EN 10219 Standard for Welded Structural Steel Tubes

I. Standard Overview

i. Standard Definition

EN 10219 is a European standard applicable to cold-formed welded hollow structural sections (HSS).

These pipes are primarily used in load-bearing and supporting structures, emphasizing dimensional accuracy, uniform mechanical properties, and weld quality.

ii. Scope of Application

Building Structures: Factory buildings, frame beams and columns, roof supports
Bridge Engineering: Truss members, supporting beams and columns
Industrial Supports: Machinery supports, pipe supports, towers
Machinery Frames: Equipment supports, conveyor supports, structural systems

iii. Differences between EN 10219 and EN 10210

Item	EN10219 (Cold-Formed Welded Pipe)	EN10210 (Hot-Formed Pipe)
Manufacturing Method	Cold-formed + ERW welding	Hot-formed + welding
Section Type	Square, Rectangular, Round	Square, Rectangular, Round
Applicable Range	Light or medium load-bearing structures, mechanical supports	Heavy load-bearing structures, bridges, main beams of factories
Material	Non-alloy steel, fine-grain steel	Carbon steel, low-alloy steel
Advantages	Low cost, high dimensional accuracy, suitable for small to medium spans	High load-bearing capacity, smooth welds, suitable for long spans and high loads

II. EN 10219 Pipe Types and Specifications

i. Cross-sectional Types

EN 10219 standard pipes mainly have three cross-sectional shapes:
Circular Hollow Section (CHS)
Square Hollow Section (SHS)
Rectangular Hollow Section (RHS)

ii. Dimensional Range and Tolerances

Section Type	Outer Diameter / Side Length Range	Wall Thickness Range	Length Range	Dimensional Tolerance
Circular Pipe (CHS)	21.3–813 mm	2.6–25 mm	6–12 m (customizable)	OD ±1%, WT ±10% (per standard)
Square Pipe (SHS)	20×20–400×400 mm	2.0–16 mm	6–12 m (customizable)	Side ±1%, WT ±10%
Rectangular Pipe (RHS)	30×20–400×300 mm	2.0–16 mm	6–12 m (customizable)	Side ±1%, WT ±10%

III. EN 10219 Hollow Structural Steel Tubes — Production Process

Steel strip raw material → Cold bending → Edge shaping → Resistance welding (ERW) → Weld leveling → Straightening → Dimensional inspection → Surface treatment → Quality inspection and packaging → Shipment

IV. EN 10219 Mechanical Properties and Material Requirements for Hollow Structural Steel Tubes

i. Material Requirements

Item	Carbon Steel	Low-Alloy Steel	Remarks
Steel Type	Non-alloy steel, fine-grain steel	Low-alloy steel containing Ni, Cr, Mo, etc.	Ensures weldability and load-bearing capacity
Chemical Composition (Typical)	C ≤0.22–0.30%, Mn 0.60–1.50%, P/S ≤0.035%, Si 0.10–0.55%	C ≤0.30%, Mn 0.60–1.50%, Ni 0.3–1.0%, Cr 0.3–1.0%, Mo 0.05–0.3%	Low-alloy steel enhances strength, corrosion resistance, and low-temperature toughness
Weldability	Good	Good, alloy content should be considered	Suitable for cold-formed + ERW manufacturing process

ii. Mechanical properties

Steel Type	Grade	Yield Strength σy (MPa)	Tensile Strength σu (MPa)	Elongation A (%)	Impact Toughness (J)	Remarks
Carbon Steel	S235	235	360–510	≥20	≥27 (20°C)	General building structures, light supports
Carbon Steel	S275	275	410–560	≥20	≥27 (20°C)	Medium-load buildings, secondary bridge beams
Carbon Steel	S355	355	470–630	≥20	≥27 (20°C)	High-strength building structures, main bridge beams
Low-Alloy Steel	S355NL	355	470–630	≥20	≥27 (−20°C)	Large outdoor structures, low-temperature bridges, load-bearing columns and beams
Low-Alloy Steel	S420	420	520–680	≥20	≥27 (−20°C)	High-strength structures, bridge trusses, towers, special industrial supports

V. EN 10219 Hollow structural steel pipes — Surface treatment and corrosion protection

Treatment	Applicable Environment	Features & Remarks	Applicable Pipe Type
Black Steel (Untreated)	Indoor dry environment	Low cost, suitable for non-corrosive environments	Carbon steel, low-alloy steel
Hot-Dip Galvanizing	Outdoor, humid environment	Thick zinc coating, strong corrosion resistance, long service life	Carbon steel, low-alloy steel
Painted / Anti-Rust Coating	Industrial environment or extra protection required	Can be applied alone or over galvanized pipes to improve corrosion resistance	Carbon steel, low-alloy steel
Composite Anti-Corrosion (Galvanized + Painted)	Coastal, chemical plant, hot and humid environments	Double protection, higher durability	Carbon steel, low-alloy steel

