Corrosion and Wear Behavior of Mooring Chain Steel in Artificial Seawater Solution

During the service processes of anchor chain steel, the friction between the chain links easily causes volume loss of the contact surface. At the same time, metal materials are often affected by corrosion and electrochemistry of ocean. There is a serious coupling effect between corrosion and wear on the anchor chain steel at the ocean environment. CM490 steel was chosen to quantitatively explore the coupling effect between friction and electrochemical corrosion of mooring chain steel in the marine environment in this paper. The CM490 anchor chain steel was made into a cylindrical specimen with a height of 4mm and a radius of 6 mm. One side of cylindrical specimen was naked, and other side was connected to a copper wire and was encapsulated with epoxy resin. Koster CS2350 electrochemical workstation and Rtec friction tester were used to carry out the corrosive wear behaviors of CM490 mooring chain steel. The dynamic corrosion wear tests were carried out using a pin-disk reciprocating motion module, with a reciprocating frequency of 0.5 Hz, a reciprocating distance of 6 mm, and a linear velocity of 6 mm/s. The normal applied loads of were set to 20 N, 50 N, and 80 N, respectively. The polarization curve, open circuit potential, coefficient of friction, surface morphology and element distribution were examined to analyze to the electrochemical corrosion volume loss and friction volume loss quantitatively, and eventually to reveal the interaction mechanism between corrosion and friction. The resulted showed that the overall volume loss rate of the CM490 material increased with the increase of the load, and were 4.2×10−2, 6.5×10−2, 7.9×10−2 mm3/h under 20, 50 and 80 N, respectively. The peak value of the open circuit potential increased with the increase of the load, and the peak value of 0.095 V was the biggest at 80 N, which indicated that there were obvious differences between the corrosion wear products and the substrate, and resulted in deepening the corrosion of the CM490 material due to the galvanic corrosion. The corrosion and wear volume loss at the wear scratch was the main volume loss, and was about 95.80%~96.82% of the total volume loss of CM490 steel. The coupling effect between the corrosion and wear significantly increased volume loss rate of materials at the friction area, and was about 47.14% to 49.37%.The promotion volume loss rate of corrosion on wear was about 98.32% to 98.65% volume loss rate to the interaction of corrosion and wear, which indicated that the interaction volume loss was mainly manifested in the promotion effect of corrosion on wear. Due to defects such as dislocations in the wear process and galvanic corrosion, the friction process deepened the corrosion of the unworn area. As a summary, the interaction effects between corrosion and friction on the surface of CM490 steel increased the volume loss rate of material at the contact wear area. Both the deformation of the CM490 steel surface caused by the high load-friction and the galvanic corrosion caused by the generated products had a significant promotion effect on the corrosion at the unworn area. This paper provides the theoretical to ensure the reliability and long-term service of the platinum chain in offshore engineering equipment. © 2022, Chongqing Wujiu Periodicals Press. All rights reserved.