- 學位論文
輥軋成形高頻感應焊管全線製程之研究
A Study on Full Line Roll Forming Seamed Tube Manufacturing Process with High-Frequency Induction Welding
摘要
有縫焊管之應用日益增加，包含輸送管線、機械重工結構管、與管件液壓下料管等，其中因結構輕量化之議題日益受到重視，製管廠逐漸開始生產先進高強度鋼(advanced high strength steel, AHSS)之有縫高頻感應焊管(high frequency induction welding, HFIW)。完整之HFIW製管產線包含粗成形段、閉口段、焊接站、正寸段與矯直段，於各段製程中皆尚有值得研究之現象與待解決之製程缺陷。本論文建立了一套完整之製管有限元素模擬模型，包括輥軋成形製管全線分析模型與HFIW焊接模型，最終藉以探討製管製程中之成形性與焊接性，並進而提出製管製程之優化設計。 本論文藉由有限元素分析方法，以實際之輥軋成形機台為基礎，並以先進高強度鋼DP980、DP780、與機械構造用鉻鉬鋼AISI 4130為材料，建立完整之製管製程分析技術，其中分為成形模擬與焊接模擬。於成形模擬中，為能準確預測製程中高強度鋼板之回彈現象，透過自行撰寫Yoshida-Uemori材料加工硬化模型子程式，可以考慮到先進高強度鋼之包辛格效應(Bauschinger effect)等反覆載荷下之特殊材料塑性變形行為，該子程式應用於輥軋成形製管之板帶幾何變化預測可達到94.4%之準確率，且透過實際製管實驗，亦驗證本論文提出之成形模擬可以準確預測製管製程缺陷與提供製程改善之設計。而焊接模擬則需要完整考慮到製程中各物理場之重要焊接參數，因此於本論文中提出一套運算效率高之耦合模型，以在電腦模擬之環境中，實現焊接製程之多重物理現象耦合，包含塑性變形、熱流、電、磁、微觀金相組織，且最終能準確預測焊道品質指標，包含焊道微結構與巨觀結構，透過實際製管產線生產之成品驗證，本論文提出之焊接模擬模型於巨觀結構預測之準確率達90.9%，而微結構預測之準確率達91%。 在實際製管製程中，粗成形段之輥輪模具需隨著欲生產之管徑、厚度、材料逐套更換與調校，除製管廠必需備齊所有模具外，更換模具與調校過程亦消耗相當多的成本與時間，因此本論文提出一套粗成形段模組化模具設計之優化模式，透過模塊抽換之方式調整粗成形段平輥之幾何參數，最終藉由模擬分析，證實本論文提出之模組化模具設計可以擴充同一套粗成形輥輪模具之成形管徑範圍，亦可以於成形相同管徑、不同級別之材料時，透過微調避免板帶邊緣挫曲與成形量不足之製程缺陷。而於製管HFIW焊接中，本論文以焊流線、熱影響區外型、焊道硬度分佈、焊道金相組織作為判斷焊接品質之指標，透過已建立之焊接模擬方法，分析重要焊接製程參數與材料參數對HFIW焊接品質指標之影響性，最終對HFIW焊接製程之焊前與焊後熱處理方法進行探討，透過電腦模擬分析提出最佳熱處理溫度建議值。焊接後，管材進入正寸站做最終修整，其中包含提高圓管真圓度之正寸圓形轉圓形，與異形管成形之正寸圓形轉方形製程，本論文最終透過所提出之模擬分析技術，分析正寸模具減徑率對成品機械性質、製程之影響性，此外亦透過模擬方法生成製程數據，進一步針對正寸模具設計參數建立大數據系統鑑別模型，提供製管廠一個更為迅速預測管材成品品質之方法，以及最終針對輥軋成形設備提出機台設計變更優化之方案，強化機台之成形負載能力，以提升機台之成形極限。 本論文成功地建立了一套完整之製管製程分析技術，且透過實際製程之驗證，更證實此套方法之準確性與計算效率，藉由這套分析技術，於本文中進一步提出之製程優化設計與參數分析流程，除在金屬成形領域具有其學術價值，也提供業界一套完整之電腦輔助分析工具，可以有效率地協助其於製程分析與優化，同時兼具應用價值。
並列摘要
Roll forming seamed tubes are commonly used in many industries, such as structural engineering, automotive engineering, and transportation pipelines. Due to the lightweight requirement, advanced high strength steels (AHSS) are also widely adopted for manufacturing seamed tubes with high frequency induction welding (HFIW). A complete HFIW seamed tube manufacturing line consists of roll forming, fin-pass, welding, and sizing. In each operation, there are still plenty of manufacturing problems to be solved. In order to assist solving the problems efficiently, a complete seamed tube manufacturing simulation model, including a comprehensive forming process simulation, and an HFIW simulation, is proposed and has been successfully established in this study. With the established simulation model, the formability and welding characteristics of HFIW tube manufacturing process have been comprehensively studied, and optimized designs have been well proposed. The proposed simulation model implemented with the finite element method was established in accordance with actual manufacturing processes for producing DP980, DP780, and AISI 4130 AHSS seamed tubes to ensure the completeness and accuracy of the model. In the forming simulation model, in order to predict the springback of AHSS sheets during roll forming process more precisely, a user subroutine code of the Yoshida-Uemori work hardening material model which well describes the Bauschinger effect has been written and attached to the commercial code ABAQUS. By implementing the subroutine code onto the simulation model, an accuracy of 94.4% has been achieved on calculating the geometry evolution during roll forming process. As validated by the measured data from actual manufacturing processes, it is further confirmed that the proposed simulation model for forming analysis established in this thesis is capable of predicting the tube manufacturing process precisely and providing optimized tooling design for ameliorating the quality of seamed tube products. As for the HFIW