What’s a profile? Types & applications

Unlike many countries around the world whose steel industry relies heavily on imports, Iran, with its abundant resources of iron ore and coal, has become one of the major industrial and steel hubs not only in the Middle East but globally.

For this reason, there are currently many factories in Iran engaged in the production of various steel products. The significance of this is that in today’s industrial world, from the desk on which we study for hours to the car we use daily for commuting, all rely on these steel products.

It is clear that in the two examples mentioned, a single type of steel cannot always be used. In other words, steel is optimally produced according to its intended application and is processed into various forms such as profiles, sheets, and other similar steel sections. Understanding the importance of steel profiles in today’s world, their production methods in factories, and their uses is a topic we aim to explore in detail.

What is a Profile?

A steel profile (known as Steel Profile in English) is the final product derived from shaping iron ore, having a square, rectangular, circular, or other cross-sectional shapes, and is produced in a long size. The difference in cross-sectional shapes leads to the production of various profiles with diverse applications, which will be introduced below.

Types of Steel Profiles

Several factors contribute to the variety of iron profiles. To use these sections in different industries, various shapes, materials, and more need to be produced. The types of steel sections can be categorized as follows:

Types of Profiles Based on Material

When we examine a profile based on its material, we are essentially referring to the sheet that is used in its production. The types of sheets used for manufacturing profiles include the following:

Galvanized Profile

The galvanized profile is one of the most commonly used materials for this section. It is named so because, after production, it is dipped into molten zinc for coating. Galvanization is a process used to increase resistance to corrosion and rust.

Structures made with galvanized profiles play an important role in humid areas, such as northern regions of the country. If galvanization is not done for the materials used in these areas, rusting occurs, weakening the structure and causing it to collapse over time.

It is not surprising that this profile is typically priced higher in the steel market compared to other types.

Composite Profile

The composite profile is made of carbon fiber, glass fiber, or aramid fiber embedded in a polymer resin. It has gained widespread use today. PVC (Polyvinyl Chloride), UPVC (Unplasticized Polyvinyl Chloride), and other similar materials are common types of this profile. Due to advantages such as low weight, resistance to corrosion and vibrations, this material is not only used in high humidity areas but also in earthquake-prone locations. By lightening the structure, it contributes to enhancing its resistance.

Aluminum Profile

The aluminum profile is one of the most widely used types in the industry. Due to its appearance and shiny silver color, it is often used in industries where aesthetics is important.

This section is also essential in the construction of transportation equipment, such as airplanes, because of its flexibility and low weight. It plays a key role in lightening and strengthening the resistance of the structure. This profile includes various types, such as simple aluminum windows, thermal break, and aluminum-wood windows. With benefits such as rust resistance, low density, and poor thermal insulation, it is used not only in vehicle construction but also in the medical industry, window and door manufacturing, and more.

Types of Profiles Based on Cross-Section Shape

There are two main types of this product when categorizing by cross-section shape. The difference in cross-section significantly affects its performance. According to this classification, the types of profiles include the following:

Open Profile and Its Types

When two sheets are not connected together during profile construction and a hollow space is not created, the resulting profile is considered an open type. The variety of this section is vast, and it includes various types as mentioned below:

The Z purlin, or Z profile, is a type of profile with an open cross-section and two flanges in the shape of the letter “Z.” Its structure consists of a horizontal flange (or top and bottom wings) and a vertical web, which connects these two wings.

The geometry and structure of the Z profile make it resistant to bending and compressive forces, preventing deformation when under load. Z purlins can be made with or without edges and, due to their high tensile strength, contribute to lightweight construction, easy installation, and design flexibility. These features make them highly suitable for various applications in the industry.

C Purlin (C Profile)

The C purlin, or C profile, is another widely used purlin in construction, consisting of two flanges and two edges. The benefits of C purlins include their low weight, durability, ease of transportation, and easy installation. They are commonly used for load-bearing walls, roofs, or lightweight industrial and semi-industrial coverings, as well as columns and walls of structures.

Key features of C purlins include:

• Easy assembly
• Recyclability
• Load-bearing capacity
• Efficient load transfer
• Thin walls
• Low weight
• Easy transportation and execution
• Cost-effectiveness

Gutter Profile

The gutter profile is a commonly used, corrosion-resistant profile, especially in the roofs of structures like warehouses (silos). Due to its unique shape, it facilitates the drainage of rainwater and snow from the roof. Gutters come in two types: box-shaped and London-style, and can be connected in a single or double-sided manner.

