Influence of brazing process on 75Ni8 gang saw steel's brazing properties

The mechanical properties and microstructures of 75Ni8 gang saw steel are investigated by changing the brazing processes. The experiments select 7 kinds of brazing materials for induction brazing. The mechanical properties and microstructure are analyzed by using mechanical test machine, impact tester, Vickers hardness tester, metallographic microscope and so on. The results show that the shear strength of sandwich HL861 brazed joint is the highest, reaching 164.87 MPa, and that the impact toughness of CT737 is the highest, reaching 50.08 J/cm². The Vickers hardness of the 75Ni8 base material area near the brazing seam is decreased rapidly, whose nadir is 1 176 MPa, while the original Vickers hardness is 4 468.91 MPa. The metallographic observation finds that the organization of the 75Ni8 base material near the brazing seam is coarse and the original is fine and uniform. The organization and property of 75Ni8 gang saw after welding are influenced by temperature.When the heating time becomes longer and the tempering temperature exceeds 600℃, the microstructure changes to the tempered troostite.