Safety Assessment Of SMA490BW Steel Welded Joint Defects

Bogie is an important part of high speed train,which affect the train operation and the traffic safety.Bogie has a complex welded structures and lots of intensive welds.Due to the presence of welding defects,welding joints become weak links throughout the bogie structure.SMA490BW steel is a high strength weathering steel,and it has high tensile strength,plasticity,good toughness and good corrosion resistance.SMA490BW steel is the preferred material of high speed train bogie.With the development of fracture mechanics,the welding criterion who based on fracture mechanics has been applied and developed,and is widely used in engineering practice.In this paper,the quality category assessment of high speed train bogie are carefully studied and the work is as follows:The joints of SMA490BW steel with different welding had been tested X-ray inspection and penetrant testing,and the results had been analyzed.According to JB/T 4730.5-2005 and JB/T 4730.2-2005,the joints of SMA490BW steel were assessed quality category.The joints of SMA490BW steel were dissected,and the results were analyzed.According to GB/T21143-2007,through the Crack Tip Open Displacement(CTOD)tests conducted,fracture toughness ?C of the SMA490BW steel had been studied with a standard TPB(three point bending)shape,and the tensile mechanical properties had been tested.According to BS7910:2005,the internal defects in SMA490BW steel joints were assessed quality category,and assessed on 2A general with known flaw size,material properties,and stress conditions.The results show that each sample quality category were qualified on 1A simple assessment and 2A general assessment,quality classification rating was Q2?Q5 by BS7910:2005,the actual situation of joints reflected more exhaustive,the study provided a design and acceptance base for the application of SMA490BW steel.