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1. A procedure is to take a core out of a piece of iron or steel plate, and then use copper and nickel alloy to round it from both sides or surfaces to form a whole, usually called 'bimetal'.
1. A procedure is to take a core out of a piece of iron or steel plate, and then use copper and nickel alloy to round it from both sides or surfaces to form a whole, usually called 'bimetal'.
