S355J0H vs S355J2H: Knowledge of Hollow Structural Sections

Introduction

When working in construction, particularly in infrastructure projects, selecting the right steel grade for structural hollow sections is critical. Two commonly specified grades are S355J0H and S355J2H, both used extensively in structural hollow sections such as Circular Hollow Sections (CHS), Square Hollow Sections (SHS), and Rectangular Hollow Sections (RHS). These grades are defined under EN 10219 (Cold-Formed Welded Structural Hollow Sections of Non-Alloy and Fine Grain Steels) and EN 10210 (Hot-Finished Structural Hollow Sections of Non-Alloy and Fine Grain Steels). This article aims to provide a detailed, expert comparison of S355J0H vs S355J2H, offering guidance on their properties, applications, and suitability for infrastructure construction projects.

Understanding S355 Steel Grades

S355 steel is widely known for its strength, durability, and versatility, making it ideal for structural components in various applications, especially in construction. Both S355J0H and S355J2H belong to the S355 family, which signifies:

S for structural steel
355 indicates the minimum yield strength of 355 MPa
J0 and J2 represent different impact toughness at specific temperatures
H denotes suitability for hollow sections

While these grades share the same minimum yield strength, their distinction lies primarily in the impact energy requirements, which directly affect their performance in different environmental conditions.

Mechanical Properties Comparison: S355J0H vs S355J2H

Both S355J0H and S355J2H share similar mechanical characteristics but differ in their ability to absorb impact at different temperatures:

Property	S355J0H	S355J2H
Yield Strength	≥ 355 MPa	≥ 355 MPa
Tensile Strength	470-630 MPa	470-630 MPa
Impact Energy	≥ 27J @ 0°C	≥ 27J @ -20°C
Elongation	20-22% (depending on section size)	20-22% (depending on section size)

S355J0H ensures a minimum impact toughness of 27 Joules at 0°C.
S355J2H offers greater toughness, with a minimum of 27 Joules at -20°C, making it more suitable for colder environments.

S355J0H vs S355J2H: Applications and Suitability

The choice between S355J0H and S355J2H often depends on the project’s environmental conditions. Below, we outline where each grade excels:

S355J0H: General Purpose Structural Steel

Usage: S355J0H is typically used in mild or temperate environments where the temperature does not drop below freezing. This makes it ideal for infrastructure in regions with moderate climates, such as parts of Southern Europe, Africa, and Southeast Asia.
Examples: Bridges, Stadiums, General buildings and towers

S355J0H performs well in environments where impact at lower temperatures is not a critical factor. This grade provides cost-efficiency while still delivering reliable structural integrity.

S355J2H: Tougher in Colder Climates

Usage: S355J2H is better suited for colder environments, such as Northern Europe, Canada, or mountainous regions, where temperatures regularly fall below zero. Its enhanced impact toughness makes it more reliable in these conditions, ensuring durability and resilience.
Examples: Offshore structures, Cold storage facilities, Projects in mountainous or northern climates

Given its higher toughness, S355J2H is often the material of choice for applications requiring increased safety margins in cold weather conditions.

Standards and Manufacturing: S355J0H vs S355J2H, EN 10219 vs EN 10210

EN 10219 (Cold-Formed Sections)

S355J0H and S355J2H both comply with the EN 10219 standard, which specifies cold-formed welded hollow sections. These sections are used when weight savings and cost-effectiveness are primary concerns.
Applications: Cold-formed sections are often used in lighter structures and where surface finish is important, such as in architectural features.

EN 10210 (Hot-Finished Sections)

S355J0H and S355J2H are also available in EN 10210 hot-finished form. This process results in sections with improved ductility, toughness, and dimensional accuracy, making them more suitable for heavier loads and harsh environments.
Applications: Hot-finished hollow sections are preferred for high-stress applications such as offshore platforms, heavy bridges, and cranes.

Cold-Formed vs. Hot-Finished Hollow Sections

While both S355J0H and S355J2H can be produced using either cold-forming (EN 10219) or hot-finishing (EN 10210), the choice between cold-formed or hot-finished sections depends on several factors:

Cold-Formed: Suitable for lightweight structures, cost-effective, aesthetically pleasing, and with a good surface finish.
Hot-Finished: Offers superior toughness, dimensional consistency, and fatigue resistance, ideal for high-load and dynamic structures.

S355J0H vs S355J2H: Key Differences and Selection Guidelines

To help you choose between S355J0H and S355J2H, here’s a breakdown of the main factors:

Factors	S355J0H	S355J2H
Impact Toughness	27J @ 0°C	27J @ -20°C
Climatic Suitability	Moderate temperatures	Colder climates, sub-zero environments
Typical Applications	Bridges, buildings, moderate climate structures	Offshore, cold storage, structures in cold areas
Standard Availability	EN 10219 and EN 10210	EN 10219 and EN 10210
Cost	Generally lower	Typically higher due to toughness properties

When selecting between these two grades:

Choose S355J0H for cost-efficiency in mild to moderate climates where sub-zero temperatures are not expected.

Choose S355J2H for better toughness and safety in colder climates or when higher impact resistance is required.

Common FAQs

Which grade is more cost-effective?

S355J0H is often more economical for projects in environments where extreme cold is not a concern.

Do I need S355J2H for all projects in cold climates?

Yes, especially in regions where temperatures fall below zero, S355J2H offers greater resilience and safety margins.

Can both grades be used in the same project?

Yes, both grades can be used in the same project, provided that their specific roles in the structure are carefully evaluated based on environmental conditions.

Conclusion: S355J0H vs S355J2H, Selecting the Right Grade for Your Project

The choice between S355J0H and S355J2H hinges largely on the environmental conditions of the project. While both grades provide robust strength and versatility for structural hollow sections, S355J2H offers superior performance in colder climates due to its enhanced impact toughness. On the other hand, S355J0H delivers a more cost-effective solution for projects in temperate regions.

For infrastructure and construction professionals, understanding the specific performance needs of your project—whether it’s a bridge, stadium, or offshore platform—is crucial in making the right material choice. Both S355J0H and S355J2H ensure high reliability, but careful selection guarantees both safety and cost-efficiency for long-term structural success.

This blog provides essential guidance on choosing between S355J0H and S355J2H for structural hollow sections in infrastructure construction. If you have any further questions or need project-specific advice, feel free to reach out for more tailored support.