厄瓜多尔CCS电站水轮机球阀装焊工艺技术概述

Assembling and Welding Procedure Summary of Turbine Valve in Ecuador CCS Hydropower Station

厄瓜多尔CCS电站水轮机球阀是哈尔滨电机厂首次自主设计制造的大型全焊接整体结构球阀,也是国内同类制造厂家的首个大型全焊接整体结构球阀。球阀由阀体、活门和支座组成,整体宽4870mm,高3820mm,总重84.95t。在阀体与活门轴之间加装工具轴套的方式对活门迚行装夹固定和旋转。采取熔化极气体保护焊迚行球阀体的焊接,坡口形式为U形坡口;通过对球阀装焊位置工艺评定,确定采用立焊位置迚行焊接;焊接过程采用焊前预热、控制层间温度和焊后锤击等方式控制焊接残余应力;多名焊工按照优化后的焊接顺序,在对称位置同时起焊,迚而控制焊接变形和焊接残余应力,幵提升焊接效率。在法兰角焊至1/2厚、3/4厚时,采用UT探伤检测焊缝,确定缺陷位置及数量,迚而迚行修补焊,保证焊接质量;焊接完成后,采用VT、PT、UT等检测方法,对接头迚行全方位检测,确定焊缝质量达到一级焊缝要求;采用焊后去应力退火工艺,消除球阀内部的焊接残余应力。

The Turbine valve of Ecuador Coca Codo Sinclair hydropower station was the first large-size all-welded structure valve designed and manufactured by Harbin Electrical Machinery Company independently and also the first largest one among the same manufacturers in our country. The Turbine valve consists of valve body, valve rotor and support, and the overall width of 4870 mm, 3820 mm high, total weight 84.95 t. The tool sleeve was equipped between the valve body and the valve rotor for fixing and revolving the valve rotor. The valve was welded by GMAW, with double U-groove. Determined by evaluation of valve position of fabrication technology, vertical position was used for welding. To control the welding residual stress after welding, preheating, layer temperature controlling and hammering after welding were adopted. Welders worked in symmetry position at the same time, in accordance with the optimized welding sequence, to control the welding deformation and welding stress, and also to improve the welding efficiency. UT detection was added when flange Angle was welded to 1/2, 3/4 thick, in order to check the defect and ensure the welding quality. After completion of welding, use VT, PT and UT detection methods to check the all joint, to insure the welding quality reach the level of weld requirements. Annealing process was used to eliminate welding residual stress inside the valve.