PENGARUH VARIASI WAKTU LAS TERHADAP BEBAN GESER MAKSIMUM DAN STRUKTUR MIKRO LASAN LAS TITIK TAHANAN LISTRIK PADA SAMBUNGAN LAP PLAT BAJA KARBON RENDAH AISI 1008

Abstract

Resistance spot welding is a welding process using electrodes to apply both electrical current and  pressure. Heat is generated by electrical resistance between two or more workpieces.

The objective of this research was to investigate the effect of welding time  on AISI 1010 weld characteristic and maximum shear loading. Welding was done on AISI 1010 low carbon steel plates. The thickness of each plates was 0.8 mm. Welding time variation were 0.75, 1.0, and 1.25 seconds at constant voltage of 1.79 V. The material testing was set on tensile-shear test and microstructure.

The results shows that the welding time increase make the nugget size enlarged. The largest shear force required  to break the specimen was 4.34 kN and occurred on specimen with welding time 1.25 seconds. That is due to the larger nugget of the two steel plate joint for 1.25 second than for 0.75 and 1.0 second.

The microstructure of the weld nugget consists of ferrite and martensite. In the PMZ, the microstructure  contains ferrite and pearlite with presence of martensite. Meanwhile the microstructure in the base metal and HAZ consists of ferrite and pearlite.