ASSAB 705 steel has a carbon content of 0.38%–0.43%. ASSAB 705 steel is used as gear components, piston connecting rods, and shafts. Efforts to make the steel more resistant to friction are made by hardening the quenching method. The purpose of this study was to determine the effect of different cooling media for the hardening process on the hardness of ASSAB 705 steel. The type of research u…