沃斯肥粒鐵型態及其對沃斯回火球墨鑄鐵機械性質的影響

Morphology of Ausferrite of Austempered Ductile Iron and Their Effect on Mechanical Properties

溫東成(Dong-Cherng Wen)

《中華技術學院學報》 19期 (1999/09) Pp. 20-27

https://doi.org/10.7095/JCIT.199909.0020

摘要

本文旨在探討在完全的沃斯韌肥粒鐵組織中沃斯肥粒鐵型態對沃斯回火球墨鑄鐵機械性質的影響，球墨鑄鐵經過900℃保溫60分鐘的沃斯田鐵化及300，325，350，375及400℃製程窗間內保溫時間的沃斯回火後處理以形成沃斯肥粒鐵的混合組織，然後探討顯微結構與機械性質的關係。實驗結果顯示沃斯回火溫渡越高組織越粗大，在325到400℃溫度區間沃斯回火，組織型態為連續網狀的富碳沃斯田鐵加上麥穗狀或羽毛狀的肥粒鐵，在300℃則成為獨立塊狀的沃斯田鐵加上針狀肥粒鐵。而沃斯田鐵與肥粒鐵型態對機械性質有重大影響，麥穗狀肥粒鐵與連續網狀沃斯田鐵的組織越明顯，則延韌性越好。

並列摘要

The aim of this paper was to study the influence of morphology of ausferrite on the mechanical properties of austempered ductile iron. The spheroidal graphite cast iron was austenitisied at 900℃ for 60 min and austempered at 300, 325, 350, 375, and 400℃ for time within the respective processing window to obtain full ausferrite microstructures. Then, the relationships between microstructures and mechanical properties were discussed. The experimental results show that the ausferrite is coarser with increasing austempering temperature, as austempering at temperatures range of 325 to 400℃ the morphology of ausferrite show that the wheat-grain-shaped or feather-shaped ferrite plates form in a continuous network of high carbon austenite in ADI. After austempering at 300℃, the subunit structure within lower ausferrite can barely be seen by SEM, the appearance of this structure includes accicular ferrite and blocky austenite. The morphology of ferrite and austenite play an important role in determination of the mechanical properties. The existence of ferritic subunit and continuous high carbon auctenite network provides ADI with a higher ductility and toughness.

並列關鍵字

ausferrite ； austempered ductile iron ； mechanical property