This research investigates into using a highly efficient magnetic abrasive finishing (MAF) method to refine the surface of an Inconel 625 bar intended for use as a stem in a hydrogen solenoid valve. In contrast to the previous choice of STS 316 material, Inconel 625 was selected due to its superior properties. The cylindrical surface of Inconel 625 bars underwent polishing using the super-fast MAF process, employing varying rotational speeds ranging from 1000 to 25,000 RPM and a potent magnetic field of 550 mT. The study evaluated the polishing outcomes concerning abrasive type, rotational speeds, and processing duration. The results demonstrated the achievement of an exceptionally smooth surface on the Inconel 625 bar, with the surface roughness (Ra) reduced significantly, reaching 0.03 μm under optimal conditions. These conditions included employing carbon nanotube (CNT) particles of 0.04g, PCD diamond abrasive of 1g, Fe of 9g, 0.5g of light oil, and a processing time of 16 minutes at 15,000 RPM. Furthermore, Ansys analysis confirmed the mechanical integrity of the polished Inconel 625 bar, exhibiting suitable strain, equivalent stress, and safety factors. This substantiates the feasibility of employing Inconel 625 bars in hydrogen tanks, surpassing the conventional STS 316L bars.

In the semiconductor manufacturing clean room, contamination that directly affects process yield is managed through the operation of a monitoring system that measures molecular contamination in the air. In this study, I presented the component inspection method, test conditions, and judgment criteria through the life test of the solenoid valve that will be applied to the sampling module of the AMC Monitoring System.

The Calorifier is a device that supplies hot water to the crew for showering and cooking. In particular, problems such as hot water not coming out when a trainee and a crew member take a shower at the same time may occur due to a malfunction of the temperature control valve that controls the temperature. In particular, when the hot water usage time is almost constant, such as a training ship, a high calorific value is required. When there is no dissatisfaction with the use of hot water, satisfaction with the educational environment is improved. Therefore, in this study, a solenoid temperature control valve is applied to increase satisfaction with hot water use, and a mechanical time switch is applied to the hot water circulating water pump to save energy.