Richard Rennack, age 14, of Greenville, miss., for his question:
JUST WHAT IS STAINLESS STEEL?
Stainless steel is the name of a family of alloy steels that resist corrosion or rust. Some 30 grades of stainless steels have been developed that have different combinations of strength, ductility and resistance to corrosion and heat.
Chromium is the chief metal alloyed with iron, carbon, manganese and silicon in making stainless steel. The more common stainless steels usually contain about eight percent nickel.
One or more of the following elements also may be added to iron to make stainless steel: molybdenum, titanium, columbium, aluminum, nitrogen, phosphorus, sulfur and selenium. Each of these elements modifies stainless steel so it can be used for a specific purpose.
As a family, the stainless steels have an easily maintained, attractive appearance. They show remarkable strength and are unique in their general resistance to the elements and the most corrosives.
Most stainless steels used in the home are highly polished, with a silvery appearance, but they do not need this finish to resist corrosion.
Stainless clad steel is commonly ordinary steel to which a thin layer of stainless steel has been bonded on one or both sides.
The most familiar use of stainless steel in the home is in kitchen knives, flatware, sinks, pots and pans and other places where cleanliness and easy maintenance are essential.
Stainless steel equipment is also used extensively in hospitals, restaurants, chemical industries, dairies and food processing plants.
Engineers use stainless steel parts for automobiles, aircraft and railroad passenger cars. Scientists use microporous stainless steel, made with a nickel alloy, to filter gases, liquids and small particles.
Elwood Haynes (1857 1925), an American metallurgist, invented stainless steel.
In addition to being a metallurgist, Haynes was also an automobile inventor and manufacturer. He was born in Portland, Ind., and graduated from Worcester Polytechnic Institute in 1881.
Haynes designed one of the first successful automobiles. The vehicle was built for him by Elmer and Edgar Apperson in Kokomo, Ind., and was first driven on July 4, 1894. It is now on exhibition in the Smithsonian Institution in Washington, D.C.
Haynes' inventions include carburetors and mufflers which improved early automobiles. In one of his own cars, Haynes made one of the first long distance auto trips, 10,000 miles from Kokomo to New York City and back.
In addition to stainless steel, Haynes created an alloy called stellite that is used in metalworking tools because it retains a good cutting edge. It is a cobalt alloy.