STUDI KUALITAS REPAIR WELDING PADA PENGELASAN METAL INERT GAS (MIG) MENGGUNAKAN METODE POST WELD HEAT TREATMENT (PWHT) PADA CAST WHEEL ALUMINIUM

The purposes of this research are : (1) To find out chemical composition and micro structure before and after welding using MIG method with PWHT on cast wheel aluminium. (2) To determines the hardness number, and the strength impact before and after welding using MIG method with PWHT on cast wheel aluminium. The research was conducted in INLASTEK laboratory Surakarta. The cast wheel aluminium of Honda Ferio was used to be sample on this research. The equipment that used for the chemical composition experiment, micro structure experiment, the hardness number experiment, and the strength impact experiment in succession are : Spectrometer Metal Scan, Olympus Metallurgycal Mocroscope, Brinell Hardness tester and Charpy tester. Based on the research results, can be conclude : (1) Chemical composition of Cast wheel alumunium was one of alluminium alloy Al-Si, due to Si is the main composition alloy that is 4, 61%. Based on micro structure of base material, Si were spread well around the surface of Al compared with the results after welding process with PWHT. (2) The hardness number on raw material is 42, 693 kgf/mm2, after PWHT treatment the hardness number on welding area becomes 29,062 kgf/mm2, HAZ area has hardness number are 23,487 kgf/mm2. The strength impact number on welding result using MIG with PWHT are 0,0717 joule/mm2 and on the raw material are 0,0924 joule/mm2. The experiments result indicate that, PWHT can switch over the micro structure, influent to the hardness number and strength impact on cast wheel aluminium. Specimen hardness and strength impack value of raw material is higher than MIG welding whit PWHT specimen