Study On Bioler Tube Of Heating Surface Failure Analysis

The reliability of the boiler is primary factor of influencing the operation reliability of the thermal power plant , especially the failure of the boiler tube of heating surface is a serious influence on safe operation of the unit, it is a common accident of the thermal power plant, generally accounts for 60%-70% of unit's troubles , the failure of the boiler tube of heating surface is a primary factor for safe operation of the power plant . Because of problems which produced in the design,manufacture,installation,operation,repairing,management of the boiler tube of heating surface and bad influences of high temperature,high pressure,corrosion,erodes in run for a long time , the times of the failure of the boiler tube of heating surface is higher than other equipments . When we grasp all kinds of features of surface feature,structural properties,the material degradation,scale,corrosion,fatigue of the tube of heating surface, we can have an object in view on the supervision and examination , find effective management and technology to prevention , improve the reliability of the unit operation , ensure the steady economical operation of the electric networks.This paper conclude the study on failure of superheater tube,reheater tube,water-wall tube,economizer tube in different conditions.The compositions,mechanical properties,microstructures of tube material of heating surface were systemically analyzed through visual examination,thickness measurement,hardness test,element analysis,tensile test,metallographic analysis and SEM , etc.The result shows that the failure of boiler tube of heating surface resulted from the comprehensive influences of material,environmental medium,temperature,pressure and operating mode . This paper has summarized the failure principles of boiler tube of heating surface, divided the failure into five kinds : stress fracture,corrosion,fatigue,erosion and failure of quality control according to the failure causes , described the causes and preventions of various failure types.