控制中低碳鋼粗晶之生產技術

Technology of Grain coarsening in Low/ Medium Carbon Steel

李世勇(S.Y. Lee) ； 吳清火(C.H. Wu) ； 張國基(K.C. Chang)

《鑛冶：中國鑛冶工程學會會刊》 51卷1期 (2007/03) Pp. 70-79

https://doi.org/10.30069/MM.200703_51(1).0007

摘要

中鋼公司因應部份中低碳鋼條線產品，在不添加較高合金設計下，為得到較佳的鋼料淬火性，因此鋼料晶粒大小必需控制於ASTM#2～5之粗晶水準。但在生產開發過程，發生部份爐次鋼料奧斯田鐵晶粒為ASTM#6～9細晶，而無法滿足最終用途品質需求。根據成分「鋁」、「鈮」、「鈦」等元素對奧斯田鐵晶粒之控制技術，及鋼料中析出物或介在物抑制晶界移動之理論基礎下。本報告探討鋼料清淨度變異，對晶粒細化之影響，進而安排鋼胚正向追蹤試驗。評估介在物和金相晶粒大小之相關性，結果印證鋼胚清淨度較差時，是導致晶粒成長被抑制，發生細晶之主因。

關鍵字

鋼料淬火性 ； 奧斯田鐵晶粒 ； 介在物

並列摘要

To attain superior hardenability of steel without further addition of alloy, austenite grain sizes should normally be controlled in the range of ASTM #2~5 for low/medium carbon wire rod. The cases were found that austenite grain size had fine grain of ASTM#6~9 in product. Based on the effect of AI, Nb, Ti elements on the fine -tuning technology of austenite grain size and the pinning effect of second- phase precipitates or inclusions on grain boundary movements, this study has examined the influence of cleanness in steel on grain refining process. The forward tracking experiments was performed to evaluate the correlation between grain size and inclusion. The results showed that the poorer quality of inclusion, providing more second-phase particles to inhibit grain growth. The first bloom in casting process should be cautiously controlled.

並列關鍵字

hardenability ； austenite grain size ； inclusions