Pengaruh Variasi Persentase Deformasi Plastis Pada Pengelasan SMAW Baja AISI 1020 Terhadap Struktur Mikro Dan Sifat Mekanik

Penelitian ini bertujuan untuk mengetahui pengaruh pengelasan SMAW (Shielded Metal Arc Welding) pada baja AISI 1020 dengan variasi persentase deformasi plastis sebesar 0%, 25%, 50% dan 75% terhadap struktur mikro dan sifat mekanik material. Pengelasan dilakukan dengan arus 80A dan tegangan 30V. Hasil pengamatan makroskopik didapatkan bahwa semakin besar persentase deformasi plastis, maka semakin besar pula lebar daerah HAZ (Heat Affected Zone). Hasil pengamatan struktur mikro dengan mikroskop optik menunjukkan bahwa semakin besar persentase deformasi plastis, maka bentuk ferit menjadi semakin halus pada daerah BM (base metal). Sebalikya pada daerah FGHAZ (Fine Grain Heat Affected Zone), bentuk ferit menjadi semakin kasar seiring dengan bertambahnya persentase deformasi plastis. Sementara itu pada daerah CGHAZ (Coarse Grain Heat Affected Zone), terbentuk fasa ferit pada batas butir dengan perlit kasar untuk masing-masing variasi deformasi plastis. Hasil uji kekerasan menunjukkan semakin besar persentase deformasi plastis, maka nilai kekerasan pada daerah BM semakin besar. Pada daerah HAZ dan WM, semakin besar persentase deformasi plastis semakin kecil nilai kekerasannya. Hasil uji tarik menunjukkan bahwa semakin besar persentase deformasi plastis semakin besar pula nilai UTS (Ultimate Tensile Strength) dan YS (Yield Strength). ======================================================================================================================================= This study aims to determine the effect of SMAW (Shielded Metal Arc Welding) welding on AISI 1020 steel with variations in the proportion of plastic deformation of 0%, 25%, 50% and 75% on the microstructure and mechanical properties of the material. Welding is carried out with a current of 80A and a voltage of 30V. The results of macroscopic observations found that the greater the proportion of plastic deformation, the greater the width of the HAZ (Heat Affected Zone). The results of microstructural observations with an optical microscope show that the greater the proportion of plastic deformation, the finer the shape of the ferrite in the BM (base metal) region. On the other hand, in the FGHAZ (Fine Grain Heat Affected Zone) region, the ferrite shape becomes coarser as the proportion of plastic deformation increases. Meanwhile in the CGHAZ (Coarse Grain Heat Affected Zone) region, a ferrite phase is formed at grain boundaries with coarse pearlite for each variation of plastic deformation. The results of the hardness test show that the greater the proportion of plastic deformation, the greater the hardness value in the BM region. In the HAZ and WM regions, the greater the proportion of plastic deformation the lower the hardness value. The results of the tensile test show that the greater the proportion of plastic deformation, the greater the UTS (Ultimate Tensile Strength) and YS (Yield Strength) values. Keywords: Plastic Deformation, Base Metal, Fine Grain Heat Affected Zone, Microstructure, Hardness, Ultimate Tensile Strength, Yield Strength