Structural Steel Grades: Choosing the Right Material for Your Project

Selecting the appropriate structural steel grade is a critical decision when it comes to construction projects. With various types of structural grade steel available, including carbon steel, stainless steel, tool steel, and alloy steel, it's essential to consider several factors to ensure the optimal choice for your project. In Nigeria, the prevalent use of low carbon steel grades in construction aligns with the specific requirements of local projects, while the demand for medium or high carbon steel and alloy steel remains relatively low. From H beams, columns, and angle bars to sheet plates, seamless pipes, and wire mesh, Nigeria relies on a diverse range of carbon steel products.

Considering the importance of choosing the right structural steel material our team at GZ Industrial Supplies have over 25 years of experience in the industry, and we are committed to providing our clients with reliable, high-quality structural steel materials. Our products are designed to meet the highest industry standards, and we take pride in our engineering expertise, hardworking nature, and commitment to achieving client satisfaction.

In this comprehensive guide, we will explore the world of structural steel grades, providing valuable insights into their properties, applications, and the key considerations for selecting the most suitable grade for your project. Whether you are embarking on a residential, commercial, or industrial construction venture, understanding the characteristics and advantages of different structural steel grades is crucial to ensure structural integrity, durability, and long-term success.

Understanding Structural Steel Grades:

Structural steel grades refer to specific classifications of steel based on their chemical composition and mechanical properties. These grades are designed to meet different requirements and conditions, allowing engineers and builders to choose the optimal steel grade for their specific project needs. Structural steel grades encompass a wide range of materials, each with its own unique set of characteristics and applications.

Structural steel grades are classified based on their chemical composition and mechanical properties, each offering unique characteristics suitable for different construction applications.

1. CARBON

a) Low Carbon Steel Grades/mild steel:

Low carbon steel has 0.04–0.3% carbon content and is the most common grade of carbon steel. Mild steel is also considered low carbon steel as it is defined as having a low carbon content of 0.05–0.25%. Mild steel is ductile, highly formable, and can be used for automobile body parts, plates, and wire products. At the higher end of the low carbon content range, and with the addition of manganese of up to 1.5%, mechanical properties are suitable for stampings, forgings, seamless tubes, and boiler plates. Let us look at some product profile of Low carbon steels commonly used for construction purposes in Nigeria.

160 IPE 6X3H Beam:

This Structural Steel H-beam 160 IPE 6x3 Hellog is a type of steel beam commonly used in construction projects. It is characterized by its "H" shape, which gives it a high load-bearing capacity and excellent resistance to bending and twisting forces. The number "160" in the name refers to the height of the beam in millimeters, while "IPE 6x3 H" denotes the size of the flanges and the web of the beam. Specifically, the flanges are 100 mm wide and 55 mm deep, while the web is 6 mm thick and 160 mm high. Our H-beams are used in various industries, including building construction works, bridge construction, industrial structures, transmission towers, and ships.

80x40 UPN(L)X6mm

The Structural channel steel 80x40 UPN(L) x 6mm stainless steel are used in all kind of industrial applications, machinery,construction projects and equipment building. The use of stainless steel channels is characterized by high design flexibility and by fast and cost effective construction (through the possibility of prefabrication in the steel production).Stainless steel profiles are produced mainly from scrap and can be recycled again after utilization so new resources can be conserved.

Structural channel steel 80x40 UPN(L) x6mm is a type of steel channel that is commonly used in construction projects. It is characterized by its "U" shape, with two parallel flanges and a perpendicular web connecting them. The "80x40" refers to the dimensions of the flanges and the "UPN(L)" refers to the shape of the channel, which is tapered on one end.

The flanges of the structural channel steel 80x40 UPN(L) x6mm are 80 mm wide and 40 mm deep, while the web is 6 mm thick. This design provides excellent strength and stability, making it ideal for use in a wide range of construction applications.

40X40X6mm Angle bar

The Structural Rolled Steel Angle bar 40x40x6mm by Hellog is a reliable and versatile solution for your construction needs. Made from high-quality carbon steel, this angle provides excellent strength and durability, making it an ideal choice for a wide range of applications.

The angle bar measures 40mm x 40mm in size, with a thickness of 6mm. The rolled steel design provides excellent torsional strength and load-bearing capacity, making it ideal for use as a support or framing element in construction projects. The angle's 90-degree design ensures a secure fit and excellent structural stability.

