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US 4,069,070 AGranted
Method of producing low carbon tin-mill gage steel without annealing border
AssigneeUnited States Steel Corporation
InventorsRobert M. Hudson, Edward J. Oles, Jr., Clair J. Warning
Life of this patent
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Abstract
The discoloration or off-luster border area called "annealing border" which frequently forms on low carbon tin-mill gage steel coils during box annealing in commercial HNX atmospheres is prevented from forming by providing the steel with less than 0.25 wt. %, and preferably less than 0.20 wt. % free manganese in solid solution.
Claims2
In the process for producing a cold rolled tin-mill gage steel coil wherein a low-carbon steel is hot rolled, pickled, cold rolled to final gage and box annealed at a temperature of 1050.degree. to 1400.degree. F in a commercial HNX atmosphere;
- the improvement comprising preventing the formation of an annealing border on the steel coil during the anneal by providing the steel with a manganese content such that the free manganese in solid solution is less than about 0.23 weight percent.
Dependencies are inferred from the claim text.