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对X80管线钢中非金属夹杂物进行金相观察、大样电解和扫描电镜分析。结果表明:从LF进站到铸坯过程中显微夹杂物呈显著的下降趋势,降幅达77.77%,在LF和RH精炼过程中,夹杂物数量降低最为明显;铸坯中夹杂物主要类型为CaO-CaS-Al2O3复合夹杂,其xCaO/xAl2O3小于12 CaO·7Al2O3的xCaO/xAl2O3=1.71,夹杂物变性效果较差。X80管线钢从转炉终点到铸坯过程中,平均T.O呈下降趋势,LF进站到钙处理后,平均w(T.O)减少了2.06×10-6,RH精炼过程平均w(T.O)降低了2.27×10-6,需提高LF精炼操作水平和RH精炼操作稳定性。RH出站到铸坯是一个增氮的过程,增氮质量分数为2.27×10-6,保护浇铸水平较高;铸坯中大型夹杂物数量为1.46 mg/10 kg,夹杂物主要为球状的钙铝酸盐夹杂物、硅铝酸盐夹杂物以及与镁铝尖晶石形成的复合夹杂物。
Metallographic observation of non-metallic inclusions in X80 pipeline steel, large-scale electrolysis and scanning electron microscopy. The results showed that the microscopic inclusions decreased significantly from 77% to 77.77% in the process of LF pitting into the slab, and the most obvious decrease was the number of inclusions in the refining process of LF and RH. The main types of inclusions in the slab CaO-CaS-Al2O3 composite inclusions, xCaO / xAl2O3 = 1.71 whose xCaO / xAl2O3 is less than 12CaO · 7Al2O3 = 1.71, the inclusion denaturation effect is poor. During the process of X80 pipeline steel from the end of the converter to the slab, the average TO showed a downward trend. The average w (TO) decreased 2.06 × 10-6 after LF pitching to calcium treatment, and the average w (TO) decreased by 2.27 × 10-6, to improve the level of LF refining operations and RH refining operation stability. RH outbound to the billet is a process of increasing nitrogen, the nitrogen content increased 2.27 × 10-6, a higher level of protection casting; large number of inclusions in slab 1.46 mg / 10 kg, the inclusions are mainly spherical Calcium aluminate inclusions, aluminosilicate inclusions, and composite inclusions formed with magnesium aluminum spinel.