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AssigneeNippon Steel Corporation
InventorsMasanori Ueda, Masamitsu Tsuchinaga, Teruo Iura, Shigeru Fujiwara
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According to the present invention, a stainless steel thin strip and sheet having a superior surface gloss and high rusting resistance is produced by heating a continuous cast slab of ferritic or martensitic stainless steel containing 10 to 35% by weight of Cr at a temperature of 1100.degree. to 1300.degree. C. selected according to the Cr content in a combustion atmosphere having an oxygen concentration lower than 7% while adjusting the furnace staying time from preheating to extrusion to within 260 minutes, carrying out hot rolling while adjusting the rolling-finish temperature to a level higher than 900.degree. C., carrying out mechanical descaling by adding a grinding and descaling agent, such as iron sand, having a maximum particle size smaller than 400 .mu.m, to high-pressure water and spraying the mixture onto the steel strip, pickling the steel strip, cold-rolling the steel strip while maintaining the relationship between the roll diameter and the reduction ratio within the "overlap"-free region shown in FIG. 3, carrying out finish cold rolling by work rolls having a diameter smaller than 100 mm, if necessary, and subjecting the steel strip to final annealing. Optionally, a winding step may be performed after hot rolling, and/or a final pickling step may be performed after the final annealing.
A process for production of stainless steel thin strip and sheets having a superior surface gloss and high rusting resistance, which comprises heating a continuously cast slab or partially processed slab of ferritic or martensitic stainless steel containing 10 to 35% by weight of Cr at a temperature of 1100.degree. to 1300.degree. C. in a combustion atmosphere having an oxygen concentration lower than 7% while adjusting the staying time of from preheating to extraction to from said atmosphere to less than about 260 minutes, carrying out hot rolling while maintaining the rolling-finish temperature at a level higher than 900.degree. C., winding the hot rolled strip at a temperature higher than 600.degree. C., carrying out mechanical descaling by adding a grinding and descaling agent having a maximum particle size smaller than 400 .mu.m to high-pressure water and spraying the mixture onto the steel strip, pickling the steel strip, cold-rolling the steel strip while maintaining the relationship between the roll diameter and the reduction ratio within the "overlap"-free region shown in FIG. 3, and subjecting the steel strip to final annealing.
A process for the production of stainless steel thin strip and sheets having a superior surface gloss and high resulting resistance, which comprises heating a continuously cast slab or partially processed slab of frerritic or martensitic stainless steel containing 10 to 35% by weight of Cr at a temperature 1100.degree. to 1300.degree. C. in a combustion atmosphere having an oxygen concentration lower than 7% while adjusting the staying time of from preheating to extraction to from said atmosphere to less than about 260 minutes, carrying out hot rolling while maintaining the rolling-finish temperature at a level higher than 900.degree. C., carrying out mechanical descaling by adding a grinding and descaling agent having a maximum particle size smaller than 400 .mu.m to high-pressure water and spraying the mixture onto the steel strip, prickling the steel strip, cold-rolling the steel strip while maintaining the relationship between the roll diameter and the reduction ratio within the "overlap"-free region shown in FIG. 3, and subjecting the steel strip to final annealing by carrying out final annealing in a combustion gas atmosphere, and then pickling he final annealed strip.
Dependencies are inferred from the claim text.