Effect of manganese and niobium on the properties of low-alloy steels

The strength and ductility characteristics, toughness parameters, and structure of low-alloy steels after thermomechanical treatment are studied. Analysis of the properties of steels with various manganese-to-niobium ratios is performed. An optimum chemical composition for sheet steel subjected to thermomechanical treatment is suggested.     

Effect of carbon and nickel on intercrystalline corrosion of austenitic chromium-nickel stainless steels

Metal Science and Heat Treatment -     

Effect on marine immersion corrosion of carbon content of low alloy steels

This paper attempts to reconcile information from a number of different sources about the effect of small changes in carbon content on the immersion corrosion of specimens of normal commercial mild and low alloy steels. It does so through interpreting the data reported in the literature in terms of the recently proposed theoretically based phenomenological model for marine immersion corrosion. This model postulates different corrosion phases as corrosion progresses. When the experimental results are interpreted in terms of the model it is found that carbon content has minimal effect on the kinetically controlled corrosion phase. The next phase, when corrosion rate is controlled by oxygen diffusion, is also unaffected, in agreement with theoretical predictions. However, carbon content does affect the two anaerobic phases, with increased corrosion as the carbon content and the water temperature increase. The model allows apparently conflicting observations to be reconciled and shows that carbon content may be influential for longer-term corrosion and for corrosion in tropical waters.     

Effect of niobium on the cold resistance of low-carbon and low-alloy steels

Conclusions Niobium in low-carbon and low-alloy steels combines carbon in NbC. The carbon is completely combined when the niobium to carbon ratio is about 1.51. A relationship was found between the carbon content of the solid solution and the niobium content of the steel: The greatest reduction in the carbon content of the solid solution occurs with the addition of 0.05–0.1% Nb. With larger niobium concentrations the amount of carbon dissolved in ferrite continues to decrease, but at a lower rate.The increase in the fracture toughness of steel is inversely proportional to the carbon content of the solid solution.I. P. Bardin Central Scientific-Research Institute of Ferrous Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 15–18, January, 1978.     

Effect of antimony on the corrosion behavior of low-alloy steel for flue gas desulfurization system

The alloying effect of Sb in a new low-alloy steel for the purpose of FGD materials was investigated by potentiodynamic polarization, linear polarization resistance measurement, electrochemical impedance spectroscopy (EIS) and weight loss measurements in an aggressive solution of 16.9 vol.% H₂SO₄ + 0.35 vol.% HCl (modified green death solution) at 60 °C, pH −0.3. All measurements confirmed the marked improvement in the corrosion behavior of the low-alloy steel via the addition of a small amount of Sb, particularly for the 0.10Sb steel. Pitting corrosion was detected by scanning electron microscopy (SEM) on the surface of blank steel and 0.05Sb steel, but not 0.10Sb steel, after weight loss measurements. X-ray photoelectron spectroscopy (XPS) analysis of the corroded surfaces after EIS and linear polarization measurements showed that the decrease in corrosion rates was due to the formation of a protective Sb₂O₅ oxide film on the surface of the Sb-containing steels. Moreover, the addition of 0.10% Sb stimulated the development of high corrosion inhibiting, Cu-containing compounds which further inhibited the anodic and cathodic reactions.     

Effect of wood species on corrosion behavior of carbon steel and stainless steels in black liquors

Black liquors produced by pulping different wood species can have different corrosivity towards carbon steel equipment in pulp mills. Inorganic constituents of black liquor alone do not correlate well with the corrosivity of different black liquors. Organic constituents of the black liquor have significant effect on determining its corrosivity. However, understanding of the role of individual organic constituents or group of constituents of black liquors in overall black liquor corrosivity is generally lacking. The objective of this study was to determine the effect selected wood species on the corrosivity of their black liquors which contained similar inorganic constituents. The role of black liquor constituent, pyrocatechols, whose presence in the black liquor has been associated with an increase in corrosion of carbon steel, was also studied. Results from electrochemical tests point to the mechanisms by which the catechols may participate in the accelerated corrosion of carbon steels. This study demonstrates the role of organic constituents of the black liquor in determining its corrosivity.