銅鉬合金化沃斯回火球墨鑄鐵顯微組織與特性之研究

Study on Microstructure and Characteristics of Copper and Molybedium Alloyed Austempered Ductile Iron

林冠廷(Kuan-Ting Lin)

指導教授 ： 許正勳

大同大學/工程學院/材料工程學系所/碩士(2009年)

摘要

本研究主要目的是針對添加1.0wt%的鉬元素、添加1.0wt%的銅元素與工業上常用之未添加合金FCD450三種延性鑄鐵，執行不同條件(300℃-3hrs、360℃-2hrs)沃斯回火熱處理使成為ADI材料，然後進一步探討與比較鑄態與ADI之顯微結構、機械性質及化學腐蝕性質的差異，以了解鉬合金化與銅合金化之相關效應。 實驗結果顯示，1.0wt%的鉬元素ADI材料可有效的增加抗拉強度、硬度、耐沖蝕及耐磨耗性等機械性質，而1.0wt%的銅元素ADI材料可有效的增加伸長率，衝擊韌性及破裂韌性等機械性質；然而，在腐蝕行為方面，無論是極化、浸漬試驗，對鑄態而言，1.0wt% Cu延性鑄鐵最耐腐蝕。對ADI而言，可以發現ADI皆比鑄態為優，而其中360℃/2hr之Cu-ADI因殘留沃斯田鐵含量較多，故其耐腐蝕性質表現最佳。

關鍵字

銅元素 ； 沃斯回火 ； 沃斯回火延性鑄鐵 ； 鉬元素

並列摘要

In this study, there kinds of ductile irons (DI), 1 wt.% Mo alloyed
Alloyed ductile iron (FCD450), were selected as the experimental materials. Both the austempering conditions consisting of 300℃-3hrs and 360℃-2hrs were respectively adopted to further treat these irons as austempered ductile iron (ADI). Then microstructural observation, mechanical tests (such as hardness, tensile, impact toughness, and KIC), and corrosion tests (such as polarization tests in 3.5wt.% NaCl, immersion tests in 10 Vol.% H2SO4 and 10 Vol.% HCl) were all performed to understand the correlation of microstructure, mechanical and corrosion behaviors of these iron.
The experimental results showed that ADI added 1 wt.% Mo could increase the hardness, tensile strength, erosion resistance, and wear resistance due to the less retained austenite content, while the addition of 1 wt.% Cu could increase the ductility, impact toughness, KIC value of ADI due to the more retained austenite content. In corrosion behavior, 1 wt.% Cu alloyed DI has the best corrosion resistance among the three as-casts. For ADI, ADI is superior to DI in corrosion resistance reganrdless of alloying addition. In particular, 1wt.% Cu-ADI treated with 360℃-2hrs has the best corrosion resistance among all the irons due to the most retained austenite in its microstructure.

並列關鍵字

Copper ； Austempered ； ADI ； Molybedium

參考文獻

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