Microstructure and Properties of SUS301L/Q450NQR1 Dissimilar Joints Welded by Laser-MIG Hybrid Welding with Different Welding Wires
In order to reduce the cost,two different welding wires,ER309LSi and CHW-55CNH,were used to weld Q450NQR1/SUS301L dissimilar steel plate by laser-MIG hybrid welding.The microstructure and properties of the weld joints obtained by the two different welding wires were compared.The results show that the weld seams obtained by the two welding wires have no defects such as incomplete penetration and fusion,and the surface of the weld seams has obvious fish scale patterns;the center area of the weld seam obtained by ER309LSi welding wire is mainly composed of dendritic austen-ite and a small amount of ferrite,while the central area of the weld seam obtained by CHW-55CNH welding wire is mainly composed of proeutectoid ferrite and pearlite;the hardness value of the weld seam obtained by CHW-55CNH welding wire(374 HV)is greater than that of the weld seam obtained by ER309LSi welding wire(217 HV);the average tensile strength of the weld joint obtained by ER309LSi welding wire(632.3 MPa)is slightly larger than that of the weld joint obtained by CHW-55CNH welding wire(608.6 MPa);the neutral salt spray corrosion test of the two welding wire joints are not much different;the electrochemical analysis test shows that the corrosion resistance of ER309LSi welding wire joint is better than that of CHW-55CNH welding wire joint.In conclusion,the CHW-55CNH welding wire with lower price can replace the ER309LSi welding wire when the stress or the corrosion resistance requirements of components are not strict.
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