中文摘要：

Ti-Mg船板钢铸态组织中发现大量晶内针状铁素体（IGF）,IGF大幅提高铸坯强韧性的同时,也给连铸弯曲矫直工艺和连铸机寿命带来影响。为探明连铸坯中IGF的诱发机制,进行了冷却速率、钢中夹杂物尺寸及分布等因素对铸态组织中IGF诱发的影响研究。结果表明：对试验钢种而言,夹杂物的尺寸和分布是该类钢种铸态组织的决定性因素。与钢板焊接热影响区中能够诱发IGF的夹杂物尺寸多为3μm以下相比,在铸坯中能够诱发IGF的夹杂物多为5~15μm。因此为保证连铸机的寿命和拉矫工艺的稳定,最好将夹杂物尺寸控制在5μm以下,以降低IGF含量。

英文摘要：

A lot of IGF had been found in the casting structure of Ti-Mg shipbuilding steel strand,the strand toughness had been strengthened by the IGF,and at the same time,the strand bending-straightening technology and the life of continuous casting machine had also been affected. For detecting IGF inducing mechanism of casting structure,cooling rate and the size and distribution of inclusions had been studied separately. The results showed that,for the experiment steel,the decisive factors for the casting structure of the slab were the size and distribution of inclusions. Compared to the inclusions which were smaller than 3μm and could induce IGF in the structure of steel plate HAZ,the inclusions induced IGF in casting structure were between 5 μm and 15 μm. For the life of continuous casting machine and the stabilization of bending-straightening technology,the inclusions size should be controlled under 5 μm to lower the IGF content of strand casting structure.