By any measure, steel is the most used metal in the world. It is highly versatile, strong, and relatively inexpensive to produce. It can be found holding together the tallest skyscrapers or the smallest kitchen cutlery. Steel plays an invaluable role in nearly every aspect of modern society. The alloy is seemingly omnipresent due to its ability to add strength and durability to all types of objects.
Steel alloys can be seen everywhere and makes possible many of the household items you use every day. Steel has transformed our cities and contributed to massive advancements in technology, transportation, even space exploration. Steel plays a vital role in roadway development through steel plate, reinforcing rebar, guardrails, signage, light poles and other supporting products. High-strength lightweight steel has contributed to the greening of America’s bridges, railways, pipelines, utilities and highways. With many calling for investments to rebuild our crumbling infrastructure, steel will undoubtedly be the metal that makes those improvements possible. So, let’s take a look back at the origins of steel and it’s progression through the ages. Discover its impressive properties, current uses and what the future of this dynamic metal may bring. And, most importantly, how steel alloys can benefit and be used by you.
THE HISTORY OF STEEL
Steel is made of iron, an incredibly hard, yet brittle metal that has been used since the beginning of the Iron Age, found as early as 1200 BCE. In this time, most metals were fabricated for weaponry. With the introduction of Iron, more durable weapons quickly replaced softer bronze swords, shields, and the like, ultimately reshaping new possibilities for war. Over the next few hundred years, raw Iron was smelted using a variety of different methods with numerous amount of alloys expanding the uses of Iron, and its common Pig Iron alloy. In this form, Pig Iron, also known as crude iron, was detrimental to forging and early fabrication projects. It wasn’t until roughly 3500 years of prototyping and experimenting beginning in the iron-age that iron became the steel we know today.
Commercial steel finds its beginning in the year 1856, where English Chemist Henry Bessemer experimented with methods of reducing carbon content of Iron to create a less brittle material. Truly, Bessemer is not credited with the entire discovery of steel, however his method’s discovery, now known as the Bessemer process, is essential to the beginning of the modern steel industry.
“I’m not in the business of making steel. I’m in the business of building men. They make steel.”
– Andrew Carnegie
Modern steel, established in the late 19th century and early 20th century, skyrocketed the world’s projects both metaphorically and literally. The ability to produce a strong, dependable metal in large quantities, paved the way for expansion, strength, and ingenuity. Steel made possible inventions like railways, personal automobiles, and even rockets. While steel is responsible for massive, highly-visible projects around the world, it has also made possible the small projects in your neighborhoods and communities all over the globe. Its high availability and variety of beneficial properties have made it the material of choice for projects large and small – from structural applications in buildings to advances in transportation and infrastructure through railways and shipping containers to smaller everyday items you can find in your own home.
STATS ON STEEL
- STEEL RAILWAYSOver 233,000 miles of steel train tracks lay across the U.S.
- STEEL AUTO INDUSTRYRoughly 253 million cars drive on U.S. Roads.
- STEEL SKYSCRAPERSOver 640 skyscrapers proudly stand in the U.S.
TYPES OF STEEL
To understand steel, you must understand the different types. The American Iron and Steel Institute (AISI) differentiates steel in four types. Remember the acronym C.A.S.T. (carbon, alloy, stainless, tool) and you will already know more about steel than most of the general population.
Carbon steel is steel in which the main interstitial alloying constituent is carbon in the range of 0.12–2.0%. Carbon steel is highly versatile and its uses and properties can vary depending on its carbon content. As the carbon percentage content rises, steel has the ability to become harder and stronger through heat treating – however, it does become less ductile. Regardless of the heat treatment, a higher carbon content reduces weldability. In carbon steels, the higher carbon content lowers the melting point.
Carbon steel is broken down into four classes based on its carbon content: low, medium, high and ultra-high. Low-carbon steel contains approximately 0.05–0.25% carbon making it malleable and ductile. Mild steel, also known as plain-carbon steel, contains a small percentage of carbon, is strong and tough but not readily tempered. Mild steel has a relatively low tensile strength, but it is cheap and easy to form making it one of the most common forms of steel.
Medium-carbon has approximately 0.3–0.6% carbon content. Medium-carbon steel balances ductility and strength and has good wear resistance – used for large parts, forging and automotive components. High-carbon steel’s carbon content ranges from 0.6-1.0% making it very strong and is used for springs, swords and high-strength wires. Ultra-high has approximately 1.25%-2.0% carbon content and is used for special purposes like knives, axles or punches.
Strictly speaking, every steel is an alloy, but not all steels are called “alloy steels” however, the term has become the standard for referring to steels that have been deliberately alloyed with other elements in addition to carbon. The most common alloyants include manganese, chromium, nickel, silicon, boron molybdenum and vanadium. Less common alloyants include aluminum, cobalt, copper, cerium, niobium, titanium, tungsten, tin, zinc, lead, and zirconium. Adding other elements in combination with heat treatment to iron and carbon can improve a range of properties including strength, hardness, toughness, ware resistance, corrosion resistance, hardenability and hot hardness. Alloy steels are broken down into two groups: low-alloy and high-alloy.
