Effect of Hot Rolling Reduction on Dynamic Recrystallization of Nb–V Bearing HSLA Steel: Physical Simulation and Microtexture Evolution

Hot rolling can improve the mechanical properties after heat treatment by improving the microstructure. The effect of hot rolling (HR) deformation on the microstructural transformation of G20CrNi2MoA bearing steel in the subsequent CQT (carburizing-quenching and tempering) and RQT (reheating-quenching and tempering) processes was studied. The results indicate that the austenite grain size decreased by 20% after 45% hot rolling reduction, and the number of large-angle grain boundaries increased due to the recovery and recrystallization induced by hot deformation. The refinement effect of hot deformation on austenite grains was retained after dual austenitizing, and the large-angle grain boundaries and massive dislocation in the grains caused by hot deformation promoted the diffusion of carbon atoms during carburization, resulting in a higher surface carbon concentration. The refined grains and higher carbon concentration affected the volume fraction and size of undissolved carbides in RQT specimens. When the initial hot rolling reduction reached 45%, the average particle size of carbides decreased by 40%, and the area volume fraction increased by 37%. The Vickers hardness increased, but the friction coefficient and wear rate were significantly reduced with the increase in the initial hot rolling reduction. The main reasons for the improved wear resistance were fine grains, superior carbide distribution and high hardness.

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Effect of hot rolling reduction and annealing treatment on grain boundary character distribution in austenitic low-density Fe-Mn-Al-C-Cr steel

Materials Letters ◽

10.1016/j.matlet.2020.128999 ◽

2021 ◽

Vol 285 ◽

pp. 128999

Author(s):

Jinxu Liu ◽

Huibin Wu ◽

Shanwu Yang ◽

Xinpan Yu ◽

Chao Ding

Keyword(s):

Grain Boundary ◽

Hot Rolling ◽

Annealing Treatment ◽

Rolling Reduction ◽

Grain Boundary Character Distribution ◽

Low Density ◽

Grain Boundary Character ◽

Character Distribution ◽

Boundary Character Distribution ◽

Effect Of Hot Rolling

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Experimental and Numerical Study of the Effects of the Reversal Hot Rolling Conditions on the Recrystallization Behavior of Austenite Model Alloys

Metals ◽

10.3390/met11010026 ◽

2020 ◽

Vol 11 (1) ◽

pp. 26

Author(s):

Krzysztof Muszka ◽

Mateusz Sitko ◽

Paulina Lisiecka-Graca ◽

Thomas Simm ◽

Eric Palmiere ◽

...

Keyword(s):

Microstructure Evolution ◽

Hot Rolling ◽

Strain Path ◽

Physical Simulation ◽

Numerical Study ◽

Kinematic Hardening ◽

Process Window ◽

Recrystallization Behavior ◽

Full Field ◽

Strain Reversal

The experimental and numerical study of the effects of the recrystallization behavior of austenite model alloys during hot plate rolling on reverse rolling is the main goal of the paper. The computer models that are currently applied for simulation of reverse rolling are not strain-path-sensitive, thus leading to overestimation of the processing parameters outside the accepted process window (e.g., deformation in the partial austenite recrystallization region). Therefore, in this work, a particular focus is put on the investigation of strain path effects that occur during hot rolling and their influence on the microstructure evolution and mechanical properties of microalloyed austenite. Both experimental and numerical techniques are employed in this study, taking advantage of the integrated computational material engineering concept. The combined isotropic–kinematic hardening model is used for the macroscale predictions to take into account softening effects due to strain reversal. The macroscale model is additionally enriched with the full-field microstructure evolution model within the cellular automata framework. Examples of obtained results, highlighting the role of the strain reversal on the microstructural response, are presented within the paper. The combination of the physical simulation of austenitic model alloys and computer modeling provided new insights into optimization of the processing routes of advanced high-strength steels (AHSS).

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