热变形参数对23Cr-6.2Mn-2.1Ni-0.28N节Ni型双相不锈钢点蚀行为的影响

Effect of hot deformation parameters on pitting corrosion behavior of 23Cr-6.2Mn-2.1Ni-0.28N low nickel duplex stainless steel

采用热模拟、动电位极化曲线、交流阻抗谱等手段研究了热变形参数对23Cr-6.2Mn-2.1Ni-0.28N节Ni型双相不锈钢点蚀行为的影响。结果表明:实验钢的耐蚀性对应变速率、变形温度比较敏感,晶粒细化有利于提高试样的耐点蚀性能。在1和10 s-1的较高应变速率下,随变形温度升高,试样的耐蚀性先增加后降低,1050℃耐蚀性最好。随应变速率增加,再结晶晶粒细化程度降低,钝化膜稳定性减弱,试样耐蚀性逐渐降低。点蚀坑主要分布在δ相和δ/γ相界,随应变速率增加点蚀坑数量明显增多,尺寸变大。

Effect of hot deformation parameters on pitting corrosion behavior of 23 Cr-6.2 Mn-2.1 Ni-0.28 N low nickel duplex stainless steel was investigated by means of thermal simulation, potentiodynamic polarization curve and AC impedance spectroscopy. The results show that the corrosion resistance of the experimental steel is sensitive to the strain rate and deformation temperature, and the grain refinement is beneficial to improve the pitting corrosion resistance of the sample. At the higher strain rates of 1 s-1 and 10 s-1, with the increase of deformation temperature, the corrosion resistance of the specimen increases first and then decreases, and the corrosion resistance at 1050 ℃ is the best. With the increase of strain rate, the degree of recrystallization grain refinement decreases, the stability of the passivation film decreases, and the corrosion resistance of the sample decreases gradually. The pitting pits are mainly distributed in the δ-phase and δ/γ-phase boundaries, with the increase of strain rate, the number of pitting pits increases obviously and the size becomes larger.