INVESTIGATION OF-WELDING QUALITY OF THE HP-IP STEAM TURBINE CASINGS

Fabricating the steam turbine casted steel casings by welding is not a conventional method. The use of smaller castings joined by welding to form the steam turbine casing halves could mean the less costs and more added value to the product in benifit of the turbine manufacturer. But providing the sound welds and effective inspection methods considering the iquality of the casted steels require severe studies, investigations and preventexperience from manufacturer. So it was why TAVANIR management assigned our committee to fully investigate the matter on the welded HP-IP turbine casings of SHAHID RAJAIE Project when :it was found that the above mentioned fabrication method was used by manufacturer. Subsequently the destructive tests of transverse weld joint of actual weldment and synthetic heat affected zone (HAZ) specimens which were prepared from fabricated casings and Gleeble machine were conducted under supervision of the committee. Based on the above, the overall evaluation of the committee was that the weld in the HP-IP casing has adequate mechanical properties however , some regions in the (HAZ) exhibit properties inferior to that of the base metal.