熱軋板碳化物組織形態對連續退火冷軋鋼片機械性質之影響

Effect of carbide morphology in hot band on the mechanical properties of continuous annealed cold-rolled sheet steel

周棟勝(Tung-Sheng Chou) ； 陳煌湶(Huang-Chuan Chen) ； 朱澎生(Peng-Sheng Ju)

《鑛冶：中國鑛冶工程學會會刊》 33卷2期 (1989/06) Pp. 149-157

https://doi.org/10.30069/MM.198906_33(2).0016

摘要

含0.03%C的低碳鋁脫氧鋼，熱軋後分別在680〜740℃間保持1小時後爐冷以模凝熱軋盤捲。經71%冷軋後以Gleeble 1500熱機動態模擬試驗機，進行連續退火處理，以探討盤捲溫度對碳化物組織形態之變異，以及對後續退火處理鋼片機械性質之影響。由結果發現，高溫盤捲處理（710℃以上）鋼料其最終退火處理後之冷軋鋼片之降伏強度约21 kg/mm^2，r值高於1.6。機械性質非常優越。光學組織顯示，高溫盤捲鋼料具有較大之肥粒鐵晶粒，粗大且較少量之碳化物。以X-ray及内耗測量的結果顯示，高溫盤捲鋼料並有較強之{111}集合組織以及較低之固溶碳含量。穿透式電子顯微鏡觀察結果顯示，碳化物四周所成核之晶粒方向極為無序。因之，高溫盤捲鋼料具有較低之降伏強度乃因碳化物粗大，使得再結晶粒較易長大，以及固溶碳量較少所致。而具有較高r值乃因碳化物數目較少，產生無序晶粒較少，使得{111}集合組織可以順利成長所致。因此，欲得到低降伏強度、高γ值之優異機械性質之連續退火冷軋鋼片，藉著高盤捲溫度使碳化物粗化是一重要因素。

並列摘要

A low carbon aluminum-killed steel (0.03% C) was heat-treated at 680~740℃ for one hour prior to hold rolling to simulate the hot coiling to investigate the effects of carbide morphology in hot band on the mechanical properties of final continuousannealed cold-rolled sheet steel. The results showed that high coiling temperature (≥710℃) treated steel has an excellent mechanical properties combination. The yield strength is about 21 kg/mm^2 and the r-value is higher than 1.6. The optical microscope revealed that high coiling temperature treated steel has larger ferrite grain, coarser and less amount of carbides than that of low coiling temperature treated steel. X-ray analysis and internal friction measurement indicated that the {111} texture and the solute carbon content was decreased with increasing the coiling temperature. In addition, the transmission electron microscopy revealed that randomly crystallized grains were nucleated around the carbide particles. Thus, the benifits by a high coiling temperature treatment to produce a low yield strength and high r-value steel are considered due to the coarsened carbides which promote the grain growth of ferrite, and decrease the solute carbon content and the amount of randomly crystallized grain to enhance the formation of {111} texture.