The temper rolling process of hot-rolled strips is the final rolling step to improve the flatness of strips and shape slippage of coiled strips. Non-flatness of hot-rolled strips causes the strip lateral movement during the temper rolling process. Manual leveling operations, the quality of which depends on the operator’s experience, control this movement but result in much lower line speed and productivity. A lack of understanding of this phenomenon has sustained manual operation and discouraged the development of an automatic control system. In this paper, both a new lateral movement model, where the temper-rolling lateral movement model and the large-deflection strip model are important parts, and a theoretical method, where lateral movement stability is equivalent to the eigenvalue problem with lateral movement static equations, are proposed. Their usefulness is confirmed by comparing the results of experimental rolling in the laboratory with those of numerical calculations. Simulation results obtained using the proposed models confirm that actual problems are solved more exactly than with the conventional linear model. The simulation can support the clarification of lateral movement and the development of an automatic control system.

Peen forming is a method of bending a metal plate by generating plastic strain near its surface when colliding with steel shots. In this study, the effect of coverage on the curvature after single-sided and double-sided peen forming of a high-strength aluminum alloy plate was investigated by experiments and finite element method (FEM) analysis. In the experiment, the curvature increased as the coverage increased in single-sided peen forming. In double-sided peen forming under the same peening conditions for both sides, the curvature is smaller than that after single-sided peening. FEM analysis was performed as follows. In step 1, multiple shot collisions was analyzed by the dynamic explicit FEM. In step 2, the plastic strain distributions analyzed in step 1 were input to the specimen to analyze the deformation by the static implicit FEM. FEM analysis results agreed with the experimental results in single-sided peen forming. In double-sided peen forming, the plastic strain distribution was calculated considering the residual stress distribution near the second surface after single-sided peen forming, and the analysis results agreed with the experimental results. A method of approximate calculation of the curvature was proposed, in which the plastic strain distribution was expressed as a function of coverage and initial stress. The curvature after single-sided and double-sided peen forming could be easily predicted by this method under various peening conditions.

Forging load generally increases for many reasons as compression proceeds. To reduce the forging load, we focused on reducing the contact area with forging dies and proposed a new method using the flexible rocking motion created in coordination with multiple linear actuators. A cylindrical specimen of annealed pure aluminum was upset between flat dies up to half its initial height. Rocking motion was applied to the lower die in the latter half of the compression. The presented method reduced the forging load by up to approximately 50% compared with conventional upsetting. The reduction of load increased with increasing rocking angle and its frequency. The upset specimen was spread more toward the rocking direction and its end face processed with the rocking die was slightly tapered. Lubrication caused sliding of the specimen during rocking even with a small rocking angle.