Weld repair of aged Cr-Mo steel piping -- A review of literature

Journal Article · Tue Feb 01 04:00:00 EST 2000 · Journal of Pressure Vessel Technology

DOI:https://doi.org/10.1115/1.556154· OSTI ID:20030381

Viswanathan, R; Gandy, D

Power plant piping operating at elevated temperatures is subject to several types of service aging-related degradation, such as softening, spheroidization, embrittlement, and creep. When cracks are found in these components, weld repair is often employed to ensure continued operation. The efficacy of the weld repairs in terms of extending the life of the aged components has, however, not been documented quantitatively. The Electric Power Research institute (EPRI) has recently undertaken a comprehensive study to evaluate weld repairs performed to aged piping. In connection with this study, results from other worldwide activities have been reviewed, leading to significant conclusions regarding weld repair. this review of results from several worldwide studies has confirmed that aged high-temperature piping can be successfully weld repaired to gain additional lives in excess of several decades. The key aspects of successful weld repair include excavation and removal of all prior creep cavitation damage, elimination of external bending stresses, and implementation of good welding practice. From merely a creep rupture point of view, postweld heat treatment (PWHT) has been concluded to be superfluous by several authors. Temperbead repairs appear to offer a promising alternative to PWHT repairs from a creep, tensile, and toughness standpoint. Choice of the repair process ultimately is dictated by many considerations such as toughness, notch sensitivity, residual stresses and hydrogen embrittlement susceptibility. Several reports suggest that gas tungsten arc welding (GTAW) repairs may outperform shielded metal arc welding (SMAW) repairs with or without PWHT.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (US)
• OSTI ID: 20030381
• Journal Information: Journal of Pressure Vessel Technology, Journal Name: Journal of Pressure Vessel Technology Journal Issue: 1 Vol. 122; ISSN 0094-9930; ISSN JPVTAS
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
36 MATERIALS SCIENCE
HYDROGEN EMBRITTLEMENT
MECHANICAL PROPERTIES
PIPES
REPAIR
SERVICE LIFE
STEEL-CR2MO
STEEL-CRMO
WELDING