初析肥粒鐵對沃斯回火球墨鑄鐵衝擊韌性的影響

Effects of Ferrite on Impact Toughness of Austempered Ductile Iron

溫東成(Dong-Cherng Wen)

《中華技術學院學報》 24期 (2002/03) Pp. 159-165

https://doi.org/10.7095/JCIT.200203.0159

摘要

本研究改變傳統沃斯回火球墨鑄鐵的熱處理程序，於沃斯田鐵化後先爐冷至700－730°C的沃斯田鐵、肥粒鐵與石墨三相共存區析出肥粒鐵後，再淬冷至低溫鹽浴槽進行沃斯回火恆溫變態，藉由不同沃斯回火時間的控制可以使基底成為5－20％體積分率的初析肥粒鐵與沃斯肥粒鐵的混合組織。實驗結果顯示隨初析肥粒鐵增加，抗拉強度與降伏強度降低，伸長率與衝擊值則有明顯的增加。初析肥粒鐵含量不超過10％則可以得到等同傳統處理於ADI製程窗間內的強度與更優異的延性與韌性。

關鍵字

沃斯回火球墨鑄鐵 ； 初析肥粒鐵 ； 衝擊韌性

並列摘要

New austempered ductile cast iron precipitated ferrite around the spheroidal graphite was produced by a modified heat treatment. The process involved austempering at 350°C for 5-30 min after furnace cooling to 700-730°C from an austenitizing temperature of 900°C for 60 min (α/M-ADI). In this process, a mixture structure of 5-20% ferrite around the graphite with ausferrite was obtained. The results show that the elongation and Charpy impact toughness of α/M-ADI with less 10% of ferrite was increased remarkably. While the tensile strength and 0.2% yield strength of α/M-ADI were at the same value level of the conventional ADI.

並列關鍵字

Austempered ductile iron ； ferrite ； impact toughness