Reliability Prediction And Creep Test Of Diffusion Welding Joint

With the rapid development of heavy industry,aerospace,nuclear industry and small-scale chemical mechanical system and the improvement of the operating temperature of power machine,creep becomes the main failure mechanism of high-temperature diffusion welding components.Therefore,it is necessary to consider the creep,research the relationship among temperature,stress,strain and time,and establish the evaluation index of mechanical properties in selecting and designing the diffusion welding components under high-temperature.In this research,the remote measurement and control system for creep testing machine is developed by using WEB and field bus technology,and the average tensile strength of 316L stainless steel diffusion welding joint at room temperature 20? and high temperature 550? is studied by the Weibull distribution.The contents and the achievements of this paper are mainly in the following two aspects:(1)Development of remote measurement and control system for creep testing machineThe remote measurement and control system for creep testing machine is developed by using WEB and field bus technology.Based on the RS485 communication technology,the field instrument,PLC controller and IPC of temperature,displacement and load compose distributed control system,which can achieve test parameter settings,field date acquisition,load loading and automatic leveling control by one IPC that can control 32 machines at the same time.Based on ASP,TCP/IP protocol password-authenticated Internet users can access the IPC Access database,remote control of multiple testing machine data acquisition,display,storage and processing,and synchronization backup technical parameter settings,data files.(2)Research on high temperature creep property of 316L stainless steel diffusion welding jointIn this paper,an extension mechanism and a fixture for small displacement measurement of creep deformation are designed,two ?70*50mm 316L stainless steel rods were used to make butt fusion welding heads and the creep curves of 316L stainless steel diffusion welded joints were measured on a newly developed high temperature creep testing machine.In accordance with the national standard GB/T 228-2002 "metal materials at room temperature tensile test method" and GB/T 4338-2002 "metallic materials high temperature tensile test method"equipped with a temperature control furnace Shimadzu material testing machine for 20?,550? short-time tensile test,to determine the average tensile strength of welding using the Weibull distribution.