PENGARUH TEKANAN ELEKTRODA PADA STRUKTURMIKRO, KEKERASAN DAN KELIATAN NUGGET HASIL LAS TITIK SKALA INDUSTRI RUMAHAN

Abstract

Resistance spot welding is a process of joining two or more metal sheets by fusion at discrete spots at the sheets interface. Resistance to current flow through the metal sheets generates heat. Temperature rises at the sheet interface till the plastic point of the metal is reached, the metal will begin to fuse and a nugget is formed. This paper is aimed to analyze the effect of electrode force on spot welding nugget’s microstructure and hardness Some material examinations which have been done include spectrometric test to know about composition, vickers hardness test to measure hardness and optical metallographic test for observing microstructure and peel test to knowing the weld’s toughness. The experiment result showed that the material used classified to low carbon and low alloy steel which was equal to AISI 1010 steel. Microstructure which was formed was FeC with ferrite-perlite and bainite structure. Giving variation force on electrode , obtained hardness of weld about 138,2HVN, 181,2HVN, 138,78HVN, 150,7HVN and 134,54HVN. It’s coming near of base metal hardness about 165,7 HVN. Peel test examination showed that the weld has a ductility by a correct welding procedure and the spot welding machine in optimal condition. Fused diameter about 1,8mm have fulfilled AWS standard. Giving the same electrode force during welding process showed it’s influence less on welding joint , while giving low electrode force in early welding process and more by the end off welding process showed that nugget was formed