Analysis on Angular Distortion and Control of Plug Welded Steel Structure

Abstract

Distortion is a shape changing phenomena that occurs in three axes of the newlineproduct during welding process. The extents of distortion vary with various welding newlineprocesses and materials. Angular, longitudinal, twist, buckling and transverse newlinedistortions are common that are encountered during fabrication of plate welded newlinestructures. Angular and longitudinal distortions predominately occur in plate welded newlinebeams. The angular distortion occurs in groove butt joint, Tee fillet weld joint, plug newlineweld of the predrilled hole and surfacing by hard facing over lay welding. newlineThe angular distortion or deflection occurs in a plate where the temperature newlinegradient prevalent across and along the thickness of the plate. In addition to newlinetemperature gradient, shrinkage of the weld and base metal enhances the angular newlinedistortion. Heavy plate thickness ranging from 16 to 53 mm is used for fabrication of newlinebeams and column in the boiler supporting structure. These beams connected by newlinespliced bolted joint at erection field to meet the equipment requirement. newlineSplice plate plays a vital role in connecting members on load transfer newlineefficiency. The hole in the splice plate or connecting parts of the beam may get newlinedislocated due to error committed in manufacturing process. The wrongly predrilled newlinebolt hole is to be plug welded for critical applications and drilled to exact location. newlineSurface flatness of the splice plate is critical to the quality requirement. Weld newlinedistortion is a major issue in splice plate joint to get a perfect contact between mating newlineparts. It necessitates controlling the distortion during fabrication itself rather than newlinecourse correction after welding. It is necessary to study the temperature distribution newlinewhile plug welding. An attempt has been made to study the effects of welding newlinesequence on angular distortion in plug weld of splice plate in the predrilled hole. The newlineeffect of anisotropy properties of as rolled plate on angular distortion was evaluated newlineby a bead on plate.