Low-alloy steels contain typically between 1-5% total alloy content and are generally weldable by most processes, as long as adequate precautions are taken to avoid defects. Low-alloy steels may contain as many as four or five alloys in varying amounts. High-strength low-alloy steel (HSLA) is a type of alloy steel that provides better mechanical properties or greater resistance to corrosion than carbon steel. HSLA steels vary from other steels in that they are not made to meet a specific chemical composition but rather to specific mechanical properties. High-alloy steels are generally more expensive and used for specialized purposes – containing alloy levels in excess of 10%, giving them outstanding properties.
Stainless steel, less commonly known as inox steel, must have a minimum of 10.5% chromium making it a high-alloy steel. Stainless steel is known for its shimmer, strength, and sterile applications. It is commonly used in the medical industry because it can be easily sterilized and is resistant to corrosion. It is also used to make surgical implants such as joint replacements and artificial hips as well as pins and plates to repair broken bones. It is ideal for food production and storage as it does not affect the flavor of the food. Stainless steel’s corrosion resistance is important as some foods, like orange juice, can be acidic. It is also used as a structural material in the automotive and aerospace industries and as a construction material in large buildings and other structures.
There are different grades and surface finishes of stainless steel to suit the environment the alloy must endure. There are different types of stainless steels including: austenitic, superaustenitic, ferritic, duplex steel, martensitic and precipitation-hardening martensitic. And over 150 grades of stainless steel.
Learn about the weldability of stainless steel.
- Stainless steel's luster and variety of finish options as well as its ability to weather the elements make it an ideal material for buildings and construction applications. Stainless steel cladding is used on the Walt Disney Concert Hall.
- Stainless steel is used to make tanks for the production of wine and beer. It is one of the more common materials used in the food production industry.
- Stainless steel is commonly used in the medical industry because it can be easily sterilized and is resistant to corrosion. It is also used to make surgical implants such as joint replacements and artificial hips as well as pins and plates to repair broken bones.
- Stainless steel is a popular material to see in the kitchen. From large appliances to counter tops and back splashes. Its easy to clean which helps keep undesirable germs at bay and stands up to wear and tear.
- Stainless steel is often used to make cookware and cutlery. It is ideal for food production and storage as it does not affect the flavor of the food. Stainless steel’s corrosion resistance is important as some foods, like orange juice, can be acidic.
- Stainless steel is great in the bathroom, where it is common to have high levels of moisture and will likely get wet, due to its high corrosion resistance.
Tool steel is particularly well-suited for making tools and shaping other materials due to its distinctive hardness, resistance to abrasion and ability to hold a cutting edge at elevated temperatures. Tool steel are manufactured under carefully controlled conditions to produce the required quality. The presence of carbides in their matrix plays the dominant role in the qualities of tool steel. The four major alloying elements in tool steel that form carbides are: tungsten, chromium, vanadium and molybdenum. Tool steel is often used by bladesmiths in making knives, axes and other weaponry. Check out our Knives + Tools board on Pinterest for inspiring works made with tool steel.
THE FUTURE OF STEEL
While the 20th century focused on creating massive skyscrapers and enormous structures, Steel in the 21st century focuses on the use of small pieces of steel for major inventions.The future of steel lies in the details, such as creating gauges and precise pieces for space exploration vehicles, microprocessors, and the like. Inventions like 3D printing, CAD printing and laser cutting allows steel to be fabricated to the most specific specifications.
The biggest hurdle for the steel industry is developing new processes for producing steel to reduce and eliminate CO2 emissions. Recycling is critical for the future of metals and steel is no exception. Recycling steel into new and improved projects will not only provide benefits for our environment but may lead to reduced costs and wider availability. While many see recycled steel as “scrap metal” or devalued material, advancements in steel recycling are making drastic economic and environmental improvements.
STEEL IN YOUR FUTURE
Its durability, recyclability and wide range of varying properties make steel alloys incredibly versatile. Plus its diverse range of steel alloys allow you to find the perfect alloy for your project. Whether you need an extremely strong, specialized material or are looking for an inexpensive option that retains many beneficial properties – there is a steel for you. We offer stainless, tool, cold roll and hot roll steel alloys. Each alloy is available in a variety of shapes and types from sheet and plates to tubes, flat bars and round rods – all can be cut-to-size allowing you to purchase just the amount you need, saving you time and money.
And with six warehouses nationwide, your order will be shipped fast and arrive quickly and conveniently to your door. Or you can choose our Will Call option and pick up your materials from one of the Online Metals warehouse locations.
What’s the difference between cold and hot rolled steel? Learn about the benefits of each in our Hot Rolled vs Cold Rolled Steel post!