Study On Mechanical Properties Of High-speed Passenger Car Bogies Welded Joints After Multiple Repair Welding

SMA490BW steel has high strength, ductility and toughness, and other mechanical properties, at the same time it was good resistance to atmospheric corrosion, it was used exclusively to make the welded frame of high-speed train bogies.The welded frame is complicated, and has many and dense welds. It will bring inevitably gas holes and some other defects because of the influence of the space constraints welding operations and other factors.In the welding process. When the welds are not allowed, it need to repair them by repair welding after cleaning, at the same time, the rework will be often. At present it mainly referenced TB1983-1987 to manage number of times of rework, what stipulates that:"the number of rework on the same part of weld can't more than twice" in article 10.3.4.2. Obviously, the part or the whole welded frame will be scrapped if the welds still can't meet the requirements after twice repairing welding, this will caused great economic losses.In this paper,analysising the microstructure and mechanical properties of SMA490BW welding joints after multiple repair welding.At the same time, analysising the influence of different repairing welding depth, width and times to welding joints by ABAQUS.The results indicate that the stretching, bending, impact and other mechanical properties of SMA490BW welding joints can still meet the requirements after two or three times repairing welding.Compared to distribution of residual stress under welding state, the residual stress will significantly improved in the weld and closed zone, what'is more the longitudinal residual tensile stress increased smaller and the transverse residual stresses significantly increased by the increasing of repairing welding depth, width and times.