糯扎渡水电站蜗壳与蝶形边多次焊接模拟试验

The Spiral Case and Butterfly Edge Multiple Welding Simulation Test for Nuozhadu Hydropower Plant

糯扎渡水电站9号水轮机蜗壳在水压试验过程中出现了异常的变形。根据最终蜗壳变形处理方案,7号～9号机组蜗壳进口段需拆除重新制造安装,这样与蝶形边就存在焊接、切割、再焊接等情况。文中提供蜗壳与蝶形边不同板厚和不同材质的多次焊接模拟试验方案,并根据试验结果对7组焊接试板的焊接接头进行力学性能试验,分别测定母材、热影响区、焊缝硬度和进行金相组织分析。砌割前不返修、切割后不返修、返修1次、返修两次及切割前返修1次,切割后不返修、返修1次、返修两次焊接情况的焊接性能完全可以满足原设计要求,焊接试验方案完全可行。

The No. 9 water turbine spiral case of Nuozhadu hydropower plant was deformed in the course of water pressure test. According to the final spiral case deformation treatment alternative the inlet sec-tions of the Nos. 7-9 generating units＇ spiral cases should be removed and re-manufactured and erec-ted, then the butterfly edges should be welded, cut and re-welded. The paper has proposed a multiple welding simulation test alternative for both spiral case and Butterfly edge different plate thickness and dif-ferent material quality, and mechanical properties tests of welded joints of 7 sets of welding test plates were conducted to measure base materials, heat affected zone and welding seam hardness and to make met-allurgical structure analysis. The test results have indicated that the welding performance can fully satisfy the original design requirements and the welding test proposal is feasible under such conditions as no repair before cutting, no repair, 1 repair, 2 repairs after cutting and 1 repair before cutting, no repair, 1 repair and 2 repairs after cutting.