- 學位論文
鎳基超合金Waspaloy之惰氣鎢極電弧銲銲接探討
An Investigation on the Tungsten inert gas Welding for Nickel-base Waspaloy Superalloy
摘要
本研究針對鎳基超合金Waspaloy施以惰性氣體鎢極電弧銲（TIG）時，探討銲道微裂縫之特性，並建立最佳銲接參數組合。選用的銲接參數為銲接電流、銲接速度、送線速度及保護氣體流量，利用田口直角表進行實驗配置規劃，實驗完成後進行金相組織觀察、SEM觀察、EDS分析及微裂縫觀測，以抗拉強度及銲道硬度為量測目標，再經田口法之平均數分析及變異數分析找出影響TIG銲接品質最重要的參數，同時建立最佳銲接參數組合。實驗結果顯示鎳基超合金Waspaloy於較大的銲接電流容易產生凝固裂紋與熱影響區之液化裂紋。在單一目標品質之參數最佳化分析中，可分別得到抗拉強度為母材強度的95.4%及銲道硬度為母材的1.14倍。實驗結果並用來建立抗拉強度與銲道硬度趨勢之關係式，如此即可藉由測量銲道硬度來推估抗拉強度，對相關製程可提供一種更為簡便之品管檢驗模式。
並列摘要
In this research the characteristics of the welded region for nicked based superalloy Waspaloy and an optimum parameter combination in conducting tungsten inert gas (TIG) welding have been investigated. The selected welding parameters include welding current, travelling speed, filler speed and flow rate of shielding gas. An orthogonal array of Taguchi method was employed to arrange experimented sets. Observations for metallography, SEM, EDS analysis and microcrackes are performed when each test finished. Tensile strength and hardness of welded region have been measured. The average and variance analyses of Taguchi method are used to identify the most important affecting welding parameter and find an optimal combination of welding parameters. It shows that solidified cracks and liquidified cracks on heat-affected zone occur easily when a higher welding current was introduced. According to the single objective with a set of optimal parameters, a 95.4% of the tensile strength and a 1.14 times of the hardness comparing with the original material are obtained, respectively. A relationship between tensile strength and hardness has also been established. It offers a convenient way to find the tensile strength by conducting measurement of hardness for a quality control mode.