Most food cans in UK are made from steel made using molten iron. Iron ore is mixed with coke and limestone where it is then heated to a very high temperature in a blast furnace. The molten iron is then poured into a vessel, where a percentage of recycled steel is added along with oxygen to produce steel.
The steel is rolled into huge coils and has a fine coating of tin or chromium oxide to protect it from oxidation before it is sent to canmakers worldwide.
For acidic foods, like tomatoes or rhubarb, a thin coating of lacquer is applied before the can bodies are stamped out.
Food cans can be made using two or three pieces.
In three piece can-making rectangles are cut out of steel to form a cylinder and the edges are welded together. The bottom end is then seamed on.
When making cans from two pieces, a disc of metal is reformed into a cylinder with an integral end. To improve strength and durability, cans are beaded with concentric circles around the middle.
Empty cans are then stacked and sent to a canning factory.
