Part 4: Traceability and identification of material from an incorrect source

A steel plate may enter the warehouse with complete certificates and identification markings. However, once it is cut into multiple components, only one section may retain the original identification. The remaining components may then be machined, installed or returned to storage without any information linking them back to the original plate.

If the plant later needs to verify material quality or confirm the material source, it may no longer be possible to identify the corresponding certificate even though the original documentation has been retained.

For this reason, traceability is not limited to checking documents at receiving. It also requires maintaining the link between the material, batch information and records throughout machining and installation.

This article focuses on identifying unusual signs, maintaining traceability after material is cut, and handling cases where the material source has not yet been verified.

1. Information required in the material traceability chain

For industrial steel plate, the traceability chain needs to link production data, material identification and the corresponding documentation.

Four links need to be managed:

Traceability link	Information to identify	Role
Heat number	Steelmaking heat from which the material was produced	Links the material to the chemical composition data for the heat
Rolling batch number	Product batch generated during the rolling process	Helps identify the product group and related production data
Identification number on the material	Code stamped or marked directly on the steel plate	Links the physical material to the corresponding records
Inspection certificate	Identification information and inspection results according to the certificate type	Used to verify material source and declared properties

These items need to remain linked.

For example, when matching a steel plate to its certificate, the quality department needs to verify that the identification number on the material matches the information recorded in the documentation.

If a certificate is available but it cannot be established which steel plate the certificate belongs to, the traceability chain is incomplete.

Conversely, a stamped number on the material does not by itself prove the material source if there is no corresponding documentation for verification.

Verification should therefore be based on the relationship between the records rather than on a single identification mark.

Further details on the evidential value of different certificate types are provided in Part 1: What do material certificates and documents prove.

2. Distinguishing stamped numbers, paint markings and labels

During storage and machining, materials may be identified in several different ways.

However, these identification methods do not provide the same level of evidence when verifying material source.

Identification method	Role in traceability	Points to consider
Number stamped directly on the material	Important link for matching the material with its certificate	Needs to match the information in the records
Paint marking	Supports identification, classification and warehouse management	Should not be used alone to determine material source
Label or tag	Supports batch management and delivery information	Needs to be linked to records for the corresponding batch
Inspection certificate	Provides material information and inspection results	Needs to be linked to the actual material

A number stamped directly on steel plate generally provides stronger traceability than paint markings or labels because it is applied directly to the material.

However, the stamped number does not by itself confirm the authenticity of the material. Traceability is established only when the identification number can be matched to the certificate and related records.

For some thin products or products supplied in bundles, identification may be managed through batch numbers, bundle labels and delivery documentation rather than a stamped number on every plate.

In such cases, the documentation chain needs to be organized according to the product’s identification method.

3. Four situations that can break the traceability chain

A material batch may be fully controlled when it enters the warehouse but lose its source link during machining.

Four situations require particular attention:

Situation	Potential risk	Control measure
Cutting one plate into multiple components	Only one component retains the original identification number	Transfer identification information before cutting
Grinding, drilling, welding or machining at the location of the stamped number	The identification mark is removed or becomes unreadable	Photograph and record the number before machining
Returning remnant material to storage	The remnant is no longer linked to the original plate	Assign a temporary code and retain the linking record
Material passing through multiple intermediaries	Documentation and identification information may not be transferred completely	Maintain traceability records at every handover

3.1. Cutting the plate before transferring identification information

This is a situation that can easily occur in the workshop.

A steel plate may have a stamped number at one specific location. Once the plate is cut into multiple components, only the section containing that number retains the original identification.

If the remaining sections are not marked separately, identifying the source of each component may depend on memory or incomplete workshop records.

For this reason, identification information needs to be transferred before the plate is cut.

3.2. Machining removes the identification number

A stamped number may be removed by grinding, drilling, milling or other machining operations performed at the identification location.

Before work begins, the workshop should photograph and record the material code.

If the original identification cannot remain on the finished component, the linking code needs to be maintained in the fabrication records.

