Vol.10, No2, 2010, pp.83-88
UDC  620.169.1 : 669.15  665.6.023.2-192

The paper presents an analysis of reliability and remaining life assessment of the reactor (coxing box) from a petrochemical plant, after the failure of the welded joint of the plated shell made out of W1.5423 (16Mo5) steel, 25 mm thickness, plated with W1.4002 stainless steel. The reactor failure has been associated with initial flaws from the welding process, which have accelerated remaining life exhaustion. The assessment was made in two steps. The VII section of ASME code specifications and iRiS-Thermo expert system for preliminary remaining life assessment was used. Concomitantly, experimental creep and thermal fatigue testing was performed. The programme results have defined creep and thermal fatigue exhaustion and the remaining life due to creep-fatigue interaction, under the condition of safety exploitation. The possibility to use an extra 40,000 hours of rehabilitated reactor under the safety condition of normal parameters was emphasized.

Keywords: coxing box, bimetal shell lining, reliability, remnant life assessment expert system