Abstract

DI LUOZZO, N et al. Characterization of TLPB joints of metallic products by means of synchrotron radiation. An. AFA [online]. 2015, vol.26, n.2, pp.88-92. ISSN 0327-358X.

The transient liquid phase bonding process was applied to metallic products (seamless hot-rolled carbon steel tubes), using an amorphous Fe-B-Si foil as interlayer. The tubes were aligned with their butted surfaces in contact with the interlayer. The joint was heated by means of an induction furnace, under a reducing atmosphere, to the process temperature T_P (≈ 1300 °C), and then held at that temperature for 7 min. The joining process was performed under a pressure of 5 MPa. Both the microstructure and the chemical composition of the joint were analyzed. It was observed that the joint was comprised only of ferrite grains, unlike the base metal, whose microstructure was composed of ferrite and pearlite. Furthermore, the joint was rich in Si and depleted of Mn. With regard to the profiles of these elements throughout the joint, it was observed that these were not necessarily symmetrical with respect to the mid-thickness of the joint. Finally, the structure of the joint was characterized by X-ray diffraction using high-resolution and high-energy synchrotron radiation. The obtained results showed that the joint was formed by ferrite, in agreement with the microstructural observations, and that the lattice parameter varies significantly across the joint, according to its chemical composition gradient. Therefore, a direct relationship between the structure, the microstructure and the chemical composition was achieved at the joint.

Keywords : Steel; Bonding; Characterization.

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