温度与应力耦合作用下高强钢海水腐蚀行为研究

目的 保证船舶设备安全，明确船用Ni-Cr-Mo-V高强钢在不同海水温度中的服役状态变化。方法 在实验室模拟环境中，通过四点弯曲装置向Ni-Cr-Mo-V高强钢施加不同应力，并结合电化学测试、腐蚀形貌和产物分析，研究温度与应力耦合对Ni-Cr-Mo-V高强钢在不同温度海水环境中腐蚀行为的影响及规律。结果 温度升高会加快Ni-Cr-Mo-V高强钢腐蚀产物的生成，但是在较高温度海水中，会使高强钢由点蚀转变为均匀腐蚀，因此较高温度海水中对高强钢施加外加应力未发现点蚀坑加深。较高温度海水相对于低温海水条件下，高强钢腐蚀产物层中的Cr、Ni含量增加，低温海水中施加应力致使腐蚀产物层中的Cr、Ni含量降低，而较高温度海水中施加应力对腐蚀产物成分的影响不大。温度对Ni-Cr-Mo-V高强钢的腐蚀作用明显强于外加应力对其的腐蚀作用。结论 在不同温度海水中，较高的温度使得Ni-Cr-Mo-V高强钢的耐蚀性能降低，但是相对于低温海水中，较高温度海水条件下施加应力对Ni-Cr-Mo-V高强钢腐蚀的影响较小，因此对于高强钢在海水中的腐蚀，温度对高强钢的影响明显大于应力的影响。

Seawater Corrosion Behavior of High-strength Steel under the Coupling Effect of Temperature and Stress

The work aims to clarify the service state of marine Ni-Cr-Mo-V high-strength steel at different seawater temperature, in order to ensure the safety of ship equipment. In the laboratory simulation environment, different stresses were applied to Ni-Cr-Mo-V high-strength steel by four-point bending device. Combined with electrochemical test, corrosion morphology and product analysis, the effect of temperature and stress coupling on the corrosion behavior of Ni-Cr-Mo-V high-strength steel in seawater environment at different temperature was studied. The increase of temperature accelerated the formation of corrosion products of Ni-Cr-Mo-V high-strength steel, but in high temperature seawater, the pitting corrosion of high-strength steel was reduced to uniform corrosion, so no increasingly serious pitting corrosion was found when external stress was applied to high-strength steel in seawater at high temperature. The content of Cr and Ni in the corrosion product layer of high-strength steel increased in high temperature seawater compared with low temperature seawater. The stress applied in low temperature seawater caused the content of Cr and Ni in the corrosion product layer to decrease, while the stress applied in high temperature seawater had little effect on the composition of corrosion products. The corrosion effect of temperature on Ni-Cr-Mo-V high-strength steel was obviously stronger than that of applied stress. In seawater at different temperature, high temperature reduces the corrosion resistance of Ni-Cr-Mo-V high-strength steel. However, compared with low temperature seawater, the stress applied in higher temperature seawater has little effect on the corrosion of Ni-Cr-Mo-V high-strength steel. Therefore, for the corrosion of high-strength steel in seawater, the effect of temperature on high-strength steel is obviously greater than that of stress.