Study of circulated nanofluids ZnO based-particle to improve hardness in quenching AISI 4140

The world community still covets hard and strong materials for various applications. One of them is that AISI 4140 material widely plays a vital role as a material for engineering goods. The material needs to be quenched to get a more complex and stronger material. The cooling speed of the material being quenched is the main factor in forming a material with hard and strong properties. Nanofluid, which has a high ability to absorb heat, can be used as a cooling medium to replace pure water, oil, and brine, which are widely used today. Research is necessary to answer the new paradigm of the potential use of nanofluid technology as a cooling medium in the quenching process. The research method to be carried out was an experiment. The stages of research activities were preliminary studies, material sample preparation, nanofluid preparation, research tool setup, testing, analysis, and conclusions. The research variables used were ZnO nanoparticle material with nanofluid concentrations of 0.1% and 0.3%, and the base fluids were water, oil, and brine. The results obtained were the best concentration of 0.3% ZnO-water nanofluid coolant with an AISI 4140 material hardness value of 677 kgf/mm2.