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Corrosion-Resistant Alloys: Five Remarkable Facts

Joanne McIntyre - 26 November 2015

This week, guest blogger Jessica Kane provides an insight into some interesting things you may not yet know about stainless steels.

About the author

Mrs Joanne McIntyre
Joanne McIntyre is the Editor in Chief of Stainless Steel World magazine, and Conference Coordinator for the Duplex Seminar & Summit.
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Today, steel plays an important role in daily life. From boats to trains to towering buildings, some important alloys help steel function well in a variety of products and structures. Five remarkable facts about corrosion-resistant alloys (CRAs) surprise many people.

Some Background: Alloys
Essentially, any mixture of two or more metals qualifies as an "alloy". Some of the elements that help form important alloys in the modern era include: iron, nickel, chromium, and cobalt. Corrosion-resistant alloys help products resist the rusting process. Just consider a few amazing facts about these substances:

  1. Two Key Alloys Contribute to Stainless Steel
    Alloys don't always occur intentionally. Some happen accidentally in nature. For instance, gold miners occasionally discover alloys of gold and silver mixed together in the ground. Humans learned how to use alloys even before the invention of written alphabets. Many early societies created cookware and other household items from copper, a soft metal. During the Bronze Age, metal workers developed a way to make longer lasting products by mixing together copper and tin. The new metal, bronze, possessed greater strength than either ingredient.
    Steel itself represents a mixture of iron with a small amount of carbon. Unfortunately, iron rusts over the course of time as elements in the air and water react with carbon. Yet by adding small quantities of nickel and chromium to molten metal, inventors discovered they could form corrosion-resistant alloys that would help prevent steel from rusting easily. The invention of "stainless steel" changed the world.
  2. Nickel Coins And Steel
    Many Americans associate the whitish-colored metal, nickel, with a five cent coin. A number of years ago, the United States Mint added nickel to copper to produce a stronger, more durable coin. Nickel in combination with chromium and iron, helps make steel easier to shape. It also offers better resistance to high temperatures.
  3. Nickel Contains Magnetic Properties
    Unlike some metals, nickel will magnetize readily. For this reason, nickel not only remains an important ingredient of corrosion-resistant steel alloys, it also plays an important role in many permanent magnets. By mixing nickel with cobalt and iron, manufacturers produce durable magnets for a variety of useful purposes.
  4. Chromium Requires a Very High Temperature to Melt
    The other metal widely used in stainless steel as an alloy, chromium, requires an even hotter temperature than nickel in order to melt. Solid chromium won't turn molten until reaching a temperature of 3,465 degrees Fahrenheit. Its ability to withstand high temperatures successfully makes chromium a very useful alloy additive for metal equipment that requires fire-resistant steel, such as the engines in jets and high-speed trains.
  5. Chromium Turns Rubies Red
    Many people appreciate the brilliant red color of rubies. Amazingly, in nature the inclusion of chromium in the minerals forming these gemstones accounts for this color. Chromium as a metal alloy plays a vital role helping stainless steel resist corrosion. It sometimes forms bright colors when combined with other metals, too, including vivid shades of yellow, green or even red.

Jessica Kane is a professional blogger who writes for Federal Steel Supply, Inc., a leading supplier of carbon, alloy and stainless steel in pipe, tube, fittings and flanges.

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