Microstructure and phases of deposited metal of SUPER304H steel under high temperature Persistent stress

In order to investigate the high temperature rupture property of deposited metal of SUPER304H steel, the high temperature tensile test was carried out, and the microstructure transformation of deposited metal of SUPER304H steel under high temperature persistent stress were studied. Most of the solidification subgrain boundaries dissolve. The effect of the high temperature enduring on the microstructure is not obvious. Temperature and time are the main factors that influence the change of microstructure. Under the action of high temperature stress, the corrosion resistance of austenite decreases significantly due to the occurrence of chromium deficiency. With the persistent stress of 200 MPa, the precipitated phase of deposited metal is Nb (C, N), M(23)C(6), NbCrN phase, and a certain amount of alpha phase is precipitated in the deposited metal with a persistent stress of 78 MPa. The precipitation of M(23)C(6) phase is the main reason for the decrease of the corrosion resistance, especially the decrease of the corrosion resistance.