不□鋼與Inconel 718超合金TIG-Flux對接之研究

Abstract

本研究之主要目的在於探討添加活性助銲劑，對於不□鋼與Inconel 718超合金對接銲件之銲道熔深影響。活性助銲劑以氧化劑粉末為主，包括 SiO2、NiO、MoS2及MoO3四種，銲接方法採用不加填料金屬，且以氬氣為保護氣體的鎢極惰氣銲(Tungsten Inert Gas, TIG)來進行Bead-on-Plate實驗。 本研究之銲件以金相實驗來觀察其微觀組織，並利用微硬度測定機來瞭解銲道之機械性質，另外，以實體顯微鏡量測銲道的幾何形態，並記錄銲道熔深及其寬度，以取得所有銲件的銲道深寬比。本研究以上述四種活性助銲劑，依各50%的比例來調配成六種混合型活性助銲劑，並探討混合型助銲劑對銲道熔深與深寬比之影響。最後，本研究應用田口方法於厚度7mm的不□鋼與Inconel 718超合金試片，進行異種材料TIG-Flux對接的最佳化實驗，選擇混合三種不同比例的SiO2與MoO3粉末的混合型助銲劑，並搭配五種銲接製程參數，包括銲接電流、銲槍走速、氬氣流量、鎢棒角度及電弧長度等，以取得此製程的最佳化參數。實驗結果發現，在固定的銲接參數下，銲件塗敷不同種類的混合型活性助銲劑於厚度6.35mm 銲件上，能有效提升銲件之銲道熔深達67%至110%，銲道深寬比提升達112%至371%。由田口方法實驗結果可知，應用田口方法可提升銲件之銲道熔深達56.2%，銲道深寬比可提升至117%。

The purpose of this study was to investigate the effect of activating fluxes to the penetration of weldment for butt-joining stainless steel and Inconel 718 superalloy. The activating fluxes used in the experiment were SiO2, NiO, MoO3, and MoS2. Bead-on-plate argon TIG(Tungsten Inert Gas) weldment was processed without filling metals. The microstructure and morphology of the weldments were examined by the optical microscope. The Vickers hardness test was used to measure the mechanical properties of the weldments. According to the measurement results of the width and penetration of the weld bead, the depth to width ratio (D/W ratio) can be calculated. Four fluxes were mixed with each other using 50% weight percent each. The six mixed fluxes were used for investigating the effect to the penetration and D/W ratio of weldment. Finally, by employing the Taguchi Methods to 7mm thickness of stainless steel and Inconel 718 superalloy, six major welding parameters were determined, which were welding current, torch moving speed, argon flow rate, vertex angle of electrode, arc length and the three weight ratio of SiO2 and MoO3. Under the same welding condition, the results indicated that all the mixed fluxes did enhance the penetration of weldment by 67%~110% for the thickness of 6.35mm. Moreover, the D/W ratio was enhanced up to 371%. The confirmed experiment analysis of Taguchi Methods demonstrated that the penetration of weldment enhanced 56.2%, and the D/W ratio also increased 117%.