What are car fuel tanks made of?

Most vehicles have their fuel tanks made of steel. There are a few exceptions, or course, but steel is a good choice for the job. For a while now fuel tanks have been made of what is called terne steel or Ni-TERNE steel. A little coating of lead-tin is applied, and sometimes with nickel (in the case of Ni-TERNE) to improve the workablity of the metal and also increase its resistance to corrosion. U.S. Steel has a page on this stuff. Who would know better than them? You got a link.