What Are The Four Types of Steel ?

Steel is the world’s most important engineering and construction material. It is used in every aspect of our lives; in cars and construction products, refrigerators and washing machines, cargo ships, surgical scalpels, Oil Rigs, etc. It can be recycled over and over again without loss of property.

Steel is such a powerful element, coming in several distinct grades and holding unique chemical compositions. Now, with steel properties and the different steel alloys being so vast, it might be shocking to realize that all kinds, even CNC machining steel, is composed of just two things: iron and carbon.

However, the real difference begins when additional carbon and alloying elements come into the picture. You see, steel's durability and strength are determined by those added aspects (such as manganese and phosphorus) that are introduced during its formulation, and is what determines its category for specific applications. So, if you are here wondering what type of steel to buy for your particular needs, you must understand the chemical structure of the physical steel properties, which are broken down into four foundational types.

THE FOUR MAIN TYPES OF STEEL：

1、CARBON STEEL

Carbon steels make up about 90% of all steel production in the world.

Carbon steel is an iron-carbon alloy containing up to 2.1 wt.% carbon. For carbon steels, there is no minimum specified content of other alloying elements, however, they often contain manganese. The maximum manganese, silicon, and copper content should be less than 1.65 wt.%, 0.6 wt.% and 0.6 wt.%, respectively.

Carbon steel looks dull, matte-like, and is known to be vulnerable to corrosion. Overall, there are three subtypes to this one: low, medium, and high carbon steel, with low containing about .30% of carbon, medium .60%, and high 1.5%. The name itself actually comes from the reality that they contain a very small amount of other alloying elements. They are exceptionally strong, which is why they are often used to make things like knives, high-tension wires, automotive parts, and other similar items.

Types of Carbon Steel:

High-carbon steel - Low hardness and cost. High ductility, toughness, machinability, and weldability.

Medium-carbon steel - Low hardenability, medium strength, ductility, and toughness.

Low-carbon steel - High hardness, strength, and low ductility.

2、ALLOY STEEL

Next up is alloy steel，which is steel that is alloyed with a variety of elements in total amounts between 1.0% and 50% by weight to improve its mechanical properties. Alloy steels are broken down into two groups: low alloy steels and high alloy steels. The difference between the two is disputed. These tend to be more on the cheaper side, more resistant to corrosion and are favored for some car parts, pipelines, ship hulls, and mechanical projects. For this one, the strength depends on the concentration of the elements that it contains.

Types Of Alloy Steel

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.

Their downright versatility makes alloys a common occurrence in many construction projects. Copper and aluminum alloy varieties are particularly popular for their low weight and heat-working properties.

3、TOOL STEEL

Tool steel is any of various carbon steels and alloy steels that are particularly well-suited to be made into tools and tooling, including cutting tools, dies, hand tools, knives, and others. They are made up of things like cobalt, molybdenum, and tungsten so they have distinctive hardness, resistance to abrasion and deformation, and their ability to hold a cutting edge at elevated temperatures. As a result, tool steels are suited for use in the shaping of other materials, for example in cutting, machining, stamping, or forging.

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 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.

4、STAINLESS STEEL

Last but not least, stainless steels are probably the most well-known type on the market. This type is shiny and generally has around 10 to 20% chromium, which is their main alloying element. With this combination, it allows the steel to be resistant to corrosion and very easily molded into varying shapes. There are over 100 grades of stainless steel, making it an incredibly versatile, customizable material. Because of their easy manipulation, flexibility, and quality, stainless steel can be found in surgical equipment, home applications, silverware, and even implemented as exterior cladding for commercial/industrial buildings.

Types Of Stainless Steel

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 is 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 whilst 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.