Abstract: Titanium-microalloyed steel is widely used in aerospace， automotive manufacturing， construction engineering and other fields. Adding Ti to the steel for microalloying can obviously increase the strength and improve the properties of the material， but TiN inclusions will be formed in the steel. The precipitation temperature of TiN is high， fine TiN inclusion can inhibit the growth of grain at high temperature， and induce the formation of inocrystalline needle ferrite （IAF）；And the thick TiN inclusion is unfavorable to the properties of the material. In this paper， the latest progress in the formation of TiN in Ti-bearing microalloyed steels at home and abroad is discussed from two aspects of the formation and control of TiN. On the formation of TiN， this paper mainly summarizes the influence TiN of formation mode ，morphology characteristics， thermodynamic and kinetic factors on the formation of TiN， as well as the harm of TiN in steel on the properties of steel. On the control of TiN， the effects of the synergistic action of Al， B and Ti on the formation of TiN， the effects of Mg treatment， Ca treatment， and rare earth （Ce， La， Y） treatment on the formation of TiN in steel are mainly summarized in this paper.The amount， size and morphology of TiN can be affected by the synergistic effect between other elements and Ti element in steel. Mg treatment， Ca treatment and rare earth treatment can provide effective nucleation inclusion for the formation of TiN， while reducing the formation of large size TiN inclusion. After Mg， Ca and rare earth treatment， TiN composite inclusions of sub-micron and nano-scale can be formed， which can effectively induce the formation of IAF and strengthen the properties of steel.

Key words: Ti Microalloyed Steel, TiN Generation Behavior, TiN Control, RE Treatment, Oxide Metallurgy

摘要： 钛微合金钢在航空航天、汽车制造、建筑工程等领域有着广泛的应用。向钢中加入Ti元素进行微合金化，可以明显地提高材料的强度，并且改善材料的性能，但会在钢中形成TiN夹杂。TiN析出温度较高，细小的TiN夹杂可以抑制高温下晶粒的长大，同时诱导晶内针状铁素体（IAF）的形成；而粗大的TiN夹杂对材料的性能不利。从TiN的生成与控制两个方面讨论了国内外近年来关于含钛微合金钢中TiN生成的最新进展。在TiN的生成上，主要总结了TiN的生成方式、形貌特征、热力学及动力学因素对TiN生成的影响，以及钢中TiN对钢材性能的危害。在TiN的控制上，主要总结了Al、B元素与Ti元素的协同作用对TiN生成的影响、Mg处理、Ca处理，以及稀土（Ce、La、Y）处理对钢中TiN生成的影响。钢中其他元素和Ti元素间的协同效应可以影响TiN的数量、尺寸及形貌。Mg处理、Ca处理以及稀土处理可以为TiN的生成提供有效形核质点，同时减少了大尺寸TiN夹杂的生成。经过Mg、Ca处理及稀土处理能生成纳米级的TiN复合夹杂，能有效诱导IAF的形成，强化钢材的性能。

关键词: 钛微合金钢, TiN生成行为, TiN控制, 稀土处理, 氧化物冶金