汽車引擎連桿之省料化與高效率化熱間鍛造製程之開發研究

A Study on the Development of High Yield and High Efficiency Hot Forging Process of Automobile Connecting Rod

楊俊彬(Jin-Bin Yang) ； 吳崇源(Chong-yuan Wu)

《鍛造》 23卷4期 (2015/12) Pp. 8-14

摘要

汽車引擎連桿傳統鍛造製程需使用楔橫軋或輥鍛機進行預成形，將材料進行體積分配至連桿的大端與小端，再進行後續粗鍛、完成鍛與切邊工序，以減少材料的浪費，但此製程材料使用率仍約50∼60%，廢料仍高達40∼50%以上，預成形滾製加工時間較長。本研究以400ton機械式熱鍛機配合水平式複動化閉塞鍛造模組進行預成形工序，取代傳統以楔橫軋與輥鍛機進行預成形備料方式，再以1,600ton熱鍛機配合四工位之快速換模模座，進行粗鍛鍛伸、完成鍛與切邊+整形之鍛造製程，且模穴設計為一模兩穴式，期能節省下料重量，提升生產效率，預估材料使用率可達約為70∼75%。首先進行鍛胚設計與鍛造製程參數設計，再使用DEFORM軟體進行1,200℃熱間鍛造成形模擬，探討材料在模具內部的流動與缺陷的產生狀況。依據模擬結果，進行模具的開發與測試，並依實際狀況進行修模。結果顯示，本研究所開發之鍛件材料使用率為70%可達預期目標，比傳統的製程提高10%以上，表面無缺陷且其連桿桿部之流線均包含在桿部內並為連續，無斷裂情形，與傳統製程並無差異。此外，本研究所開發設計之模具可進行兩件式連桿鍛件之預成形、粗鍛、完成鍛與切邊+整形之多工位連續鍛造，具有高生產效率與量產可行性。

並列摘要

Traditionally, the forging process of engine connecting rod was made by forging roller or cross rolling machine to distribute the material into both big and small terminal to reduce the material waste, and then following by blocking, forging and trimming. However, the yield was around 50-60% in such process. On the other word, there was 40-50% material wasted. Besides, longer operation time was needed during performing due to gradual rolling. In this study, the 400 ton forging press equipping with horizontal multi-action closed forging dieset was used to do the perform instead of the rolling machine and then the following steps such as blocking, forging and trimming+sizing were proceeded by the other 1600 ton hot forging press. It was expected to save the materials, up to 70%~75% for the yield, and to elevate the production efficiency. First, forging billets and process variables were designed and simulated in 1,200℃ hot forging process by using DEFORM software to investigate the materials flow in die cavity and the occurrence of forging defects. According to the results of simulation, the dies were manufactured, tested and modified by the actual testing results. The results showed that the yield of the developing forgings around 70% reached the expect target, which was at least 10% lower than that by the conventional forging process. After inspection, there was no defect such as lapping and crack on the surface of forgings and the flow line was continuous in the interior of forgings similar to that of the conventional forging process. Then, the two piece connecting rod forgings were forged continuously through the steps such as performing by multi-action dieset, blocking, forging and trimming+sizing. So, the designed forging process was of high efficiency and feasible for mass production.