Understanding Marking and Traceability in Marine Grade Steel Plates

In the global maritime industry, marine grade steel plates form the structural backbone of ships, offshore platforms, subsea modules, and critical marine equipment. Given the extreme conditions these structures face, ensuring safety, reliability, and compliance is essential. One of the most crucial yet often overlooked aspects of marine steel quality control is marking and traceability. These two elements allow engineers, shipyards, inspectors, and classification societies to verify the identity, origin, and compliance of every steel plate used in construction.

As the industry moves toward stricter international regulations and more complex supply chains, the role of marking and traceability becomes even more important. Leading suppliers such as sakysteel integrate advanced traceability systems and standardized marking protocols to guarantee that every marine grade steel plate can be tracked from raw material to vessel installation.

This article explores the importance of marking and traceability in marine grade steel plates, the requirements set by major classification societies, marking formats, document controls, and how enhanced traceability supports safer and more efficient shipbuilding operations.

What Is Traceability in Marine Grade Steel Plates

Traceability refers to the ability to track a steel plate’s entire manufacturing history. This includes:

  1. Steelmaking and melting origin

  2. Heat number and batch identification

  3. Chemical composition results

  4. Rolling and heat treatment data

  5. Mechanical testing results

  6. Inspection records

  7. Classification society certification

  8. Delivery documentation

For a steel plate to be approved for marine or offshore use, its identity must remain unbroken throughout every stage of processing. An accurate traceability system ensures that the plate used in critical ship structures has passed every required test and meets all relevant standards.

Why Marking and Traceability Are Critical in Shipbuilding

1. Ensures Compliance With Classification Societies

Marine projects typically require certification from ABS, LR, DNV, BV, CCS, NK, KR, or RINA. These societies demand detailed traceability to verify mechanical performance, toughness, and material origin before installation.

2. Prevents Material Mix-Ups

Shipyards often process large volumes of plates with different grades like AH36, DH36, EH36, S355G10, or Q345. Proper marking prevents dangerous and costly mix-ups that could lead to structural failures.

3. Improves Safety and Reliability

Marine steel structures are exposed to corrosive seawater, wave impact, vibration, and sometimes Arctic temperatures. Using fully traceable steel ensures that only plates with validated performance are used in critical areas.

4. Required for Audits and Project Documentation

Large-scale shipbuilding or offshore EPC projects often require complete documentation packages. Traceable materials simplify audits and demonstrate compliance to regulators, insurers, and shipowners.

5. Supports Repairs, Maintenance, and Lifetime Service

Traceability helps identify original steel specifications during repairs, upgrades, or material replacement tasks occurring years after construction.

Key Elements of Steel Plate Marking

Marking is the physical information written or printed directly onto the steel plate. It must remain visible from production to installation.

Common marking elements include:

  • Steel grade (AH36, DH36, EH36, S355, etc.)

  • Heat number

  • Plate dimensions (thickness, width, length)

  • Manufacturer name or logo

  • Standard (ASTM A131, EN 10025, etc.)

  • Classification society approval

  • Production date or batch number

  • Rolling direction indicator

  • Order or project number

These markings allow immediate identification without referring to documents.

Marking Techniques

Steel plates may be marked using:

  • Paint marking

  • Stamping

  • Laser marking

  • Hard punching

  • Tagging or sticker systems (used on stainless/aluminum plates)

Marine-grade plates primarily use paint stamping due to durability and visibility.

Traceability Documentation Required for Marine Steel Plates

While markings are placed directly on the steel, documentation completes the traceability chain.

1. Mill Test Certificate (MTC) EN 10204 3.1 or 3.2

The MTC is the most important document in the traceability system. It includes:

  • Heat number

  • Chemical composition analysis

  • Tensile test results

  • Impact toughness results

  • Proof of compliance with standards

  • Inspector signatures

  • Classification society endorsement (for 3.2 certificates)

2. Heat Treatment Records

For normalized or TMCP plates, detailed heating curves and process logs are retained.

