Square Steel Bar: Sizes, Weight Table and Prices

Square steel bar is a solid steel bar with four sides of equal length. It is commonly referred to as a “square steel bar,” “solid square bar,” or simply “square bar.” Thanks to its durable structure, machinability, and weldability, it is used in a wide range of applications, from machine manufacturing and ornamental ironwork to die making and steel construction. In this guide, you will find square steel bar sizes, a weight table, information on which steel grades are suitable for different applications, and the main factors that determine square steel bar prices.

What is a square steel bar? How is it different from a square hollow section?

What is a square steel bar? A square steel bar has a completely solid cross-section. It should not be confused with a square hollow section (square steel tube), which has a hollow interior. The solid cross-section gives square steel bars significantly higher load-bearing capacity and resistance to torsion and impact. For this reason, they are preferred for components subjected to mechanical loads, keys and pins, as well as parts that will be shaped by forging or machining. Hot-rolled square steel bars are manufactured according to EN 10059, while cold-drawn square steel bars are manufactured according to EN 10278.

Square steel bar applications

The main applications of square steel bars include:

• Machine components, guides, and fastening elements
• Keys, pins, and tool holders
• Raw material for forged components
• Ornamental ironwork, gates, railings, and decorative applications
• Dies, molds, and fixture components
• Connection details in steel structures

Which square steel grade should you choose?

The most important factor determining the price and performance of a square steel bar is the material grade. The most commonly preferred grades for different applications include:

Square steel bar sizes and weight table

Square steel bar size is specified by its side length (a). The weight per meter is calculated using the following formula:

• Weight (kg/m) = a² × 0.00785 (a: mm)

For sizes not included in the table, you can use our free Uyar Çelik Weight Calculator. The values are theoretical; actual weight may vary slightly due to corner radii and manufacturing tolerances.

Difference between hot-rolled and cold-drawn square steel bars

Hot-rolled square steel bars are formed at high temperatures, resulting in a mill-scale surface, slightly rounded corners, and wider dimensional tolerances. Because they are economical, they are ideal for structural applications and components that will undergo further machining. Cold-drawn square steel bars, on the other hand, are produced by drawing the material through a die at room temperature. They offer a bright surface, sharper corners, tighter tolerances, and higher strength. By reducing machining requirements, cold-drawn square bars can lower total production costs in high-volume manufacturing. They are generally preferred for components such as keys and pins that are installed with little or no additional machining.

How are square steel bar prices determined?

Square steel bar prices are calculated by weight and vary depending on the following factors:

• Steel grade: Non-alloy S235JR is generally the most economical option, while grades such as C45, 16MnCr5, and 42CrMo4 are typically more expensive.
• Manufacturing method: Cold-drawn square steel bars are generally more expensive than hot-rolled bars.
• Size and stock availability: Standard sizes can generally be supplied faster and at a more competitive price.
• Quantity: The price per kilogram is generally more competitive for orders placed by the ton.
• Cutting and delivery: Custom-length cutting and transportation costs are added to the total price.
• Market conditions: Scrap, energy, and exchange-rate fluctuations can periodically affect square steel bar prices.

Practical example: A 40×40 mm square steel bar weighs approximately 12.56 kg per meter. Ten 6-meter lengths therefore have a total weight of approximately 753.6 kg. The total material cost can be calculated by multiplying this weight by the current price per kilogram.

What should you consider when ordering square steel bars?

• Grade and standard: Specify them clearly (e.g., C45 – EN 10083-2, hot-rolled – EN 10059).
• Corner profile and tolerance: Specify your requirements for corner geometry and dimensional tolerance.
• Length: Specify whether you require 6 m, 12 m, or custom-cut lengths.
• Welding: If the material will be welded, consider grades with a lower carbon equivalent.
• Certification: Request an EN 10204 3.1 certificate for critical applications.

A brief guide to square steel bar tolerances

For hot-rolled square steel bars, tolerances for side dimensions, corner radii, straightness, and twist are defined by EN 10059. These tolerances are generally sufficient for components that will undergo subsequent machining. For components that will be assembled directly, fitted into keyways, or used as guides, cold-drawn square steel bars with h9–h11 tolerances according to EN 10278 should be considered. For more information about tolerances, see our article What Are Steel Tolerances?.

Square steel bar or round steel bar?

In some applications, square and round steel bars can be considered alternatives. If the component will rotate or be machined on a lathe, a round steel bar is generally more economical. For components where flat surfaces are important, such as keys, guides, and tool holders, or parts that will be milled or must be prevented from rotating, a square steel bar can reduce both machining time and material waste.

Square steel bar supply from Uyar Çelik

Uyar Çelik supplies hot-rolled square steel bars compliant with EN 10059 and cold-drawn square steel bars compliant with EN 10278 in S235JR, S355JR, C22, C45, 16MnCr5, and many other grades. In addition to standard 6–12 meter lengths, we offer custom-length cutting and production with standard or special tolerances.

Frequently asked questions

Are square steel bars and square hollow sections the same?

No. A square steel bar has a solid cross-section, while a square hollow section is a hollow tube. Their load-bearing capacities and applications are different.

How much does a 20×20 mm square steel bar weigh?

A 20×20 mm square steel bar weighs approximately 3.14 kg per meter. A 6-meter length weighs approximately 18.84 kg.

Can square steel bars be welded?

Low-carbon grades such as S235JR, S355JR, and C22 are generally easy to weld. Additional precautions such as preheating may be required for C45 and alloy steel grades.

Conclusion

A square steel bar is a solid-section steel product that offers high load-bearing capacity and impact resistance and is used in a wide range of applications, from machine manufacturing to ornamental ironwork. To make the right selection, steel grade, manufacturing method, tolerance, and dimensions should be evaluated together. Contact us for square steel bar prices and available stock sizes: +90 (212) 485 98 98 or visit our contact page.