Titanium tetrachloride carried by argon gas was reduced by sponge titanium to lower chloride; and then, the chloride was spread over hign carbon steel to make titanium carbide film formed on the steel surface at 850-1000°C.The properties of titanium carbide layer formed at above 900°C were fairly good in adhesive power and no porosity. The thickness of the layer attained to about 14μ at 1000°C for 225min. with considerably large leveling power. The growth rate was in accordance with the Law of √t and the activation energy was found to be 48Kcal/mol. The rate determining step was supposed to be the diffusion process of carbon from high carbon steel. As the results of electron probe microanalyzer, it was found that the intensity of titanium diffraction in titanium carbide layer was 80-85% of that of pure titanium. That value corresponded to the concentration of titanium in titanium carbide in consideration of that titanium lattice points were partly replaced by 2-7% of iron impurities.
The Friction Stir Welding (FSW) with heating of A5052-H34 aluminum alloy, which is a narrow welding condition material in FSW, was conducted to clarify the improvement of welding rate by heating effect. At first, the FSW with heating on temperatures of 150 and 300°C was examined at welding rates of 600 to 900mm/min. And the joint integrity was evaluated by observation of appearances of welded part and its cross section. Good joints in FSW with heating were obtained at welding rate up to 700mm/min for heating of 150°C, and up to 900mm/min for heating of 300°C. In addition, the hardness profile and tensile strength of joints by FSW with heating showed a good level as much as non-heating one with low welding rate. As the result, welding rate in FSW with heating could expand a conventional welding rate. Therefore, the improvement of welding rate in FSW with heating clarified would be feasible.
