FeCrAl合金管TIG焊焊接接头的组织及性能

Microstructure and Property of TIG Welded Joint of FeCrAl Alloy Tube

采用TIG(Tungsten inert gas welding,TIG)焊对FeCrAl合金管同质材料进行焊接,通过扫描电子显微镜、透射电子显微镜及能谱仪等手段研究了焊后接头的显微组织特征、焊后接头不同区域氧化物颗粒的分布情况及焊接接头的力学性能。FeCrAl合金TIG焊通过填充等成分的FeCrAl合金丝材进行焊接,焊后焊接接头主要由焊缝区、热影响区及母材组成。其中焊缝区为粗大的铁素体组织,热影响区为细小的等轴晶组织。焊缝区的Y_(2)O_(3)氧化物颗粒发生了明显粗化并与基体反应生成复合氧化物Y_(3)Al_(5)O_(12)。TIG焊焊接FeCrAl合金管热处理后,焊接接头最大抗拉强度值为530 MPa,约为母材强度的80.8%,可以实现大口径、大壁厚的FeCrAl合金管材的对接接头的力学性能要求。

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,Y_(2)O_(3) oxide particles decompose and react with matrix to form composite oxide Y_(3)Al_(5)O_(12).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.