Microstructure development in Nd:YAG laser welding of AISI 304 and Inconel 600 |
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Authors: | Maurício David M. das Neves André Lotto José Roberto Berretta Wagner de Rossi Nilson Dias V. Júnior |
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Affiliation: | 1. Institute of Energy and Nuclear Research – IPEN CNEN/SP, Centre of Science and Materials Technology (CCTM) , S?o Paulo, S?o Paulo State, Brazil;2. University Centre of the Faculty of Industrial Engineering of S. B. C. , S?o Paulo, S?o Paulo State, Brazil;3. CTMSP – Centre of Naval Technology in S?o Paulo , S?o Paulo, S?o Paulo State, Brazil;4. Institute of Energy and Nuclear Research, Centre for Lasers and Applications (CLA) , S?o Paulo, S?o Paulo State, Brazil |
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Abstract: | In this work, the morphology of solidification of the weld zone (WZ) was studied in a joint formed from dissimilar materials, composed of austenitic AISI 304 stainless steel and Inconel 600 nickel alloy, welded with an Nd:YAG-pulsed laser. The laser beam and optical system parameters were selected with a view to obtain a weld with total penetration and good surface finish. The microstructural characterization was carried out using an optical microscope, in which a WZ was seen with total penetration, keyhole-type, presence of small pores and absence of cracks. The welded joints were also characterized by means of an electron scan microscope. Measurements taken by X-ray spectrometry for dispersion of the energy in the WZ indicated a slightly heterogeneous distribution of nickel and iron. It was seen that the start of solidification in the WZ occurred by means of epitaxial growth. The morphology of WZ solidification was basically denditric and cellular, being influenced by the temperature gradient, solidification speed and chemical composition. The variations in chemical composition and solidification morphology do not significantly alter the Vickers microhardness values in the WZ. Results obtained in the tensile tests indicate suitably effective welding values. |
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Keywords: | laser welding using Nd:YAG stainless steel AISI 304 Inconel 600 dissimilar materials |
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