低碳鋼與JIS SKD61工具鋼真空滲碳之研究

A Study of Vacuum Carburized Low Carbon Steel and JIS SKD61 Tool Steel

杜威宏(Wei-hung Tu)

指導教授 ： 邱六合

大同大學/工程學院/材料工程學系所/碩士(2011年)

摘要

本研究探討JIS S15C低碳鋼以及15B22M、A516、AH/DH 32、SA537四種微合金低碳鋼與JIS SKD61熱作模具鋼真空滲碳效能之比較，利用真空爐通入乙炔氣體作為增碳氣體，腔體內維持5 torr。微合金低碳鋼進行950 ~ 1050℃滲碳30 ~ 210分鐘80℃油淬，再經880℃沃斯田體化10分鐘油淬，並於180℃回火60分鐘。JIS SKD 61進行1000℃滲碳30 ~ 60分鐘以2 kg/mm2之氮氣淬冷至常溫，隨後進行200 ~ 600℃回火120分鐘。實驗分析包括微結構、沃斯田體晶粒尺寸、x-ray繞射、元素縱深分佈和沖蝕磨耗分析等。
結果顯示，JIS S15C及微合金低碳鋼經滲碳30分鐘，其表面最高硬度平均為725 HV，有效滲碳深度及全滲碳深度最高分別可達0.6及0.65 mm，心部硬度隨各鋼材本身含碳量多寡而有差異。JIS SKD61經滲碳30分鐘淬火表面最高硬度為880 HV，心部硬度為480HV，全滲碳深度0.59 mm。由於A516、AH/DH 32及SA537含有較多量抑制晶粒成長之元素，因此高溫滲碳保持原沃斯田體晶粒尺寸之能力較15B22M和JIS S15C佳。沖蝕磨耗以30°進行沖蝕時，隨著滲碳件其滲碳層厚度增加，重量損失與沖蝕深度降低，顯示愈能抵抗沖蝕磨耗之平行分力；以90°進行沖蝕時，不論滲碳件其滲碳層之厚薄，重量損失與沖蝕深度差異不大，皆能抵抗沖蝕磨耗之正向應力。

關鍵字

真空滲碳 ； 微合金低碳鋼 ； JIS SKD61 ； 乙炔 ； 沖蝕磨耗

並列摘要

The vacuum carburizing of JIS S15C low carbon steel, 4 kind of low alloy low carbon steels and JIS SKD61 hot work mold steels have been studied in a vacuum furnace under a 5 torr acetylene atmosphere. The low carbon steels were carburized at 950 ~ 1050℃ for 30 ~ 120 min, oil quenched from the carburizing temperature to 80℃ and then tempered at 180℃ for 60 min. JIS SKD61 steels were carburized at 1000℃for 30 ~ 60 min, gas quenched from the carburizing temperature and then tempered at 200 ~ 600℃ for 120 min. The microstructures, austenite grain size, X-ray, QDP, and Slurry Erosion of the carburized steels were investigated. The results show that the average surface microhardness of the carburized carbon steels for 30 min was 725 HV, the value of effective case depth (ECD) and total case depth (TCD) was 0.6 and 0.65 mm, respectively, and the core microhardness was based on the carbon content of the original steels. The surface and core microhardness of the carburized JIS SKD61 for 30 min was 880 HV and 480 HV, respectively, and the TCD was 0.59 mm. The inhibiting grain growth ability of the carburized A516, TMCP, SA537 were better than those of 15B22M and JIS S15C, because the A516, AH/DH 32 and SA537 have the inhibiting grain growth elements such as Al, Nb etc. After 30° angle slurry erosion test, the mass loss and eroding depth quantity decreased by the carburized layer was thickened because the carburized layer can resist the parallel force of slurry erosion. After 90° angle slurry erosion test, the mass loss and eroding depth quantity is less diversity no matter the thickness of the carburized layer is thick or thin.

並列關鍵字

Vacuum Carburizing ； low alloy low carbon Steels ； JIS SKD61 ； Acetylene ； Slurry Erosion

參考文獻

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