Types of Structural Steel and their Benefits

Introduction

The use of steel in the construction industry is increasing rapidly. Steel possesses a number of qualities that make it a versatile material. Starting from invisible pipelines all the way up to skyscrapers, steel has made its way to become one of the most used materials in modern structures.

Here are some of the most prominent types of structural steel used in the modern era:

Carbon Steel
Stainless Steel
High strength low Alloy Steel
Forged Steel
Quenched and Tempered Alloy Steel

Let’s have a look at each one of these types of structural steel in detail.

Carbon Steel

Carbon Steel is an alloy of Iron and Carbon. The percentage of carbon in the alloy may vary from 0.05% to 1.5%. Depending upon the carbon content, Carbon Steel can be classified into the following types:

Low Carbon Steel (up to 0.3% carbon)
Medium Carbon Steel (0.3% – 0.60% carbon)
High Carbon Steel (more than 0.6% carbon)

Carbon steel enjoys a privileged position when it comes to structures, owing to its high tensile strength and cost-effectiveness. Some of the benefits of using carbon steel are:

– Durability

Carbon steel is extremely strong and ductile. The main reason for its use in structures is its high strength. It can resist shocks very well. The structures made up of carbon steel can withstand natural disasters like earthquakes and tornadoes more efficiently as compared to ordinary steel structures.

– Environment Friendly

Carbon steel can be easily recycled, giving it an environment-friendly nature.

– Affordability

Carbon steel is normally four to five times less expensive than stainless steel and is hence preferred by both manufacturers as well as the users.

– Workable

Due to its malleable nature, low carbon steel is particularly famous for the ease with which it can be worked upon. It can easily be cut, drawn into wires and sheets, and twisted into desired shapes.

Carbon Steel is renowned in the construction industry for its use in structural members like beams, reinforcement bars, highway plates, and bridges.

Stainless Steel

Stainless steel, like Carbon steel, is an alloy of Iron and Carbon but with an additional element, Chromium. Chromium is the main component that helps impart corrosion-resistant properties to stainless steel. It forms a thin protective layer of Chromium Oxide on the outside and protects the underlying material. Another composition with a small percentage of Molybdenum is also used which further strengthens the corrosion resistance. What’s interesting about stainless steel is that it has self-repairing properties. It can heal itself if damaged in some way.

Talking about the benefits of stainless steel, it has a lot of them. The first one goes without saying that it resists corrosion. Next, it is extensively used in kitchens, the food industry, and hospitals – places where high standards of hygiene are to be maintained. It’s because stainless steel can be cleaned very easily. Due to the bright and shiny surface, stainless steel is also used to give beautiful and aesthetic appearances to buildings. And just like any other steel, it is a low-maintenance material that can last for reasonably long times.

High Strength Low Alloy Steel

As the name indicates, High Strength Low Alloy Steel (HSLA) is manufactured to meet some high strength requirements. Thus, the main focus in its production is not on the chemical composition but on the mechanical properties of the steel. Since it is a stronger type of steel, more effort and time are required in its production as compared to other types of steel. Compared to the steels with the same strengths, HSLA usually has lesser weight.

Below are some common advantages of HSLA:

– Formable/Ductile

The most notable advantage of using HSLA in structures is its ‘formability’. Its high yield strength allows it to take different shapes and bends without developing any cracks.

– Corrosion Resistance

Another benefit of HSLA over standard carbon steel is that it resists corrosion relatively better.

– Light-weight

HSLA’s composition is such that it bears a high strength to weight ratio. It means that less amount of steel is used to provide the same strength that would have required more material in other steels. This property ultimately makes it cost-effective as well.

– Performance in tough conditions

HSLA can efficiently bear high temperatures due to which it finds extensive use in the automotive industry. Combustion engines, where the temperature is usually high, incorporate HSLA steel to bear high temperatures. Similarly, HSLA steel is used in oil and gas refinery plants as well.

Forged Steels

When Iron and Carbon are joined under high-pressure conditions, the resulting material is known as ‘Forged Steel’. It is an extremely hard and strong form of steel, owing to the compaction pressure applied.

Forged Steel possesses a tight-grained structure, with minimum or no voids at all. Due to its compact structure, it can resist impacts quite efficiently and is hence used extensively in heavy machinery and hydraulic press equipment. Another advantage of forged steel is that it is made at such high temperatures that we can cast the material into our desired shapes. Forged steel also behaves strongly towards thermal changes and overall residual stress is low.

While manufacturing forged steel, we have a wide range of possible combinations of alloys. Each combination aims to fulfill a specific purpose and serves as a versatile material.

Quenched and Tempered Alloy Steel

Before we talk about Quenched and Tempered steel, let’s try to understand the process of quenching first. So quenching is basically a heat treatment process in which the steel is heated to a temperature slightly above its ‘recrystallization temperature’. Once the steel reaches this point, the arrangement of its particles is disturbed. The next step in the process is to cool the material down rapidly!

Rapid cooling causes a change in the crystal lattice of steel, which cannot be achieved by slow cooling. The new crystalline structure is way stronger than the previous one.

The process of quenching improves the ductility of steel without any significant compromise on its strength. Quenched and Tempered Alloy Steel finds extensive use in construction, automotive, mining, and heavy mechanical equipment.

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Types of Structural Steel and their Benefits

Introduction