不同接口型式銅與不鏽鋼異種金屬雷射銲接之製程分析

本研究探討以光纖雷射對異種金屬銅管與不鏽鋼圓管改變其接口型式，因圓管銲接大多數是對接型式為主，在單獨作業或是特殊環境狀況下，使用銲接工法會造成不穩或是錯位，而間接導致銲道偏差、管內壁落差、或是空隙距離過大，影響到整體的強度、氣密、效率，讓其可靠度下降，將其改善此接口把原本的對接型式改成鋼底嵌入銅及銅底嵌入鋼，換句話說就是做公母接頭，在進行銲接時不會因為人為疏失或是製作夾具讓缺陷增加及成本提高，可將其能提升接口可靠性。針對兩者異種金屬材料混合之情況調整銲接參數，主要調整焦距及功率，在以抗拉強度作為品質標準之一，研究顯示雷射光斑大小會影響到能量密度進而改變銲道熔池的深寬比，在銅管銲接實驗組中的銅嵌入鋼底接口型式焦距110mm及功率1900W的雷射參數下有趨近於對照組的對接型式的機械性質，抗拉強度為265.77MPa，高於銅母材之36.29%。進一步檢驗分析三種銲接型式之微觀組織及成分分析，觀察出實驗組中銅嵌入鋼底型式的接口，上層熔融不銹鋼牢牢的釘進銅母材，銲接型式像搭接銲；與另一實驗組鋼嵌入銅底型式相比，銅金屬無法滲透到下層不銹鋼，母材接合的銲接面積不足造成其抗拉強度為142.59MPa遠低於銅母材。且在成分分析也得到，銅嵌入鋼底的型式在銲道熔池區的Cu元素成分佔比大於Fe元素，反之鋼嵌入銅底的型式Fe元素成分佔比大於Cu元素，由此可得知接口設計的幾何形狀及金屬的特性可使銲接後的機械性質相差甚遠，透過適當調整焦距能避免因加工的公差進而影響到整體銲道品質。最後利用測漏試驗證實其實驗組銅嵌入鋼底型式，在壓力90psi持壓5分鐘，銲道能保持密封不漏氣，因此此接口型式是具有可靠性得以信賴。

關鍵字

接口型式；光纖雷射銲接；異種金屬

並列摘要

This study discusses how to change the interface type of dissimilar metal copper tube and stainless steel round tube by optical fiber laser. Because most of the round tube welding is the butt type, in a single operation or under special environmental conditions, the use of the welding method will cause instability or dislocation, which indirectly leads to the deviation of the weld bead, the drop of the inner wall of the pipe, or the excessive gap distance, which affects the overall strength, air tightness, and efficiency, and reduces its reliability. Improve this interface and change the original butt type to steel bottom embedded in copper and copper bottom embedded in steel to form male and female joints. When welding, it will not increase defects and increase costs due to human negligence or the production of fixtures. It can be used. Improve interface reliability. Adjust the welding parameters according to the mixing of the two dissimilar metal materials, mainly adjust the focal length and power, and take the tensile strength as one of the quality standards. The research shows that the laser spot size will affect the energy density and then change the aspect ratio of the weld pool. In the copper tube welding experimental group, the copper embedded steel bottom interface type has a focal length of 110mm and a laser parameter of 1900W. The mechanical properties of the butt type of the control group, the tensile strength is 265.77MPa, which is 36.29% higher than that of the copper base metal. The microstructure and composition analysis of the three welding types were further examined and analyzed, and it was observed that in the experimental group, the interface of the copper embedded in the steel bottom type, the upper molten stainless steel was firmly nailed into the copper base metal, and the welding type was like lap welding; Compared with the type of steel embedded in the copper bottom, copper metal cannot penetrate the underlying stainless steel, and the welding area of the base metal is insufficient, resulting in its tensile strength of 142.59MPa, which is much lower than that of the copper base. And in the composition analysis, it is also found that the proportion of Cu element in the type of copper embedded in the steel bottom is larger than that of Fe element in the weld pool area. On the contrary, the proportion of Fe element in the type of steel embedded in the copper bottom is larger than that of the Cu element. The geometry of the interface design and the properties of the metal can make the mechanical properties after welding very different. By properly adjusting the focal length, the overall weld bead quality can be avoided due to machining tolerances. Finally, the leakage test was used to confirm that the copper-embedded steel bottom type of the experimental group was maintained at a pressure of 90 psi for 5 minutes, and the weld bead could be kept sealed and air-tight, so this interface type was reliable.