Influência das variáveis do processo de soldagem TIG alimentado duplo arame quente na diluição e morfologia de cordões de solda de inconel 625 depositados em um aço AISI/SAE 4130

Abstract

Equipment used in offshore oil production are subject to severe damage due toexposure to corrosive compounds present in the produced fluid. Therefore, corrosion resistant materials such as nickel base super alloy UNS N06625 (Inconel® 625), are used in the production fluid passage areas. However, the high cost of this alloy limits its use in all equipment. As a solution to this problem equipment with lower cost materials, overlaid with the noblest alloy, are manufactured. For these overlays the TIG twin hot wire welding process is seen as an option for generate quality weld with productivity. So the aim of this study is to determine the influence of the average current (Im), welding speed (Vs), feed rate (Va), filler material current (Ia) and shielding gas composition (Gs) on the dilution (D), penetration (P), width (W) and reinforcement (R) of the weld beads deposited by TIG twin hot wire welding process on steel AISI / SAE 4130. For this analysis it was used a DOE (Design of) central composite five factors planning totalling thirty-two (32) deposition conditions of weld beads. Using a stereoscopic and image analysis software, measurements of areas and dimensions of width, penetration and reinforcement were made in cross sections of the deposited beads. Furthermore, analysis of the chemical elements in these sections were performed using energy dispersive spectrometry to determine the content of Fe element and hence the dilution. To analyse the behaviour of variables and determine an empirical model, the response surface methodology (RSM - Response Surface Methodology) was used. It was found that all variables influence the dilution, and for the adopted model the minimal dilution obtained was 6.37%. In addition, It was obtained penetration between 0.37 and 2.16 mm, width ranging from 8.09 to 10.04 mm and reinforcement between 1.93 to 3.16 mm.