硫化物之助銲劑對1020低碳鋼與304不□鋼銲道穿深能力之研究

Abstract

TIG銲接製程主要應用於要求全滲透之高品質高精度銲道，但對TIG銲接的缺點常因滲透不足或熔深不一，此外TIG銲接熔池較寬且淺的特性也限制生產效率。以TIG-Flux方式可以有效提高銲道熔深法，且引起世界各地銲接者的重視，目前已經應用於反應爐管、海軍造船等重要工業。 本研究主要在探討添加硫化物成分之助銲劑，對SAE 1020低碳鋼與SUS 304沃斯田鐵系不□鋼銲道外觀及型態之影響和作用機制，並針對銲道穿深能力之增加機制進行探討與分析。助銲劑選用MoS2、FeS、BaS、ZnS四種硫化物粉末。 實驗結果顯示:(1)以深度與外觀為評估指標時，以MoS2助銲劑效果最佳，對不□鋼銲道深度可達8mm，低碳鋼也有6.6mm；(2)電漿電弧柱收縮與陽極斑點收縮等現象的共同作用應是助銲劑可有效提高銲道穿深能力的主要因素；(3)SOB Test來評估銲接金屬熱裂敏感性時，添加硫化物助銲劑之試片，其裂縫總長度比未添加助銲劑明顯減少。

Gas Tungsten Arc Welding (GTAW) has been hindered by the limitation in the depth of penetration in the depth of penetration that can be achieved in a single weld. A new method of increasing the weld penetration has been invented and used in pipe and ship-building industry. This new method uses a thin layer of inorganic powders which are applied to the surface of base metal prior to welding. The purpose of this research is to study the effect of adding of four kinds of sulfide flux (MoS2,FeS,BaS,ZnS) on the weld penetration of SUS stainless steel and SAE 1020 carbon steel using GTAW. Metallographic examination, angular distortion measurement, micro-hardness and ferrite number measurements and hot cracking test were performed. In addition, a CCD camera was used to record the real time shape of plasma arc during welding. The results show that flux MoS2 is the best of all fluxes according to the appearance and weld penetration. The contractions of both plasma arc and anode spot are the reasons of deep penetration of fusion zone with the use of flux. Hot cracks are reduced with the application of any sulfide flux.