Sheet pile 12mm thickness

The Structural Steel Sheet Pile 12mm hellog is constructed from structural steel, ensuring exceptional load-bearing capacity and resistance to external forces. With a thickness of 12mm, it offers enhanced durability and rigidity, allowing it to withstand the demands of challenging construction environments. Featuring an interlocking design, this sheet pile facilitates easy installation and ensures a secure and tight connection between individual piles. This enables efficient and reliable earth retention, making it suitable for applications such as retaining walls, cofferdams, bulkheads, and flood protection structures. The product's dimensions and lengths can be customized to meet specific project requirements. This flexibility allows for seamless integration into a wide range of construction designs, ensuring optimal performance and efficiency.

300x300 H beam

Structural Steel H-Beam Size 300x300 80Kg Hellog is a powerful and versatile solution for your construction and structural support needs. This H-shaped steel beam combines exceptional strength and durability, making it an ideal choice for a wide range of applications in the construction industry.

The Structural Steel H-Beam Size 300x300 80Kg Hellog has dimensions of 300mm x 300mm, providing substantial load-bearing capacity and stability. The versatility of the Structural Steel H-Beam Size 300x300 allows for various applications. It can be used as a primary structural component, providing support for roof systems, floor systems, and mezzanine platforms. It can also be utilized for bracing, trusses, and framework in construction projects.

Medium carbon steel has a carbon range of 0.31–0.6% and a manganese range of 0.6–1.65%. This steel can be heat treated and quenched to further adjust the microstructure and mechanical properties. Popular applications include shafts, axles, gears, rails, and railway wheels.

c) High carbon steel:

High carbon steel has a carbon range of 0.6–1% with a 0.3–0.9% manganese content. Properties of high carbon steels make them suitable for use as springs and high-strength wires. These products cannot be welded unless a detailed program of heat treatment is included in the welding procedure. High carbon steel is used for edged tools, high-strength wires, and springs.

d) Ultra-high carbon steels

Ultra-high carbon steel has a carbon range of 1.25–2%, and are known as an experimental alloy. Tempering can produce a steel with a great hardness level, which is useful for applications like knives, axles, or punches.

2. Alloy steel Grade:

Alloy steel is a type of steel that contains alloying elements in addition to carbon, which helps enhance its mechanical properties such as strength, hardness, and wear resistance. There are numerous alloy steel grades available, each with its own unique composition and properties. Here is a list of some common alloy steel grades: ASTM A572 Grade 50, AISI 4140, AISI 4340, AISI 8620, ASTM A387 Grade 11, and ASTM A514 Grade B.

3. Tool steel:

Tool steel is a type of metal alloy that is used primarily in manufacturing tools. It is usually made from iron, carbon, and other elements such as chromium, molybdenum, or tungsten. It is often heat-treated to increase its durability and strength. This makes it an ideal material for making parts that must withstand high levels of force or friction without breaking or wearing down quickly. Tool steels are often used to make knives, punches, dies, cutting tools, drill bits, taps, reamers, saws, and hammers. Tool steel is a specialized type of alloy steel that is designed and manufactured specifically for use in the production of tools, dies, and cutting implements. It possesses excellent hardness, wear resistance, and toughness, making it suitable for applications that require high strength and durability. Here is a list of some commonly used tool steel grades:

1. AISI D2 (DIN 1.2379)
2. AISI O1 (DIN 1.2510)
3. AISI A2 (DIN 1.2363)

4. Stainless steel Grade:

Stainless steel is a widely used metal alloy known for its exceptional corrosion resistance, durability, and versatility. It is composed primarily of iron, along with varying amounts of chromium, nickel, and other elements, depending on the specific grade. The selection of a stainless steel grade depends on the desired properties and the intended application. Let's explore the various aspects of stainless steel grades in more detail:

1.Austenitic Stainless Steel:

Austenitic stainless steels are the most common and widely used grades due to their excellent corrosion resistance, formability, and weldability. They are non-magnetic and have a face-centered cubic crystal structure. The two most popular austenitic grades are:

Grade 304 (UNS S30400):

This grade is known for its general-purpose corrosion resistance and versatility. It is commonly used in kitchen appliances, architectural applications, and food processing equipment.

Grade 316 (UNS S31600):

With the addition of molybdenum, Grade 316 offers superior resistance to corrosive environments, particularly in chloride-rich conditions. It is widely used in marine applications, chemical processing plants, and medical equipment.

