| Summary: | 碩士 === 國立交通大學 === 工學院碩士在職專班精密與自動化工程組 === 97 === This research goal is mainly discusses forging/ extrusion titanium alloy carries on welds melts the aging heat treatment after welding stress relieving and the melting aging treatment of metal to influence of the mechanical property. The experiment material selects the present field universal use the Ti-6Al-4V alloy, carries on a series of mechanical properties and the Microstructure analyzes. The welding method uses the TIG automatic welding equipment, and by argon atmosphere protection, after the aging, forges the material and the forging material, the forging material with extrusion material and extrusion material with to extrusion material to carry on the multi-level TIG butt welding separately.
The experimental result showed that titanium alloy after the over weld melts the aging treatment of metal to be possible to obtain the best tensile strength; The forging material approximately increases 21.73% and extrusion material approximately to increase 24.89%; The elongation ratio actually suddenly drops to the minimum value; The forging material approximately reduces 85.27% and extrusion material approximately to reduce 79.05%. However, after welding, only serves with tensile strength of the stress relieving (forging material 1026.85MPa, extrusion material 946.59MPa) with the elongation ratio (forging material 8.71%, extrusion material 6.71%) still might maintain after welding does not serve with any heat treatment the tensile strength (forging material 1007.86MPa, extrusion material 935.78MPa) and the elongation ratio (forging material 8.76%, extrusion material 8.45%) the standard, may obtain the good working condition. Another titanium alloy forging material with extrusion material carries out when the butt welding tensile strength homogeneous material quality welding to lowly, demonstrated when the titanium alloy component must carry on the neterogeny material welding, tensile strength of value the engineering design should appraise prudently.
This experimental study contribution, when the titanium alloy carries out multi-level TIG weld, to obtain time the good tensile strength and the elongation ratio, uses stress relieving, may maintain the suitable mechanical property. Because after welding, although melts the aging treatment of metal to be possible to obtain the highest tensile strength, but the extensibility actually changes is very bad, and the weldment has the deviation brittle phenomenon.
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