊接施工,由于焊缝收缩而使焊缝承受强大的拘束应力,焊缝易于产生焊接裂纹。为保证蝶阀安装焊缝的顺利施工,对合拢焊缝进行焊接拘束应力的施工监测,利用实测数据进行具体分析,从而指导蝶阀安装合拢焊缝的焊接施工。