tailieunhanh - Manufacturing Processes phần 3

và thi công tuyệt vời (lớn dòng chảy mà không có lỗi vật liệu) có thể được thực hiện trong phạm vi làm việc nóng. Làm việc nhiệt độ nóng, tuy nhiên, cũng có nghĩa là dung nạp người nghèo chiều (tổng chiều lỗi), kết thúc bề mặt người nghèo, và thiệt hại vật chất do sự tích tụ quy mô. Giả mạo nhiệt độ trên 1300 C (2372 F) có thể dẫn đến khó nóng biểu hiện bằng | DRAWING 13-21 Fig. Drawing of magnesium sheets at elevated temperatures. a Flow stress of magnesium AZ61. Chabbi et al. 2000 Hot and Cold Forming Behavior of Magnesium Alloys AZ31 and AZ61 in K. U. Kainer ed. Magnesium Alloys and Their Applications Wiley-VCH D pp. 621-627. b Drawn AZ31B cups at room temperature left and at 230OC right . S. Novotni Innenhochdruk-Umformen von Belchen aus Aluminium-und Magnesiumlegierungen bei erhohter Temperatur . thesis Elrangen University Germany. Fig. a Many parts are formed separately and joined to form side panels and pillars b single blank is trimmed and then formed. Source Ruch et al. Grobserienfertigung von Aluminumkarosserien in K. Siegert Neuere Entwicklungen inder Blechumformung MATINFO Frankfurt D 2000 . mm BH 260 370 mm BH 260 370 mm DP 100 1000 mm DP 100 1000 mm DP 100 1000 Tailor Welded Blanks TWB in Forming With the demand for reducing both automotive structure weight and manufacturing costs many new processes are being employed 1. Different parts are formed separately and then joined by laser. Part forming is independently optimized followed by trimming and weld assembly. Forming is easier but welding along curved lines is more complex Fig. . 2. The blanks are welded and then the panel is formed in one die. Welding is simpler but forming is considerably more complex. Dimensional tolerances are better controlled Fig. . 3. Blanks of varying thickness are tailor-welded using laser techniques to create a single blank that subsequently is formed into the required geometry Fig. . The forming process of TWBs is very complex as the blank areas with different thicknesses flow differently during the drawing operation. 4. Friction stir welding is used to create a single blank made of different materials or different sheet thickness. This composite blank is then drawn to final geometry Fig. . Hot drawing above the recrystallization range applies .