使用Sysweld進行銲件殘餘熱應力及變形之研究

Abstract

本研究利用法國ESI公司所推出的銲接模擬軟體SYSWELD對兩組合金，進行鎢電極氣體保護銲(TIG)的銲接模擬。此兩組材料分別是工業上常用的316L不銹鋼以ER 308銲條進行同種合金對銲，另外一組則是316L不銹鋼利用Inco 82銲料對銲常用於壓力容器之鋼材A508。研究中除了電腦模擬計算之外，亦以實際實驗來佐證模擬結果，對照兩者之熔池形狀、殘留應力場以及材料變形量，於此來確定電腦模擬計算結果之準確性，以及可以改進的製程參數。 本文實驗分成模擬計算以及實際操作兩大部分來進行，實際實驗是先委託廠商以TIG銲製得試片，取得試片後，先以鐵尺量得試片最外圍厚度方向變形量，接著以盲孔法測得殘留應力，之後再對試片進行切割、鑲埋、研磨、拋光、腐蝕後，進行金相實驗來取得熔池形狀。而模擬計算則分成建模、求解、結果觀察三個階段，建模部分以Visual-Environment套裝軟體內的Visual-Mesh建立兩個長寬高為200 mm*100 mm*3 mm的板材，再開槽60度並預留銲道間隙2mm，建模後直接對模型劃分成約15,000個網格，接著再以VE內建的Visual-Weld建立與實際實驗相同銲接相關參數，然後再以Visual-Weld內掛載SYSWELD進行求解，模擬結束後再以Visual-Viewer來呈現最終結果並與實際實驗進行比對。實驗的結果顯示，SYSWELD的模擬計算和實際實驗，在變形之趨勢上相當匹配。而透過模擬結果，將可以更了解工件內部溫度場、殘留應力的分佈，未來可以用來優化銲接製程。

In this study, the welding process simulation software, SYSWELD, is used to conduct the simulation of a tungsten inert gas (TIG) welding process using two combinations alloys. The two groups of materials are 316L/ER308/316L and 316L/Incoly82/A508 and all of these materials are widely used in nuclear power plants. In addition, experiments are carried out to support the simulation results. By comparing the shape of weld pools, residual stresses, and displacements of both results, the accuracy of the simulation results can be confirmed. The research is composed of two parts, actual experiments and computer simulations. For the actual experiments, the samples is prepared by outsourcing. After getting sample, using the ruler to measure the displacements of sample’s four edge and the High Speed Hole-Drilling Method is subsequently carried out to measure residual stresses of the sample. After finishing the above procedures, observing the shape of weld pool by metallographical analysis. On the other side, the computer simulation is divided into three steps, modeling, solving, and observing the results. First, finite element method (FEM) model with 15,000 meshes of workpiece is established by using the Visual-Mesh, and the weld bead of workpiece is single grooved with 60 degree. Second, the actual process parameters are input to Visual-Weld and then simulate the welding process by SYSWELD. After solving, simulation results can be displayed on Visual-Viewer for comparing both results. The results of actual experiment and simulation indicate that the both displacement and the shape of weld pool are approximately equal. Through the simulation results, the temperature and stress field can be much more clearly. Therefore, the SYSWELD welding process simulation shows potential for industrial applications.