EN 10219 Cold-Formed Welded Structural Hollow Sections

EN 10219 Standard is the EU standard for cold-formed or unheat-treated welded steel tubes, primarily applicable to round, square and rectangular tubes. These products are classified as building materials in the EU and are regulated by a specific directive under the CE marking, namely, CPR-Regulation (EU) No. 305/2011. The implementation of this standard signifies uniformity and standardization in the manufacture, inspection, and use of steel tube products.

Basic Contents of EN 10219:

EN 10219 applies primarily to cold-formed (cold-finished) welded hollow sections (such as square tubes, rectangular tubes and round tubes) for building and engineering structures, particularly those used in load-bearing structures. It specifies requirements for the chemical composition, manufacturing process, mechanical properties, dimensional tolerances, appearance quality, welding requirements, and inspection methods.

The EN 10219 standard is divided into two main parts:

EN 10219-1: Technical Delivery Conditions

1. Material Requirements: This specifies the grade and properties of the steel used in the manufacture of steel tubes, typically based on the steel specified in EN 10219 itself or EN 10210 (Hot-Formed Hollow Sections).
2. Manufacturing Process: This specifies that the tubes are formed by cold forming (cold bending) and then welded together at the edges. This is different from hot rolling or hot forming.
3. Welding Requirements: This sets out strict standards for welding procedures, welder qualifications, and weld quality (such as non-destructive testing) to ensure weld strength and integrity.

4. Chemical Composition:
EN 10219 also provides detailed specifications for the chemical composition of square, rectangular, and round tubes. The standard requires that the chemical composition of the material comply with the requirements of relevant European standards, such as EN 10028.

The standard specifies the content ranges of key elements such as C, Si, Mn, P, and S to ensure the material's mechanical and weldability. Specific content requirements vary depending on the application and performance requirements of the steel pipe. For example, for steel pipes used in load-bearing structures, lower sulfur and phosphorus contents can improve the steel's toughness and ductility, thereby extending its service life.

5. Mechanical Properties:
EN 10219 sets requirements for the mechanical properties of square, rectangular, and round tubes. Mechanical properties are important indicators for evaluating the quality of steel pipes. The standard stipulates that the material must possess certain tensile strength, yield strength, and elongation. It also specifies hardness and impact toughness. These mechanical properties are designed to ensure the safety and reliability of square, rectangular, and round tubes during use.

It specifies the minimum mechanical properties that the steel must meet, including:
Yield strength (ReH): The stress at which the material begins to permanently deform.

Tensile strength (Rm): The maximum stress the material can withstand before breaking. 

Elongation (A): The ability of a material to stretch before breaking, representing its toughness.

The tensile strength of round tubes is generally required to be above 400 MPa, while the yield strength must be above 235 MPa. These performance parameters ensure that the steel tube can withstand certain tensile and compressive forces in practical applications without deforming or breaking.

6. Dimensions and Tolerances: 

Used in conjunction with Part 2, these parameters specify the permissible deviations within dimensions.

During the production process, the outer diameter and wall thickness of steel tubes are critical technical parameters. The outer diameter not only affects the strength and load-bearing capacity of the tube, but also influences the connection and installation methods. Wall thickness directly affects the pipe's pressure resistance and corrosion resistance. Different wall thicknesses are suitable for different applications. For example, thicker wall materials are more suitable for environments subject to high pressure.

EN10219 specifies the dimensions and shapes of square and rectangular tubes. For square tubes, the standard stipulates that the cross-sectional dimensions must meet the relevant tolerance requirements, while for rectangular tubes, the dimensions specify the ratios of height, width, and diagonal. In addition, shape tolerances, such as curvature and straightness, are specified for square and rectangular tubes.

7. Appearance Quality:
The EN 10219 standard also has corresponding requirements. The surface of steel tubes should be smooth and free of obvious defects such as cracks, dents, and rust. Surface quality directly affects subsequent painting and anti-corrosion treatments. Therefore, during the production process, manufacturers must strictly control and inspect the production process to ensure that the final product's appearance meets the standard.

8. Inspection and Testing: This section specifies the types of tests required (such as tensile tests, impact tests, flattening tests, and flaring tests) and the frequency of these tests.
9. Marking and Certification: This section specifies how products should be marked (such as standard number, steel grade, dimensions, and manufacturer), as well as the required compliance documents (such as the Factory Production Control Certificate (FPC)).

EN 10219-2: Dimensions and Cross-sectional Properties

This section provides detailed dimensions, cross-sectional properties (such as cross-sectional area, moment of inertia, section modulus, etc.), and tolerance tables for square, rectangular, and circular tubes. Engineers and designers use the data and tables in this section for structural calculations and design.

Features and Differences between EN 10219 and EN 10210:

Cold Forming vs. Hot Forming: This is the most fundamental difference between EN 10219 and another important standard, EN 10210.
EN 10219: Cold forming. Steel sheet or strip is cold-bent into the desired shape at room temperature and then welded. This method produces tubes with thinner walls, more precise dimensions, and a smoother surface finish.
EN 10210: Hot forming. Steel billets are pierced, rolled, or extruded at high temperatures. Hot-formed tubes typically have thicker walls and larger outer radii at corners (square/rectangular tubes).

Commonly Used Steel Grades:

The EN 10219 standard covers a variety of steel grades, the most common of which are the S series (structural steel) and the L series (pipeline steel), such as:

S235JRH, S275J0H, S275J2H, S355J0H, S355J2H, S355K2H, etc.
L245NB, L290NB, etc. (mostly used in pipeline applications).

The "H" suffix here indicates that it is suitable for hollow sections.

Applications of EN 10219 Standard Steel:

EN 10219 standard hollow sections are widely used in various modern buildings and engineering structures due to their light weight, high strength, flexible and aesthetically pleasing design:

1. Building Structures: These typically serve as supporting and connecting members, bearing the weight and external pressure of the building, such as the roofs and main structures of airport terminals, stadiums, commercial centers, and office buildings. 2. Space trusses and grid structures: Construction of large, column-free spaces.
3. Machinery and equipment manufacturing: Hoisting machinery, agricultural machinery, vehicle chassis, etc.
4. Bridge construction: Used to manufacture bridge girders and support columns, ensuring the stability and safety of bridges, such as pedestrian overpasses and decorative bridge components.
5. Home furnishings and decoration: Furniture, stairs, guardrails, etc.

Conclusion:
EN 10219 is the comprehensive European product standard for cold-formed welded structural hollow steel sections. It ensures consistent quality, dimensions, and performance across manufacturers, providing structural designers with a reliable design basis and guaranteeing the safety and reliability of the resulting building structure.

In China, the corresponding national standard is GB/T 6728 "Cold-formed Hollow Steel Sections for Structural Use."

Read more: EN 10219 vs EN 10210: Comprehensive Comparison or ASTM A500 Structural Pipe