99 Studi Kasus Pengaruh Variasi Multiple Repair Pengelasan GTAW Pipa Baja Karbon Terhadap Struktur Mikro dan Sifat Mekanik Hardness Vickers

Abstract

In the construction industry, contractor companies have a role in completing infrastructure
projects, one of which is a piping system installation project. In working on a piping system
installation project, the possibility of errors in the welding process cannot be avoided. The above can
occur due to technical or non-technical errors resulting in defects. To overcome this, repair treatment
is needed, if errors in the welding process are made repeatedly, it is necessary to do multiple repairs
to the weld joint. The result of multiple repairs carried out will affect the hardness of the material
itself. The purpose of this final project is to analyze the effect of multiple repairs on the microstructure
and hardness of the material. The material used is A53 Grade B using the GTAW welding method
with ER 70-S electrodes. The micro test results produce grain sizes that get smaller as the number of
repairs increases. The amount of repair will increase the percentage of pearlite phase in the HAZ
area. The hardness test results produced the highest hardness value in the Weld Metal area with 3x
repair 187.50 HV, 2x repair 173.60 HV, 1x repair 164.12 HV, without repair 157.96 HV. This indicates
that the more pipe joints undergo a repair process, the mechanical properties are more brittle than
pipe joints without a repair process.