KEKASARAN & KEDALAMAN PERMUKAAN BAJA ST-40 DAN BAJA ST-60 DENGAN PENGUKURAN IMAGEJ PADA VARIASI KOMPOSISI LUBRIKASI BIO-OIL MINYAK JARAK DENGAN CARRIER-OIL MINYAK KEDELAI DAN MINYAK BUNGA MATAHARI

In an effort to provide jatropha seeds as raw material, it is necessary to provide cultivation technology and high-yielding varieties, but so far there is no adequate superior variety. Therefore, it is necessary to develop technology to find other raw materials as a substitute for petroleum-based lubricating oil, namely by using the power of vegetable oils. The purpose of this study was to determine the effect of variations in the composition of the mixture of Bio-Oil Lubrication Castor Oil with Carrier-Oil Soybean Oil and Sunflower Oil on the depth and surface roughness of ST-40 steel and ST-60 steel using ImageJ software. The method in this research uses ST-40 and ST-60 steel as test specimens, with Bio-Oil Lubrication Castor Oil with Carrier-Oil Soybean Oil and Sunflower Oil is a mixed oil composition for lubricant to be used in the turning process. The test used is the surface roughness test to find the lowest ra value and surface depth using ImageJ software. The results of the surface roughness test for ST-40 steel obtained the lowest ra value, namely 41,235 µm at 100% castor oil composition, the highest Ra value was 82,506 µm at 0% castor oil composition with 100% soybean oil. For ST-60 steel, the lowest ra value is 46,093 µm at 100% castor oil composition, the highest ra value is 91,954 µm at 0% castor oil composition with 100% soybean oil. In calculating the depth of variation of 100% castor oil and 0% soybean oil on ST40 steel, the lowest depth value is 181,984 µm and the highest depth calculation value is 206.494 µm at the composition of 0% castor oil and 100% soybean oil. In ST60 steel the composition of 100% castor oil and 0% soybean oil variations, the lowest depth measurement value is 161.395 µm and the highest depth measurement value is 204.19 µm at 0% castor oil variation and 100% soybean oil