Some peculiarities of the structure of high boron steels
Alloying of high boron steels with titanium leads to the formation of high melting particles of titanium diborides in the melt and in the process of crystallization. This is accompanied by effects of incoculation and inversion which have a favorable influence on the structure and the properties of the metal.
Enriching the melt with titanium under conditions of open, and especially plasma melting of steel, causes saturation with hydrogen; this has a deleterious influence on the homogeneity of structure of the ingots because it enhances the development of defects such as whiskers, braids, and internal cracks.
The application of active degassing helps in suppressing the appearance and development of many defects of ingots. Degassing (dehydrogenation) of titanium containing metal is successfully attained both by melting it in vacuum furnaces and by methods of treatment outside the furnace including the addition of accurately dosed amounts of highly disperse calcium boride (CaB6) or other calcium containing compounds or hardners during pouring.
KeywordsHydrogen Calcium Titanium Crystallization Furnace
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- 1.I. M. Spiridinova, "The structure and properties of iron-boron alloys," Metalloved. Term. Obrab. Met., No. 2, 58–61 (1984).Google Scholar
- 2.A. K. Shurin and V. E. Pakarin, "The phase diagram of iron with interstitial phases as the basis for devising wear resistant eutectic steels," Metalloved. Term. Obrab. Met., No. 2, 55–57 (1984).Google Scholar
- 3.B. I. Medovar, N. I. Pinchuk, and L. V. Chekhotilo, Austenitic Boride Steels and Alloys for Welded Structures [in Russian], Naukova Dumka, Kiev (1970).Google Scholar
- 4."Introducing boron- 0-a stainless steel for the nuclear industry," Stainless Steel Ind.,9, 10–11 (1959).Google Scholar
- 5.M. Iman, Tetsu to Hagane. J. Iron Steel Inst. Jpn,45, No. 9. 1117–1119 (1959).Google Scholar
- 6.V. I. Prosvirin, N. S. Kreshchanovskii, and É. S. Ginzburg, "The effect of boron on the structure and properties of austenitic steels," in: Problems of the Metal Science of Austenitic Steels, Mashgiz, Moscow (1952), pp. 185–235.Google Scholar
- 7.Ya. E. Gol'dshtein and V. G. Mizin, Modification and Doping of Cast Iron and Steel [in Russian], Metallurgiya, Moscow (1986).Google Scholar
- 8.Ya. E. Gol'dshtein, V. G. Mizin, and N. S. Khismatullina, "The modifying ability of diborides of high melting metals," Izv. Akad. Nauk SSSR, Met., No. 5, 101–106 (1987).Google Scholar
- 9.A. Edzhima, T. Émm, K. Suzuki, I. Hebu, and K. Sanovongi, "Criterion of uniform distribution of sulfides of REE in the crystallization of large ingots," in: Processes of Reduction and of the Formation of Nonmetallic Inclusions in Steel, Nauka, Moscow (1977), pp. 108–127.Google Scholar
- 10.V. M. Tageev and Yu. D. Smirnov, "Prevention of whiskers in the crystallization of steel with the aid of REE," Stal', No. 9, 823–828 (1957).Google Scholar
- 11.A. N. Morozov, Hydrogen and Nitrogen in Steel [in Russian], Metallurgizdat, Moscow (1968).Google Scholar