Papers by Keyword: Joining Strength

Abstract: Joining by forming is an attractive assembly method for mass produced parts due to easiness in execution, no heat effect, various material combinations etc. and industrial applications have been increased in electric and automotive industries. In this paper, a disc plate and stepped shaft is assembled by forming. Assembling is achieved by indenting the disc with a stepped and grooved shaft up to a certain depth. Through the experiments using an aluminum disc and a steel shaft, the influence of the overlap length and penetrating depth of the stepped section on joining force, axial strength and dimensional change of the disc plate are investigated. Disassembling tests revealed that the joint by the proposed method had sufficient axial strength if the groove of the shaft was completely filled.

Abstract: In Order to Improve the Joining Strength of Friction Stir Spot Welded PVC Joint, Sic Particle was Compounded by the Stirring in the Welding Process. the Influence of Sic Particle Sizes on the Joining Strength was Investigated in this Study. in Case of the Specimen Compounded Sic Particle with Size of 14.6μm, Heat Generated during the Process Significantly Increased and Resulted in Increasing Width of Welded Region. however, According to Result of Hardness Test, Excessive Heat Generated during the Process Led to Degradation of Mechanical Property of the Welded Area in the Specimen Compounded Sic Particle with Size of 14.6μm. on the other Hand, in Case of the Specimen Compounded Sic Particle with Size of 6.5μm, Width of Welded Area was Smaller than that of the Specimen Compounded Sic Particle with Size of 14.6μm and was Similar as that of the Specimen Compounded Sic Particle with Size of 0.5μm. it was Observed that Hardness of the Welded Area was Uniformly Higher in the Joint Compounded Sic Particle with Size of 6.5μm. Specimen Compounded Sic Particle with Size of 6.5μm Showed the Highest Strength among the Joints Tested. it is Considered that the Joining Strength was Affected by both Width and Mechanical Property of the Welded Area.

Abstract: Soldering processes involving the use of Pb have been known and practiced for more than 5000 years. In 2000, the European Union imposed a ban on the use of Pb because of the fact that Pb is poisonous to humans. Consequently, attempts are being made worldwide to develop a Pb-free solder. Among the various Pb-free solders, the Sn–0.75wt%Cu (Sn-0.75Cu) solder is the suitable one from the viewpoint of cost. Moreover, its acoustic properties are superior to those of the other Pb-free solders. However, the Sn-0.75Cu solder has a few disadvantages: its joining strength is lower than that of the other solders, and its melting temperature is higher than that of the Sn-37wt%Pb (Sn–Pb) solder. Therefore, we have attempted to decrease the melting temperature and improve the joining strength of Sn-0.75Cu to match those of the Sn–Pb solder. It is well known that when Ga is added to a Sn-based alloy, the melting temperature of the alloy decreases. Moreover, Ga has superior wettability. Therefore, we added Ga to the Sn-0.75Cu solder in order to improve the joining strength and decrease the melting temperature of the solder. We observed that the melting temperature of Sn95.3Cu0.7Ga4 reduced to less than that of the Sn–Pb solder. We also investigated the joining strength between the Ga-added solder and a Cu wire. We observed that the joining strength increased with an increase in Ga content, was the highest for Sn97.3Cu0.7Ga2, and then decreased with an increase in Ga content. The peak joining strength of the Ga-added solder was almost 1.5 times that of the Sn-0.75Cu solder. However, the brittleness of the solder increased with an increase in the Ga content. This is a disadvantage of the addition of Ga to Sn.

Abstract: A novel, online-joining of C/SiC-C/SiC method, precursor infiltration and pyrolysis, was used to obtain high temperature stable joining SiC composition, while joining process was highly consistent with C/SiC preparation process. The compositions of joining ingredients and process parameters were investigated to determine the maximum joining strength of C/SiC-C/SiC at room and high temperatures. The optimum weight ratio of (polycarbosilane/divinyl benzene)/SiC powder is 3/1, and ramping rate of pyrolysis is 2°C/min, and cycles of infiltration and pyrolysis is 6. The flexural strengths of joining components remained stable up to 1200°C (50.8MPa), but decreased to 30.5MPa at 1500°C, while the tensile strengths remained rather stable (20.5MPa) up to 1500°C, and decreased to 8.4MPa at 1800°C.