水轮机座环蜗壳组合缝的焊接及其工艺评定

广蓄电站二期工程共安装四台单机容量为３００ＭＷ的混流式水泵———水轮发电机组，其水轮机和发电机设备分别由德国伏依特（ＶＯＩＴＨ）公司和西门子公司制造。由伏依特公司分两瓣制造供货的水轮机座环蜗壳部件运到电站厂房安装间组合焊接成整体，并在加工好座环上下平面后再吊入机坑安装。座环和蜗壳分别用德国产的ＧＳ－２０ＭｎＭｏＮｉ５５铸钢和ＳＴＥ６９０Ｖ高强钢制成，这两种钢都是低碳调质高强钢，用于我国水轮机座环蜗壳中尚属首次。本文简要介绍水轮机座环蜗壳组合缝的焊接工艺、焊接质量控制及组合缝焊接前所进行的焊接工艺评定，可为其它大型电站类似高强钢部件的焊接提供借鉴。

Welding and Its Techology Evaluation of Turbine Stay Ring and Spiral-case Composite Joint of Turbine

The Second stage Guangzhou Pumped-storage Power Station accommodates four 300 MW mixed flow pump-turbine generator units manufactured by VOITH and Siemens in Germany respectively. The two halves of the turbine stay ring spiral-case manufactured by VOITH were transported to and assembled by welding in the assembly bay of the powerhouse, and then the welded turbine stay ring spiral-case was erected in the pit after the top and bottom surfaces of the stay ring being processed. The stay ring and the spiral-case were made of GS-20 MnMoNi 55 cast steel and STE690 V high strength steel produced in Germany respectively which are both low carbon, high guality and strength steel, and have first been used for the stay ring spiral-case of the turbine in China. This paper gives a brief introduction to the evaluation of the welding and composite joint welding technology and quality control of the trubine stay ring spiral-case, which can be used for reference in welding similar high strength steel components for other large hydropower stations.