Research On Corrosion Properties Of Low Alloy Steel Sheet Piles In Marine Environment

Steel sheet pile is widely used in cofferdam engineering because of its own light quality,high strength,strong carrying capacity,good water stop performance,repeated recycling,high site construction efficiency,and many other advantages,such as steel sheet pile has been widely used in cofferdam engineering.In the construction of marine environment,such as bank berm and berm.Corrosion resistance of marine steel sheet pile is also an important index to evaluate its performance.However,the research on seawater corrosion of steel sheet pile is far from enough,and the mechanism of seawater corrosion of steel plate pile is not clear at present.Two low-alloy steel sheet piles with typical alloy content and strong contrast in the most commonly used low-alloy steel sheet pile materials at home and abroad are selected as experimental materials.In this paper,the indoor corrosion test was carried out by simulating the marine corrosive environment.The corrosion performance and the inclusions were used as the reference angles.The scanning electron microscope was used to observe the microscopic state of the 1# and 2# experimental steels.Under the surface morphology change and cross-sectional morphology change,the electron energy spectrometer and X-ray diffractometer were used to observe the element distribution of corrosion products in the corrosion rust layer of the experimental steel and the corrosion rust layer structure,combined with the corrosion dynamics weight loss results,AC impedance spectroscopy The results of detection and analysis of graphs and polarization curves,considering the effects of alloy content,microstructure,inclusions and corrosion products on the corrosion reaction of experimental steels,discussed the mechanism and main influencing factors of seawater corrosion kinetics of two experimental steels.Research shows:(1)In the experiment of indoor simulated marine atmospheric corrosion,the corrosion rate of 1# steel is higher than that of 2# steel.(2)The AC impedance spectra of 1# steel and 2# steel were analyzed in 3.5% sodium chloride salt solution for 7 days,and the polarization resistance value of the 2# steel was found to be large,and the corrosion resistance of the 2# steel was excellent.The order of the resistance from small to large(the corrosion rate was from fast to slow)was as follows: 1#> 2#.From the result of linear fitting of polarization curve,it can be seen that the corrosion current of 2# steel is less,and the corrosion progress of 1# steel and 2# steel is:1# steel> 2# steel.(3)The results of this paper show that the alloy elements,microstructure and corrosion products in the experimental steel material,the type,size and distribution of the inclusions are most important for the corrosion of 1# steel and 2# steel.