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Alloying Elements and Impurities in Steel
Published in Vladimir B. Ginzburg, Steel-Rolling Technology, 1989
Principal functions of aluminum are [3]: 1. It restricts grain growth by forming an effective fine dispersion with nitrogen or oxygen. It forms an effective surface-hardening layer by relatively low-temperature dif fusion of nitrogen (nitriding).It restricts corrosion by forming a strong layer of aluminum oxide on the steel surface.Aluminum is an excellent deoxidizer.Its contribution to hardenability is moderate.
Interfacial Phenomena of High-Temperature Melts and Materials Processing
Published in Mukai Kusuhiro, Matsushita Taishi, Interfacial Physical Chemistry of High-Temperature Melts, 2019
Mukai Kusuhiro, Matsushita Taishi
In the deoxidation process of molten steel at the final stage of steel refining, aluminum is commonly used as a deoxidizer. However, there remain some unknown facts in the aluminum deoxidation process; for example, the origin of non-equilibrium phases of alumina, such as γ and δ phases,8 which are observed at the initial stage of the deoxidation. Meanwhile, it has been reported that, when the deoxidation equilibrium between aluminum and oxygen is experimentally measured, a supersaturation phenomenon is found.9 However, this phenomenon has also not been reasonably explained.
Effect of Alloying Elements in Steel
Published in P. C. Angelo, B. Ravisankar, Introduction to Steels, 2019
Silicon: Like aluminium, silicon is added as deoxidizer. The residue silicon is present as its oxide. Silicon is a ferrite stabilizer and it is one of the ferrite stabilizers that does not form carbides. Silicon is normally added in magnetic steels as it improves magnetic properties and in valve steels as it improves the high temperature properties of steels. Precaution has to be taken while adding silicon because silicon is a powerful graphatizer that accelerates metastable cementite to reach its stable state as iron and carbon (graphite).
Analysis and control of annular pressure caused by leakage effect of completion string for HP/HT/HHS gas wells in Sichuan Basin
Published in Petroleum Science and Technology, 2023
For gas wells containing H2S in annulus air samples, alkaline protective fluid must be added into the annulus at the same time of pressure relief to increase the PH value of the annulus protective fluid. In other case, for gas wells where the annulus liquid level drops, the protective fluid also needs be added to raise the annulus liquid level. During the actual operation of the two cases, the pressure relief and filling protective fluid are carried out alternately. At the same time, the density of the protective fluid can be reduced in the filling process in order to improve the annulus liquid level. The specific formula of protective fluid used in the “three high” gas wells in Sichuan Basin is: water + 2.5% corrosion inhibitor + 0.25% deoxidizer + 0.05% sodium hydroxide + 0.25% fungicide + 0.5% sulfur remover. The PH value of the protective fluid is 13, and the density of initial used protective fluid is 1.3 g/cm3.
Two-Body Abrasion Behaviors Characterization of White Cast Iron with Various Chromium Concentrations
Published in Tribology Transactions, 2020
Baochao Zheng, Jiandong Xing, Yangzhen Liu, Wei Li
White cast iron samples were produced by smelting and sand casting. The chemical composition of the samples is given in Table 1. The chromium contents by mass were 0, 2, and 4%, termed C0, C2, and C4, respectively. Original materials were added to an 18 kg intermediate frequency furnace in order, including pure iron, ferrosilicon, ferrochromium, pig iron, and ferromanganese. The melting temperature was maintained at 1550 ± 10 °C for 10 min. The deoxidizer, pure aluminum, was added to the white cast iron melts, and the slag was removed from the molten steel surface. The melt was poured into sodium sand molds to obtain Y-style ingots at 1450 ± 10 °C according to ASTM A781/A781-M95 (17). Each specimen was cut by spark cutting from the ingots at room temperature to a diameter of 5.9 mm and height of 10 mm. Metallographic observations were made on the polished plane, which had been etched in 4% Nital.
Gaseous Reduction of Manganese Ores: A Review and Theoretical Insight
Published in Mineral Processing and Extractive Metallurgy Review, 2020
Alireza Cheraghi, Hossein Yoozbashizadeh, Jafar Safarian
Over 90% of the world manganese (Mn) production is in the form of manganese ferroalloys and is consumed in the steel industry as a deoxidizer, desulphurizer, and alloying element (Schottman 1988; Olsen et al. 2007). As a result, the demand for ferroalloys of Mn has changed in relation to steel production trends. The total steel and Mn ferroalloys production in the last 10 years is shown in Figure 1. It is observed in the figure that there has been a correlation between the products, where the total Mn ferroalloys production has been about 1% of the total steel production. Different grades of Mn ferroalloys are produced based on the final steel chemical composition requirements and specifications. Mn ferroalloys can be classified into three main groups: silicomanganese (SiMn), high-carbon ferromanganese (HC-FeMn), and refined ferromanganese (medium-carbon [MC-FeMn] and low-carbon [LC-FeMn]). Various grades of Mn ferroalloys are produced commercially, and a typical composition is shown in Table 1.