2.Ferritic Stainless Steel:

Ferritic stainless steels have a body-centered cubic crystal structure and contain higher chromium content. They offer good corrosion resistance and have magnetic properties. Common ferritic grades include:

Grade 430 (UNS S43000):

This grade is known for its good corrosion resistance, especially in mildly corrosive environments. It finds applications in automotive trim, kitchen equipment, and decorative applications.

Grade 446 (UNS S44600):

With added molybdenum, Grade 446 offers improved resistance to high-temperature oxidation and scaling. It is used in applications such as furnace components, heat exchangers, and combustion chambers.

3. Martensitic Stainless Steel:

Martensitic stainless steels are characterized by their high strength and hardness. They have a body-centered tetragonal crystal structure. Common martensitic grades include:

Grade 410 (UNS S41000):

This grade provides good corrosion resistance, high strength, and moderate toughness. It is commonly used in cutlery, valves, and pump components.

Grade 420 (UNS S42000): With higher carbon content, Grade 420 offers increased hardness and wear resistance. It finds applications in surgical instruments, molds, and cutting tools.

4. Duplex Stainless Steel:

Duplex stainless steels combine the properties of austenitic and ferritic grades. They offer a good balance of strength and corrosion resistance. Common duplex grades include:

Grade 2205 (UNS S32205):

This grade provides excellent corrosion resistance and high strength, making it suitable for chemical processing, oil and gas, and marine applications.

Grade 2507 (UNS S32750):

Also known as "super duplex," Grade 2507 offers even higher strength and improved corrosion resistance compared to Grade 2205. It is used in aggressive environments and demanding applications.

5.Precipitation Hardening Stainless Steel:

Precipitation hardening stainless steels are heat treatable and offer high strength combined with good corrosion resistance. A prominent grade is:

Grade 17-4 PH (UNS S17400):

This grade can be hardened by heat treatment, providing excellent strength, toughness, and corrosion resistance. It finds applications in aerospace components, nuclear reactors, and offshore structures.

Types of Structural Steel Used for Building Construction in Nigeria

Structural steel is a vital building material for its durability, versatility, and strength. It's used in various applications, from bridges and transmission towers to commercial and residential buildings. The following are some of the commonly used types of structural steel in building construction:

A36: 

A36 is a low-carbon steel with a yield strength of 36,000 psi. A36 is commonly used for columns, beams, decking, and finish elements. It's widely preferred and versatile due to its excellent machinability and low cost.

A572: 

A572 is a high-strength low-alloy steel (HSLA) plate with yield and tensile strength similar to A36 steel. It's better suited for higher strength-per-weight ratio applications like transmission towers, roller coasters, and bridges.

A588: 

A588 steel has a yield and tensile strength greater than 46,000 psi, higher than A36 and A572. It offers superior atmospheric corrosion resistance, making it ideal for outdoor applications.

A514: 

A514 is a high-performance alloy steel with a yield strength of 100,000 psi and good weldability. It primarily supports heavy loads in cranes and other high-wear machine applications.

Approximately 25% of buildings comprise structural steel, including steel frames, beams, columns, bars, and plates. Understanding the different types of structural steel and their properties is crucial in selecting the suitable material for a specific building application.

Application of structural steel grade in Nigeria

The Low carbon steel grades have a wide range of uses in various industries in Nigeria. Let's explore some of the key applications:

1. Steel Frame Buildings:

Low carbon steel is often chosen for constructing steel frame buildings due to its unique structural properties. It provides sufficient strength to meet seismic and wind requirements while offering durability. Additionally, low carbon steel is resistant to damage from insects, impervious to rot, and has excellent fire resistance. These qualities make it a reliable choice for constructing sturdy and long-lasting building frames.

2. Machinery Parts:

Low carbon steel is widely used in the manufacturing of machinery parts. It is a combination of carbon and iron, and the ratio of these elements determines the strength, ductility, and hardness of the steel. The malleability of low carbon steel allows for easy shaping and working without the risk of breaking. This makes it ideal for fabricating machine parts, including steel sheets used in car body panels.

3. Cookware:

While stainless steel is commonly used in cookware, there is a market for carbon steel cookware as well. Low carbon steel, in particular, offers advantages such as rust resistance, the ability to hold an edge, and excellent temperature resistance. With proper treatment, low carbon steel can become essentially non-stick and maintain sharpness for longer periods. Although it requires more care and maintenance, it provides enhanced performance for discerning chefs.

