稀土钇对管线钢耐蚀性和物理化学行为的影响

试验管线钢（/%:0.04~0.05C，0.20~0.24Si，1.80~1.88Mn，0.010~0.012P，0.004~0.005S，0.27~0.30Cr，0.42~0.46Ni，0.24~0.28Mo，0.20Cu，0.005V，0~0.017Y，0.0031~0.0053O）由10 kg感应炉熔炼,并轧成试棒。采用扫描电镜和能谱仪、电化学技术以及热力学计算的方法研究了稀土钇对管线钢在模拟海水溶液（3.5%NaCl）中抗腐蚀性能的影响。结果表明,稀土可以对钢中夹杂产生变质作用,将大尺寸、尖角状的Al₂O₃夹杂变质为小尺寸、球状的稀土复合夹杂,所以有利于形成连续致密的内锈层,减少钢基的点蚀源,从而提高钢的抗腐蚀性能。

Effect of Rare Earth Yttrium on Corrosion Resistance and Physicochemical Behavior of Pipeline Steel

Test pipeline steel (/%： 0.04-0.05C, 0.20-0.24Si, 1.80-1.88Mn, 0.010-0.012P, 0.004-0.005S, 0.27-0.30Cr, 0.42-0.46Ni, 0.24-0.28Mo, 0.20Cu, 0.005V, 0-0.017Y, 0.0031 -0.0053O) is melt by a 10 kg induction furnace and rolled to test bar. The effect of rare earth yttrium on corrosion resistance of pipeline steel in simulated seawater (3.5% NaCl) is studied by using scanning electron microscope and energy spectrum analysis, electrochemical techniques and thermodynamics calculated method. Results show that the rare earth has modification effect on inclusions in steel to modify the large scale and spinel structure Al₂O₃ inclusions to small spheroidal rare earth compound inclusions； therefore it is favorable to form the continuous and compact inner rust layer, decrease the pitting corrosion source and increase the corrosion resistance of steel.