Ar-CO2混合氣體與活性助銲劑包覆銲線對不□鋼銲道特性之研究

Abstract

本研究目的主要在探討不同比例之氬-二氧化碳混合型保護氣體與混合型活性助銲劑添加，對沃斯田鐵不□鋼材銲接時銲道型態及銲接變形之影響。實驗材料選用AISI 304沃斯田鐵型不鏽鋼及308不□鋼銲線，活性助銲劑採用自行調配之混合型助銲劑25﹪Cr2O3 － 25﹪TiO2 － 30﹪SiO2 － 10﹪MoS － 10﹪MoO3 ，銲接方法採用配合不同比例之Ar-CO2銲接保護氣體添加，來進行在活性助銲劑氣體鎢極電弧銲(Activating-Tungsten Inert Gas, A-TIG)之Bead-on-Plate實驗。銲接過程中利用影像擷取系統(Charge -Coupled Device, CCD)記錄電弧動態影像及電弧電壓的變化；銲道分析以實體顯微鏡來量測銲道形態，並記錄銲道熔深及寬度以計算深寬比；以金相實驗來觀察微觀組織；利用肥粒鐵含量量測儀/微硬度測定機來瞭解銲道機械性質；並針對不□鋼銲道外觀及型態之影響和作用機制，及銲道穿深能力之增加機制進行探討與分析。 實驗結果顯示： (1).以深寬比及銲道外觀作為評估指標時，此混合型助銲劑可提升熔透深度及機械性質，皆優於傳統氬銲製程。 (2). CO2氣體添加於A-TIG及TIG製程中，並無法使其熔透深度及硬度再進一步強化與提昇。 (3).助銲劑添加於母材或銲條上，其皆可使熔透深度及機械性質獲得有效提昇。

The purpose of this research is to study the effect of the difference concentration of Ar-CO2 mixed shielding gas and specific mixed activating flux on the angular distortion and mechanical properties of TIG welding process on the 5mm thick austenitic stainless steel plates. The AISI 304 stainless steel plates and 308 wire were selected , the mixed flux is 25﹪Cr2O3-25﹪TiO2-30﹪SiO2 -10﹪MoS-10﹪MoO3. A bead on plate weldment was made using activating- tungsten inert gas arc welding (A-TIG) process. During the welding process, a charge-coupled device (CCD) was used to record the images of arc profile and voltage variation. Besides, the microstructure and morphology of the weldments were examined by the optical microscope, 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 Furthermore, the Ferrite Scope and Vickers hardness tester was used to determine the mechanical properties of the weldments. According to measurements of surface appearance, welding morphology, and deep of weld shape, micro-hardness, and angular distortion on the weldments were analyzed and studied the influence of Ar-CO2 and flux cladding wire addition to weldments. The experimental results show that: 1. According to the surface appearance and weld penetration, the mixed activating flux can enhance the depth of weld and hardness. 2. The addition of CO2 shielding gas to A-TIG or TIG process shows no effect on the depth of weld and mechanical properties. 3. The cladding of mixed activating flux on both plate and wire can effectively increase the depth of weld.