應用田口方法分析構造用合金鋼氬銲參數並藉以探討助銲劑之影響研究

The Application of Taguchi Method in the Process Parameters of Gas Tungsten Arc Welding to Explore the Effects of Flux on the Weld Peculiarities of Structural Alloy Steel

莊富珍(Fu-Chen Chuang)

指導教授 ： 黃和悅

國立虎尾科技大學/工程學院/材料科學與綠色能源工程研究所在職專班/碩士(2010年)

摘要

本研究運用田口方法尋找影響氣體鎢極電弧銲接製程參數之最佳組合，運用L16 直交表研究四個控制因子與水準，配合訊號雜訊比值及變異數分析理論進行分析，並以銲接最大熔透深度與最小熔融面積為品質特性。影響銲接品質的重要參數選定銲接電流、銲接速度、鎢棒角度及電弧長度，經由分析後得知，銲接電流與銲接速度影響銲道幾何形狀之品質特性甚大，所求得之最適條件經由確認實驗來驗證其再現性，其訊號雜訊比皆落在95％信賴區間。之後以獲得之最佳參數來探討助銲劑對構造用合金鋼銲接特性之影響，實驗結果顯示酸性助銲劑能有效地提高銲道熔透深度，甚至可達全熔透狀態。在金相組織分析中，母材的顯微結構為肥粒鐵與波來鐵，而銲道金屬則為麻田散鐵與變韌鐵混合組織，由於兩者顯微結構的差異性導致其微硬度值也產生明顯的變化。

關鍵字

助銲劑 ； 鹼性指數 ； 氬氣鎢極電弧銲

並列摘要

In this study, the Taguchi method was used to find the optimal process parameters for gas tungsten arc welding. A 4-factor 4-level (L16) orthogonal array, the signal-to-noise ratio, and analysis of variance were employed to study the weld penetration and bead area in welding of structural alloy steel. Four welding process parameters namely, welding current, welding speed, electrode tip angle and arc length, are optimized with the objective of producing welded joint with higher penetration and minimum bead area. The welding current and the welding speed were the major parameters that influence the weld bead geometry. Besides, a confirmation test was conducted subsequently, and the results were found to be within the 95% confidence interval. The optimum conditions were determined, and then effect of flux on the weld peculiarities of structural alloy steel was evaluated. The results showed that the acidic fluxes increased the weld penetration effectively and some of fluxes were enough to obtain full penetration welds. Optical microscopy revealed that the matrix microstructure of the base metal was ferrite and pearlite, while the microstructure of the weld metal was bainite and martensite. Because of different microstructures, the hardness of the weld metal was significantly different from that of the base metal.

並列關鍵字

flux ； basicity index ； argon gas tungsten arc welding

參考文獻

1.Her-Yueh Huang,”Effects of Shielding Gas Composition Activating Flux on GTAW Weldment”,Materials and Design,30,2009,p2404-2409.

10.O. E. Ostrovsky, V.N. Krjukovski and B.B. Buk, “The Effect of Activating Fluxes on the Penetration Capability of the Welding Arc and the Energy Concentration in the Anode spot”,Welding Production(English translation of Svarochnoe Proizvodstvo), 3, 1997, p3-4.

13.D. Fan and Y. Huang, “Study on Activating TIG Welding for Aluminum Alloys” ,Weldng in the world, p49(1-2).

14.Y. Huang and D.Fan, “Mechanism of weld Penetration Increased by SiO2 in AC A-TIG Welding for Aluminum Alloy”,Hanjie Xuebao/Transactions of the china Welding Institution, ,2008 ,29(1), p45-49.

16.D.s Howse and W. Lucas, “Investigation into Arc Constriction by Active Fluxes for Tungsten Inert Gas Welding”, Science and Technology of Welding and Joining , 5 (3), 2000, p189-193.