analysis, the necessary physical fields, including electro-magnetic field, heat transfer, phase transformation, and plastic deformation, are considered in the present study, resulting in a multi-fields coupled simulation model. A computation time-efficient approach has hence been proposed to construct the simulation model for analyzing those important welding parameters completely. Furthermore, the welding simulation model can be utilized to predict the micro and macro structures of the weldment resulted from the HFIW process. Comparing with experimental data obtained from the actual HFIW process, it is validated that the proposed HFIW simulation model can achieve an accuracy of 91% in predicting the micro structure, and of 90.9% in predicting the macro structure of the HFIW weldment, respectively. In the roll forming process, the shape of roll in each forming stand needs to be re-designed and tuned for tubes manufactured with different geometrical dimensions or with different materials, resulting in a higher production cost. Therefore, in this study, a modularized forming roll design has been proposed. By drawing out and re-arranging the roll blocks of forming stand, specific forming width and curvature can be achieved, and thus, various tubular products with different tube diameters within a certain range can be manufactured with the same set of rolls. It is further confirmed that the manufacturing defects, such as edge buckling and insufficient forming while producing tubes with the same geometry but different strength of materials can be improved with the proposed design. As for the HFIW process, the effects of important HFIW process parameters, such as line speed, upset quantity, and welding power on the quality of the weldment are investigated in details using the established welding simulation model. Furthermore, coupled with the analysis of the effect of heat treatment temperature on weldment, a method of approach for designing an optimal HFIW process with suitable welding parameters and heat treatment temperature to achieve the required weldment quality has been proposed. Finally, as for the sizing process after welding, both the processes for roll-forming round tubes or into a rectangular shape have been examined, respectively. The effect of sizing ratio on the tubular quality of subsequent roll-formed round or rectangular tube is analyzed using the established roll-forming simulation model. In addition, the proposed simulation analysis approach has been used to generate manufacturing data for constructing a systematic identification model, which can provide a faster approach for the industry to estimate the tubular quality with the process parameters selected. In the end, the loading capacity of the tube manufacturing machine is also investigated using the established simulation model and optimal designs are proposed for reinforcing the capacity of critical structural components. The optimized structure design proposed in this study has strengthened the loading capacity of the tube manufacturing machine and a significant increase in capacity limit has been achieved. A complete HFIW seamed tube manufacturing simulation model has been proposed and successfully established in the present study. The accuracy and effectiveness of the proposed simulation model have been validated by the actual tube manufacturing processes. The proposed design concept and method of approaches could be valuable references for the academic research in the metal forming field, and the established simulation model could provide the industry with an effective computer-aided tool for the HFIW seamed tube manufacturing process design.