CHARACTERIZATION OF WELDED JOINTS OF STEEL ASTM A36 IN PRESENCE OF THE HYDROGEN
Roneles de Santana Silva1; José Hilton Ferreira da Silva1
1 Universidade Federal da Paraíba
doi:10.20906/CPS/COB-2015-0899
Resumo
In this paper was carried out a study to evaluate the mechanical behavior of welded joints in the presence of hydrogen. Welded joints of ASTM A36 steel were obtained by GMAW and FCAW processes. Experimental development was performed entirely random manner, using a procedure known as factorial design (FD); were used as variables influence the AWS ER70S-6 and AWS E70C-6M wires, and the shielding gas composition (75% Argon + 25% CO2 and 70% Argon + 25% CO2 + 5% H2). In response variables were analyzed mechanical properties (tensile strength, toughness and hardness), microstructure and fracture mechanisms in the regions of the welded joint. The results were submitted to analysis variance and 90% confidence interval was utilized. The results showed that the absorption of hydrogen contained in the shielding gas does not influence the mechanical behavior of the weld; however, it was found that hydrogen contained in the mixture changed static characteristics of the electric arc and hence produced microstructure and fracture mechanisms changes, besides causing defects such as pores and blisters.
Palavras-chave: Welding; Hydrogen; Microstructure; Mechanical properties