海洋环境下锈蚀Q690高强钢力学性能退化研究

RESEARCH ON MECHANICAL PROPERTY DEGRADATION OF CORRODED Q690 HIGH-STRENGTH STEEL IN THE MARINE ENVIRONMENT

在周期性浸润和湿热环境下对Q690高强钢进行0~100 d的加速腐蚀试验,通过单轴拉伸试验研究了钢材力学性能的退化规律,采用二次塑流模型建立了锈蚀试件的应力-应变退化本构模型,得到了参数s1、s2随腐蚀时间变化的关系,对锈蚀试件进行有限元模拟,并与试验结果进行对比分析。结果表明:由于腐蚀的不断增加,Q690高强钢的屈服强度、抗拉强度和断后伸长率等力学性能指标都有不同程度的下降,弹性模量在腐蚀前期变化不明显,而腐蚀后期最大下降10.2%。所采用的二次塑流模型能较好地反映腐蚀钢材的本构关系,有限元模拟锈坑对钢材的剥削能较好地反映锈蚀高强钢材的承载力退化规律,与试验结果吻合较好。

The accelerated corrosion test of Q690 high-strength steel was carried out for 0-100 d in the periodic wetting and humid hot environment.The degradation law of mechanical properties of steel was studied by uniaxial tensile test.The stress-strain degradation constitutive model of corroded specimen was established by using secondary plastic flow model,and the relationships between parameters s1 and corrosion time,s2 and corrosion time were obtained.The results were compared with the experimental results.It could be concluded that the yield strength,tensile strength and elongation after fracture and other mechanical properties of Q690 high-strength steel decreased in varying degrees due to the increasing corrosion.The elastic modulus of Q690 high-strength steel had no obvious change in the early stage of corrosion,but it decreased by 10.2%in the later stage of corrosion.The secondary plastic flow model could better reflect the constitutive relationship of corroded steel.The finite element simulation of corrosion pit exploitation of steel could better reflect the degradation of bearing capacity of corroded high-strength steel,which was in good agreement with the test results.