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The Effect of Ti and Ti°1Mb Additions on a Formation and Restoration during Intercritical Rolling and Holding of C-Mn Structural Steels

Journal Article


Abstract


  • Single-pass rolling in the (γ + α) two-phase region has been carried out to investigate the effect of Ti and Ti-Nb additions on the γ→α transformation and the restoration characteristics of deformed a in a 0.13%C-1.45%Mn base steel. The microalloyed steels consisted of 0.016%Ti, and 0.019%Ti plus 0.024% Nb. Experimental results showed that rolling in the (γ + α) two-phase region accelerated the γ→α transformation, and the presence of Ti or Ti plus Nb enhanced this accelerative effect. In undeformed and lightly deformed samples, a grains nucleated mainly at y grain boundaries during and/or after rolling. In samples rolled with reductions higher than a critical value, a grains nucleated at y grain boundaries as well as interiors, mainly at the boundaries of deformation bands and deformed annealing twins. Depending on the rolling reductions, holding time and alloy composition, deformed α grains developed into cell and/or subgrains, or recrystallization occurred resulting in equiaxed grains. Recovery and recrystallization of deformed α proceeded rapidly in the C-Mn steel, but was sluggish in the Ti and Ti-Nb steels. The incubation time for recrystallization of deformed α was retarded by 1-2 orders of magnitude in the Ti and Ti-Nb steels compared with the base C-Mn steel, because of the presence of alloy carbide/nitride precipitate particles. Ti and Ti-Nb additions also produced finer initial y grains after reheating before rolling, and stabilized the dislocation substructures during and after rolling. The substructures resulted in increased nucleation sites for the γ→α transformation. These effects led to finer α grains and a higher hardness (and strength) in the microalloyed steels than in the C-Mn steel after the same rolling and holding treatments. © 1991, The Iron and Steel Institute of Japan. All rights reserved.

Publication Date


  • 1991

Citation


  • Dunne, D. P., Feng, B., & Chandra, T. (1991). The Effect of Ti and Ti°1Mb Additions on a Formation and Restoration during Intercritical Rolling and Holding of C-Mn Structural Steels. ISIJ International, 31(11), 1354-1361. doi:10.2355/isijinternational.31.1354

Scopus Eid


  • 2-s2.0-0026392898

Web Of Science Accession Number


Start Page


  • 1354

End Page


  • 1361

Volume


  • 31

Issue


  • 11

Abstract


  • Single-pass rolling in the (γ + α) two-phase region has been carried out to investigate the effect of Ti and Ti-Nb additions on the γ→α transformation and the restoration characteristics of deformed a in a 0.13%C-1.45%Mn base steel. The microalloyed steels consisted of 0.016%Ti, and 0.019%Ti plus 0.024% Nb. Experimental results showed that rolling in the (γ + α) two-phase region accelerated the γ→α transformation, and the presence of Ti or Ti plus Nb enhanced this accelerative effect. In undeformed and lightly deformed samples, a grains nucleated mainly at y grain boundaries during and/or after rolling. In samples rolled with reductions higher than a critical value, a grains nucleated at y grain boundaries as well as interiors, mainly at the boundaries of deformation bands and deformed annealing twins. Depending on the rolling reductions, holding time and alloy composition, deformed α grains developed into cell and/or subgrains, or recrystallization occurred resulting in equiaxed grains. Recovery and recrystallization of deformed α proceeded rapidly in the C-Mn steel, but was sluggish in the Ti and Ti-Nb steels. The incubation time for recrystallization of deformed α was retarded by 1-2 orders of magnitude in the Ti and Ti-Nb steels compared with the base C-Mn steel, because of the presence of alloy carbide/nitride precipitate particles. Ti and Ti-Nb additions also produced finer initial y grains after reheating before rolling, and stabilized the dislocation substructures during and after rolling. The substructures resulted in increased nucleation sites for the γ→α transformation. These effects led to finer α grains and a higher hardness (and strength) in the microalloyed steels than in the C-Mn steel after the same rolling and holding treatments. © 1991, The Iron and Steel Institute of Japan. All rights reserved.

Publication Date


  • 1991

Citation


  • Dunne, D. P., Feng, B., & Chandra, T. (1991). The Effect of Ti and Ti°1Mb Additions on a Formation and Restoration during Intercritical Rolling and Holding of C-Mn Structural Steels. ISIJ International, 31(11), 1354-1361. doi:10.2355/isijinternational.31.1354

Scopus Eid


  • 2-s2.0-0026392898

Web Of Science Accession Number


Start Page


  • 1354

End Page


  • 1361

Volume


  • 31

Issue


  • 11