3. Non-Destructive Testing (NDT) Reports

Depending on project requirements, plates may require:

  • UT ultrasonic testing

  • RT radiographic testing

  • Z-direction testing

4. Dimensional Inspection Records

Flatness, thickness, and edge quality reports verify conformity.

5. Shipping and Packing Lists

These link heat numbers to shipping batches, maintaining traceability during transportation.

How Classification Societies Regulate Marking and Traceability

ABS Requirements

ABS mandates:

  • Clear marking of grade, heat number, ABS logo, and mill identification

  • Full traceability from steelmaking to delivery

  • MTC showing chemical and mechanical results

LR Requirements

Lloyd’s Register requires:

  • Permanent markings resistant to handling

  • Clear linkage between plate marking and certificate

  • LR surveyor approval for critical materials

DNV Requirements

DNV focuses on:

  • Heat number essential for mechanical property verification

  • Additional traceability for offshore steel

  • Enhanced documentation for higher-strength grades

BV Requirements

Bureau Veritas requires:

  • Both paint markings and traceable documents

  • Strict control on batch testing and chemical analysis records

  • 3.2 certification for key offshore components

All societies require plate markings to match documentation exactly, with errors leading to rejection or re-inspection.

How Marking and Traceability Prevent Risks in Marine Structures

1. Avoiding Structural Failure

Incorrect or non-traceable steel used in hulls, decks, or frames can compromise a vessel’s safety.

2. Ensuring Welding Compatibility

Different grades respond differently to heat input. Traceability ensures welders use the correct parameters.

3. Ensuring Proper Installation in Critical Areas

High-impact zones such as bow structures, ice belts, and offshore legs must use materials with verified toughness. Traceability ensures correct placement.

4. Simplifying Material Substitution Approvals

When substitutions are needed, traceability allows engineers to quickly verify compatibility.

Common Traceability Problems and Their Solutions

Problem 1: Markings Lost During Cutting

Solution:
Steel should be re-marked immediately after cutting and before moving to fabrication.

Problem 2: Incorrect Heat Numbers

Solution:
Double-check markings during receiving inspection. Suppliers like sakysteel use digital verification systems to avoid errors.

Problem 3: Missing Certificates

Solution:
Maintain digital backups and require full MTC packages before shipment.

Problem 4: Mixing Different Grades During Storage

Solution:
Color-coding or segregated storage systems reduce mix-up risks.

Digitalization of Traceability in the Marine Industry

Modern shipyards increasingly adopt:

  • QR code traceability

  • Digital heat number databases

  • RFID tagging systems

  • Automated material tracking software

  • Real-time traceability dashboards

Digital traceability reduces human error and speeds up verification processes.

The Role of Reliable Suppliers

A supplier’s traceability system directly influences the accuracy of the shipyard’s project documentation. Companies like sakysteel implement strict quality assurance measures:

  1. Unique heat number tracking from melting to rolling

  2. Fully documented inspection processes

  3. 3.1 and 3.2 MTC packages

  4. Clear marking using automated paint systems

  5. Batch-by-batch traceability checks before shipment

This ensures that every plate delivered is ready for classification society approval and immediate use in fabrication.

Conclusion

Marking and traceability are essential pillars of modern shipbuilding and offshore engineering. They ensure that every marine grade steel plate can be identified, verified, certified, and confidently used in demanding maritime environments. Clear marking prevents dangerous mix-ups during fabrication, while strong traceability guarantees compliance with ABS, LR, DNV, BV, and global regulatory requirements.

As marine structures become more complex, the importance of accurate traceability systems continues to grow. Shipyards rely on dependable suppliers with robust documentation and marking protocols to guarantee project success. Through advanced quality control and precise marking practices, suppliers like sakysteel support the global maritime industry with reliable, fully traceable steel materials that meet the highest safety and compliance standards.

Post time: Nov-14-2025