JPS5561302A - Rolling method for metallic sheet with high yield - Google Patents

Abstract

PURPOSE: To reduce the amount of generated crops on purpose to improve the product yield, by executing the rolling works sequentially as follows; at the first pass, the metal piece to be hot rolled is broadside rolled; next, the half breadth of the metal piece is rolled in the finishing direction; then, another half breadth being unrolled in the first pass is broadside rolled, and further is rolled in the finishing direction to stretch the length.

CONSTITUTION: The broadside rolling is applied to the slab S possessing length L₀ in the finishing direction, breadth B₀ and thickness H₀, at the first pass, in order to roll a half breadth in the finishing direction. Next, the unrolled part of the slab S is rolled in the finishing direction in order to reduce thickness by ΔH₁, leaving behind the length L₁=L₀ (1+ΔH₁/H₁) on one side of the slab S. Then, the broadside rolling is applied by the rolling mill with the roll gap H₂=H₁×H₁/H₀, in order to reduce thickness by ΔH₂=H₁-H₂ leaving behind the unrolled part of thcikness H₁ and breadth ΔB₁ on the side opposite to the side unrolled in the first pass. Additionally, the rolling is given in order to reduce thickness by ΔH₂ and to obtain length L₁ on above unrolled side; hereby, the slab with whickness H₂ and flat faces of H- (concave) type is manufactured.

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