Improvement of the technology of welding high-temperature diaphragms in steam turbine flow section
The Paton Welding Journal
Special features and causes for operational damage in welded components of high-temperature diaphragms are considered. Comparative testing was performed of welding-technological properties of some commercially available coated electrode grades for welding heat-resistant steels of Cr-Mo and Cr-Mo-V compositions. Implant procedure and welding of Tekken technological samples were used to assess the delayed fracture susceptibility of 15Kh12VNMF + 15Kh1M1FL steel welded joints at application of
... ted electrodes. It is established that to ensure a high cold cracking resistance of these steel welded joints, it is necessary to apply preheating at 200-250 °C. Proceeding from the data of measurement of metal hardness in welds and HAZ of welded joints and weld metal impact toughness, an optimum mode of heat treatment of 15Kh12VNMF + 15Kh1M1FL steel welded joints was determined. It is shown that a softening zone of lower hardness forms in the HAZ metal structure of 15Kh12VNMF steel, in which the samples fail at testing for static tension at working temperature of 570 °C. 8 Ref., 4 Tables, 10 Figures. K e y w o r d s : arc welding, heat-resistant steels, dissimilar steel welded joints, cold cracks, heat treatment * Based on materials of the work performed under purpose-oriented integrated program of the NAS of Ukraine «Problems of residual life and safe operation of structures, constructions and machines» (2013-2015).