Stabilisation of ferritic stainless steels with Zr and Ti additions

Abstract

Traditional 11·5 wt-%Cr ferritic stainless steels are single stabilised with Ti or dual stabilised with Ti–Nb additions. A dual-stabilised ferritic stainless steel 409 with Zr–Ti additions was studied, which was selected through thermodynamic and kinetics analysis. The alloy was subjected to thermomechanical processing using both hot and cold rolling and annealing. The intergranular corrosion resistance and microstructure of this alloy was evaluated. Of particular interest was to study the stabilisation behaviour of this alloy under all processing conditions. The results showed that the precipitation of CrxCy was effectively prevented; hence, the alloy used in this investigation had an excellent resistance to intergranular corrosion.

Formation and Evolution of Oxide Inclusions in Titanium-Stabilized 18Cr Stainless Steel

“…Jingyu LI, 1) Guoguang CHENG, 1) * Qiang RUAN, 2) Jixiang PAN 2) and Xingrun CHEN 2) the oxide compounds in MgO-Al 2 O 3 -Ti 2 O 3 and molten iron to avoid Al 2 O 3 or MgO-Al 2 O 3 formation and for inclusion control. According to their experimental results, it is necessary to lower the Al content and to adjust the Ti content to an appropriate concentration range to form MgTi 2 O 4 instead of MgAl 2 O 4 .…”

“…The LF refining process of Ti-stabilized stainless steel melts involves deoxidation by Al followed by Ti alloy addition for binding the interstitial elements C and N. 1,2) However, the deoxidation products can potentially cause the clogging of submerged entry nozzle (SEN) and the surface defects of steel products. [3][4][5] Thus, it is necessary to control the formation of oxide inclusions in Ti-bearing stainless steel.…”

Evolution Mechanism of Inclusions in Al-killed, Ti-bearing 11Cr Stainless Steel with Ca Treatment

“…Jingyu LI, 1) Guoguang CHENG, 1) * Qiang RUAN, 2) Jucang LI, 2) Jixiang PAN 2) and Xingrun CHEN The evolution mechanism of non-metallic inclusions in Al-killed, Ti-bearing 11Cr stainless steel with Ca treatment was investigated by industrial trials and thermodynamic calculation. The morphology, composition, and size distribution of inclusions in steel specimens were analyzed by scanning electron microscopy and energy dispersive spectroscopy.…”

“…Titanium suppresses chromium carbide precipitation at grain boundary through the formation of more stable titanium carbide, which substantially improves the resistance to intergranular corrosion. 1,2) What is more, the heterogeneous nucleation of delta ferrite on the TiN formed during primary solidification of stainless steel promotes the generation of the equiaxed fine-grain structure. 3,4) However, the generation of oxide inclusions is inevitable due to de-oxidation by Al before Ti alloy addition and the interactions between reactive elements in the steel melt and its environment (slag, refractory, or atmosphere).…”

Effect of CaO–MgO–SiO₂–Al₂O₃–TiO₂ Slags with Different CaF₂ Contents on Inclusions in Ti-Stabilized 20Cr Stainless Steel

“…Titanium can bind the interstitial elements C, N and improve the intergranular corrosion resistance of stainless steel. 1,2) Meanwhile, the heterogeneous nucleation of delta ferrite on the TiN formed during primary solidification of stainless steel promotes the generation of the equiaxed fine-grained structure. 3) Therefore, the addition of titanium to stainless steel in the ladle for improving properties has increased in recent years.…”