Comparative study of tube to tubesheet welding qualification on heat exchanger

Abstract

Plant turnarounds are one of the most critical events in the Saudi Arabian oil and gas industries. Shutdowns have the potential to affect the plant’s cash flow and objectives either in a constructive nor a bad way. A heat exchanger is an essential equipment for some procedures in the oil and gas refineries plant and it will decide the plant’s shutdown span. In a heat exchanger, welded tube to tubesheet joint is a basic factor which requires a different qualification. In this paper, tube to tubesheet welding for various material combination (carbon steel-stainless steel, stainless steel-stainless steel, and alloy steel-alloy steel) is qualified. According to American Society of Mechanical Engineers (ASME) Section IX QW-193 mock up qualification is done and QW-193.1 to QW-193.1.3 (visual test, liquid penetrant test and macro etching test) likewise is followed and lab tested for acceptance criteria. Ten model welds are needed to determine the eligibility of each procedure according to the required standard and totally 60 models (every 20) tried to rate this 3 procedure qualification record and welder qualification test record (PQR / WQTR). Qualification of the sheet from tube to tube follows all needed variables referred to in QW-288. This study proposes the improved minimum and maximum value for current (I), voltage (V), and travel speed (mm/min) required for above said materials qualifications. Further discourse is made over the heat input (KJ/mm), after effects of minimum leak path all things considered (Macro etching test), and classifies the range qualified against utilized base material for better understanding according to QW-288 essential variables.