稀土管线钢中夹杂物热力学分析及实验研究

Thermodynamic Analysis and Observation of Inclusions in RE-pipeline Steel

为了研究含稀土钇管线钢中稀土夹杂的存在种类及稀土对其它有害夹杂的变质作用,本文首先在理论上对实验钢进行了有关夹杂物的热力学计算,并在实践中利用扫描电镜和能谱仪对普通管线钢及含钇管线钢的主要夹杂物进行了随机观察。结果表明,含稀土钇管线钢中稀土夹杂主要以Y2O3、Y2O2S夹杂的形式存在,而不能以Y2S3、YS的形式存在;Y2O2S夹杂会被Y2O3夹杂所取代;同时,适量Y能将钢中有害的尖角状、5 um左右的Al2O3夹杂变质为球状、2 um的Y2O2S或Y2O3夹杂。通过对夹杂物进行分析比较可以得出,钢中加入适量稀土有利于提高钢的性能。

In this paper the thermodynamic calculation was used to analyze the kinds of rare earth inclusions and rare earth＇metamorphism to harmful inclusions. Scanning electron microscope（ SEM） and energy dispersive spectrometer（ EDS）were used to observe the main inclusions of pipeline steel and yttrium-containing pipeline steel. The results show that the rare earths inclusions in yttrium-containing pipeline steel are mainly Y2O3 and Y2O2 S rather than Y2S3 and YS. Y2O2 S inclusions can be changed into Y2O3. Through the metamorphism of yttrium,harmful,sharp-angled and 5 um Al2O3 inclusions are modified into axiolitic and 2 um Y2O2 S or Y2O3 inclusions. Rare earth containing in steel is beneficial to improve the performance of steel through the comparison of different inclusions.