鈷元素添加對矽固溶強化肥粒體基球墨鑄鐵之鑄態與沃斯回火熱處理微觀組織及機械性質影響探討

The Effect of Cobalt Addition on Microstructure and Mechanical Properties of As-Cast and Austempering Heat Treatment of Si-Solution Strengthened Ferritic Ductile Iron

陳科憲(K. H. Chen) ； 林宏茂(H. M. Lin) ； 張瑞模(R. M. Chang) ； 黃滋艷(Z. Y. Hung) ； 吳家州(J. Z. Wu)

《鑄造工程學刊》 45卷4期 (2019/12) Pp. 21-36

摘要

EN-GJS-500-7及EN-GJS-600-3球墨鑄鐵常應用於自動化設備用鑄鐵液壓控制閥、轉向節殼體及產業機械（如塑膠射出機、螺絲或螺帽成形母機）本體之中，一般添加銅、錫、鉻、錳及鉬等元素，來提高其強度及硬度，但也增加其鑄態組織中波來體及碳化物含量，因而降低其材料加工性。而利用矽的固溶強化肥粒體基球墨鑄鐵因其可改善材料加工性、硬度均勻性及提高鑄件精度，故為近年來所開發的新材質。本研究主要針對鈷元素添加於EN-GJS-500及EN-GJS-600之矽固溶強化肥粒體基球墨鑄鐵中，用以探討鈷元素對其微觀組織、硬度及機械性質之影響。並評估沃斯回火處理對鈷元素添加之矽固溶強化肥粒體基球墨鑄鐵的微結構、硬度、強度及延性之影響。實驗結果顯示矽固溶強化肥粒體基球墨鑄鐵隨著鈷含量增加，其基地組織主要為肥粒體，且硬度、降伏強度及抗拉強度有隨之上升的趨勢，而伸長率則有隨之下降的傾向。鈷合金化之矽固溶強化肥粒體基球墨鑄鐵（EN-GJS-500-14及EN-GJS-600-10）經沃斯回火熱處理後，其實驗結果顯示EN-GJS-500-14及EN-GJS-600-10試片之微觀組織主要為上沃斯肥粒體，而其降伏強度及抗拉強度有隨著鈷含量增加而上升的趨勢，而延伸率則隨著鈷含量增加而下降。

關鍵字

矽固溶強化 ； 肥粒體基球墨鑄鐵 ； 沃斯回火 ； 鈷元素添加

並列摘要

EN-GJS-500-7and EN-GJS-600-3 ductile iron are widely used in the hydraulic block control block for automatic equipment and swivel housing. Alloying elements such as copper, tin, chromium, manganese and molybdenum are generally added to increase the strength and hardness uniformity, but also increase the content of the pearlite and carbide in the as-cast structure, thereby reducing the material machinability. The silicon solid solution strengthened ferritic ductile iron is a new material developed in recent years because it can improve material machinability, hardness uniformity and casting precision. This study focused on the investigation of the effect of cobalt (Co) addition to the EN-GJS-500-14 and EN-GJS-600-10 solid solution-strengthened ferritic ductile irons on their microstructure, hardness and mechanical properties. The effect of austempering treatment on the microstructure, hardness, strength and ductility of cobalt-alloyed solid solution-strengthened ferritic ductile iron were also evaluated. The experimental results show that with the increase of cobalt content, the matrix structure is mainly ferritic, and the hardness, yield strength and tensile strength increase, while the elongation tends to decrease. Cobalt alloyed Si-solid solution-strengthened ferritic ductile iron (EN-GJS-500-14 and EN-GJS-600-10) after austempering heat treatment, the experimental results show that the microstructure of EN-GJS-500-14 and EN-GJS-600-10 are mainly the upper ausferrite, and also the yield strength and tensile strength tend to increase with increasing cobalt content, while the elongation decreases with increasing cobalt content.

並列關鍵字

Si-solid solution-strengthened ferritic ductile iron ； Austempering ； Cobalt