Pengaruh Variasi Suhu Preheat dan Jarak Pengelasan Terhadap Kekerasan, Struktur Mikro dan Lebar HAZ Pada Material ASTM A 106 B.

Abstract

In welding, it is important to space the welds at sufficient distance so that the heat affected
zones (HAZ) do not overlap. The distance between welding joints is usually determined based on
needs and conditions in the field, but there are minimum requirements based on geometric and
technical considerations. This includes avoiding overlapping stress concentrations, providing access
for inspection, and avoiding residual stresses and distortion. This research examines the effect of
variations in preheat temperature and welding distance on microstructure hardness and HAZ area in
ASTM A 106 B material. The results of observations show that there is no HAZ overlap in all
variations of welding distance and preheat spesimens. Vickers hardness testing indicates that material
with a welding distance of "20 mm" without preheat has the highest hardness value, namely 235.08
HV on average, while the lowest hardness value is found in material with a welding distance of "32
mm" and preheat of 250°C, with an average value -average 215.55 HV. This shows that preheat and
welding distance can influence the hardness of the material. Microstructural analysis shows
significant differences in each spesimen variation. The ferrite structure dominates in spesimens that
receive preheat treatment at higher temperatures, which contributes to a decrease in the hardness
value of the material.