Evaluating of creep property of distinct zones in P92 steel welded joint by small punch creep test

Small punch creep tests were carried out on four different micro zones in P92 steel welded joint: base metal, welded metal, fine grain heat affected zone and coarse grain heat affected zone. In addition to the creep rupture times, the full deflection curves during creep were also obtained, from which the creep properties of different welded joint micro zones could be derived. Furthermore, finite element method (FEM) analysis implanted with continuum damage mechanics was performed to investigate the variation of the creep damage, stress and strain during the test process. The validity of FEM results was certified by the agreement with experimental results. Then, on the basis of the experimental data, FEM results and theoretical models, the relationship of load in small punch creep test and stress in uniaxial creep test and the correlation of deflection and strain were established, respectively. According to these relations, the creep properties of the different distinct zones in P92 steel welded joint were obtained.

► Creep property of micro zones of P92 steel welded joint is obtained using SPC.
► Variation of creep damage and creep strain during SPC are obtained using FEM.
► Largest damage and localized necking occur in bottom surface of contact area.
► Correlation between applied load and stress in SPC depends on yield strength.
► General strain model is used to demonstrate creep strain level of SPC.