One-sided welding with cordierite ceramic backing

Abstract

This paper presents an evaluation of welded joints using ceramic backing produced in the laboratory. The one-sided welding technique was used to weld A-36 steel plate with 6.4 and 15.8 mm thicknesses by employing the GMAW process. With the 6.4 mm steel plate, only the root bead welded over the ceramic backing was evaluated. With the 15.8 mm steel plate, a multipass welded joint was made. After welding, the welded joints were submitted to visual inspection, dye penetrant, macrograph, Vickers microhardness, optical microscopy, bending and tensile testing and chemical analysis using non-destructive test. The results show that the root pass made over the ceramic backing presented adequate shape, free from discontinuities, with adequate penetration in the edges of the groove and adequate reinforcement. With regard to the welded joint, the microstructure of the fusion zone presented predominance of primary ferrite, consisting of grain boundary ferrite and polygonal ferrite, and ferrite with an aligned second phase. The Vickers microhardness obtained mean values below 180 VH both in the heat affected zone and the fusion zone. Bending tests did not show discontinuities greater than 3 mm and in the tensile tests, the rupture occurred in the base metal, indicating that the welding procedure was adequate. The chemical composition of the inclusions both in the root pass and in the last weld bead have the same constituents, despite different proportions, indicating that there was no contamination of the ceramic backing material into the weld bead.

Keywords:

• one-sided welding
• ceramic backing

Acknowledgements

The authors thank FAPERJ, the CNPq and SHIMADZU for their support.

Notes

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