Creep crack growth in service-exposed weld metal of 2.25Cr1Mo

• Published in: The International journal of pressure vessels and piping Vol. 78; no. 11; pp. 749 - 755
• Main Authors: Andersson, Henrik C.M, Sandström, Rolf
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2001
• Subjects: Creep cavity; Creep crack growth; CrMo-steel; Ex-service; P22; STRAIN; P22; CrMo-steel; Ex-service; Creep crack growth; Creep cavity
• ISSN: 0308-0161; 1879-3541; 1879-3541
• DOI: 10.1016/S0308-0161(01)00086-2

Creep crack growth (CCG) has been studied for ex-service weld metal of 2.25Cr1Mo (P22). The testing was conducted at a temperature of 550°C and prior to testing, the material had been exposed to high temperature service for 110 000 h at 530°C. The results show a marked effect of the service exposure on the CCG properties of the material when compared to similar testing performed on a new material. The CCG rate was higher by a factor 3.1 in the service-exposed material, which should be compared to the model value of 3.2 based on the relations between the elongation values. The consumed deformation capacity was also estimated with the omega model for tertiary creep. In this case, an enhanced growth rate of 2.4 was obtained. Within a distance of about 10 mm in front of the propagating cracks, the number of creep cavities was significantly higher than in the surrounding material. The variation of the density of cavities as a function of distance from the crack tip was successfully modelled.