Pengaruh PWHT Pengelasan Dissimilar Material Stainless Steel Dengan Carbon Steel Terhadap Sifat Mekanik, Struktur Mikro Material dan Luas HAZ

Abstract

This study investigates the effect of PWHT on welding different materials between SA 312
TP304L and SA 106 Grade B. Welding is not carried out PWHT which causes high residual stress
and potential cracks. PWHT is part of the heat treatment process that aims to eliminate residual
stresses formed due to the welding process. The research methodology includes hardness test,
microstructure observation with optical microscope, and HAZ width measurement. The results
showed that PWHT improved the welding quality in terms of mechanical properties, microstructure,
and HAZ area. The width of HAZ in specimens with PWHT is smaller than without PWHT. Hardness
test shows that the specimen without PWHT has an average hardness of 175.38 HV, while with PWHT
is 167.94 HV. The microstructure shows that the CS base metal produces ferrite and pearlite phases,
PWHT shows that the ferrite phase is more dominating. In SS base metal shows lamellar pearlite and
austenite phases, PWHT specimen lamellar pearlite dominates. In the carbon steel HAZ, PWHT
produces cementite and ferrite with weaker cementite bonds, while in the SS HAZ, PWHT shows
austenite and pearlite phases, while without PWHT shows austenite, pearlite and lamellar pearlite
phases. In the weld metal, the microstructure consists of pearlite and ferrite.