Why Is Tin Used to Protect Steel Cans?
Steel cans, also commonly called "tin cans" because of their thin tin coating, have been part of our society for more than a century, according to the Steel Recycling Institute.
Cans made of steel and tin are used to package a variety of products from foods like fruits and vegetables to pet food, as well as to transport and store commodities like paint.
Tin is used to coat steel cans to protect the can and its contents from corrosion, according to "The McGraw Hill Recycling Handbook." Tin is inherently corrosion resistant in neutral to mildly acidic aqueous environments, making it the perfect choice for preventing rust in steel cans, according to the book, "Corrosion Science and Technology."
Tin-plated steel is a safe and effective medium for preserving food in cans. The tin can method of food preservation was particularly useful before refrigeration, although steel cans are still used for food packaging today. "The McGraw Hill Recycling Handbook" says that in 2001, 90 per cent of metal food containers were made of tin-coated steel.
Although tin is not the only material with anticorrosive and preservative qualities, it is a good choice for protecting steel cans, particularly steel food cans, because it is non-toxic if digested in small amounts. A 2002 study by the U.K.'s Food Standards Agency looked at the tin levels of the contents of 1,200 cans of food for sale in the U.K. It concluded that tin concentrations in canned food were well under levels which could cause stomach upset in sensitive people.