Title: Boride precipitation and mechanical behaviour of high boron stainless steel with boron and titanium additions

Authors: Xiao-Qiu Zheng; Ying Liu; Jun Li; Lin He; Lai-Chang Zhang

Addresses: School of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China; School of Mechanical and Electrical Engineering, Jinggangshan University, Ji'an 343009, China ' School of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China ' School of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China ' School of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China ' School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, Perth, WA, 6027, Australia

Abstract: High boron stainless steel (HBSS) was produced by vacuum induction melting (VIM) technique. The effects of boron and titanium on the microstructure and mechanical properties of the HBSS were investigated. The results show that the boron can be formed into Fe_1.1Cr_0.9B_0.9 boride particulates which lead to poor mechanical properties, especially the ductility, of the as-cast HBSS. With the boron content of the as-cast HBSS increased from 0.4 wt. % to 1.4 wt. %, the elongations to rupture (Er) and the impact toughness decrease from 7.8% and 11.45 J/cm² to 2.3% and 4.21 J/cm², respectively. The formation of TiB₂, which replaces most of the prior Fe_1.1Cr_0.9B_0.9 boride particulates, benefits the refinement of the microstructures and the improvement of the mechanical properties. The impact toughness of the as-rolled and then heat treated HBSS, what's more, has tremendous increase from 28.1 J/cm² to 42.6 J/cm².

Keywords: high boron stainless steel; HBSS; mechanical behaviour; microstructure; boride precipitation; titanium; vacuum induction melting; VIM; ductility; impact toughness.

DOI: 10.1504/IJMPT.2015.072559

International Journal of Materials and Product Technology, 2015 Vol.51 No.4, pp.332 - 344

Accepted: 02 Apr 2015
Published online: 19 Oct 2015 *

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