Study on the Form Tapping Process for Ultra High-Strength Steel

[[abstract]]高張力鋼板具備高強度、良好的韌性、熔接性、加工性、疲勞特性及耐候性等性質，目前在汽車板金、3C產品機殼及大型液晶電視框架等皆逐步使用厚度0 5mm以下及抗拉強度440MPa以上規格之高張力鋼板。 本研究以JSC440MPa、JSC590MPa、JSC780MPa、JSC980MPa四種不同抗拉強度等級之高張力鋼板為例，進行公制牙M6×1、M8×1 25、M10×1 5之無屑擠製攻牙製程參數之研究，其研究流程分為二階段執行，其研究包括：第一階段「不同抗拉強度等級高張力鋼板之沖孔參數最佳化研究」與第二階段「不同抗拉強度等級高張力鋼板對孔凸緣成形與無屑擠製攻牙之研究」。 第一階段研究中透過實際開發模具進行沖孔實驗與商用有限元素分析軟體DEFORM 2D進行沖孔模擬分析驗證比對，再搭配最佳化方法以獲得不同抗拉強度等級高張力鋼板之最佳沖孔參數。在第二階段研究中，以第一階段實驗結果來延續探討不同抗拉強度等級高張力鋼板在孔凸緣成形與無屑擠製攻牙研究，並應用商用分析軟體DEFORM 2D與DEFORM 3D模擬不同抗拉強度等級高張力鋼板之孔凸緣成形與無屑擠製攻牙；同時，實際開發模具進行實驗與驗證。 結果顯示，分析模擬亦能有效預測出沖孔、孔凸緣與無屑擠製攻牙之成形結果。此外，JSC440MPa、JSC590MPa、JSC780MPa、JSC980MPa等級之高張力鋼板在無屑擠製攻牙製程的最大孔凸緣率分別為45 65%、40 22%、27 27%、25 17%。[[abstract]]The Ultra high-strength steel has the higher strength good tenacity better weldabailty workability fatigueability and weatherability At present the high tensity steel sheets are used below 0 5mm of thickness and above 390 MPa of tensile strength gradually in the automobile sheet metal the 3C product casing and the large-scale casing of liquid crystal display TV In this study is to investigate the process parameters of form-tapping with the metric tooth M6 × 1 M8 × 1 25 M10 × 1 5 on JSC440MPa JSC590MPa JSC780MPa and JSC980MPa Ultra high-strength steel The study is consist of two tasks First “tensile strength of different grades of Ultra high-strength steel piercing parameter optimization study” Second “tensile strength of different grades of Ultra high-strength steel flanging and form-tapping process study” The study of first task is to use the software of finite element method as DEFORM 2D for simulation piercing Meanwhile to develop experiment die to experiment and prove and then to use the the best method for the best piercing parameters The study of second task is to perform flanging and form-tapping on Ultra high-strength steel by the results from first task and use the software of finite element method as DEFORM 2D for simulation flanging and DEFORM 3D for form-tapping Meanwhile develop experiment die to experiment and prove The results show that the simulation can predict results of the piercing flanging and form-tapping The maximum rates of flanging on JSC440MPa JSC590MPa JSC780MPa and JSC980MPa Ultra high-strength steel are 45 65% 40 22% 27 27% and 25 17% respectivel