scrap iron
Noun
Meaning
iron to be melted again and reworked
Source: WordNetHypernyms
Examples
London. 1972. p. 135: "two fifty-gallon oil drums packed tight with old nails, bits of scrap iron, hinges, rusty metal filings.
In 1938 his enemies ridiculed him as "Pig Iron Bob", the result of his industrial battle with waterside workers who refused to load scrap iron being sold to imperial Japan.
The top breech door is shut, and the TDU is flooded and equalized with sea pressure, the ball valve is opened and the cans fall out assisted by scrap iron weights in the cans.
This is achieved by remelting pig iron, often along with substantial quantities of steel and scrap iron, removing undesirable contaminants, adding alloys, and adjusting the carbon content.