鎳對片狀石墨鑄鐵顯微組織之影響

Effects of Ni Addition on the Microstructure of the Flake Graphite Cast Iron

楊榮顯(Rong-Shean Yang) ； 呂易諠(Yi-Xuan Lu) ； 陳政佑

《鑄造工程學刊》 39卷4期 (2013/12) Pp. 20-37

摘要

具有不同厚度鑄件，凝固冷卻後因顯微組織差異關係，極易造成表面及內部硬度不均現象。而此硬度均勻性與否，會直接影響機械加工性、表面粗糙度、機械性質等，更進而影響鑄件組立後所構成單元、成品等之精度、壽命等。本研究即在探討添加Ni（0~3.0 wt.%）時，其對於片狀石墨鑄鐵鑄件不同厚度部位（10、20、40、80mm）之表面及中心剖面的顯微組織（基地組織、石墨大小等）之影響。研究結果顯示，在顯微組織方面，針對鑄件四個不同厚度部位W（80mm）、X（40mm）、Y（20mm）、Z（10mm）之表面及中心剖面的顯微組織進行影像解析結果，可發現隨著Ni添加量之增加，波來鐵面積率有增加之趨勢，而肥粒鐵與石墨面積率則有減少之趨勢，片狀石墨也由粗大變為細小。此外，隨著Ni添加量之增加，顯微組織中之波來鐵、肥粒鐵、石墨之面積率有均勻化之效果，換言之可獲得均質之顯微組織。

關鍵字

合金元素鎳 ； 片狀石墨鑄鐵 ； 表面 ； 中心剖面 ； 均勻性 ； 顯微組織

並列摘要

Casting with differentsection thickness will cause diverse microstructure at each portion after solidification and cooling, and easily induce non-uniform surface and cross-sectional hardness. The uniformity of hardness will affect the machinability, surface roughness, mechanical properties, etc., directly. Moreover, it will affect the precision and life of the assembled unit or product of the castings.The objective of this research is to investigate the effects of nickel addition on the microstructure (matrix structure, graphite size, etc.) of flake graphite cast iron castings with differentsection thickness (10, 20, 40, 80mm).From the surface and center cross-sectionalmicrostructure image analysis of the casting at four differentsection, it is observed that the pearlite percentage is gradually increased, the percentage of ferrite and graphite are gradually reduced, and the flake graphite changes from coarse to fine, with increasing the amount of Ni.From the microstructureat different positions on the same center cross section and on the surface of casting, it is observed that the percentages of pearlite, ferrite and graphite become more uniform; which represent the microstructure becomes more homogeneous with the increasing of Ni.

並列關鍵字

nickel ； flake graphite cast iron ； surface ； center cross section ； uniformity ； microstructure