Service damage and repair of triple welded joints in steamlines made of heat-resisting, chromium-molybdenum-vanadium steels service life of repaired welded triple pieces under creep conditions

• Published in: Welding international 1996-01, Vol.10 (2), p.150-153
• Main Authors: Khromchenko, F A, Lappa, V A
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Joining, thermal cutting: metallurgical aspects; Metals. Metallurgy; Welding
• ISSN: 0950-7116; 1754-2138
• DOI: 10.1080/09507119609548970

Evaluation of the residual life of repaired welded joints is based on using the initial and residual endurance in comparison with the equivalent stresses and taking into account local softening of the weld metal for creep conditions. The results show that the reduction of endurance as a result of softening the weld metal when using non-recommended repair technology may reach 20%. The strength factor of these joints at a service temperature of 530 deg C and higher decreases to 0.55-0.6 at a normalised level of 0.7. The dependence of the residual service life of the repaired welded joints of steam lines of 15Kh1M1F steel on the equivalent stresses was determined for creep conditions at 545 deg C after operation for approx168 000 h. The residual life of triple welded joints with weld metal of the 09Kh1MF type in the failure stage at sigma sub eq = 80.5 MPa was 100 000 and 45 000 h, depending on repair technology (position of the repair weld).