Roll Forming Die Geometry and Cage Forming Process Designs for Welded Pipes
| Autor: | WANG,JING-KAI, 王敬凱 |
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| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 Electric resistance welding (ERW) pipe cage roll forming process adopts many cages to do the rough forming instead of using the upper-lower rolls and the side rolls applied in the conventional cold roll forming method. The advantages of cage roll forming are lower spring back, applicable to make several pipe diameters, easy to change and adjust roll orientations, high efficiency and low cost. Design method of the cage roll and the layout of cage position and orientation were proposed to make a API pipe with 88.9mm diameter. Taguchi method was adopted to get the optimum combination of the design factors. A L9(34) orthogonal array was used to arrange the combinations of the three level design factors. The design factors considered are material (Grade A, X56, X80 for API pipe), cage roll geometry, thickness of blank, cage layout profile along blank edge in the area of cage forming. The objective function is minimization of the edge curvature variation of the cross section at the exit of cage forming area. The CAE simulations had shown the blank edge profile design of the cage roll forming process change the curvatures of the blank dramatically. The transition of the curvatures along the transverse direction of the blank gives obvious changes from segment to segment. The curvature varied locally due to the characteristics of the three-roll bending feature of the cage roll forming. Regions of the middle and the edge of the blank contact the rolls directly and have larger contact forces .The response chart had shown the most significant design factors are the material and the thickness of blank. The optimum combination of design factors is the material Grade A, the concave cage roll profile, the thin tube, and the linear cage layout profile along the blank edge. The predicted edge curvature variation is 0.022 which is very close to the CAE confirmation result 0.0004. This demonstrated the optimization prediction is convincible. The optimum combination was applied to make a smaller pipe (60.3mm in diameter). The edge curvature variation is 0.002 which is good enough to enter the fin pass of pipe making. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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