Study On Mechanical Properties And Microstructure Of E911 Steel

The heat treatment processes of E911 steel were analyzed which was produced by Vallourec & Mannesmann Company. The optimum parameters of heat treatment process are normalizing at 1040℃and tempering at 790℃. The comparision tests were completed in terms of the mechanical properties, impact values, high temperature creep rupture strength and antioxidant properties of new methods and original preocess, the microstructure and fracture surface were analyzed by means of optical microscope, transmission electron microscope (TEM) and scanning electron microscope (SEM) meanwhile. The results shown that, after aging treatment at 650℃for 3 000 hours, the properties of this steel at room temperature and high temperature were much better than those of the original processes, such as the impact values increased up to 1.5 times of the original processes, FATT decreaded 20℃, and furthermore, the tube made of E911 was not of oxidant at 650℃based on GB/T13303-91. The high temperature creep rupture strengths of the body and welding joint were measured for this steel in the study.It is suggested that E911 steel could completely replace TP304H,TP321H and TP347H stainless steel. It is a better solution to the heterogeneous welding problems and reduces the manufacturing cost of boiler.