連續退火線(Continuous Annealing Line，簡稱CAL)具有快速和高產能的優點，可大幅降低生產成本，提高產品競爭力。然而所生產的電磁鋼片在沖製EI片後會有翹曲的現象，並且翹曲量會隨著沖製尺寸變寬而加大。這種現象與鋼帶殘留應力分佈不均有關，推測其原因為鋼帶在通過爐輥時產生的彎曲應力以及鋼帶寬度方向不均勻溫度分佈所致。連續退火線內有許多的工作區域，本論文研究的區段為第一區段-預熱區，主要係探討鋼帶三維的應力與溫度分佈。此為力學與熱傳的耦合場 (Coupled-field analysis)問題，本論文運用有限元素分析軟體ANSYS分別建立鋼帶力學與熱傳模型，並且把爐輥對鋼帶的接觸熱傳效應考慮進來。模擬結果顯示，雖然鋼帶通過爐輥的時間極短，但是因為接觸熱阻小以及鋼帶厚度薄，所以造成鋼帶與爐輥接觸的區域溫度急遽上升，導致鋼帶在寬度方向的溫差急遽增加。在預熱爐內，鋼帶沿著寬度方向的溫度分佈是中間高於兩側，應力則是兩側高於中間，同時在爐輥錐度附近有應力較大的現象。

　　The process of continuous annealing line (CAL) exhibits the advantage of high production rate. Therefore, the cost of production can be significantly reduced and the competition of production can be enhanced. However, the electromagnetic sheet shows the phenomenon of bowing after having cut into pieces of the EI shapes. Moreover, the larger the cutting size, the more serious the strip bows. The phenomenon of strip bowing may relate to the non-uniform residual stress distribution of steel strip, which may introduce by the bending stress as the strip passes through the rollers and non-uniform distribution of temperature and stress of the strip in width. The process of CAL consists of several zones. This study investigates the 3-D distributions of the stress and the temperature within the preheating furnace. The problem shows a coupled mechanical and thermal phenomena in nature and is solved by using the finite element analysis software ANSYS. The effects of the contact heat transfer between the rollers and the strip upon the distributions of the stress and the temperature are taken into consideration in this study. The simulation results show that, although the time for a strip passing through the roller is very short, the temperature of the strip still goes up rapidly due to small contact thermal resistance and thin thickness of the strip. This phenomenon results in the temperature difference along the width of the strip. The temperature of the strip in two sides is smaller than the middle, while the stress in two sides is larger than the middle. Moreover, a much high stress is induced in the strip near the crown of the roller.

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