Custom-Dimension Prefabricated Steel Truss for Heavy Industrial Factory Roofs - GB/T 1591 (Q355B)

• Customization: Available
• After-sales Service: 24/7 Online Technical Support
• Connection Form: Welded Connection
• Model NO.: Truss
• Construction Member: Steeltruss
• Grade: Low-Alloy High-Tensile Structural Steel
• Molding Method: Hot-Rolled Steel
• Residential Wall Structure: Wall Stud
• Standard: ASTM
• Steel Type: High-Strength Steel
• Structure: Truss Structure
• Material Grade: Q355b High-Strength Low-Alloy Structural Steel
• Structural Form: Triangular Lattice / Warren / Pratt / Howe
• Primary Application: Heavy Industrial Factory Roofs
• Transport Package: Seaworthy Packing
• Specification: Heavy Section Steel
• Trademark: Quality Carbon Structural Steel and Alloy Structur
• Origin: China
• HS Code: 730890000
• Package Size: 150.00cm * 120.00cm * 80.00cm
• Package Gross Weight: 300.000kg
• Lead Time: 180 days (1 - 100 Tons) ; To be negotiated ( > 100 Tons)

Product Description

Our Custom-Dimension Prefabricated Steel Truss is engineered for heavy industrial factory roofs where span requirements, load conditions, and building layouts vary from project to project. Manufactured from Q355B high-strength structural steel under GB/T 1591-2018 – a grade equivalent to S355JR and ASTM A572 Gr.50 – this truss delivers exceptional load-bearing capacity with minimal steel consumption.

The triangular lattice configuration transfers loads through axial forces, enabling column-free factory interiors that maximise usable floor space for production lines, equipment, and material handling. Every truss is factory prefabricated to your custom dimensions and supplied with complete documentation for rapid on-site erection.

Q355B – The High-Strength Steel Behind the Performance
Q355B is a low-alloy high-strength structural steel defined in GB/T 1591-2018, the current Chinese standard for high-strength structural steels. This material delivers a minimum yield strength of 355 MPa for thicknesses up to 16mm (and 345 MPa for 16-40mm thickness), with tensile strength ranging from 470 to 630 MPa and elongation of at least 21%. It offers impact toughness of 34J at 20°C (B-grade) and an excellent Carbon Equivalent Value (CEV) of ≤0.45%, ensuring superior weldability without preheating for most thicknesses.

International Equivalents: Q355B is fully interchangeable with S355JR (EN 10025-2) for European projects, ASTM A572 Grade 50 for American-standard projects, DIN St52-3 (Germany), and JIS SS540 (Japan). The higher yield strength – 51% above Q235B – enables lighter sections and reduced steel tonnage, directly lowering material costs and foundation requirements.

Custom-Dimension Engineering – Designed for Your Factory

Every factory is different. We don't offer one-size-fits-all – each truss is engineered to your specific project requirements:

What We Customise:

• Span length – matched to your column spacing and layout
• Roof slope – single pitch, double pitch, or flat
• Member sections – H-beams, channels, angles, or tubes
• Connection details – bolted or welded per your preference
• Load capacity – crane loads, snow, wind, seismic (per local codes)
• Surface treatment – primer, paint, or hot-dip galvanized
Engineering Deliverables:

• Full shop drawings with dimensioned members
• Erection plans with step-by-step assembly sequence
• Connection details for field assembly
• Material take-offs and weight calculations
Our in-house engineering team uses Tekla Structures and STAAD Pro for 3D modelling, structural analysis, and detailed shop drawing production.

Factory Prefabrication – Quality in Control, Not on Site
Why prefabrication matters:

All fabrication occurs in our ISO 9001-certified facility with precision CNC equipment – not on your site. This means:

• Consistent quality – controlled conditions, not weather-dependent
• Dimensional accuracy – CNC cutting and drilling to tight tolerances
• Certified welders – EN ISO 9606-1 qualified, with approved WPS
• Full inspection – before shipment, not after installation
• Faster site erection – components arrive ready to bolt together
The Workflow:

• CNC cutting & drilling – exact lengths and hole positions
• Jig-set assembly – consistent geometry across all trusses
• Welding – by certified welders using approved WPS (SMAW/GMAW/SAW)
• Dimensional inspection – verified against shop drawings
• NDT (UT/MT) – on critical joints as required
• Surface treatment – abrasive blast + primer or galvanizing
• Marking & packing – each member tagged for easy site identification

Structural Efficiency – The Triangular Advantage

The triangular lattice configuration is not arbitrary – it's the most efficient structural form for spanning large distances:

