The Research On The Application Properties Of The Enamel Coating Steel RST330 For Water Condition

This paper is attempted to offer the guidance of the application and evaluation of the performances of the water environment enamel coating steel RST330 through three aspects: high temperature property, fatigue property and enamel property.During the study of the high temperature property, we used the facility Gleeble3500 to perform the tensile tests of RST330 plates under different temperatures, and acquired the disciplines that how its mechanical behaves during different high temperatures, then studied the grain structure behaviours during the enamel process with the facility high temperature microscope, after that, super depth of field microscope and environment scan electron microscope was used to show the morphologies of the fractures of RST330 plates that caused by tensile tests under different high temperatures and analyzed them. We found that RST330 plates showed great capacities for high temperature deformation, in order to ensure its mechanical property not to be ruined by the firing process of enamel, 850℃ was recommended to be the proper temperature for enamel.Fatigue test machine was used to perform the fatigue test of RST330 plates, we acquired the stress-cycle curve(S-N curve), and used super depth of field microscope and environment scan electron microscope to inspect the morphologies of the fractures that caused by different fatigue stresses and then analyzed them, we found that RST330 was capable of being the material of the inner structure of the water storage devices, the fatigue limit was approximately 268 MPa, high above the stress that ordinary water storage devices received during the working condition.During the study of the enamel property, we enameled the RST330 plates under different temperatures following the common production procedures, and observed the surfaces and evaluated the quality, super depth of field microscope and environment scan electron microscope were used again to show the morphologies of the steel-enamel interfaces, the surface quality of the coating indicated that enamel temperature should be above 800℃, but if the thickness of the coating should be homogeneous, then below 900℃, the morphologies of the interfaces suggested that the higher enamel temperature resulted in better mechanical adherence. The thermo mechanical analysis device was used to acquire the discipline of the coefficients of the thermo expansion of the RST330 plates and the enamel block to the temperature changes, and calculated the shrinkage differences between them. We found that the enamel shrinkage was slightly smaller than the RST330’s, this made the enamel under the pressure and enhance the adherence, besides, the shrinkage difference between the steel and the enamel was so small, the remaining stress was beyond our concern, they fitted with each other well. Then, X-ray diffraction and energy dispersive spectroscopy were used to analyze the enamel powder’s composition and structures, we found that the powder’s main constituent was Si O2, TiO2 was added, and many other common oxides of metal. Then transmission electron microscope was used to analyze the essence and diffusion behaviour of precipitated phase particles in the RST330 plates before and after enamel, and then with the help of Hydrogen permeation test to testify the effects of the precipitated phase particles, we found that the amount of precipitated phase particles in the plates increased after the enamel process, and the most of particles were TiN(or Ti(CN)) and they diffused more homogeneously within the plates, and the time it took for the first Hydrogen atom passed through the steel plate to show up was much longer after the enamel process, the resistance against fish scale crack increased.