Titanium effect on the microstructure and properties of laminated high boron steel plates

Abstract

High-boron steel is an important material used for thermal neutron shielding. The appropriate amount of added boron must be determined because excessive boron may deteriorate the steel’s workability. A uniform microstructure can be formed by adding titanium to boron steel. In this study, casting and hot rolling were used to fabricate laminated high-boron steel plates whose cores contained 2.25wt% boron and 0wt%–7.9wt% titanium. The effects of titanium content and hot-rolling and heat-treatment processes on the microstructure and properties of the laminated plates were studied. The results indicated that the optimum titanium content was 5.7wt% when the boron content was 2.25wt%, and that the best overall properties were obtained after heat treatment at 1100°C for 4 h. The tensile strength, yield strength, and elongation at the specified temperature and holding time were as high as 526.88 MPa, 219.36 MPa, and 29%, respectively.

Keywords

boron steel / laminated materials / titanium / boride / hot rolling / heat treatment

References

[1] McGregor D.S., Unruh T.C., McNeil W.J. Thermal neutron detection with pyrolytic boron nitride. Nucl. Instrum. Methods Phys. Res. Sect. A, 2008, 591(3): 530.

[2] Machiels A., Lambert R. Handbook on Neutron Absorber Materials for Spent Nuclear Fuel Applications, 2005 3-1.

[3] Wang G., Ding Y.G., Wang J.S., She X.F., Xue Q.G. Effect of carbon species on the reduction and melting behavior of boron-bearing iron concentrate/carbon composite pellets. Int. J. Miner. Metall. Mater., 2013, 20(6): 522.

[4] Liu Z.L., Cheng X., Li Y.X., Hu K.H. High boron iron-based alloy and its modification. J. Iron. Steel. Res. Int., 2009, 16(3): 37.

[5] Grebennikov R.V., Chirkin A.V., Vukolova V.N., Shavrova T.N., Balanik I.S. Influence of titanium on the phase composition and deformability of high boron steels. Sov. At. Energy, 1967, 22(5): 481.

[6] Acosta P., Jimenez J.A., Frommeyer G., Ruano O.A. Microstructural characterization of an ultrahigh carbon and boron tool steel processed by different routes. Mater. Sci. Eng. A, 1996, 206(2): 194.

[7] Sercombe T.B. Sintering of freeformed maraging steel with boron additions. Mater. Sci. Eng. A, 2003, 363, 242.

[8] Derun E.M., Kipcak A.S. Characterization of some boron minerals against neutron shielding and 12 year performance of neutron permeability. J. Radioanal. Nucl. Chem., 2012, 292(2): 871.

[9] Li G., Jian M., Wang M.L., Wang G.C., Liu X.Z. Research progress in neutron absorbers materials for reactor spent fuel storage and transportation applications. Mater. Rev., 2011, 25(7): 110.

[10] Liu C.S., Chen S.Y., Wang Z.T., Chen F.S., Liu Y.X., Liang D.K., Xiao L.M. Microstructure and properties of high boron bearing steel. Acta. Metall. Sin. Engl. Lett., 2002, 15(2): 248.

[11] Jiménez J.A., González-Doncel G., Ruano O.A. Mechanical properties of ultrahigh boron steels. Adv. Mater., 1995, 7(2): 130.

[12] Fu H.G., Xiao Q., Kuang J.C., Jiang Z.Q., Xing J.D. Effect of rare earth and titanium additions on the microstructures and properties of low carbon Fe–B cast steel. Mater. Sci. Eng. A, 2007, 466(1–2): 160.

[13] Xie G.L. Research on the Processing and Application of New Type Laminated Composite Materials, 2011, Beijing, University of Science and Technology Beijing, 76.

[14] Yuan L.L., Han J.T., Liu J. Analysis of boride phase composition in high boron alloyed stainless steel containing titanium. Adv. Mater. Res., 2014, 941–944, 226.

[15] Ye D.L., Hu J.H. Practical Handbook of Thermodynamic Data for Inorganic Compounds, 2002 2 Beijing, Metallurgical Industry Press, 1.

[16] He L., Liu Y., Li J., Li B.H. Effects of hot rolling and titanium content on the microstructure and mechanical properties of high boron Fe–B alloys. Mater. Des., 2012, 36, 88.

[17] ASTM E562-11. Standard Test Method for Determining Volume Fraction by Systematic Manual Point Count, 2011, West Conshohocken, USA, ASTM International

[18] Robino C.V., Cieslak M.J. High-temperature metallurgy of advanced borated stainless steels. Metall. Mater. Trans. A, 1995, 26, 1673.

[19] Liu Y., Li B.H., Li J., He L., Gao S.J., Nieh T.G. Effect of titanium on the ductilization of Fe–B alloys with high boron content. Mater. Lett., 2010, 64(11): 1299.

[20] ASTM A887-89. Standard Specification for Borated Blanks, Sheet, and Strip for Nuclear Application, 2014, Philadelphia, USA, Annual Book of ASTM Standards