Influence of cooling treatment on corrosion behaviour of steel EH40 in extremely cold seawater

The high strength ocean engineering structural steel EH40 exhibited great potential for the building of polar expedition ships due to high performance strength, relevant low-temperature impact toughness, prominent ship plate steel extensions, and outstanding weldability. The corrosion behavior of modified EH40 steel in low-temperature (0 ºC) 3.5Wt% NaCl solution over a 56-day period was investigated using mass loss techniques, surface characterization, component analysis, and electrochemical measurements. The results showed that the corrosion rate of EH40 steel in low-temperature artificial seawater was relatively high compared to artificial seawater at room-temperature after 14 days of immersion. Notably, in the low-temperature NaCl solution, the scale deposits consisted mainly of Fe(ClxOy) under which, corrosion pits were initiated. Moreover, uneven corrosion products formed on the steel surface and the size of the pit gradually increased with immersion time. In contrast, for the room temperature NaCl solution, a compact and thick corrosion product film covered the steel surfaces, protecting the steel from further corrosion and a characteristic uniform corrosion was present in the steel.

The Influence of Low Temperature on the Corrosion of EH40 Steel in a NaCl Solution

Shen¹

2018

Investigation of Influence of Microstructure on FH32 Steel Corrosion Properties using Gleeble Simulation of Heat-Affected Zone and Electrochemical Methods

Zhao¹

2019

The corrosion behavior was investigated for each heat-affected zone (HAZ) comprising a FH32 steel immersed in 3.5% NaCl solutions. To research the corrosion behavior of each HAZ sub-region, HAZ thermo-mechanical simulations were performed prior to the electrochemical tests. The results revealed that the corrosion resistance of the fine-grained HAZ (FGHAZ) comprising the steel is superior to that of other HAZ sub-regions. Moreover, the coarse-grained HAZ (CGHAZ) exhibited the worst corrosion resistance of the weld joint. The changes in the corrosion resistance of the HAZ sub-regions were attributed to variations in the microstructural sensitivity to corrosion behavior. Furthermore, the results indicated that the number, size, and distribution of martensite/austenite (M/A) constituents, as well as the grain size of the relevant phase can affect the resistance.

Initial Corrosion Behavior of EH36 Marine Steel in Simulated Polar Marine Environment

Li¹

2022

The corrosion behavior of grade EH36 steel in a simulated polar marine atmospheric environment (3.5%NaCl) for 10 d was studied using corrosion weight loss, surface morphology analysis, composition analysis, and electrochemical testing techniques. The results demonstrate that the corrosion rate of EH36 steel at low temperatures was high and it was still in the accelerated corrosion stage. After 240 h of corrosion, the corrosion rate was 0.47 g•m -2 •h -1 . The corrosion products were mainly composed of β-FeOOH, Fe3O4, and small amounts of γ-FeOOH and α-FeOOH. The corrosion pit depth increased from 8.81 μm in 48 h of corrosion to 31.70 μm in 240 h. The study of the early corrosion behavior and mechanism of EH36 ship plate steel in polar marine atmospheric environment can provide an important reference for the composition design of ship plate steel and its application in marine environments.