矽固溶強化肥粒鐵基球墨鑄鐵之研究

Study on the Silicon Solution Strengthened Ferritic Ductile Cast Iron

呂冠龍(G. L. Lu) ； 潘永寧(Y. N. Pan)

《鑄造工程學刊》 44卷3期 (2018/09) Pp. 1-10

摘要

本研究分析固溶強化肥粒鐵基球墨鑄鐵(Solution Strengthened Ferritic Ductile Cast Iron, SSFDI)，所謂之新世代球墨鑄鐵，在不同Si含量(3.95 wt%、4.28 wt%、4.48 wt%)之機械性質特性。並在相同的強度等級下，比較SSF球墨鑄鐵(EN-GJS-600-10規格)與傳統肥粒鐵-波來鐵基球墨鑄鐵(EN-GJS-600-3規格)之機械性質及壁厚敏感性(wall thickness sensitivity)。研究結果顯示，SSF球墨鑄鐵之抗拉強度與降伏強度皆隨Si含量的增加而增加，但伸長率則隨之減少。此係由於Si會固溶於肥粒鐵相內，而具有硬化及強化肥粒鐵相之作用。另一方面，SSF球墨鑄鐵之衝擊值會隨Si含量之增加而降低，此與Si之脆化作用有關。此外，SSF規格之球墨鑄鐵之硬度變化(或壁厚敏感性)均較傳統肥粒鐵-波來鐵基球墨鑄鐵稍低。在相同的抗拉強度等級下，SSF球墨鑄鐵之降伏強度優於傳統之肥粒鐵-波來鐵基球墨鑄鐵，而伸長率則可達傳統球墨鑄鐵之2～3倍，但衝擊值則較傳統球墨鑄鐵為低。

關鍵字

矽固溶強化球墨鑄鐵 ； 機械性質 ； 壁厚敏感性

並列摘要

The objective of this research is to evaluate the property characteristics of solution strengthened ferritic ductile iron (SSFDI), the so-call new generation ductile iron, with different Si contents(3.95 wt%、4.28 wt%、4.48 wt%). In addition, the properties of SSF ductile iron grade of EN-GJS-600-10 were compared with the conventional ductile iron grade of EN-GJS-600-3. The tensile test results of SSF ductile irons show that both the tensile and yield strengths increase, while the elongation decreases, as the Si content increases. This is due to the solution strengthening effect of Si on the ferrite phase in the matrix. However, the impact property of SSF ductile irons decreases with increasing Si content due to its embrittling effect. Furthermore, the variation in hardness or the wall thickness sensitivity of SSF ductile irons is less than that of the conventional ductile irons. At an approximately same level of tensile strength, SSF ductile irons exhibit higher yield strength and much better elongation (some 2 to 3 times higher) than the conventional ductile irons.

並列關鍵字

Solution strengthened ferritic ductile iron ； Mechanical property ； Wall thickness sensitivity