The formation mechanism of edge-seam defects at the edges of hot-rolled strips of ferritic stainless steel was examined experimentally using a ferritic stainless-steel slab and crystal plasticity finite element analysis. Wrinkles in rolled strips occur owing to differences in deformation between coarse grains formed in orientation rotation as the reduction ratio increases, determined on the basis of the crystal anisotropy of coarse grains with random orientations that were formed during slab heating. In the initial stage of hot rolling, the depth of wrinkles increases with the diameter of such grains. Because the T.D. deformation of {111} is small and that of {001} is large, a grain sandwiched between {111} and {001} grains undergoes a large amount of deformation owing to the large constraining force of the grain boundaries of such grains. As a result, the formation of edge-seam defects is divided into two stages. In the early stage, wrinkles are formed by the crystal anisotropy on the side of the slab. In the second stage, those wrinkles extend toward the strip surfaces as a result of bulging during horizontal hot rolling.

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The effects of the ridge length and angle of various convex anvils on the concave shape formed at the side of a lead plate after width pressing and the bulging deformation behavior that occurs during rolling were investigated experimentally using a lead model and three-dimensional FE analysis. The control of edge-seam defects was then studied under the condition of increasing of the amount of width pressing. On the basis of the results, it is clear that the concave depth at the slab sides can be increased by shortening the ridge length of the convex anvils and can be controlled by adjusting the anvil angle. A rectangular shape at the sides of hot-rolled bars can be obtained by using a suitable convex shape and by subsequent bulging deformation during rolling. Therefore, edge-seam defects due to the maneuvering of wrinkles toward strip surfaces can be controlled by decreasing the amount of bulging deformation at the hot-rolled bar sides. That is, the mechanism behind the control of edge-seam defects by using convex anvils is equivalent to that of rolling a thinner rectangular slab. This technology for decreasing edge-seam defects has been applied to actual rolling equipment, and as a result, the amount of edge-seam defects has been reduced.

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Because of the need for high-mix low-volume production, the use of CO₂ laser cutting is spreading rapidly in the sheet metal processing sector. Recently, aluminum alloy sheets of many kinds have found increased use in the industry because of social demands for environmental protection. We have investigated the heat effects of laser cutting materials by Electron Backscatter Diffraction and X-Ray Diffraction analysis. The specimens used were 1050 pure aluminum and 6022 aluminum alloy sheets processed by cold-rolling. In this report, we describes the distribution of plastic strain, the geometrically necessary dislocation density, and stored energy in the heat-affected zone from misorientations such as microscopic kernel average misorientation and grain orientation spread determined by EBSD measurement. Heat-affected zones showed reduced plastic strain, dislocation density, and stored energy with the recrystallization upon laser cutting. Therefore, mechanical properties such as hardness were also reduced.

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