Abstract The formation of acicular ferrite (AF) in steel containing Lanthanum (La) with different contents of Aluminum (Al) has been investigated. It has been found that the amount of AF in La treated steel killed by Al is less than the one with little content of Al. The reasons are as follows: first, Al can change the type of La-containing inclusions and may reduce the effectiveness of La inclusion to induce the nucleation of AF. second, Al can make the cooling rate range of AF nucleation narrower in La treated steel. What’s more, Al can increase the decomposition temperature of austenite, and all these make AF formation difficult. In this study, the content of Al should be controlled to less than 0.018 wt% to obtain a more effective inclusion to induce the formation of AF.

中文翻译：

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Al脱氧对含La钢针状铁素体形成的影响

摘要 研究了含有不同铝 (Al) 含量的镧 (La) 钢中针状铁素体 (AF) 的形成。已经发现被Al杀死的La处理钢中AF的量少于Al含量少的钢。其原因如下：首先，Al可以改变含La夹杂物的类型，并可能降低La夹杂物诱导AF形核的有效性。其次，Al可以使La处理钢中AF形核的冷却速度范围变窄。更重要的是，Al可以提高奥氏体的分解温度，这些都使AF的形成变得困难。在本研究中，Al 的含量应控制在 0.018 wt% 以下，以获得更有效的夹杂物来诱导 AF 的形成。