ANALISIS PENGARUH PREHEAT DAN ARUS PENGELASAN PADA SAMBUNGAN T BAJA KI-A TERHADAP STRUKTUR MIKRO DAN NILAI KEKERASAN

Abstract

The ramp door hinge mount connection process has a T-shaped connection with
dimensions on the connection plate having a thickness of 25 mm and 20 mm with a KI-A plate type
and is carried out with a FCAW welding process. In the BKI Vol VI rules, materials with a thickness
above 20 mm must be preheated. This research method is an experiment with non preheat, 75°C and
150°C variations of preheat and 120A and 150A of welding current as specimens. microstructure
testing has the same structure in the base metal, HAZ and weld metal areas, namely ferrite (light) and
pearlite (dark). In specimens with preheat, a larger ferrite area is formed, the higher the preheat
temperature used, the less pearlite structure, these results are in line with the results of the hardness
test, the results obtained by specimens without preheat have the highest average hardness value of
203.03 and 211.35 HVN in the weld metal area. The conclusion of this study is that preheat and
welding current can reduce the value of hardness and microstructure, there is no significant effect on
the results of penetrant, macro structure, micro and hardness values.