The damaged propeller shafts caused by the fatigue failure will be repaired by shield metal arc welding process. The service life dependeds on fatigue endurance limit of welding surface. This study was aimed to compare the fatigue resistance of two types of hard facing electrodes using the same arc welding repair process. The investigation of fatigue stress at 517 MPa in failure criteria showed that the propeller shafts repair by Flux core arc welding Process using electrode grade E110T5-K4H4 provided the approximate same service life as that using electrode grade X111-T5-K4 but lowered the repair costs up to thirty-five bath per kilogram electrode. As a result the total maintenance cost decrease 68250 baht per year.

The objective of this research is to investigate microstructure and mechanical properties of brass welded by diffusion welding process. The diffusion welding (DW) of brass welded over lap joints bonding parameters were pressure at temperature 500 650 and 800 0C contact pressure of 12 MPa and holding time for 60 minutes respectively. The microstructure mechanical properties and behaviour during bonding were investigated. The results show that in weld zone (Bond Line) diffusion of atom the brass significantly. The mechanical properties after diffusion welding process increased higher temperature

The purposes of the research were to create and find efticiency validation of computer assisted instruction focused on the fundamental of welding for the standard 90/90 and analyze the students learning achievement after using computer assisted instruction. The samples were the 20 first year Bachelor of Engineering Program in Industrial Engineering Rajamangala University of Technology Phra Nakhon. The researcher experimented by using pretest and then using the computer assisted instruction focus on the fundamental ofwelding and analyzed the students learning achievement after studying. The result revealed that the computer assisted instruction efficiency was efficient for standard 90/90. And after studying by using computer assisted instruction the students learning achievement increased significantly at 0.05.