Formation of Acicular Ferrite in Mg Treated Ti-bearing C–Mn Steel
Formation of Acicular Ferrite in Mg Treated Ti-bearing C–Mn Steel
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DOI：
10.2355/isijinternational.55.1468
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发表时间：
2015-07
影响因子：
1.8
通讯作者：
Ming-ming Song;B. Song;Chunwei Hu;Wenbin Xin;Gaoyang Song
中科院分区：
文献类型：
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作者：
Ming-ming Song;B. Song;Chunwei Hu;Wenbin Xin;Gaoyang Song
在炼钢过程中，细化晶粒是在不降低韧性的前提下提高强度的唯一方法。自1990年日本冶金学者S根据夹杂物在焊缝中的作用提出“氧化物冶金”技术理论以来，1)夹杂物在钢的组织转变过程中的作用引起了人们的极大兴趣。针状铁素体(AF)在夹杂物表面晶内形核，具有无序的晶向。2)这种结构延缓了解理裂纹在金属中的扩展。此外，它还使高强度钢具有很大的韧性和良好的焊接性。大量研究表明，夹杂物(如Ti/Al/Zr氧化物和Ti/Nb/V碳氮化物)对AF形核有重要作用。到目前为止，氧化物冶金技术已经成为提高厚板钢、低碳非调质钢、高强度低合金钢和大热输入焊接接头性能的有效途径。3-5)然而，随着焊接技术的发展，焊接热输入的增加导致峰值温度高达1673K，从而使热影响区温度过高，停留时间过长，大量的TiN颗粒会重新溶解到γ-Fe基体中。镁处理含钛碳锰钢在针状铁素体形成高峰期缺乏足够的夹杂物钉扎晶界
Grain refinement is the only method to enhance strength without deteriorating toughness in steelmaking. Since 1990 s, the Japanese metallurgical scholars proposed the technical theory of “Oxides Metallurgy” based on the function of inclusions in weld,1) a lot of interests have been drawn to study the effect of inclusions during microstructure transformation process in steel. The acicular ferrite (AF), which nucleated intra-granularly on the surface of inclusions, has a chaotic crystallographic orientation.2) This structure retards of the propagation of cleavage crack in the metal. In addition, it makes high strength steel have great toughness and good weldability. A large number of studies indicated that the inclusions, such as Ti/Al/Zr oxides and Ti/Nb/V carbonitrides, could contribute to AF nucleation. So far, oxides metallurgy technology has already become an effective way to improve the performance of thick plate steel, low carbon nontempered steel, high-strength low-alloy (HSLA) steel and welded joints of large heat input welding.3–5) However, with the development of welding technology, welding heat input increasing causes the peak temperature rising up to 1 673 K, which makes the heat affect zone (HAZ) temperature too high and residence time too long, lots of TiN particles will redissolve into the γ-Fe matrix. Due to the lack of sufficient inclusion pinning grain boundary during period of high Formation of Acicular Ferrite in Mg Treated Ti-bearing C–Mn Steel