STRUKTUR MIKRO LAS BAJA C-Mn PADA PENGELASAN BUSUR TERENDAM DENGAN VARIASI MASUKAN PANAS (Microstructure of Submerged Arc C-Mn Steel Weld Metals with Variation of Heat Inputs)

Abstract

ABSTRACT The present investigation aims to study the effect of heat input on the microstructure of submerged arc C-Mn steel weld metals. Specific attention was paid to the formation of acicular ferrite which improved weld mechanical properties. The welding process was carried out using four different heat inputs, namely 3.99 kJ/mm, 3.19 kJ/mm, 2.12 kJ/mm, and 1.77 kJ/mm. Microstructural examinations were performed using optical microscope in combination with scanning electron microscope (SEM) to study the mechanism in which acicular ferrite was performed. Results showed that weld metal with heat input of 2.12 kJ/mm produced weld metal with a large amount of acicular ferrite at the expense of grain boundary ferrite and Widmanstatten ferrite. It is evident that this acicular ferrite nucleates on the inclusions in the forms of Si02, TiO, and Al203. Key words : heat input, acicular ferrite, mechanical propertie