• Axial force transfer – members carry only tension or compression, eliminating bending moments
• Material efficiency – less steel for the same load capacity vs. solid-web beams
• Column-free spans – maximise usable floor space in your factory
• Stability – triangular geometry provides inherent resistance to buckling
Available configurations:

• Warren Truss – zigzag diagonals for uniform loads
• Pratt Truss – diagonals slope to centre for heavy loads
• Howe Truss – diagonals slope away for shorter spans
• Custom Lattice – tailored geometry for specific requirements

Quality Assurance – Built-In Reliability
We operate a multi-layer quality system that goes beyond routine inspection:

• Full material traceability – every component linked to its heat number and Mill Test Certificate
• Certified welders – with approved WPS and PQR
• In-process inspection – checks at every fabrication stage
• NDT (Ultrasonic Testing / Magnetic Particle) – on critical joints
• Dimensional verification – against shop drawings
• Pre-shipment inspection – final check before packing
Third-party inspection – we welcome SGS, BV, TÜV, or your chosen inspector at any stage.

Specification

Item	Detailed Description
Material & Mechanical Properties	Grade: Q355B (GB/T 1591-2018). Yield: ≥355 MPa (≤16mm) / ≥345 MPa (16-40mm). Tensile: 470–630 MPa. Elongation: ≥21%. Impact: ≥34J at 20°C (B-grade). CEV: ≤0.45% for excellent weldability. Equivalents: S355JR (EN 10025-2), ASTM A572 Gr.50. Full MTCs with heat number traceability provided.
Custom-Dimension Engineering	Span: Custom-engineered per project (typical 15–60m+). Roof slope: Per architectural requirements. Member sections: H-beams (up to 900mm), channels, angles, tubes. Thickness: 6–40mm. Truss types: Warren, Pratt, Howe, or custom lattice. All designs verified for local and global buckling per GB 50017 / AISC 360 / Eurocode 3.
Fabrication & Tolerances	Fabrication: CNC cutting/drilling, jig-set assembly, welding by EN ISO 9606-1 certified welders. Tolerances: Length ±2mm, Straightness ≤L/1000, Hole centre ±1.5mm. NDT: UT on butt welds, MT on surface defects as required. Pre-assembly: Trial assembly in workshop before disassembly and packing.
Surface Protection	Standard: Abrasive blast to Sa2.5 (ISO 8501-1) → Zinc-rich primer 75μm DFT → Epoxy/polyurethane topcoat, total DFT 120–160μm. Upgrade: Hot-dip galvanizing per GB/T 13912 / EN ISO 1461, mean ≥85μm. Suitability: C2–C5 corrosivity categories per ISO 12944.
Design Life	Engineered for 30–50 year service life in industrial atmospheric conditions. Seismic design: Per GB 50011 / AISC 341 / Eurocode 8 available. Load capacity: Customised to project-specific dead, live, snow, wind, and crane loads.

All specifications are fully customisable to your project drawings and local building codes.

Packaging & Shipping

• Crating: Heavy-duty steel-framed crates or bundled with edge protection, shrink-wrapped with VCI paper to prevent moisture ingress during sea freight.
• Marking: Every member is clearly stencilled with an erection tag matching assembly drawings – ensuring error-free site sorting.
• Transport: Flat-rack or open-top containers for standard spans; break-bulk shipping available for extra-long members.
• Documentation: Packing list, lifting plan, erection sequence, and all quality certificates (MTCs, NDT reports) included with shipment.

After Sales Service

• Installation support: Detailed erection drawings and step-by-step sequences provided. On-site supervision available on request.
• Warranty: 12 months on material and workmanship.
• Technical assistance: Engineering team responds to post-shipment queries within 24 hours.
• Full documentation: Mill Test Certificates, NDT reports, as-built drawings provided for your project file.

Company Profile

Hangzhou FAMOUS Steel Engineering Co., Ltd. (FASECbuilding) is a steel structure manufacturer specialising in custom-dimension prefabricated steel trusses for heavy industrial factory roofs worldwide.

• Engineering: In-house team proficient in Tekla Structures, STAAD Pro, and major design codes (GB 50017, AISC 360, Eurocode 3).
• Certifications: ISO 9001, with EN 1090 capability for European projects.
• Global Experience: Supplied steel trusses for industrial factories, workshops, and heavy industrial facilities across Asia, Europe, the Americas, and the Middle East.
• Capacity: Stable production output capable of handling projects of all scales with reliable delivery schedules.
We deliver custom-dimension prefabricated steel trusses – Q355B strength, GB/T 1591 compliance, and fabrication precision for your heavy industrial factory roof.