銲藥添加對不□鋼TIG銲件之影響

Abstract

本研究目的主要在探討不同成份組成之活性助銲劑添加對沃斯田鐵不□鋼銲道形態及銲接變形之影響行為與作用機制。實驗材料選用Type 304沃斯田鐵型不□鋼，活性助銲劑選用氧化物碳酸鹽基與氟化物，銲接方法採用不加填料金屬的氬氣保護鎢極電弧銲來進行Bead-on-plate實驗。實驗結果顯示在同一銲接製程參數條件下，添加氧化物組成之SiO 、Cr O 及TiO 等活性助銲劑時，除了可得到窄而深的銲道截面與較窄的熱影響區外，亦可有效降低銲件角變形量。其中，SiO 活性助銲劑的添加更可達到完全熔透及低變形量之不□鋼氬銲應用需求。本實驗結果亦發現添加SiO 、Cr O 、TiO 、CaF 及NaF等活性助銲劑對沃斯田鐵不□鋼銲道微觀組織與機械性質之影響並不大。當提高銲接電流時，氧化物型助銲劑與無添加助銲劑之銲道凸面高度呈現增加的趨勢。熱影響區的大小變寬及銲道深寬比與銲道熔深╱母材厚度之比在0.5之比例時，銲件之角變形均呈現最高值。另外添加氧化物型助銲劑之銲接電流增加至200A時，銲道會形成銲蝕(undercut)的現象。

The effect of adding activating fluxes on the morphology, distortion in austenitic stainless steel were investigated. An autogenous gas tungsten arc welding was conducted on type 304 stainless steel . activating fluxes of oxide, Carbonate and fluoride where used to produce a bead-on-plate weld. The experimental results indicate that the activating fluxes SiO 、Cr O , and TiO can give a full penetrated, narrower heat-affected zone, and beneficial effect on reducing angular distortion in stainless steel weldments under the same welding process parameters. Furthermore, the SiO can obtain a full penetration and lower distortion in TIG-flux stainless steel weldment. It was also found that the fluxes of SiO ,Cr O , TiO , CaF and NaF can not cause a significant change on microstructure and mechanical property in austenitic stainless steel welds. By increasing welding current, the oxide flux can create wider heat-affected zone,and weld convex length. In addition, the half of proportion on depth/width ratio and depth/thickness ratio can give the maximum of angular distortion. Furthermore, the oxide flux can obtain a phenomenon of undercut in TIG weldments of stainless steel under increasing welding current up to 200A.