Marine & Offshore Products

Marine & Offshore Steel Structures & Heavy Hardware for Shipbuilding

Heavy-duty steel structures and engineered hardware built for marine, offshore, and port infrastructure applications. Manufactured from certified marine-grade carbon and alloy steels, these assemblies undergo stringent structural welding, non-destructive testing, and marine-spec corrosion protection to withstand extreme offshore environments. Available for build-to-print OEM fabrication according to classification society standards and project specifications.

Hot-Dip Galvanized Steel Mooring Plates For Marine & Offs...

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What We Manufacture

We operate a specialized heavy structural fabrication facility configured for large-scale marine components, integrating high-precision cutting, heavy plate rolling, structural welding, and surface treatment lines.

Plate & Profile Processing

CNC plasma and flame cutting with automated beveling for heavy structural sections up to 100 mm thickness.

Welding Operations

Multi-process structural welding including Flux-Cored Arc Welding (FCAW), Submerged Arc Welding (SAW), and certified manual MIG/TIG stations.

Post-Weld Treatment

Stress-relieving thermal treatment and abrasive blast cleaning to Sa 2.5 standards prior to coating application.

Technical Specifications

Parameter	Specification
Marine Steel Grades	ABS / LR / DNV Rules: Grade A, B, D, E, AH36, DH36, EH36
Structural Steel Standards	ASTM A572 Grade 50; EN 10025 S355J2 / S355ML
Maximum Single Structure Weight	Up to 35 metric tons
Heavy Plate Cutting Width	Up to 4,000 mm
Heavy Plate Cutting Length	Up to 12,000 mm
Corrosion Protection – Marine Coating	NORSOK M-501 compliant coating systems, including epoxy zinc-rich primer + high-build epoxy intermediate + polyurethane finish
Hot-Dip Galvanizing	ASTM A123 / ISO 1461 for secondary hardware
Dimensional Tolerance	Heavy welded structures controlled in accordance with ISO 13920 Class B

Materials & Fabrication Options

Hot-Dip Galvanized Steel Mooring Plates For Marine & Offshore

Base Materials

Normalized and thermo-mechanical rolled (TMCP) structural steel plates, stainless steel plates (304L, 316L), and duplex stainless steels.

Consumables

Low-hydrogen welding electrodes and wires matching high impact toughness requirements at sub-zero temperatures (-20 deg C to -40 deg C CVN test verified).

Non-Destructive Testing (NDT)

In-house and third-party verified Ultrasonic Testing (UT), Magnetic Particle Testing (MT), Radiographic Testing (RT), and Dye Penetrant Testing (PT).

Surface Preparation

Automated centrifugal shot blasting to profile Rugotest No. 3 (Medium) followed by multi-layer marine paint application.

Application / Working Environment

01.

Shipbuilding & Commercial Fleet

Bulk carriers, container ships, oil tankers, and offshore support vessels (OSVs).

02.

Offshore Oil & Gas

Fixed platforms, floating production storage and offloading (FPSO) units, and drilling rig structural modules.

03.

Marine Renewable Energy

Offshore wind turbine jacket foundations, substation transition pieces, and mooring anchor frames.

04.

Port & Harbor Infrastructure

Heavy quay wall anchors, fender panels, and maritime terminal structural supports.

Manufacturing & Quality Control

Material Traceability

100% heat number transfer tracking backed by EN 10204 3.1 Mill Test Certificates.

Dimensional Verification

Total station laser measurement and digital template checks for complex multi-axis alignment and interface hole centers.

Weld Quality Inspection

100% visual inspection (VT) by certified welding inspectors (CSWIP / AWS-CWI), supplemented by 10% to 100% volumetric NDT based on joint criticality.

Coating Inspection

Dry film thickness (DFT) gauge testing, salt contamination checks, and pull-off adhesion testing adhering to SSPC/NACE standards.

Customization & OEM Process

Drawing & Specification Review

Submission of CAD files (STEP, DWG, DXF) alongside classification society rules or project engineering specifications.

Engineering & Procedure Submittal

Development of Welding Procedure Specifications (WPS) and Procedure Qualification Records (PQR) for approval.

Material Procurement & FAI

Raw material verification, test coupon sampling, and First Article Inspection report generation.

Fabrication & Documentation Package

Volume production executed under strict quality checkpoints, delivered with complete Quality Dossier including MTCs, NDT reports, and coating records.

Packaging & Delivery

Secure Transport Configuration

Heavy-duty steel structural skids, custom timber crutches, and threaded rod securing for multi-point container or flat-rack lashing.

Moisture & Salt Spray Prevention

Application of vapor corrosion inhibitor (VCI) films and sealed waterproof wrapping for precision machined faces and bolt holes.

Shipping Terms & Ports

FOB Qingdao, CIF, or DDP terms managed with global maritime logistics partners.

Documentation Handover

Commercial invoice, packing list, bill of lading, classification society certificates (if required), and full QC Dossier.

FAQ

Q: What marine steel grades do you use, and can you provide classification society certification?

A: We regularly process ABS Grade A/B/D/E, AH36, DH36, EH36, and EN 10025 structural steels. Mill Test Certificates (EN 10204 3.1) are supplied for every batch, and third-party inspection by classification societies (ABS, DNV, LR, CCS) can be arranged based on contract requirements.

Q: What non-destructive testing (NDT) methods do you apply to critical marine welds?

A: We perform 100% visual inspection (VT) on all structural welds. Depending on joint category and client specifications, we utilize Ultrasonic Testing (UT) for full-penetration butt welds, Magnetic Particle Testing (MT) for fillet welds, and Radiographic Testing (RT) when mandated by design rules.

Q: How do you ensure corrosion resistance for structures operating in seawater environments?

A: We execute abrasive blast cleaning to Sa 2.5 and apply marine-grade coating systems adhering to NORSOK M-501 or ISO 12944 (C5-M high marine environment standards). Multi-layer epoxy and polyurethane systems are applied in temperature-controlled painting booths to ensure proper film thickness and adhesion.

Q: What is the maximum handling weight and dimensional capacity of your fabrication facility?

A: Our heavy fabrication bays are equipped with dual-overhead crane lifting capacities up to 35 metric tons. We routinely handle large structural assemblies up to 12 meters in length and 4 meters in width.

Q: Can you perform pre-machining on bolt holes, mounting pads, and interface connections?

A: Yes. Following heavy welding and post-weld stress relieving, we utilize large-format CNC boring and milling machines to machine critical mounting surfaces and hole patterns to tight tolerances, ensuring trouble-free on-site assembly.

Q: What welding standards and welder qualifications do your facilities maintain?

A: Our welding procedures and operators are qualified in accordance with AWS D1.1, AWS D1.4, and ISO 9606 standards. All welders hold valid certifications for specific structural steel positions and FCAW/SAW processes.

Q: What file formats are required for reviewing and quoting custom marine structural drawings?

A: We accept 2D manufacturing drawings in PDF or DWG/DXF formats and 3D solid models in STEP, IGES, or SolidWorks formats. Complete welding symbols, coating specifications, and tolerance requirements should be clearly indicated.

Q: What is your typical production lead time for custom heavy marine structures?

A: Standard production lead times range from 35 to 55 days, depending on raw material sourcing (such as certified ship plates), complexity of welding, NDT scheduling, and specialized coating cure times. Urgent project phases can be scheduled upon agreement.

We're well-known as one of the leading custom welded structures manufacturers and suppliers in China. With a professional production team, we are able to meet the needs of the majority of our customers. Please rest assured to buy customized custom welded structures from our factory.