Since gutters are constantly in contact with water, they must be made from stainless steel sheets to prevent corrosion and weakening of the structure. They are used in various roofing systems, including sloping roofs, parking lots, sandwich panel roofing, and similar applications.

The gutter profile in construction needs to have the following structural characteristics:

• Ability to bear high loads
• UV resistance
• Long lifespan
• Paintability
• Resistance to rust and corrosion

Casket (Cage Profile or Profile)

One of the materials used in metal frames is referred to in the iron market as “Casket” or “Gem,” which is a steel section either shaped internally or externally. Its primary application is in the frames for doors and windows and the construction of anti-theft doors. Its weight with a 2mm thickness ranges from 24 to 28 kilograms, and due to its high durability and considerable strength, it has gained significant attention from various industries and individuals.

Steel Beam (I-Beam)

A steel beam (also known as I-beam or H-beam) consists of one web and two flanges, typically in the shape of an “I” or “H.” Unlike most other sections, it is produced through hot rolling, and its primary purpose is to bear the pressure and stresses caused by bending moments and shear forces.

I-beams come in various types such as INP, IPE, IPB, and CNP and are available in sizes like 14, 16, 18, and 20. They are primarily used in the construction of structural columns, foundation columns, building skeletons, tie beams, main beams, narrow chrome beams, trusses, and more.

Some of the advantages and disadvantages of I-beams include:

• Ability to expand after the completion of the structure
• Capability to connect multiple pieces together
• Usability in high-rise structures
• Susceptibility to buckling
• Lack of resistance to corrosion
• High weight and cost

L Profile (Angle Iron)

An L-profile or angle iron (also known as V-profile in some cases) is a section shaped like the letter “L” or “V” in English and is manufactured either through pressing or fabrication. Angles can be equal-legged or unequal-legged. The first type results in a “V” shape with an angle less than 90 degrees, and the second type results in an “L” shape with a right angle (90 degrees).

Some of the most common types of angle iron include galvanized, rust-resistant, spiral, PVC, aluminum, A36, and T316. This type of steel profile is widely used in the construction of trusses, connections for steel beams, facade framing, power transmission towers, and more.

U Channel (C Channel)

The U channel or C channel is a section with an open cross-section, consisting of one web and two flanges. It is made in two forms: parallel flanges and non-parallel flanges. When the flanges are parallel, it resembles a “U” shape, and when the flanges are non-parallel, it takes the appearance of a “C.”

This profile is made to European standards such as DIN-1026, UPN, UNP, corrosion-resistant standards like DIN EN ISO 12944-3, and French standards NF A 45-255. The high resistance of U channels makes them suitable for use in automotive manufacturing, structural columns, home facades, and more.

French Profile

The French profile is a type of door and window frame, known for its high strength and other benefits. Made from ST37 steel sheets, it is commonly used in the construction of window frames, including metallic and non-metallic ones such as PVC and aluminum frames.

Roman Profile

The Roman frame is a popular type of metal frame often confused with the Mexican frame, though they differ. Unlike the Mexican type, the Roman frame is curved at the top and lacks a bend at the bottom.

When purchasing this steel profile, it is important to ensure that the material matches the intended use. High-quality welding is essential to guarantee the structural strength of the frame. Additionally, it should be coated with high-quality oven-baked paint.

T Profile (Tees or T-Section)

A T-profile, or T-section, is a type of steel section with an open cross-section consisting of a web and long flanges. T-profiles can be either pressed or fabricated and come in different variations such as equal-leg tees, unequal-leg tees, and high-profile tees. T-sections are used in bridge-to-column connections, doors, windows, guardrails, dam construction, and more. They are produced through hot or cold rolling or by cutting beams.

Simple Frame

A frame is the connection point for doors and windows in a building. The simple metal frame is the most basic type and offers lower resistance than the other types mentioned above. It was mostly used in the past.

Closed Profile

In contrast to open profiles, closed profiles have a cavity formed either by connecting sheet edges or drilling a solid bar. This results in a closed cross-section. The variety of closed profiles is relatively limited and includes:

Steel Square Tube (Casing)

Steel square tubes, or casing, have a closed cross-section in the shape of a square or rectangle. They can either be shaped directly from sheet metal or formed indirectly by rolling steel pipes.

