應用有限元素法於U型異形材熱輥軋製程與孔型設計之分析

本研究係針對U型異型材熱輥軋進行研究，應用有限元素軟體DEFORM-3D分析輥軋加工時，製程參數對於輥軋的影響。探討的對象有壓延力分析、殘留應力分析以及組織變化分析。分析模式在壓延力與組織變化分析時採用塑性模式，而在殘留應力部分則採用彈塑性模式，皆假設輥軋之輥輪為剛體，並對板材施以一前向拉力。探討孔型設計、摩擦因子、輥軋速度及板材溫度對於壓延力、殘留應力及組織變化有何影響，之後利用田口方法找出最佳製程參數，與模擬之值做一比較，並利用類神經網路法來預測與比較其最佳製程參數所模擬而得到之值，研究後可得到：孔型設計對於壓延力之影響不大，而對於殘留應力之影響，則是孔型設計越大其殘留應力越大，而對於組織變化之影響則是孔型設計越大其25μm以下之結晶所佔之區域也越大。摩擦因子對於壓延力之影響為摩擦因子越小壓延力也越小，而對於殘留應力其趨勢相同，而對於組織變化之影響則是當摩擦因子大到某一程度時其影響程度不明顯。輥軋速度對於壓延力之影響為輥軋速度越快其壓延力越大，而對於殘留應力之趨勢較不明顯，而對於組織變化之影響看來，輥軋速度越快時其25μm以下之結晶所佔之區域也越大。板材溫度對於壓延力之影響為，當板材溫度越高其壓延力則越小，而對於殘留應力來說，也是板材溫度越高時其殘留應力則越小，而對於組織變化來說，當板材溫度越高時則其25μm以下之結晶所佔之區域也會越大。利用田口法及類神經網路法來預測模擬方面，在塑性問題，如壓延力與組織變化方面有較為準確之預測性，但若為預測較為複雜之彈塑性問題時，因彈塑性問題有彈性與塑性交互間之影響，其預測之準確性較為不佳。關鍵字：U型異型材、熱輥軋、有限元素

關鍵字

U型異型材；熱輥軋；有限元素

並列摘要

To research the hot rolling of U-shaped cross-section in this study. Using finite element method DEFORM-3D to analyze the hot rolling process. The effect of parameter to rolling. Investigated the load, residual stress and microstructure. When analyzing load and microstructure, used Rigid-Plastic model. The part of residual stress used Elastic-Plastic model. Suppose the rolls of rolling were rigid and give the sheet a front-speed. Investigated the effect of the design of the caliber, friction, speed of rolling and temperature of sheet to load, residual stress and microstructure. Then Taguchi method will be applied to find out the value of Optimal Process Parameters and compare with the value of simulation. Finally, using abductive network to forecast the value and compare with the value of simulation. After research: The effect of the design of the caliber isn’t important to load. When the design of the caliber is bigger, the residual stress will be bigger. Also, the design of the caliber is bigger, under the 25μm of grains will have more area. The effect of the fraction is when the fraction is smaller, the load will be smaller. And the trend is the same to the residual stress. The effect to microstructure is, when the fraction is bigger until certain level, the effect will be not obvious. The effect of the speed of rolling is when the speed of rolling is faster, the load will be bigger. And the trend of the residual stress isn’t obvious. The effect to the microstructure is, when the speed of rolling is faster, under the 25μm of grains will have more area. The effect of temperature of sheet is when the temperature is higher, the load will be smaller. And the effect to the residual stress is the same. To the microstructure, when the temperature of sheet is higher, under the 25μm of grains will have more area. Using Taguchi method and abductive network to forecast in the simulation. In the Plastic problem, such as load and microstructure have the better accuracy of forecast. But when forecast the complex of Elastic-Plastic problem, the accuracy of forecast is low. Because Elastic-Plastic problem had effect between Elastic and Plastic. Key word: U-shaped cross-section, hot rolling, finite element