High Strength Seamless Carbon Steel Round Tube for Structure - China Factory and Suppliers
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Frequently Asked Questions
Manufacturing complies with GB/T 706-2016 hot-rolling standards, with post-galvanization physical properties significantly upgraded: Zinc coating hardness reaches 250HV (35% higher than substrate), bending stiffness increases by 15% (ASTM E8 three-point test), while maintaining yield strength ≥235MPa. Zero uncoated defects ensured by 100% eddy-current testing (ISO 1461 Class A), surface homogeneity tolerance ≤±10μm.
Excels in renewable energy and infrastructure: Ideal for solar mounting systems (UL 2703 certified, annual zinc loss <0.8%), offshore platform legs (resists chloride erosion, EN ISO 9227 CX class), and chemical plant frameworks (pH3-11 chemical tolerance per ASTM G31). Outperforms painted steel in installability – eliminating post-weld anti-rust treatment – with cut/punched edges self-protected by cathodic action (ASTM A780 repair compounds).
Leads in sustainability and economy: Zinc recyclability >95% (ISO 14021 certified), reducing lifecycle costs by 40%. Over a 30-year span, saves $220/ton in maintenance versus painted steel. EU exports comply with REACH Annex XVII lead-free requirements (Pb<0.01%), while US projects meet ASTM A123 Type 8 zinc specifications.
Customization services: Equal/unequal angle cutting (±0.5mm laser tolerance), pre-punching/slotting (DIN 1022 standard), backed by SGS material certificates, third-party inspections, and ISTA 3E transit test reports.
Equal Angle: e.g., L50×50×5 (50mm width, 5mm thickness).
Unequal Angle: e.g., L100×80×8 (100mm long side, 80mm short side, 8mm thickness).
Equal Angle: Width 20-250mm, thickness 3-24mm.
Unequal Angle: Long side 25-200mm, short side 16-125mm, thickness 3-18mm.
Construction (e.g., bridges, factory frameworks).
Machinery manufacturing (equipment supports, connectors).
Power transmission towers, brackets.
Decorative engineering (e.g., metal doors/windows).
China: GB/T 706-2016 (Hot-rolled steel standard).
International: ASTM A36 (USA), JIS G3192 (Japan), EN 10056 (Europe).
Production: Hot-rolling (high-temperature), cold-forming (room-temperature).
Mechanical properties: Tensile strength ≥375MPa, yield strength ≥235MPa (e.g., Q235).
Galvanizing (anti-corrosion, for outdoor use).
Painting/Powder coating (decoration or rust prevention).
Black (untreated, direct use).
FAQ
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Q: How to verify zinc coating thickness? Rust prevention during shipping?
A: Magnetic induction gauge (ISO 2178) with 3-point random sampling. VCI anti-rust agent + desiccants applied pre-shipment. Port reinspection available
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Q: Can we return goods if dimensions exceed ±1mm vs drawing?
A: ASTM A6 tolerance applies: ±0.8mm width, ±0.3mm thickness. Free replacement for non-conformity with inspection report..
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Q: Do you provide UL 2703 certification for solar projects?
A: UL-certified galvanized angles available (+15% cost). Certificate includes zinc composition & UV resistance data (5000hrs aging test).
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Q: Can we order 1 ton trial? Who pays LCL charges?
A: Minimum 22 tons for FCL. LCL surcharge: $180/ton. Recommend 15-ton full 20GP container.
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Q: Compensation if straps break causing deformation?
A: Submit photos + third-party survey report. Replacement shipped within 72 hours with freight covered.
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Q: Can you drill holes per our drawings and remove zinc dross?
A: Laser cutting/punching (±0.5mm tolerance) with automatic zinc-rich coating at cut edges (ASTM A780 compliant).
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Q: Does it meet EU REACH lead content <0.1%?
A: Zinc coating Pb <0.01% (SGS test-MSDS Section 15). CoC (Conformity Certificate) included.
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