Performance of repair welds on aged Cr-Mo piping girth welds
- 156 Downloads
This article documents the results of an industry survey of weld repair practices and describes the results of experimental evaluations performed on service-aged 21/4 Cr-1Mo steel piping using SMAW with both conventional postweld heat treatments and temper bead repair techniques. The overall results of this program provide substantial evidence that service-aged piping systems can be successfully weld repaired with and without postweld heat treatments and that life extension by several decades is achievable under the right design and repair conditions. Weld repairs performed on degraded exservice welds resulted in restoration or improvement of tensile and creep properties. Microhardness test results within the heat-affected zone of each weldment indicated that the temper bead weld repairs produced only slightly higher peak hardness values than those measured for the fully postweld heat treated repairs. Finally, in terms of toughness, temper bead weld repairs consistently produced higher impact properties than those measured for the postweld heat treated weldments. Gas tungsten arc weld repairs with postweld heat treatment resulted in the best combination of tensile strength, uniform microhardness distribution across the weld, Charpy toughness, and creep rupture life.
KeywordsCr-Mo steels gas tungsten arc welds mechanical properties postweld heat treatment shielded metal arc welds welding
Unable to display preview. Download preview PDF.
- 1.“State-of-the-Art Weld Repair Technology for High Temperature and Pressure Parts, Vol. 1: Life Assessment; Vol. 2: Repair Guidelines; Vol. 3: Utility Survey, Vendor Survey and Bibliography; and Vol. 4: Weld Repair of 2-1/4Cr-1Mo Pipe/Header Girth Welds,” Report TR-103592-V1-V4, EPRI, Palo Alto, CA, November 1997Google Scholar
- 2.R.V. Hart, Assessment of Remaining Creep Life Using Accelerated Stress-Rupture Tests, Met. Technol., Vol 13, 1976, p 1–7Google Scholar
- 3.J. Stubbe and C. van Melsen, Symposium on Residual Life of Constructions Operating at Elevated Temperatures, Den Haag, The Netherlands Institute of Welding, 1977, p 71–140Google Scholar
- 4.R. Viswanathan and S.M. Gehl, Effect of Aging on the Creep Rupture Behavior of Steels, First International Conf. on Microstructures and Mechanical Properties of Aging Materials, P.K. Liaw et al., Ed., TMS, Warrendale, PA, 1992, p 35–41Google Scholar
- 5.S.M. Beech, D.J. Gooch, and A. Strang, Remanent Life Assessment of 1CrMoV HP and IP Steam Turbine Rotors, Materials Engineering in Turbines and Compressors, Proc. of the Third International Charles Parsons Turbine Conference, R.D. Conroy, M.J. Goulette, and A. Strang, Ed., The Institute of Materials, 1995, p 277–292Google Scholar
- 7.R. Viswanathan and D.W. Gandy, “Review of Worldwide Literature,” Fracture, Design Analysis of Pressure Vessels, Heat Exchangers, Piping Components and Fitness for Service, K.K. Yoon, Ed., ASME PVP, Vol 388, p 383–395Google Scholar