3.3. Remnant material is returned to storage

Material remaining after cutting may later be used for other orders or components.

If traceability information is not retained, the warehouse may only know the dimensions and material type stated on a temporary label without having enough data to identify the original batch.

Each remnant should therefore have a temporary identification code and a record linking it to the original plate.

3.4. Documentation is not transferred completely

When material passes through multiple intermediaries, the documentation can become separated from the physical material.

For example, the receiving party may receive only a delivery note and dimensional information without sufficient records to link the material to its inspection certificate.

In this situation, procurement needs to coordinate with the supplier to complete the documentation chain before the material source is confirmed.

4. Procedure for transferring identification information when cutting steel plate

To maintain traceability after fabrication, identification transfer can be organized in four steps.

Step	Action	Data to retain
1. Record the original plate	Photograph the complete plate and a clear image of the stamped number before cutting	Plate image, stamped-number image, material code
2. Prepare the cutting plan	Define the position and code of each component to be cut	Cutting plan linked to the original plate code
3. Mark each component	Assign a temporary identification number to each section after cutting	Temporary code for each component
4. Maintain the linking table	Match the original stamped number with the temporary codes	“Original stamped number ↔ temporary number” table

4.1. Record data before cutting

The photographs need to show both the material plate and the original identification number.

A close-up image of the stamped number alone should not be used if it does not provide enough context to identify which plate the marking belongs to.

If several plates are processed at the same time, the images and records need to be organized so they cannot be confused between plates.

4.2. Assign temporary codes according to the cutting plan

Each component after cutting needs to receive a temporary code corresponding to the prepared cutting plan.

This allows the fabrication team to identify which plate each component came from even when the original stamped number is no longer present.

The temporary code needs to remain linked through subsequent operations until corresponding handover or installation records are available.

4.3. Link the material code to the fabrication release records

When the component is completed and handed over, the fabrication release records need to identify the material code used.

This enables reverse traceability from the finished component through:

Fabricated component → Temporary code → Original plate → Batch number → Inspection certificate.

This provides the basis for tracing material source when quality verification or post-installation failure assessment is required.

5. Identifying signs of material with an unverified source

During receiving, the warehouse and quality department may identify unusual signs related to packaging, identification markings or documentation.

However, one unusual sign alone is not sufficient to conclude that the material comes from an incorrect source or is counterfeit.

The following signs should only be used to identify cases requiring additional verification.

Sign requiring attention	What needs to be verified
Packaging or bundling differs from previous batches	Check supplier information, batch number and delivery documentation
Paint markings or primer appearance is unusual	Compare the identification method with information from the supplier
Signs of grinding or covering appear where identification is normally located	Inspect the actual identification marking and related records
Certificate lacks standard-version information or has an unusual format	Verify the certificate and issuing organization

These signs may result from changes in packaging, preservation procedures or document format.

They should therefore not be used as standalone evidence that the material comes from an incorrect source.

If two or more unusual signs are identified, the warehouse and quality department should record and report them so that additional verification can be arranged.

This threshold is an internal management warning level, not a technical-standard criterion for identifying counterfeit material.

6. What to do when the material source cannot yet be verified

If the identification number does not match or several unusual signs are identified, the material batch should be withheld from use until verification is complete.

The process can be organized in four steps:

Step	Action	Responsible function
1. Segregate the material batch	Mark the status as “Under inspection” and prevent release or machining	Warehouse
2. Record the evidence	Photograph the complete batch, identification numbers, packaging and related documents	Warehouse and quality department
3. Report on the same day	Notify procurement and technical teams so that verification can be coordinated	Warehouse and quality department
4. Determine the next action	Review records, coordinate with the supplier and agree on a conclusion before use	Procurement and technical teams in coordination with the quality department

The important point is to maintain controlled status for the material batch throughout the verification process.

The material should not be released, returned or declared counterfeit without sufficient evidence.

If the source is fully verified, the batch can continue through the normal receiving and acceptance inspection process.

