Friction and Wear Properties of TMCP FH36 Marine Steel Plate at Different Temperatures

FH36 steel, which is an urgent basic material for large cargo ships, passenger ships and marine equipment that can be used in low-temperature and harsh environment, has attracted extensive attention because of its high strength and high toughness under low-temperature condition. When the FH36 steel is used in the ice environment, it will be inevitably damaged by friction and wear under ice load. In this paper, the friction and wear properties of the FH36 grade marine steel plates with different thickness, which were prepared by controlled rolling and controlled cooling process (Thermo mechanical control process, TMCP), were investigated at 20, −5 and −20 ℃. The UMT-2 tribolab multifunctional friction and wear tester was used for friction and wear test. A diameter of 8 mm alumina grinding ball was adopted to apply spherical contact friction. The reciprocating friction distance was 5 mm, the load was 20 N, the frequency was 2 Hz, and the test time was 2 hours. Bruker contour GT-1 white light interferometer was used to measure the wear trace profile of steel sample after friction and wear. The wear amount of steel samples was calculated through the volume loss of steel sample after friction and wear test, and the friction coefficient and wear amount obtained from friction and wear test are compared and analyzed. Cxs-5tah-118340 scanning electron microscope was used to observe the surface morphology of the steel sample and analyze the friction and wear mechanism. Test results showed that different microstructures occurred at different rolling depths, which resulted in different wear resistance. The surface microstructure of the rolled steel plates was mainly ferrite and pearlite, which changed to ferrite, pearlite and granular bainite at the center of the steel. For both the rolled steel plates with different thickness, the hardness at the surface was higher than that at the center. The hardnesses at the surface and the center of the steel with a thickness of 20 mm were 490 HV and 441 HV, respectively, while the corresponding values of the steel with a thickness of 40 mm were 507 HV and 451 HV. The average friction coefficients of the steel plates at the surface were significantly higher than those of the steel plates at the center; while the wear depth, wear width, and wear amount were on the contrary. In addition, the wear resistance of the FH36 marine steel plate decreased gradually with decreasing temperature. The main wear mechanism of the FH36 marine steel plate was abrasive wear, accompanied by fatigue wear and adhesive wear.