不銹鋼薄板應用脈衝式雷射銲接之數值分析

Numerical analysis of stainless steel welding with pulsed laser

謝欣涵(Hsin-Han Hsieh)

指導教授 ： 屠名正 ； 鄭慶民

國立臺灣師範大學/科技學院/工業教育學系/碩士(2008年)

摘要

本研究以數值分析方法模擬對接薄板雷射銲接之過程，並以實驗所得量測結果對照作驗證。主要係探討溫度場與應力場的變化情形，銲接材料為SUS 304不銹鋼，方法為Nd:YAG雷射銲接。數值模擬採用有限元素分析軟體ANSYS，考慮非線性材料特性且利用熱-力結構耦合分析過程。實驗使用熱電偶量測溫度循環曲線，再以游標高度規測量銲後角變形。
分析結果顯示，在溫度場分析中，薄板雷射銲接僅需施加高斯柱狀體熱源且利用銲接峰值功率計算出的脈衝時間，能精準的模擬出溫度分佈。在應力場分析中，因銲接熱源的高溫作用使銲道附近有較高的溫度梯度存在，且受到遠離銲道熱源周圍材料的拘束，因而產生較高的壓縮熱應力。隨銲接熱源的消失，靠近銲道附近區域受到冷卻而收縮，故產生較高的拉伸殘留應力。
對照數值模擬分析結果與實驗量測數據，顯示出本研究的有限元素分析可準確的模擬不銹鋼薄板雷射銲接過程。

關鍵字

雷射銲接 ； 有限元素法 ； 數值分析 ； 溫度場 ； 角變形 ； 不銹鋼

並列摘要

This study simulates the laser welding process for butt joint of sheet metal verified by experiments. It aims at to investigate the changes of the temperature and stress field. The method of welding process is Nd: YAG laser welding with SUS 304 stainless steel as welding material. The finite element software Ansys is used for numerical simulation, which employs thermo-mechanical coupling process with consideration on non-linear material characteristics. The experiments measure the thermal cycle temperature in the welding process with thermocouple and the angular distortion with vernier height gage.
The analysis results show that to accurately simulate the temperature distribution in the laser welding for sheet metal it only requires to apply the Gauss cylinder volume heat source with pulse time figured out from peak power. The temperature fields adjacent to the heat source are rather steep because of the locally concentrated heat source. The transient thermal stresses are in compressive state since the expansions of these regions are restrained by surrounding cold metal that is at lower temperatures. As the heat source had passed by, the fusion zones have been cooled and hence have a tendency of contraction. A great tensile residual stress was produced in solidified welds, and then rapidly decreased over the area which is far away from welded zone.
Compare experimental data with results from simulation, it shows that the finite element analysis of this study can accurately simulate the laser welding process for butt joint of sheet metal.

並列關鍵字

Laser welding ； Finite element ； Numerical analysis ； Temperature field ； Angular distortion ； Stainless steel

參考文獻

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