EN10210-3 Hollow Structural Sections / S690QH / S690QLH / Q690MC / Q690D / Q690E Square Tubes

S690QH/S690QLH/S690QL1H High-Strength Steel Hollow Structural Profiles — World-Class Research-Grade Structural Steel Tubes, with relevant research published in Engineering Structures !

Advanced high-strength steel hollow structural sections (square / rectangular / circular tubes) of S690QH/S690QLH/S690QL1H that resolve small MOQ challenges, overcome HAZ softening and pass CTOD tests.

In modern long-span trusses, super high-rise mega-braces and heavy offshore engineering, S690QH/S690QLH/S690QL1H serve as core materials to realise structural lightweighting and large-space design.

Nevertheless, conventional high-strength steel tubes suffer from microstructure softening and embrittlement in the Heat Affected Zone (HAZ) during welding. In addition, overseas steel mills impose extremely high Minimum Order Quantities (MOQ), making material procurement unfeasible for small-batch projects.

Backed by solid research capabilities, Peakkong Special Steel breaks industry monopolies by adopting self-developed hybrid welding technology and brand-new custom tubular production lines. We deliver flexible batch production with customisation options and no MOQ barriers. Our products fully comply with the latest European high-strength hollow section standards EN 10210-3 (hot finished / heat treated) and EN 10219-3 (cold formed / quenched & tempered).

Product Specifications for S690QH/S690QLH/S690QL1H Hollow Structural Sections
With our in-house custom tubular production lines, Peakkong Special Steel can precisely customise various outer diameters and wall thicknesses according to project drawings. Weld seams and HAZ achieve full penetration, equal strength and high toughness:

• Square Hollow Sections (SHS)

Wall thickness (T): 5mm to 30mm

• Rectangular Hollow Sections (RHS)

• Circular Hollow Sections (CHS)

Wall thickness (T): 5mm to 30mm

> Note: Our new custom tubular production line eliminates small-batch MOQ restrictions. We can rapidly schedule production and deliver even for special small-size profiles at R&D stage or small-scale infrastructure projects.

Six Core Advantages of S690QH/S690QLH/S690QL1H Hollow Structural Tubes
1. Solving small-batch procurement challenges (Key commercial benefit)
Equipped with flexible custom tubular production lines, we can adjust production dimensions freely without the high MOQ requirements of large traditional steel mills, greatly cutting material procurement and inventory costs for medium-small projects or R&D phases.

2. Full compliance with dual European standards
Products are manufactured in strict accordance with EN 10210-3 and EN 10219-3. They satisfy stringent requirements for hot-finished / heat-treated structural tubes as well as high-performance criteria for cold-formed quenched & tempered tubes.

3. Approved welding procedures
Welding procedure approvals from TUV, SGS and DNV. Supported by robust fracture mechanics theory, fully supporting engineers’ Material Submission for project approval.

4. CTOD tested (Fracture toughness guarantee)
Welded joints have passed CTOD fracture toughness tests. This means the tubes possess excellent resistance against unexpected crack propagation under long-term high-cycle fatigue loads, dynamic heavy loads or sudden impact, completely preventing catastrophic brittle fracture.

5. HAZ softening and embrittlement fully resolved
Our proprietary in-house welding technology precisely controls welding heat input, ensuring the mechanical properties and metallographic microstructure of the HAZ at tube joints match the base metal of S690QH/S690QLH/S690QL1H.

6. Ultra-high strength for extreme structural lightweighting
Minimum yield strength reaches 690 MPa, nearly twice that of conventional S355 steel tubes. Under identical torsional stiffness and axial load requirements, thinner tube walls can be adopted. Structural self-weight can be reduced by 30%–50%, substantially lowering costs for transportation, foundation works and lifting.

Typical Applications of S690QH/S690QLH/S690QL1H Hollow Structural Sections
Space trusses & long-span venues
Steel tube trusses and reticulated shell structures for airport terminals, high-speed railway stations and large stadiums. Slimmer tube profiles achieve larger column-free spans with modern aesthetic lines.

Mega-bracing for super high-rise buildings
Suitable for Concrete-Filled Steel Tube (CFT) columns, outer-frame diagonal bracing and core wall structures of skyscrapers. It delivers ultra-high load capacity within compact space to maximise usable indoor floor area.

Offshore engineering, offshore wind & polar operations
Supported by DNV marine welding procedure approval, CTOD fracture toughness and -40°C low-temperature impact resistance. Ideal for main chord members, foundation piles of offshore wind jackets and heavy lift arm frameworks on marine vessels.

Heavy lifting & transport machinery
Used for lattice booms of crawler cranes and mobile cranes, telescopic booms of aerial work platforms, significantly improving lifting capacity, torsional stiffness and operational stability of equipment.

Contact Us
If you are planning and designing complex steel structures, large-scale infrastructure, high-rise buildings or offshore projects, and are seeking premium high-strength hollow sections with no MOQ limits, complying with EN 10210-3 / EN 10219-3, backed by published international research and CTOD test certification:

If you wish to learn more about S690QH/S690QLH/S690QL1H High-Strength Steel Hollow Structural Profiles, welcome to contact us!