| In the early stage of the development of P92 steel,defects such as ?-ferrite and inclusions are often found in P92 steel of Beiman Special Steel with over standard and component imbalance.In this study,we aim to control excessive ?-ferrite in P92 steel and carry out technical researches by means of electric furnace steelmaking,intermediate frequency induction furnace steelmaking ingredient optimization of microstructure observation and laboratory conditions and mechanical properties test.?-ferrite formation factors were studied in the P92 steel to put forward the production process control details for ?-ferrite content.The microstructure and mechanical properties of P92 steel were analyzed.The thermoplastic and cold plasticity parameters of P92 steel were explored,and the optimal plasticity denaturing area of P92 steel was determined,which provided guidance for the actual production of P92 steel.The research results show that:(1)Unreasonable control of chemical composition of P92 steel is the main factor leading to the appearance of ?-ferrite structure in steel;Reasonable control of Cr equivalent and Ni equivalent of P92 steel can reduce or eliminate P92 steel ?-ferrite structure.(2)As the heating temperature increases,the ?-ferrite structure in P92 steel shows a tendency of aggregation growth.Forging heating temperature control under 1200?,can be brought up to avoid ?-ferrite in steel.(3)To determine the best heat treatment technology of P92 steel,in this paper,experimental conditions,P92 steel at 1050? normalizing+760? tempering,has the best strong toughness match.(4)1050?1150? is the best plastic deformation range of P92 steel.P92 steel in 1050?1150?,deformation rate under the condition of 10?40 S-1 for plastic deformation,can avoid the cracks in the process of forging defects.(5)At 625?,load stress under the condition of 100 MPa,P92 steel has no fracture after 11000 hours of high temperature tensile,showed P92 steel good high temperature duration performance.According to the extrapolation method,the high-temperature duration strength of P92 test steel under 100,000 hours is 99.1 MPa,higher than 87.4 MPa calculated by ASME CODE CASE 2179-6. |
PDF Full Text Request