Title

AVALIAÇÃO DAS TENSÕES RESIDUAIS EM AMOSTRAS 1 DE AÇO ASTM A516 GR70 SOLDADAS COM MULTIPASSE

RESIDUAL STRESS EVALUATION IN MULTIPASS WELDED SAMPLES OF STRUCTURAL ASTM A516 G70 STEEL

Authorship

Oliveira, George Luiz Gomes de; Silva, Thiago Ferreira da; Miranda, Hélio Cordeiro de; Motta, Marcelo Ferreira

Oliveira, George Luiz Gomes de

I am this author

Silva, Thiago Ferreira da

I am this author

Miranda, Hélio Cordeiro de

I am this author

Motta, Marcelo Ferreira

I am this author

DOI

10.5151/2594-5327-14669

Downloads

Abstract

Este trabalho tem como objetivo avaliar o efeito da soldagem multipasse sobre as tensões residuais resultantes, a microdureza e a microestrutura final do aço ASTM A516 Gr70. Amostras foram soldadas com energias distintas e então foram levadas a um difratômetro de raios-x para levantamento dos perfis de tensão residual. Posteriormente, as mesmas foram submetidas a ensaios metalográficos. Os perfis de tensão residual encontrados apresentaram comportamento distinto do encontrado na literatura para amostras soldadas com único passe, com tensões compressivas na superfície de enchimento e trativas na raiz. A microestrutura predominante no metal de solda foi a ferrita acicular, o que se acredita ser um dos motivos dos níveis compressivos de tensão residual nestas regiões. Os perfis de microdureza obtidos mostraram comportamento semelhante, apresentando picos nas regiões compreendidas pela ZAC.

The aim of this work is to evaluate the effect of multipass welding on the final residual stress profile, microhardness and microstructure of structural ASTM A516 Gr70 steel. The samples were welded with different levels of energy and the residual stress measurement was accomplished through x-ray diffraction, using a minidiffractometer for measurement in field. Metallographic analysis was accomplished in the transverse section of the welded joint, using optic microscopy and scanning electron microscopy. It were determined the microhardness profiles in the traverse section of the welded joint. The results showed that the multipass welding residual stresses on the surface of the analyzed samples are compressive in the weld metal and tensile in the HAZ. In the weld root, the welding residual stresses are tensile as in the weld metal as in the HAZ. The founded microstructures and microhardness were similar for all samples and it has believed that the acicular ferrite founded in the weld metal was one of the causes of the compressive characteristics of the welding residual stresses in the joints.

Keywords

Tensões residuais; Soldagem multipasse; Ferrita acicular.

Residual stress; Multipass welding; Acicular ferrite.