Feasibility Analysis of Changing the Machining Standard for the Split Surface Bolts on the Hydro-turbine Top Cover in Shuibuya Hydropower Plant
During the extended overhaul of the hydro-turbine units in Shuibuya Hydropower Plant,the split surface bolts on the unit top cover were replaced.While,the new blackened bolts failed to reach the specified tensile value under the designed stretching pressure.On-site comparative tests were then conducted and it was determined that the excessive stretching of the M80×6 bolts on the top cover split surface caused thread damage.The remaining elongation of the bolts after stretching was too small,resulting in a gap between the nuts and the flange.After the stretching pressure was re-moved,the gap caused excessive rebound,which is the specific reason for the jam of the round nuts and the inability to rotate.Then,the feasibility of changing the bolt machining standard to DIN2510 is analyzed.
NETL
NSTL
万方数据
