Influence of hot bending on microstructure changes of thick-walled P92 steel pipe

0450292 - ÚFM 2016 RIV FR eng A - Abstract
Král, Petr - Sklenička, Václav - Kuchařová, Květa - Kvapilová, Marie - Svobodová, M.
Influence of hot bending on microstructure changes of thick-walled P92 steel pipe.
BOOK OF ABSTRACTS. 13th International Conference on Creep and Fracture of Engineering Materials and Structures. Toulouse: Institut Carnot CIRIMAT, 2015. s. 182-183.
[CREEP 2015 - International Conference on Creep and Fracture of Engineering Materials and Structures /13./. 31.05.2015-04.06.2015, Toulouse]
R&D Projects: GA TA ČR TA02010260
Institutional support: RVO:68081723
Keywords : hot bending * P92 steel pipe * creep behaviour * microstructure * EBSD
Subject RIV: JG - Metallurgy

The microstructure of P92 steel pipe processed by hot bending was evaluated in order to characterize the influence of hot bending on microstructure changes in extrados and intrados of bend. The straight pipe was normalized and tempered. The thick-walled P92 steel pipe was hot bended at 920-960 °C. The bends were normalized and tempered after hot bending. The selected specimens, machined from different locations, were additionally thermal aged at 650 °C for 10 000 h to simulate microstructure degradation. Constant load tensile creep tests of aged state were conducted at 600°C and 140 MPa. Microstructure was investigated by SEM-EBSD. The significant detrimental effect on creep resistance of pipe was found after longterm static annealing due to formation of new phases and microstructure stability. Further, creep behaviour was also significantly influenced by specimen positions. Tensile creep tests showed that hot bending caused deterioration in creep properties of bends in comparison with those of straight pipe. The different creep behaviour of straight part of pipe and bends may be explained by different distribution of secondary phases and changes in interboundary spacing due to their different thermo-mechanical treatment.
Permanent Link: http://hdl.handle.net/11104/0251703