Effect of Magnesium on Inclusion Formation in Ti-Killed Steels and Microstructural Evolution in Welding Induced Coarse-Grained Heat Affected Zone
Effect of Magnesium on Inclusion Formation in Ti-Killed Steels and Microstructural Evolution in Welding Induced Coarse-Grained Heat Affected Zone
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DOI：
10.1016/s1006-706x(09)60013-3
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发表时间：
2009-01-01
影响因子：
2.5
通讯作者：
Xu Zhou
中科院分区：
文献类型：
--
作者：
Chai Feng;Yang Cai-fu;Xu Zhou
通过实验观察和热力学计算，验证了Mg对含ti夹杂物的化学成分和尺寸分布的影响，有利于ti淬火钢焊接诱导的粗晶热影响区（CGHAZ）晶粒细化，提高了钢的冲击韧性。结果表明：随着Mg含量从0.003%增加到0.006%，包裹体的化学成分逐渐由Ti-O+Ti-Mg-O复合氧化物转变为Ti-Mg-O+MgO复合氧化物和单相MgO；微量Mg（约0.002%）的加入使含ti夹杂物细化，形成Ti-Mg-O复合氧化物，使夹杂物的尺寸分布有利于针状铁素体的转变，在chaz中具有较高的成核速率，在chaz中获得了高体积分数的针状铁素体，提高了冲击韧性。另外，高Mg含量（约0.006%）生成的单相MgO不能形成针状铁素体形核，在chaz中形成由铁素体侧板和晶界铁素体组成的微观结构。热力学计算证实了实验结果。
Effects of Mg on the chemical component and size distribution of Ti-bearing inclusions favored grain refinement of the welding induced coarse-grained heat affected zone (CGHAZ), with enhanced impact toughness in Ti-killed steels, which were examined based on experimental observations and thermodynamic calculations. The results indicated that the chemical constituents of the inclusions gradually varied from the Ti-O+Ti-Mg-O compound oxide to the Ti-Mg-O+MgO compound oxide and the single-phase MgO, as the Mg content increased from 0.002 3% to 0.006%. A trace addition of Mg (approximately 0.002%) led to the refinement of Ti-bearing inclusions by creating the Ti-Mg-O compound oxide and provided favorable size distribution of the inclusions for acicular ferrite transformation with a high nucleation rate in the CGHAZ, and a high volume fraction of acicular ferrite was obtained in the CGHAZ with enhanced impact toughness. Otherwise, a high content of Mg (approximately 0.006%) produced a single-phase MgO, which was impotent to nucleate an acicular ferrite, and a microstructure comprised of a ferrite side plate and a grain boundary ferrite developed in the CGHAZ. The experimental results were confirmed by thermodynamic calculations.