为了探究回火温度对针状铁素体耐腐蚀性能的影响，采用动电位极化曲线测试、电化学阻抗测试和恒电位测试等手段对低合金高强度钢焊缝熔敷金属中针状铁素体高温回火前后的耐海水腐蚀性能进行了研究，结合组织和力学性能进行进一步分析。结果表明，经不同温度回火后，低合金高强度钢焊缝熔敷金属中针状铁素体的自腐蚀电位均有小幅上升，腐蚀倾向减弱；提高回火温度，自腐蚀电流密度显著减小、阻抗逐渐增大，恒电流密度也逐渐降低，说明针状铁素体经回火后耐腐蚀性能提高。针状铁素体回火耐腐蚀性能的提高主要归因于回火后组织更加均匀，使电偶效应降低，以及针状铁素体能态和电位差更低，而非钝化膜。

Acicular ferrite, renowned for its excellent combination of strength and toughness, has been a focal point of research since the inception of “Oxides Metallurgy” in the 1990s. Researchers have devoted considerable attention to understanding the formation and control mechanisms of acicular ferrite, because it plays a crucial role in refining the austenite grain during the cooling process. In practical applications, acicular ferrite is used in corrosive environment, such as seawater. Therefore, assessing its corrosion resistance performance is imperative. Despite its importance, the corrosion resistance mechanism of acicular ferrite remains somewhat unclear, warranting further investigation to elucidate it and potential corrosion resistance enhancement strategies. Previous studies have paid scant attention to the corrosion resistance performance of acicular ferrite, particularly after tempering. Herein, the seawater corrosion resistance performance of acicular ferrite in the weld metal of high-strength low-alloy steel before and after high-temperature tempering was studied. To understand the effects of tempering temperature and seawater exposure on the corrosion resistance performance of acicular ferrite, the potentiodynamic polarization tests, electrochemical impedance spectroscopy, and potentiostatic polarization tests were performed. Additionally, microstructures and mechanical properties to complement findings were detailed analyzed. Results show that tempering at temperatures of 580, 610, and 640 ^oC for 10 h results in a slight increase in the corrosion potential of acicular ferrite in the weld metal, indicating a weakened tendency of corrosion. As the tempering temperature increases, the corrosion current density decreases substantially, accompanied by an increase in impedance. Moreover, the potentiostatic current density decreases, indicating improved corrosion resistance of acicular ferrite after prolonged high-temperature tempering. Furthermore, the corrosion resistance of acicular ferrite remains considerably stable after tempering. The improvement of corrosion resistance of in acicular ferrite is mainly attributed to the decrease in martensite/austenite (M/A) islands, resulting in a highly homogeneous microstructure that mitigates galvanic couple effects. The observed reduced free energy and potential difference of acicular ferrite further contribute to its improved passivation film formation.