田口方法對汽車空調元件硬銲最佳化製程研究

Abstract

在汽車冷氣系統中，冷氣管路及其重要零組件如壓縮機、冷凝器等接合，需靠轉接頭從中進行連結，而管與轉接頭的結合大部份是採用噴炬硬銲銲接。本研究利用管6063(T6)與轉接頭6061(T6)之鋁合金母材試片，模擬現行汽車冷氣管與轉接頭應用噴炬硬銲製程，並選擇會影響銲接品質的重要參數，如搭接距離、間隙、銲接氣體混合壓力、銲接前「預熱強火時間」、銲接「中火時間」、銲接「填料時間點」及「填料時間」等，並以銲件最大荷重(Max. load)為品質特性，應用田口方法之望大特性求SN比，獲得最適噴炬硬銲參數，以提供業界之參考，另外，透過變異數分析(Analysis of Variance, ANOVA)，找出銲接參數的影響程度。 實驗結果顯示，經由田口方法得到之最適噴炬硬銲參數，其銲接試片之最大荷重為851.83kgf較現行817kgf，提昇34.83 kgf。管路氣密檢測合格率為98.3%較現行83.6%，提昇14.7%。證實以田口方法可以快速找到最適銲接條件。並經由田口方法得知，銲接「中火時間」及銲接「填料供給時間點」，影響銲件之品質特性甚大。 管6063(T6)與轉接頭6061(T6)之鋁合金在硬銲後拉伸實驗，均成延性破壞，且母材的強度與硬度均大幅下降，主要為母材係經擠製加工後之材料，施銲時，受熱影響產生再結晶及晶粒成長之現象。若要恢復原母材機械性質，建議銲後可再實施熱處理予以恢復。

In the automobile air condition system, the pipeline and other important components such as compressor and condenser are linked by joint flange using torch brazing process. The major brazing parameters are overlap distance, joint thickness, preheating time, brazing time, post-heating time, overlap distance, joint thickness, and filler metal feeding time. Tensile test, micro-hardness test, water-leak test, and optical metallograpy test were conducted. Taguchi method was used to determine the optimum brazing parameters. The experimental results show that the maximum load capacity can be increased from 817 kgf to 851 kgf by using the optimum brazing conditions. The water-leak qualified pass rate can also be increased from 83.65 to 98.3%. Through this study, it was found that the duration times of different process stages can also influence the performance of the brazed product. In order to restore the original mechanical properties which were affected during heating cycle, proper post-weld heat treatment is suggested.