拘束式鍛粗模具應用於熱鍛製程之預成形工序研究

環首螺栓（eye-bolt）主要用於機械產業上，因為鍛件體積分佈差異大，傳統熱間製程一般先進行前擠預成形做體積分配，重新加熱，再進行完成鍛，接著沖孔+切邊。本研究規劃以Ф11 mm棒材下料，進行拘束式鍛粗預成形、有毛邊完成鍛、沖孔+切邊，探討製程可行性。首先藉由成形軟體DEFORM－3D進行熱間鍛造之模擬，探討材料流動，成形負荷與製程設計。根據模擬結果，進行實體模具之開發與實際測試，建立出較佳之製程參數及設計。結果顯示，本研究實際熱間鍛造成形狀況與模擬相符。鍛件可完全成形，無缺陷。拘束式鍛粗預形熱鍛製程，可將長俓比5.45:1之材料一次鍛粗成形，總負荷為106 ton。最終鍛造完成後，比傳統製程節省15%之材料。本研究顯示拘束式鍛粗預形熱鍛製程可縮短製程、提升材料使用率、進而降低成本。

The eye-bolts are widely used in mechanical industry. Due to the highly varied cross sections of different castings, perform process is needed to distribute the volume to reduce the usage of the materials. Generally, the perform should be done by extrusion. After the perform, the billets need to be heated again before upset forging and finished forging following by piercing and trimming process. In this study, the constrained upsetting was developed to investigate the optimal forging process of the eye-bolt. The steps are upset preforming by the constrained die, finishing with flash and piercing plus trimming by using the billet of Ф11 mm. DEFROM-3D is used to investigate the feasibility of this process. The actual dies are made afterward. The results show that the actual forging was similar to the simulation, which the parts are fully filled with no defects. Compared with the conventional forging, the materials can be saved up to 15%. The load of the constrained upset forging is around 160 ton. Moreover, for the constrained upset preform, one hit upsetting is feasible for the billet of L/D value of 5.45. Therefore, the constrained upset preform process is the better forging process for eye-bolt due to shortened cycle time, reduced materials and cost.