FeCrAI 合金管ＴIG 焊焊接接头的组织及性能

The homogenous materials of FeCrAl alloy tube were welded by TIG welding. By scanning electron microscopy,transmission electron microscopy and energy dispersive spectroscopy,the microstructure characteristics of the welded joint,the distribution of oxide particles in different areas of the welded joint and the mechanical properties of the welded joint were investigated. TIG welding of FeCrAl alloy was carried out by filling FeCrAl alloy wire. The welding joint was mainly composed of weld zone,heat affected zone and base metal. The weld metal zone is composed of coarse ferrite microstructure. The heat affected zone is composed of fine equiaxed crystal microstructure. The oxide particles are obviously coarsened in the weld metal zone. A certain number of oxide particles can still be guaranteed in the weld metal zone. Oxide particles grow up from the original nano oxide particles into sub-micron oxide particles duringthe welding process. Moreover,Y₂O₃ oxide particles decompose and react with matrix to form composite oxide Y₃Al₅O₁₂. The maximum tensile strength of TIG welded FeCrAl alloy tube reaches 530 MPa,which is about 80. 8% of the strength of base material. The mechanical properties of butt joints of FeCrAl alloy tube with large diameter and large wall thickness can be achieved.