Analysis of deformation characteristics and microstructure variation of thick plate during asymmetric shear rolling

Aluminium alloy thick plate is widely used in field of aerospace and automobile industry for its light weight, high strength, good corrosion resistance and formability. Hot rolling is the key process of preparation for thick plates, however, the conventional symmetrical rolling process causes large deformation on the surface and small deformation in the central portion of the thick plate, resulting in inhomogeneous deformation, microstructure and property distributions through the thickness direction of the plate. Asynchronous rolling is beneficial for deformation permeation into the central part of thick plate with introduction of strong shear strain due to velocity asymmetry of two work rolls. However, the plate will bend towards the slower roll due to deformation asymmetry at upper and lower surface of the plate and serious bending is bad for multi-pass rolling process. Asymmetrical shear rolling with velocity asymmetry and geometry asymmetry is adopted in this study. Compared to asynchronous rolling, there is a horizontal offset distance of upper roll in outlet direction. A moment will be applied to the plate in the opposite direction of bending towards the slower roll by an offset distance of the slower roll. The comparisons of distributions of equivalent strain, temperature, DRX fraction and average grain size between symmetrical rolling and asymmetrical shear rolling are studied. The effects of velocity asymmetry and offset distance on microstructure variation and microstructure distribution at different positions of the plate are studied. Due to larger velocity of lower work roll, larger equivalent strain and higher temperature appear at lower layer of the plate, which results in higher DRX fraction and finer grain size. The speed ratio contributes greatly to sufficient DRX process and finer grain size; while the ascending offset distance decreases the DRX fraction. Therefore, speed ratio plays significant role in deformation permeation and grain refinement in asymmetrical shear rolling and the offset distance is mainly used to decrease the bending behaviour of the plate. This study can provide guidance to thick plate preparation with good properties in asymmetrical rolling process.

The Effect of Cold Asynchronous Rolling Technique on High Manganese Steel Mn13

High manganese steel is a wear-resisting steel. With the rapidly development of industry, it is very important to improve the wear resistance of high manganese steel. We do some experiments with cold asynchronous rolling technique on austenitic high manganese steel.The results show that hardness and impact abrasion resistance are enhanced greatly with the increase of deformation, and the toughness not decrease to very low.

Effect of Deformation Degree and Diameter Ratio on Performance of Hadfield Steel during Cold Asynchronous Rolling

Hadfield steel is wear-resisting steel and widely used where the devices have high impact wearing performance requirements. Cold asynchronous rolling technique can improve the mechanical performances of high manganese steel to a certain degree. Through experimental research, this paper studied the effect of deformation degree and diameter ratio on its mechanical performances during asynchronous rolling.

Effect of Asynchronous Rolling on Deforming Texture in Al Alloy 6111

The rolling texture and its distribution along thickness direction in the Al alloy 6111 sheet cold rolled by synchronous Rolling and asynchronous rolling have been investigated with orientation distribution functions. The results show that the texture distribution is asymmetric on both sides of center layer of the sheet after cross shear rolling. The orientation densities of the main texture compounds on the slow roller side are higher, but are lower on the fast rolled side. The asymmetry of the texture distribution increases with improving the velocity ratio of asynchronous rolling.

Effect of Asynchronous Rolling on Wear-Resisting Performance of High Manganese Steel

In order to study the effect of pre-deforming on the wearability of austenitic high manganese steel, domestic and foreign scholars did many pre-deforming tests. While the study of rolling pre-deformation is almost blank. By taking the cold asynchronous rolling technique, simulated roll test was carried out on austenitic high manganese steel. The microstructure and the performance after rolling showed that a great deal of high density twin crystals merged , the capability of work hardening and impact abrasion resistance enhanced greatly, wear-resisting performance improved with the increase of deformation.