真空硬銲時間與不同冷卻壓力對WC-Co與KDA1工具鋼硬銲接合件特性之影響

Effect of Vacuum Brazing Time and Different Cooling Pressure on the Properties of Vacuum Brazed WC-Co/KDA1 Tool Steel Joint

張舫誠(Fang-Cheng Chang)

指導教授 ： 邱六合

大同大學/工程學院/材料工程學系所/碩士(2010年)

摘要

本研究係針對耐磨性高之碳化鎢與SKD61改良型的KDA1熱作工具鋼兩種異質材料，利用Cu-9Sn之青銅片作為硬銲填料，進行真空硬銲接合。透過硬銲接合件之微觀結構觀察、硬度及剪切測試，探討不同持溫時間及冷卻壓力、填料與基材界面之反應以及不同Co含量之碳化鎢對硬銲接合件及接合母材之影響。實驗結果顯示利用Cu-9Sn填料進行真空硬銲接合，其剪切強度隨持溫時間增加而有上升之趨勢，在硬銲條件為1050℃持溫25分鐘時，有最大剪切強度276 ± 13 MPa。從持溫增加至20分鐘後之WC-Co/Cu-9Sn/KDA1接合件SEM圖配合EPMA分析可以觀察到在WC-Co/Cu-9Sn的界面，會有一層1~2 μm厚的Co-Fe-Cu凝固層產生。持溫15分鐘後以真空冷卻及氣淬之WC-13Co/Cu-9Sn/KDA1接合件，銲道內會有30~40 %縮孔及裂痕等明顯缺陷產生，造成其剪切強度由爐冷之260 ± 18 MPa下降至206~237 MPa，下降約9~20 %。

關鍵字

熱作工具鋼 ； 剪切測試 ； 真空氣淬 ； 真空硬銲 ； 碳化鎢

並列摘要

The vacuum brazing of Cemented Tungsten Carbide (WC-Co) and KDA1 Hot Work Tool Steel using Cu-9Sn braze alloy has been studied. By the microstructure observation, hardness and the shear test of the brazed joint, the effect of the brazing time, cooling pressure, interface reaction of filler and base metal on the joint was discussed. Beside that, different Co content in the cermet on the microstructures and properties of brazed joints was also investigated. The experimental results show that the shear strength of the joints is increased with the increasing bond time and the maximum shear strength among all testing conditions is 270 ± 13 MPa for the joint brazed at 1050°C for 25 min. From SEM micrographs, a Co-Fe-Cu alloy layer was formed at WC-Co/Cu-9Sn interface. The 30~40 % shrink holes and the hair cracks were observed in the brazed zone of WC-13Co/Cu-9Sn/KDA1 joints, cooled by the vacuum cooling and the gas quench. It will decrease its shear strength of joint from 260 ± 18 MPa to 206-237 MPa during the furnace cooling, will dropping approximately 9~20 %.

並列關鍵字

Vacuum Gas Quench ； Vacuum Brazing ； Tungsten Carbide ； Shear Test ； Hot Work Tool Steel

參考文獻

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