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研究了X80管线钢在3.5%NaCl溶液中的电化学腐蚀行为。结果表明:经离子渗氮的样品,表面硬度显著提高,且随渗氮温度的升高而增加;渗氮层的耐蚀性明显优于基体材料,腐蚀电流密度降低一个数量级;腐蚀电位明显正移。当渗氮温度为450℃时,样品渗氮层由ε相和少量的γ’相构成,表面硬度约为810 HV,耐蚀性最好,腐蚀电流最小,约为0.56μA/cm2,腐蚀电位最高,约为-214 m V。当渗氮温度为570℃时,样品渗氮层全部为γ’相,表面硬度约为930 HV,耐蚀性明显降低。离子渗氮温度显著影响X80钢表面渗氮层的相组成,引起表面硬度和耐蚀性不同。
The electrochemical corrosion behavior of X80 pipeline steel in 3.5% NaCl solution was studied. The results showed that the surface hardness increased significantly with the increase of nitriding temperature, and the corrosion resistance of the nitrided layer was obviously better than that of the matrix. The corrosion current density decreased by one order of magnitude and the corrosion potential was significantly positive shift. When the nitriding temperature is 450 ℃, the nitriding layer consists of ε phase and a small amount of γ ’phase, the surface hardness is about 810 HV, the corrosion resistance is the best, and the corrosion current is the smallest, about 0.56 μA / cm2. The corrosion potential The highest, about -214 mV. When the nitriding temperature is 570 ℃, the nitriding layer is all γ ’phase, the surface hardness is about 930 HV, and the corrosion resistance obviously decreases. Ion nitriding temperature significantly affects the phase composition of the nitrided layer on the surface of X80 steel, resulting in different surface hardness and corrosion resistance.