Effect of Imposed Shear During Oval-Caliber Rolling on the Properties of Mn–Si Low-Alloy Steel
Nogayev K. Abishkenov M. Ashkeyev Z. Akhmetova G. Kydyrbayeva S. Tavshanov I.
October 2025Multidisciplinary Digital Publishing Institute (MDPI)
Eng
2025#6Issue 10
The present study examines the effect of a modified oval–round rolling scheme incorporating inclined oval calibers on the mechanical behavior and microstructural evolution of Mn–Si low-alloy steel (25G2S). Cylindrical billets were hot rolled through both classical and modified sequences under identical thermal and kinematic conditions. Tensile testing demonstrated that, relative to the unrolled condition (σ0.2 ≈ 269 MPa; σᵤ ≈ 494 MPa), the classical route increased yield and ultimate strengths to ~444 MPa and ~584 MPa, respectively, whereas the modified scheme yielded comparable values (~433 MPa and ~572 MPa) while providing superior ductility (δ ≈ 26.8%, ψ ≈ 68.6%). Vickers microhardness decreased systematically from 244 HV (unrolled) to 213 HV (classical) and 184 HV (modified), with the modified scheme exhibiting the lowest scatter (±4.8 HV), confirming enhanced structural uniformity. Scanning electron microscopy revealed ferrite–pearlite refinement under both rolling sequences, with the modified scheme producing finer equiaxed ferrite grains (~3–5 µm) and attenuated longitudinal banding. These features are indicative of shear-assisted dynamic recrystallization, activated by the inclined oval calibers. The findings highlight that the modified rolling strategy achieves a favorable strength–ductility balance and improved homogeneity, suggesting its applicability for advanced thermomechanical processing of low-alloy steels.
dynamic recrystallization (DRX) , ferrite–pearlite morphology , inclined oval calibers , microhardness , Mn–Si low-alloy steel , oval–round rolling , strength–ductility balance
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Department of Technological Machines and Transportation, Karaganda Industrial University, Temirtau, 101400, Kazakhstan
Department of Metallurgy and Materials Science, Karaganda Industrial University, Temirtau, 101400, Kazakhstan
Department of Technological Machines and Transportation
Department of Metallurgy and Materials Science
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