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A novel pressure-controlled joule-heat forge welding method to fabricate sound carbon steel joints below the A1 point

2021; Elsevier BV; Volume: 68; Linguagem: Inglês

10.1016/j.jmapro.2021.06.008

2212-4616

Huihong Liu, Tetsuya Miyagaki, Yeongseok Lim, Masayoshi Kamai, Hidetoshi Fujii,

Microstructure and Mechanical Properties of Steels

A novel solid-state joining method, that we called Pressure-controlled Joule-heat Forge Welding (PJFW), in which electric resistance heat is utilized as the heat source, was successfully developed. Medium carbon steel, S45C, rods were joined using this PJFW method under various conditions. The welding temperature can be determined uniquely by the applied pressure in the PJFW. The fabricated joints show homogeneous temperature distribution and hence hardness distribution along the weld interfaces. A sound S45C joint showing superior tensile properties comparable with the base material was successfully fabricated by providing an appropriate high pressure to lower the welding temperature below the A1 point in order to prevent the brittle martensitic transformation, and applying a sufficiently large faying-surface deformation, not only to introduce significant microstructural refinement and large strains to prevent the softening, but to also sufficiently fragment the oxide layers, generate fresh surfaces, promote their atomic bonding and eliminate weld interface defects.