Sulphidation of Low-Alloyed Steels Used in Power Industry

Abstract

This paper reports the results obtained from sulphidation tests on a low-alloyed steels 15HM (T/P12), 16M (T/P1), 18K and 10HM2 (T/P22) in the temperature range 450-550 °C for 100 h. Tests were conducted using a gas mixture of 1%H 2 S 99% Ar at 1 bar. The results indicate that the low-alloyed steels underwent a high degree of corrosion degradation due to the formation of an Fe 1−X S scale. The scale thicknesses and chemical compositions of the scales formed on the exposed samples were analysed by means of standard techniques, including scanning electron microscopy coupled with energy X-ray dispersive spectroscopy. In addition, a phase diagram for the Fe-S system was calculated using FACTSAGE software to aid interpretation of the results. Based on the study conducted, relevant defect equations were proposed.

Sulfidation of Ceramic-Based Coatings Deposited on Low-Alloyed Steel 16Mo3 Exposed at High Temperature

“…The enamel symbols are not continuous, there are no coatings denoted as FCHO2, FCHO4, FCHO5, FCHO9 and finally FCHO10-these samples during preparation for high-temperature testing at 773.15 K showed weak mechanical behavior, spallation occurred and cracks on the sample surfaces were observed; therefore, the samples were rejected from the further examination. Water suspensions with densities of around 1.60 ± 0.5 g/cm 3 were spread by a spray method onto the steel surface and fired in the conditions given in Table 5.…”

Sulfidation-Oxidation Resistance of Thermal Diffusion Multi-Layered Coatings on Steels

“…The list of materials for sulfidation-oxidation testing is shown in Table 2 . It should be noted that bare carbon steel was not included in the study since carbon and low-alloy steels have poor performance in sulfidation conditions [ 12 ] and are not reliable for industrial high-temperature corrosion applications.…”

“…The testing was conducted in the 1% (Vol.) H 2 S-air gas flow (50 Nml/min); the H 2 S concentration in the gas mixture was selected according to the general assumption that H 2 S contents in coal-fired boiler combustion gases are below or approximately 1 Vol.% [ 12 , 39 ]. The gas mixture was provided by Air Products.…”

“…Relatively inexpensive carbon steels and low-alloy steels, mostly used for tubing in power generation, have rather poor performances in high-temperature (above 500 °C) oxidation, sulfidation, or sulfidation-oxidation conditions. It is related to their rapid oxidation with the formation of detachable iron oxide scales (in case of oxidation environments) or formation of porous iron sulfide scales (FeSx), which are easily peeled off, as well as surface cracking [10][11][12]. Stainless steels and even more expensive Ni-based and Ti-based alloys also experience corrosion issues due to detachment of the sulfide scales and surface micro-cracking at service temperatures (350-500 °C), although to a lesser extent [4,6,[13][14][15][16][17].…”

Fatigue damage development in 10CrMo9-10 steel for power plant pipes in as-received state and after 280,000 h of exploitation

“…With an increasing demand of the power plant industry, the operating parameters of working elements increased significantly in comparison to those used in the past. The aggressive conditions including the high temperature and internal pressure of the piping systems notably accelerate material degradation [1]. Such a situation requires continuous monitoring, which needs to be performed to maintain the required properties, and, as a consequence, further state exploitation and efficient estimation of the service life of working components [2].…”