Analisa sifat mekanis sambungan rel R54-R42 hasil pengelasan thermite ditinjau dari nilai kekerasan dan struktur mikro

Abstract

Rail play a important part in train if there is any problem at rail then simply train cannot operate as well or cannot operate. Undesirable problems that is extension of rail because can endanger safety, so many research to make extension of rail be better. Rail R42 used in Indonesia since long time, because time efficiency factor and usage of train more than past time so needing larger ones rail. Changed R42 with R54 as used rail in Indonesian but usage in bridge isn’t change because have to change bridge structure. Therefore writer research of welding rail extension R54-R42,purpose to know and analyse material characteristic of rail, analysing microstructure of extension result of thermite welding, knowing the nature of is mechanical of extension result of rail thermite welding R54-R42. Some material testing which have been done there are spectrometric test that used to know about the composition and influence composition toward hardness step, microhardness vickers for measure hardness value, and SEM for observing surface topograph. This research showing if hardness of R54 rail base metal have big value better than R42 base metal. Kinds of defect is porosity, crack, and inclusion. Defect is much appear in HAZ section there of base metal and welding metal section from rail extension R54-R42. Defect more visible in SEM result. For reduce the existence of defect so needed change at process thermite welding time. Keywords : Rail R54-R42, thermite welding, vickers microhardness, SEM, defect, porosity, inclucion.