VI. EN 10219 Selection Guide for Hollow Structural Steel Tubes

i. Select steel grade according to load-bearing requirements

Project Type	Recommended Steel Grade	Remarks
Light Building Structures (small span, low load)	S235	Economical choice, meets general load-bearing requirements
Medium Buildings, Secondary Bridge Beams, Factory Frames	S275	Moderate strength, balances cost and load-bearing capacity
Large-Span Buildings, Main Bridge Beams, Industrial Towers	S355	High-strength steel, allows reduced section size and lower self-weight
Low-Temperature Environments or Outdoor High-Load Structures	Low-Alloy Steel S355NL / S420	Provides low-temperature toughness and corrosion resistance, ensures safety

ii. Select according to cross-sectional shape

Load Direction / Scenario	Recommended Section Type	Remarks
Multi-directional loads (trusses, towers)	Circular Pipe (CHS)	Excellent resistance to bending and torsion in all directions
Unidirectional bending or compression (beams, columns, frame supports)	Square Pipe (SHS) / Rectangular Pipe (RHS)	Easy for welding or bolted connections, high bending strength
Aesthetic or industrial architecture	Square / Rectangular Pipe	Neat appearance, convenient for installation and pipe routing

iii. Select according to environmental and corrosion prevention requirements

Environment Type	Recommended Anti-Corrosion Method	Remarks
Indoor, dry	Black Steel	Low cost, no additional corrosion protection required
Outdoor, humid	Hot-Dip Galvanized	Long service life, reliable corrosion resistance
Coastal, chemical plants	Galvanized + Painted	Double protection, extends service life

VII. EN 10219 Hollow Structural Steel Tubes — Application Selection Reference Table

Application	Load Characteristics	Recommended Steel Grade	Section Type	Wall Thickness / Size Reference	Anti-Corrosion Method	End Type	Selection Notes
Factory beams and columns, light frame structures	Low to medium load	S235	Square / Rectangular Pipe	WT 2–6 mm, side 50–150 mm	Black Steel / Galvanized (indoor/outdoor)	Plain or Socket End	Small span, low load, cost-priority
Medium industrial factories, secondary bridge beams	Medium load, medium span	S275	Square / Rectangular Pipe	WT 4–8 mm, side 100–200 mm	Hot-Dip Galvanized	Plain End	Medium load, suitable for outdoor or mild corrosive environments
Large-span factories, main bridge beams	High load, long span	S355	Circular / Rectangular Pipe	WT 6–12 mm, diameter/side 150–400 mm	Hot-Dip Galvanized or Composite Anti-Corrosion	Plain End	High-strength requirement, reduce section size while ensuring load capacity
Towers, trusses, communication poles	Multi-directional load	S355 / S420 Low-Alloy Steel	Circular Pipe (CHS)	WT 6–10 mm, diameter 100–300 mm	Hot-Dip Galvanized or Composite Anti-Corrosion	Plain End	Suitable for outdoor, low-temperature or corrosive environments
Machinery supports, equipment frameworks	Local load, small to medium span	S235 / S275	Square / Rectangular Pipe	WT 3–6 mm, side 50–150 mm	Black Steel or Painted	Socket or Plain End	Frequently moved or removable supports, easy assembly and disassembly
Coastal facilities, chemical plant supports	High corrosion, high load	S355NL / S420 Low-Alloy Steel	Circular / Rectangular Pipe	WT 6–12 mm	Galvanized + Painted (Composite Anti-Corrosion)	Plain End	High-corrosion environment, ensures long-term use and safety

VIII. EN 10219 Quality Inspection Standard for Hollow Structural Steel Pipes

Test Item	Test Method / Standard	Acceptance Criteria / Parameters	Remarks
Chemical Composition	Optical Emission Spectroscopy (OES) or Chemical Analysis	C ≤0.22–0.30%, Mn 0.60–1.50%, S / P ≤0.035%; Low-Alloy Steel may contain Ni 0.3–1.0%, Cr 0.3–1.0%, Mo 0.05–0.3%	Ensures mechanical properties and weldability meet standards
Yield Strength σy	Tensile Test	Carbon Steel: S235 ≥235 MPa, S275 ≥275 MPa, S355 ≥355 MPa; Low-Alloy Steel: S355NL ≥355 MPa, S420 ≥420 MPa	Ensures structural load-bearing capacity
Tensile Strength σu	Tensile Test	Carbon Steel: 360–510 / 410–560 / 470–630 MPa; Low-Alloy Steel: 470–630 / 520–680 MPa	Meets steel grade design requirements
Elongation A	Tensile Test	≥20%	Ensures plasticity, facilitates welding and installation
Impact Toughness (KV / J)	Impact Test	Carbon Steel ≥27 J (20°C); Low-Alloy Steel ≥27 J (−20°C)	Ensures toughness for low-temperature or outdoor applications
Wall Thickness & OD / Side Tolerance	Dimensional Measurement (Caliper, Ultrasonic Gauge)	WT ±10%, OD / side ±1%	Ensures accurate cross-section for installation and structural safety
Straightness	Spirit Level or Laser Measurement	Bending ≤0.5% × L (length)	Ensures straight pipes, convenient for installation
Weld Quality	Ultrasonic or X-Ray Testing	Continuous welds, free of cracks, no lack of penetration	Ensures load-bearing capacity and safety
Surface Quality	Visual Inspection or Magnetic Particle Testing	Smooth surface, no visible cracks, pits, shrinkage, or porosity	Improves appearance and coating adhesion
End Treatment	Visual / Dimensional Measurement	Threaded ends: threads complete; Socket ends: dimensions compliant; Plain ends: flat	Ensures reliable connection and easy installation
Marking & Batch Certification	Check factory markings and MTC	Complete markings with Material Test Certificate (MTC)	Facilitates acceptance and traceability