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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.

Although Steel consists of more than 3500+ Grades they are fundamentally broken down into four foundational types:

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.

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. Stainless Steel

There are over 100 grades of stainless steel, making it an incredibly versatile, customizable material.

Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals, and metals to obtain other desired properties. Stainless steel's resistance to corrosion results from chromium, which forms a passive film that can protect the material and self-heal in the presence of oxygen.

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.

3. Alloy Steel

Alloy steel 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.

Alloy steel as a grouping includes a diverse range of alloys with an equally diverse range of properties. Shipping containers use a complex alloy that combines multiple elements to produce a durable and lasting product. Silicon isn’t often thought of as a component of steel, but its magnetic properties make it a perfect component of most large machinery. Aluminum is versatile and used in revolutionary building materials that are both lightweight and extremely durable.

Some of the elements that combine with iron and carbon to produce alloys are also found in tool steels — cobalt, tungsten, and molybdenum, for example, are ultra-hard metals that are desired for their impact resistance and cutting abilities.

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.

4. Tool Steel