Características da ZTA na soldagem de uma serpentina tipo HALF-PIPE JACKET em reator de processo

Abstract

This work aims to characterize the HAZ coils Half-Pipes Jackets type in process equipment to the joints of the top type (vertical position) and fillet (horizontal and over head position). This need of characterization was due to the lack of detailed knowledge about failures observed in vessels with such a constructive arrangement, making remedial activities a sequence of actions with little theoretical basis to make the most efficient intervention. It was performed three specimens containing each type of joint and welding position of interest in order to identify the characteristics separately for each of the HAZ in welding position TIG (Tungsten Inert Gas). The bevels settings used were equivalent to the settings found in existing process equipment in chemical plants. The bodies of the test piece consisted of plates of ASME SA-516M Grade 415 and pipe ASME SA-106M Grade B, both of low-carbon steels, an arrangement that simulated the welding conditions of a coil type Half-Jackets pipes with pipes and plates in thicknesses equivalent settings and the actual equipment. The welding followed WPS qualified in accordance with ASME Section VIII Division 1 and ASME Section IX, and qualified welder in accordance with ASME Section IX. The parameters were monitored and maintained within the ranges established by WPS. It was found that the HAZ of the tube butt joints mean area greater than the mean area of the HAZ tube for fillet joints, despite having lower average Heat input. The measured hardness values remained below the reference value adopted. Under the statistical perspective, the average hardness of the HAZ face values above the mean values measured in the root ZTA. Analyzing the relationship of hardness between the fillet joints, comparing each other regions equivalent to the horizontal position and over-head, the average hardness found to horizontal position (Heat input lower) were higher than the average hardness found to stand on over-head (Heat input higher). The microstructures found showed no difference than was predicted by the literature.