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低合金高強度鋼的耐模擬工業大氣腐蝕行為研究

2021-04-23 15:56:29 作者：孫永偉來源：中國腐蝕與防護學報分享至：

摘要

選擇Q345E和Cr-Ni-Cu兩種典型的低合金高強度鋼，在0.052% （質量分數） NaHSO3水溶液中進行極化實驗和間浸掛片實驗，比較了兩種鋼的腐蝕速率，評價了兩種鋼的耐蝕性。利用SEM和XRD分析兩種鋼的腐蝕形貌，銹層結構及其相組成。結果表明，Q345E和Cr-Ni-Cu鋼的腐蝕電位分別為-730和-705 mV；兩種鋼的腐蝕銹層物相均含有γ-FeO（OH）和少量的α-Fe，隨腐蝕時間延長，存在少量α-FeO（OH）和Fe3O4。Cr-Ni-Cu鋼相比Q345E鋼，其腐蝕速率較低，Cr，Ni和Cu等元素的存在提高了其耐蝕性能；Cr-Ni-Cu鋼的表面銹層比Q345E鋼更加致密，銹層微裂紋更少。

關鍵詞：低合金高強度鋼 ; 大氣腐蝕 ; 銹層特征 ; 間浸腐蝕 ; 腐蝕速率

Abstract

The corrosion resistance of Q345E and Cr-Ni-Cu steels was comparatively assessed by means of potentiodynamic polarization and cyclic immersion corrosion tests in 0.052% （mass fraction） NaHSO3 solution, which aims to simulate the common SO2-containing atmosphere. The characteristic of corrosion rust was studied by means of scanning electron microscope （SEM） and X-ray diffraction （XRD）。 Results show that the open circuit corrosion potential of Q345E and Cr-Ni-Cu steel are -730 and -705 mV, respectively. The rust layers of two steels contain γ-FeO（OH） and α-Fe phase. Some α-FeO（OH） and Fe3O4 products generate with increasing of the corrosion time. Compared with Q345E steel, the Cr-Ni-Cu steel has lower corrosion rate due to the formation of a much more compact rust layer containing elements such as Cr, Ni and Cu, which are beneficial to corrosion resistance.

Keywords： low-alloy high strength steel ; atmospheric corrosion ; rust characteristic ; cyclic immersion corrosion ; corrosion rate