PENGARUH VARIASI LAMA PENCELUPAN DAN VARIASI MEDIA PENDINGINAN TERHADAP KUALITAS PRODUK HASIL HOT DIP GALVANIZING

Abstract

Hot dip galvanizing protects steel from corrosion by providing a thick, tough metallic zinc envelope, which completely covers the steel surface and seals it from the corrosive action of it’s environment. Protection of the steel is maintained by the cathodic action of the surrounding galvanized coating. Prepared items are galvanized by immersion in molten zinc. The surface of the work is completely covered, producing a uniform coating of zinc and zinc-iron alloy layers. This paper describes the effect of immersion period and quenching method to the coating thickness and surface roughness of the galvanized product conform with Australian Standard (AS) 1650. Immersion period of 1, 3 and 5 minutes have been used with 3 variation of a quenching method using water, oil, and air. The specimen which used is low carbon steel, whose the chemical compositions are 98,71% Fe; 0,095% C; 0,308% Si; 0,345% Mn; 0,073% P; 0,018% S; 0,087% Cr; 0,059% Mo; 0,062% Al, 0,037W%, 0,008%Ti and 0,016%Nb. The experimental method is True Experiment Research, where all of activities done in laboratory. This experiment showed that longer immersion period provided given thicker coating thickness. Measurement of thickness, Microstructure and surface roughness test shows that product with 3 minute immersion period using water quenching method gave the coating thickness, surface finish and galvanized coating layers that conformed with AS 1650. Key Words :Hot dip galvanizing, immersion period, variation of quenching method