Effect of Accumulative Bending Conditions on Grain Refinement on Hot-rolled Sheet

Abstract

As a technology to manufacture fine-grained steel, accumulative bending process after hot rolling was proposed, and multi-bending equipment of laboratory scale were established. The effects of accumulative bending on microstructure and ferrite grain size by changing the thermo-mechanical conditions were investigated. As the results, a microstructure with the grain size of 2.2 μm was obtained at specimen surface by accumulative bending after hot rolling in the optimized thermal condition. By the results of FE analysis, it was cleared that equivalent strain was accumulated on not only surface but also center of thickness.

Formation of submicrocrystalline structural state of AD31 alloy while rolling in the helical rolls and longitudinal wedge mill

“…The japanese firm JFE Steel offered a method of multiple sequential alternating bending of the steel strip after hot rolling (the method of deformation accumulation by bending) [14]. The work shows that the application of reverse bending allows rolling the sheet blank without changing its thickness in comparison with the conventional rolling.…”

“…According to work [14], this method can be used in the industry to improve the quality of rolled metal products. This is due to the fact that rolling by the cyclic bending results in obtaining hot-rolled strips with the ferrite grains size of 1 micron or less.…”

Special Features of Structure Formation During Rolling Strips in the Helical Rolls and Longitudinal Wedge Mill

“…The Japanese firm JFE Steel proposed a method for multiple consecutive alternating bending of the steel strip after hot rolling (the method of deformation accumulation by bending) [12]. It can be seen from the materials of the work that, in contrast to conventional rolling, the use of alternating bending makes it possible to roll a sheet blank without changing its thickness.…”

“…This makes it possible to obtain hot-rolled strips with an ultrafine-grained structure. According to the authors of [12], this method of rolling can be used in industry to improve the quality of rolled metal. This is due to the fact that rolling by cyclic bending led to the production of hot-rolled strips with a grain size of ferrite of 1 μm or less.…”