Textures of Non-Oriented Electrical Steel Sheets Produced by Skew Cold Rolling and Annealing

In order to investigate the effect of cold rolling deformation mode and initial texture on the final textures of non-oriented electrical steels, a special rolling technique, i.e., skew rolling, was utilized to cold reduce steels. This not only altered initial textures but also changed the rolling deformation mode from plane-strain compression (2D) to a more complicated 3D mode consisting of thickness reduction, strip elongation, strip width spread and bending. This 3D deformation induced significantly different cold-rolling textures from those observed with conventional rolling, especially for steels containing low (0.88 wt%) and medium (1.83 wt%) amounts of silicon at high skew angles (30° and 45°). The difference in cold-rolling texture was attributed to the change of initial texture and the high shear strain resulting from skew rolling. After annealing, significantly different recrystallization textures also formed, which did not show continuous <110>//RD (rolling direction) and <111>//ND (normal direction) fibers as commonly observed in conventionally rolled and annealed steels. At some skew angles (e.g., 15–30°), the desired <001>//ND texture was largely enhanced, while at other angles (e.g., 45°), this fiber was essentially unchanged. The formation mechanisms of the cold rolling and recrystallization textures were qualitatively discussed.

A Comparative Analysis of the Physical Modelling of Two Methods of Balls Separation

The article presents the results of model tests with which a comparative analysis of two methods of ball separation during the skew rolling process was carried out. A verification of the results obtained in the physical modelling process with the results obtained in the real process of skew ball rolling was also carried out. During the physical modelling, the effect of changing the ball separation method on the quality of the products obtained, variations in maximum torque values and maximum radial forces were analyzed. In the case of real tests, the results were verified with the results of physical modelling, in which the surface quality and torque values for one of the tool sets were compared. Physical modelling was used to verify the differences between the two methods of ball separation. Commercial plasticine based on synthetic wax from the manufacturer PRIMO was used as a model material for physical analysis. The plasticine used for testing was cooled to 0 °C and the cooling process took 24 h. The tools used for the physical modelling were 3D printed and the material used was ABS. The method of physical modelling using plasticine as a model material allows for a correct analysis of hot metal forming processes.

A New Method of Manufacturing Hollow Shafts via Flexible Skew Rolling

The existing rolling process of large and long axle parts, such as the cross wedge rolling (CWR) process, requires special molds and larger equipment. Flexible skew rolling (FSR) hollow shafts with mandrel is a near net-shape rolling technology which can achieve the diversified production of rolled parts without special molds. It has significant advantages such as small equipment tonnage, small die size, low rolling load, simple process adjustment, and especially suitable for multi-variety and small-batch production. This paper proposes hollow train shafts formed by FSR with mandrel. Reasonable parameters were selected for experiments, and the forming process was calculated by finite element (FE) software. The experimental results are consistent with the simulation results, indicating that the FE model is reliable. The rolling force and rolling torque are analyzed by simulation. Finally, the microstructure of different positions of the rolled-piece is analyzed, and the microstructure of the rolled part is refined. It is provide a feasible scheme for the rolling of large hollow shaft parts.

Study of the process of rolling steel balls in skew rolling mill – metallographic analysis

This paper presents the results of metallographic research studies carried out for stock materials as well as the samples collected from the balls formed in the rolling process in a skew rolling mill. The stock material was bearing steel 100Cr6 and the steel from rail scrap. The rolling process was carried out in parallel for the two assumptions: the conventional method (hereinafter referred to as conventional rolling) and the modified method (hereinafter referred to as modified rolling). After the rolling process, three cooling media were used: air, water and oil. The pictures below, which depict microstructures, were taken using the bright-field and the dark-field microscopy technique, the samples were etched with a 4% solution of picral.