From buildings to medical equipment and vehicles, the world literally runs on steel products. But not all steel materials are made alike.
There are multiple steel types and alloys that each have unique properties — making them each suited to specific production goals. Some steels are sturdy and heavy, while other steels are ductile and versatile.
Frequently, our customers approach us regarding the best type of steel for their application. We put together this quick guide to help you navigate the language of steel. Of course, you may still have questions regarding the application. Feel free to reach out to us with any unique property needs so that we can help you find the right steel for your needs.
- Carbon Steel:
Technically, carbon steel is a metal alloy that contains both iron and carbon. But in the manufacturing industry, carbon steel is often defined in multiple ways. Both of the following constitutes a “carbon steel” in the metals market.
- Steel that contains up to 2% carbon
- Steel that does not contain any standard amounts of elements that would classify it as an “alloy steel” (e.g., cobalt, nickel, tungsten, molybdenum, titanium, zirconium, vanadium, chromium, etc.)
Types Of Carbon Steel
Below the 2% carbon threshold, carbon steel can be grouped into three categories: low, medium, and high carbon. Each type retains the inherent strength of carbon, but its useful purpose will change as the carbon content increases.
- Low Carbon: This is the most common and the least expensive type. It’s easy to form due to its high ductility — its innate ability to be stretched under strain. Wires, bolts and pipes use this type of steel. Some uses for low carbon steel are: Structural components, Machinery, Pipes, Domestic appliances, Automobile components, Surgical instruments, Medical equipment, Wires, Bolts, Stampings, etc.
- Medium Carbon: A carbon content between 0.31% and 0.60% gives this variety a higher strength and lower ductility than lower carbon varieties. Medium carbons are found in gears and railroad tracks. Some uses for Medium Carbon Steel are: Machinery parts, Pressure structures, Cranks, Gears, Railway tracks.
- High Carbon: The toughest variety is more than 0.61% carbon and is often used to produce brick nails and sharp cutting tools like trencher blades. They do not contain more than 2% carbon. Some uses for High Carbon Steel are: Railways, Bars, Spring steel, Plates, etc.
Carbon steel’s relative adaptability and low cost make it an ideal choice for a variety of construction projects, both large and small-scale.
- Stainless Steel:
This type is commonly known for its role in manufacturing medical equipment and appliances, but its range of use is far greater than just the gas range in your kitchen. Chromium is the alloy that sets stainless steel apart, lending the material its distinctive luster.
While carbon steel is typically defined by its carbon content, stainless steel is defined by its 10.5% minimum chromium content. Like carbon steel, stainless steel also contains carbon and iron, but the extra chromium is the key that gives it its unique properties.
One of the biggest benefits of stainless steel is that it protects the steel for oxidization — which degrades metals over time. Stainless steel is also identified by its sheen, a property provided by the chromium. Some uses of stainless steel are: utilization in cookware, knives, and medical equipment.
Types Of Stainless Steel
Kitchen, medical and automotive applications are common, but stainless steel is highly valued for other uses as well. It is grouped into four subcategories that each serve a different purpose.
- Martensitic Alloys: Toughness is a hallmark of martensitic alloys, but they’re prone to corrosion. They’re formed by a rapid-cooling process that makes them ideal for heat treatment and are found in medical instruments, cutlery and pliers.
- Ferritic Alloys: These are less-expensive steels with low amounts of carbon and nickel. Automotive applications are common final destinations for ferritic alloys because of their chromium-induced strength and sheen.
- Austenitic Alloys: Austenitic alloys have higher chromium and nickel contents, improving their resistance to corrosion and causing them to become non-magnetic. They’re present in commercial kitchen appliances and are popular because they’re durable and easy to clean.
- Duplex Alloys: A combination of austenitic and ferritic alloys results in a duplex alloy that inherits the properties of both while doubling strength. They’re also ductile and corrosion-resistant due to their fairly high chromium content.
Stainless steel variants, when used in the construction industry, are prized for their corrosion resistance and strength. They’re well-suited for a variety of building applications, as well as storage functions for hazardous construction materials.
- Alloy Steels:
The widest and most diverse range of steel alloys is “alloy steels.” These are made by combining carbon steel with various alloying elements to provide unique properties to each steel.
Due to the incredible variety of alloy steels, you can create steels with almost every possible property using alloy elements. That being said, some of these steels are relatively expensive.
Types Of Alloy Steel
The varied potential of alloy steel allows for intense customization for specific applications. However, because the secondary elements involved are not always easy to come by like carbon or chromium, certain alloys command a steep price.
Some of the most common alloys include:
- Aluminum: Lightweight, heat-resistant steel that’s ductile and easy to work with and is often used in hot exhaust systems and power generators.
- Copper: Corrosion-resistant steel that conducts heat very efficiently, making it a great choice for electrical wiring and industrial heat exchangers.
- Manganese: Impact-resistant steel that’s extremely tough. It can be found in bulletproof cabinets, anti-drill plates and high-strength safes.
- Molybdenum: Weldable, corrosion-resistant steel that performs under high pressure, making it well-suited for underwater construction or oil and gas pipelines.
- Silicon: Soft-natured steel that’s malleable and highly magnetic, and creates strong permanent magnets that are used in electrical transformers.
- Vanadium: High-impact steel that’s shock-absorbent and vibration-resistant, and often found in automotive parts like springs and shocks.
- Tooling Steels:
The final steel group is Tooling Steels. These are steels used for tooling activities such as drilling. Commonly made up of molybdenum, vanadium, tungsten, and cobalt, tooling steels are heat-resistant, durable, and strong.
Tool steels are up-front about their business: they’re used to tool manufacturing machinery. Tempering, the process of adding high heat, cooling quickly then heating again, creates tool steel that’s extremely hard and heat-resistant. They’re usually used in high-impact environments and are very abrasive.
Types of Tool Steel
Different types of tools require different types of tool steel in production. Tool steel is used in a variety of ways to best serve the production requirements of a particular tool. Added elements will determine which particular applications that it’s suited for.
- Air-hardening: The high chromium content in this steel allows it to be exposed to high temperatures without distorting.
- Water-hardening: This steel is water-quenched during use; it’s the most affordable tooling type and is used to make common tools.
- Oil-hardening: This oil-quenched steel is exceptionally wear-resistant from slipping, and is used to produce knives and shears.
- High-speed: High-speed steel is highly abrasive and impact-resistant. It’s found in drill bits and power saws.
- Hot-working: The name gives it away, but this steel can withstand extreme heat and is used in forging and casting.
- Shock-Resisting: Small amounts of carbon, silicon and molybdenum harden this steel and suit it for punches and riveting tools.
These types can be further separated by the industry they’re used in, as well as their hardness and toughness.
What Are the Different Grades of Steel?
Steel is notably complicated due to its many properties and applications. Two comprehensive grading systems have been developed to accurately categorize a particular type, even within subgroups. These systems are standardized across industries so that material integrity can be insured. The two grading systems are:
- ASTM (American Society for Testing and Materials): Alphanumeric classification that denotes the steel’s overall categorization and specific attributes.
- SAE (Society of Automotive Engineers): Four-digit numerical classification that highlights steel type and carbon content along with the presence of other alloying elements.
You can find steel everywhere, materialized in different forms to suit various needs. It’s is an essential component of many building materials, home appliances and even tools used to make other tools. By combining the right elements, an exact steel match is available for almost any application.