Steel tubes with a thickness of 2mm or less are considered light tubes (often used for furniture), while tubes with a thickness greater than 2mm are classified as heavy tubes, with types such as industrial column tubes and construction column tubes.

The material used for light tubes is usually cold-rolled steel, while black steel is used for heavy tubes to improve surface quality, torsional and bending stability, and welding capability.

Steel Pipes

Steel pipes are an indispensable component in fluid transportation industries. They are made by welding the edges of sheets together or by drilling solid steel billets. The first type is called welded pipe, and the second type, which is typically imported, is referred to as seamless pipe or Mannesmann pipe.

Door and Window Profiles

Door and window profiles are among the most commonly used closed-section profiles. As the name suggests, these profiles are used in the construction of doors and windows for houses and buildings. They come in various types, such as T-profiles, door leaf profiles, and frame profiles. These sections are made from various materials, including steel, aluminum, composite, and wood, depending on the application.

Applications of Steel Profiles in Industries

• Previously, we discussed the specific uses of open and closed profiles. However, we will now provide a broader overview of industries dependent on these steel sections:
• Construction of concrete structures such as bridges and dams.
• Manufacturing parts for vehicles, including trucks and heavy machinery, using angle iron and U-channels.
• Transportation of fluids using steel pipes.
• Construction of warehouses and residential or commercial buildings using I-beams, Z-profiles, C-profiles, and others.
• Gas, water, and sewage piping.
• Designing and constructing furniture and desks using square tubes.
• Building roofs with water runoff profiles.
• Manufacturing doors and windows with both open and closed profiles.

Light and Heavy Profiles: Differences

Steel profiles, as we’ve seen so far, are mostly produced by rolling sheets. If the sheet used in the profile is thinner than 2mm, the profile is considered light. If the thickness exceeds 2mm, the profile is classified as heavy.

It is important to note that light and heavy profiles are mostly used for square tubes, with light profiles often referred to as “furniture profiles” in the steel market. The distinction between the two is significant in terms of structure and application. While heavier profiles are expected to cost more due to their material volume, the production complexity of light profiles means they may be priced higher than anticipated, not due to material costs, but due to the more intricate manufacturing process and structural finesse.

Industrial vs. Construction Profiles

When talking about industrial and construction profiles, we are typically referring to heavy square tubes. The construction profiles are made with thinner sheets (2 to 6mm) and typically use galvanized sheets, whereas industrial profiles are produced with sheets over 6mm thick and usually made from black steel. Industrial profiles are stronger and have higher torsional stability, while construction profiles are used in lighter structures.

Differences Between Industrial and Construction Profiles

Key differences between industrial and construction profiles include:

• Thickness
• Type of sheet used
• Length of the sections
• Applications and uses

Profile Production Methods

The production method largely depends on the type of profile being produced. For example, thick profiles are made using hot rolling, while profiles requiring high precision are made through cold rolling.

Hot Rolling

Hot rolling is the first method used to produce steel profiles. It is ideal for producing thick profiles like T-profiles, I-beams, and U-channels. The process involves heating the steel billet to a high temperature in furnaces to increase flexibility and shapeability. Afterward, the billet passes through several rolling mills to reduce thickness while increasing width and length. Finally, the steel is cooled and shaped into the desired profile.

Hot rolling is also used for producing seamless steel pipes (Mannesmann pipes) through methods like mandrel piercing or extrusion, where the steel billet is drilled to create a pipe without seams. These pipes are stronger and more resistant to leaks, but due to the production complexities, they are more expensive than welded pipes.

Cold Rolling

Cold rolling is another method used to produce many steel profiles. It is used when a high level of precision and strength is needed. However, it’s important to note that no product is entirely formed by cold rolling; instead, products are either made entirely from hot rolling or from a combination of both hot and cold rolling.

In cold rolling, the steel sheet is passed through rollers or pre-formed molds to shape the profile, and since this process happens at room temperature, the material’s mechanical properties remain unchanged. Cold rolling is especially important for producing square tubes and steel pipes, where the sheet edges are welded together to form a closed profile.

Conclusion

Steel profiles have become essential components in various industries like construction, petrochemicals, and automotive manufacturing. The main categories of these products are open and closed profiles, with a wide range of types including Z-profiles, square tubes, pipes, water runoff profiles, and door/window profiles. Steel alloys, with their high strength and flexibility in design and production, play a significant role across various sectors.