PERBANDINGAN KUALITAS HASIL PENGECORAN PASIR CETAK BASAH DENGAN CAMPURAN BENTONIT 3% DAN 5% PADA BESI COR KELABU

Abstract

The purposes of this research are: (1) Analyze the effect of bentonite mixture variation at green sand molds to gray cast iron microstructure result of casting. (2) Analyze the effect of bentonite mixture variation at green sand molds to gray cast iron hardeness result of casting.(3) Analyze the effect of bentonite mixture variation at green sand molds to gray cast iron tensile strength result of casting.

The research has donein the laboratory of Politeknik Manufaktur Ceper. This research does casting by using gray cast iron material. Techniques of data analysis in this research using descriptive data analysis that is directly observed experimental results are then analyzed and summing up the results of the research. As an input parameter in analyzing the data include: microstructure assaying, hardness and tensile strength.

Based on result of inferential research that specimen microstructure at this research is casting result gray cast iron having metric of strong and firm pearlite. Flakegraphiteat specimen I (Bentonite 3%) harsher compared to specimen II (Bentonite 5%). Ferritein thespecimensImorethanferriteinspecimenII. Specimen I has pearlite structures which rather rugged, while specimen II has smooth pearlite. The hardness of gray cast iron owned by specimen II 66,5 HRA higher compared to hardness of gray cast iron owned by specimen I that is 55,8 HRA. Tensile strength at specimen II is 278,68 N/mm² higher compared to specimen tensile strength I that is 222,92 N/mm².