DEFECT ANALYSIS OF LEAK TEST IN CYLINDER HEAD TYPE-A PRODUCT PROCESSED USING LOW PRESSURE DIE CASTING WITH AC4B MATERIAL AT PT. X

• Main Author: Wahyudi
• Format: Theses
• Language: Indonesia
• Subjects: Teknik, prosedur, alat, perlengkapan, materi
• Online Access: https://digilib.itb.ac.id/gdl/view/37907
• Institution: Institut Teknologi Bandung

Cylinder Head Type-A is one of the products which must be produced in large quantity, fast, and in good quality. Cylinder Head Type-A is made of JIS H-5202 standard AC4B material produced using low pressure die casting. Currently, in LPDC section, there are many defects in the casting products. This is evident in the data of defect on January-June 2018 at PT. X in which the highest total percentage of defects was 20.64% in LPDC In Plant and Next Process sections on April 2018. The most common types of defect in the LPDC in Plant section was Misrun in the chain wall, which amounts to 3.48%, and in LPDC Next Process section was leak test failure, which amounts to 4.93%. %. This certainly inflicts great losses on the company in terms of higher production cost and longer production time. Observation and characterization were performed in order to obtain data that can be used to conduct an analysis. The characterizations performed in the present study were leak lest, radiography (x-ray), chemical composition test using OES method, penetrant, metallography, SEM, and EDS test. Based on the characterization result, products which failed leak test had internal damage, i.e. shrinkage porosity. Based on the analysis result, the defect phenomenon of shrinkage porosity was caused by inclusion of aluminum oxide which was carried into Cylinder Head Type-A, initiating the formation of shrinkage porosity. The presence of aluminum oxide in Cylinder Head Type-A was caused by relatively long transfer time of molten from melting furnace and relatively high distance of auto carrier, affecting time of pouring into holding furnace.