4. Pipelines:

Low carbon steel tubes, especially galvanized plain carbon steel tubes, are extensively used as poles and piles for their exceptional ductility. They are essential materials for withstanding harsh weather conditions and environments. Steel pipelines made from low carbon steel are widely employed in water transportation, natural gas distribution, and even beer pipelines. These pipes are easily welded and offer flexibility to prevent cracking or breaking under pressure. In cold climates, they can be insulated to ensure optimal performance and prevent structural issues.

5. Metal Gates/Fencing:

Low carbon steel is a preferred material for manufacturing aesthetically pleasing metal gates and fencing. It combines strength with durability, making it difficult to break. It can be machined and welded to achieve desired designs, and it can be painted for a longer-lasting and low-maintenance finish. Galvanizing the steel adds an extra layer of zinc coating, providing protection against corrosion and enhancing its longevity.

These are just a few examples of how low carbon steel grades are utilized in Nigeria. The versatility, strength, and corrosion resistance of low carbon steel make it a valuable material across various industries, contributing to the development of infrastructure, machinery, and everyday products.

Learn more: Steel vs. Concrete: Which Material Reigns Supreme for Construction in Nigeria?

Factors to Consider When Choosing Structural Steel Grades:

1. Load-bearing requirements and structural design considerations:

The intended load and structural design of your project will dictate the required strength and stiffness of the steel. Assessing the anticipated loads and stresses will help determine the appropriate grade.

2. Environmental conditions and corrosion resistance:

Consider the project's location and exposure to elements such as moisture, chemicals, or extreme temperatures. Opt for steel grades with enhanced corrosion resistance properties for longevity and maintenance purposes.

3.Temperature extremes and thermal properties:

If your project will be subjected to high or low temperatures, select a steel grade that can withstand these conditions without compromising its structural integrity.

4. Weldability and fabrication requirements:

Depending on the complexity of the design and fabrication process, certain steel grades may offer better weldability and workability, facilitating efficient construction.

5.Cost considerations and availability of specific grades:

Evaluate the cost-effectiveness of various steel grades while considering their availability in the market. Strike a balance between project requirements and budget constraints.

How to Select the Right Structural Steel Grade for Your Project:

To choose the most appropriate structural steel grade for your project, consider the following steps:

1.Conduct a comprehensive project analysis:

Assess the specific requirements, including load conditions, environmental factors, and design constraints.

2. Consult with structural engineers and steel suppliers:

Seek expert advice to ensure you make an informed decision based on their experience and knowledge.

3.Evaluate project requirements and constraints:

Consider factors such as cost, project timeline, and local building codes to narrow down your options.

4.Weigh the pros and cons of different steel grades:

Compare the properties and capabilities of various grades to find the one that best meets your project's needs.

Conclusion

The choice of steel grade directly impacts the strength, durability, and performance of on any construction project. Throughout this guide, we have explored the various types of structural steel grades, including low carbon steel, stainless steel, tool steel, and alloy steel and each steel grade has its unique properties and characteristics that make it suitable for specific applications. Low carbon steel grades are commonly used in Nigeria due to their affordability, availability, and suitability for construction projects. Stainless steel grades offer excellent corrosion resistance and are ideal for applications where hygiene and aesthetics are crucial. Tool steel grades are preferred for their exceptional hardness, strength, and wear resistance, making them suitable for cutting, shaping, and forming tools. Alloy steel grades provide enhanced mechanical properties and are often utilized in demanding applications where high strength and toughness are required.

When choosing the right structural steel grade for your project, it is essential to consider factors such as the nature of the construction project, environmental conditions, load requirements, and budget constraints. Consulting with structural engineers, architects, and steel suppliers can provide valuable insights and guidance in making an informed decision.

Remember, selecting the appropriate steel grade is not only about meeting structural requirements but also ensuring the long-term durability and performance of the project. By understanding the properties, applications, and considerations associated with different structural steel grades, you can make confident decisions that result in successful and resilient structures.

In summary, the right choice of structural steel grade is crucial for achieving optimal results in your construction project. Carefully assess your project requirements, consult experts, and select the steel grade that best matches your specific needs. With the right material at hand, you can build robust, safe, and efficient structures that stand the test of time.