鈷合金化ADI之微結構及機械性質研究

Study on Microstructure and Mechanical Properties of Co-Alloyed ADI

許正勳(C. H. Hsu) ； 呂佳鴻(J. H. Lu) ； 韓濟帆(C. F. Han)

《鑄造工程學刊》 33卷1期 (2007/03) Pp. 33-41

https://doi.org/10.29809/JTFS.200703.0004

摘要

本研究針對添加鈷元素(4wt%)之球墨鑄鐵素材進行ADI熱處理，即先施以沃斯田鐵化處理(910℃-1.5hrs)後，淬火至不同回火溫度（分別為300、360℃）並持溫2hrs後，再空冷之；然後進一步藉由金相觀察、殘留沃斯田鐵含量量測及各種機械性質（硬度、拉伸、衝擊韌性等）試驗來瞭解Co合金化ADI微結構與機械性質之關係。實驗結果顯示由於4wt%Co的添加，使得：(1)鑄態微結構之球墨數及肥粒鐵含量增加；(2)ADI殘留沃斯田鐵含量減少，但殘留沃斯田鐵之碳含量略增；(3)ADI強度皆增加，其中又以300℃-2hrs沃斯回火處理者最明顯；(4)沃斯回火溫度對ADI衝擊韌性之影響程度變小。

關鍵字

沃斯回火球墨鑄鐵 ； 鈷元素 ； 微結構 ； 機械性質

並列摘要

In this study, 4wt% cobalt element was added to ductile iron (DI) as the experimental material, which was treated with the different austempering temperatures of 300 and 360℃ at the same holding time (2 hours), respectively, and then cooled in the air. Microstructures of DI and ADI were observed and various mechanical tests were also carried out. The purpose was to understand the effects of Co addition on microstructure and mechanical properties (hardness, tensile strength, elongation, and impact toughness) of these materials. The experimental results showed as follows: (1) DI with 4% Co addition increases the nodule count and ferrite in the matrix; (2) Co-alloyed ADI reduces the retained austenite content, but rises carbon content in the retained austenite as compared to unalloyed ADI; (3) Co-alloyed ADI has the higher tensile strength than unalloyed one, and 300z-2hrs is an optimum austempering condition; (4) Co addition could mitigate the effect of austempering temperature in the impact toughness of ADI.

並列關鍵字

Austempered ductile iron ； Cobalt element ； Microstructure ； Mechanical properties