THE PRECIPITATION BEHAVIOUR OF BORIDE DURING COOLING
Yin Shike (Central Iron and Steel Research Institute; Ministry of Metallurgical Industry; Beijing); Hajime Komatsu; Mitsuru Tanino (Fundamental Research Laboratories; Nippon Steel Corporation; Japan)
Cite this article:
Yin Shike (Central Iron and Steel Research Institute; Ministry of Metallurgical Industry; Beijing); Hajime Komatsu; Mitsuru Tanino (Fundamental Research Laboratories; Nippon Steel Corporation; Japan). THE PRECIPITATION BEHAVIOUR OF BORIDE DURING COOLING. Acta Metall Sin, 1982, 18(5): 559-644.
Abstract The boride precipitation behaviour of steel containing B 18 ppm, N 19ppm and C 0.1% during cooling has been investigated by using the fission track etching and electron microscopy. It was found that the carbon-boride Fe_(23)(C, B)_6 precipitates out along the austenitic grain boundary of solid solution treatment specimen after water cooled even in iced salt water. The Fe_(23)(C, B)_6 appears an acid soluble thin plate on rapid cooling. At the cooling rate up to 20℃/s, the precipitate is further presented in the interior of the grain. Both intergranular and intragranular ones may quickly grow up by isothermal treatment at 750℃. While the isothermal treating temperature raised to 850℃, the boride, to form BN instead, precipitates out around the spherical MnS grain as nucleus of crystallization to obtain a compound of MnS+BN.
