Microstructure and Properties of Isothermally Quenched High Boron White Cast Iron

Abstract:

Microstructure and properties of isothermally quenched high boron white cast iron were investigated in this paper. The results show that the microstructure of high boron white cast iron is mainly composed of many continuous and netlike eutectic borides, pearlite and ferrite under as-cast condition. The microhardness of Fe2B ranges in 1200-1600HV whose value seems to approximate that of (Fe,Cr)7C3–type carbide (HV1200~1800) in high chromium white cast iron. After isothermal quenching, the matrix transforms into lower bainite in which carbide precipitations are arranged in parallel rows at an angle of 60 deg to the long axis of the plates, but the morphology of boride remains nearly unchanged compared with its as-cast condition. Moreover, precipitation particles with the size of about 1~4 μm can be found in the matrix of isothermally quenched high boron white cast iron. Impact fracture morphology of isothermally quenched high boron white cast iron indicates that fracture propagated more easily through boride/matrix interface than through matrix.

• Periodical: Key Engineering Materials (Volume 457)
• Pages: 207-212
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.457.207
• Online since: December 2010
• Authors: Jian Jun Zhang, Yi Min Gao, Jian Dong Xing, Sheng Qiang Ma, Wan Qin Yan, Jing Bo Yan
• Keywords: Boride, High Boron White Cast Iron, Isothermal Quenching, Lower Bainite

References

[1] H. G. Fu, D. M. Fu, J. D. Xing. Her: Mater. Manuf. Process Vol. 23 (2008), p.123.

[2] H. G. FU: Acta Metall. Sin. Vol. 42 (2006), p.545.

[3] C. Q. Guo and S. Z. Gao: Foundary Vol. 53 (2004), p.761.

[4] Okita T，Wolfer W G，Garner F A and Sekimura N: J. Nucl. Mater. Vol. 329-333 (2004), p.1013.

[5] S. Q. Ma, J. D. Xing, H. G. Fu, D. W. Yi, X. H. Zhi, and Y. F. Li: Surf. Coat. Technol. Vol. 204 (2010), p.2208.

[6] H. G. Fu, Q. Xiao, J. C. Kuang, Z. Q. Jiang, and J. D. Xing: Mat. Sci. Eng. A-Struct. Vol. 466 (2007), p.160.

[7] Z. L. Liu, X. Chen, Y. X. Li, and K. H. Hu: Metall. Mater. Trans. A Vol. 39 (2008), p.636.

[8] E. S. Davenport and E. C. Bain: AIME Vol. 90 (1930), pp.117-54.

[9] R.F. Mehl: Hardenability of Alloy Steels, ASM, Cleveland, OH, (1939), p.1.

[10] Y. H. Liu: Trans. ASM Vol. 69 (1969), p.55.

[11] Benxi Iron & Steel Co: Boron Steel, Metallurgical Industry Press, Beijing (1977).

[12] R.F. Hehemann: Phase Transformations, ASM, Metals Park, OH, 1970, pp.397-432.

[13] P. D. Zavattieri, H. D. Espinosa: Acta Mater. Vol. 49 (2001), p.4291.

[14] R. H. Frost and G. K. Tmajewski: AFS Trans., Vol. 94 (1986), p.292.

[15] H. G. Fu, Q. Xiao, J. C. Kuang, Z. Q. Jiang, and J. D. Xing: Mat. Sci. Eng. A-Struct. Vol. 466 (2007), p.160.