Avaliação do revenimento da ZAC-GG em juntas semi-V de um aço ABNT 4140 soldado pela técnica da dupla camada

Abstract

The present work evaluated the efficiency of the refine and tempering produced by double layer technique on the coarsening grain heat affected zone (CGHAZ) of the first layer of a semi-V joint in a ABNT 4140 steel, welded with different energy relationships between the first and second layer. The energy levels selected from the Higuchi test were 5/5, 5/10 and 15/5 kJ/cm. Refine and/or tempering evaluation of first layer CGHAZ was accomplished through metallographics analysis and microhardness measurements. It was observed that inside the samples the wanted effect of refine and/or tempering of the first layer CGHAZ was reached, however, in the first layer CGHAZ extremities was preserved part of his coarsening grain, showing that there is need of a corrective action in the sense of promoting it refining and/or tempering of this specific area for not harming the hardness and toughness of the material. A rigorous control of the welding parameters and qualified welders guarantee the efficiency of the double layer technique.