If the relationship between the material and the certificate still cannot be established, the batch should remain segregated until a handling decision is made according to the applicable agreement.

7. Traceability for thin steel plate without stamped identification

Not every steel product has a stamped identification number on each individual plate.

For some thin products or products supplied in bundles, identification may be managed through batch codes and bundle labels.

In this situation, three groups of evidence can be used:

Evidence	Required information
Supplier certificate	Batch number and corresponding material information
Receiving photographs	Complete bundle and bundle label at the time of receiving
Warehouse receiving record	Batch number and information linking it to the documentation

These three groups of information need to be recorded at the same time during receiving.

If the bundle has already been opened, divided or moved into fabrication before photographs and records are prepared, traceability may be limited.

For materials without a stamped identification number on each plate, receiving records and batch codes therefore play a particularly important role in maintaining the traceability chain.

8. What should traceability records be able to answer after several years?

The value of traceability does not end at the time of receiving.

After a component has been installed and operated for several years, the plant may still need to determine what material was used, where it came from and the original basis for its selection.

A complete record should help answer five questions:

Information to determine	Records used
What material was the component fabricated from?	Fabrication records and material code at release
Which batch did the material come from?	Warehouse receiving records and corresponding certificate
Which original plate was the component cut from?	Linking table between original stamped number and temporary code
Which function selected the material and on what basis?	Survey records and approved material selection proposal
Was operating performance measured afterwards?	Monitoring records and post-installation measurements

If the linking data from the original plate to the finished component is missing, determining the source of the component several years later may be difficult.

Similarly, if only the certificate is retained without material-selection and operating data, the plant still does not have enough information to evaluate how effectively the material performed.

Further details on retaining selection records, acceptance criteria and responsibilities are provided in Part 5: Acceptance criteria and responsibility for material selection.

9. Three common errors in managing traceability records

Management error	Consequence	Corrective action
Recording only the batch number without linking it to the actual identification number	Difficult to determine which material plate the certificate belongs to	Verify and retain identification information during receiving
Failing to transfer identification information after cutting	Components lose their link to the original plate	Prepare a cutting plan and an original-to-temporary identification table
Filing records by supplier instead of by batch	Difficult to retrieve data for a specific component	Organize records by batch number and identification number

Of these, failing to transfer identification information after cutting can break the traceability chain directly in the workshop even when the initial receiving process was completed correctly.

Maintaining the material code should therefore be considered part of the fabrication process, not only a warehouse responsibility.

10. Responsibilities of the different functions

To maintain the traceability chain, each function needs to manage material information at the relevant stage.

Task	Responsible function
Check identification numbers and documents at receiving	Warehouse and quality department
Record, mark and segregate batches showing unusual signs	Warehouse
Photograph the identification number before cutting	Fabrication workshop
Prepare the cutting plan and transfer identification information to each component	Fabrication workshop
Maintain the original-to-temporary identification table	Fabrication workshop in coordination with the warehouse
Verify discrepancies with the supplier	Procurement and technical teams
File documents by batch number	Warehouse and quality department
Record the material code in fabrication release records	Fabrication workshop

Among these tasks, transferring identification information before cutting is a critical step in maintaining traceability from incoming material to the finished component.

Without this step, the documentation may remain complete but no longer be linked to the fabricated component.

11. Notes on applying this knowledge

First, an identification number marked directly on the material is an important link in the traceability chain, but it does not by itself prove material source or authenticity. It needs to be checked against the certificate and related records.

Second, paint markings, labels and packaging can support identification. These signs should not be used individually to conclude that the material is from the correct or incorrect source.

Third, unusual signs and the warning threshold of two or more signs are internal management guidelines, not criteria for identifying counterfeit material under a technical standard.

Fourth, when the material source has not yet been verified, the batch needs to be segregated and maintained under “Under inspection” status. It should not be declared counterfeit, released or returned before verification is complete and an appropriate handling decision has been made.

Fifth, for products without stamped identification on each plate, the traceability chain needs to be maintained through batch codes, bundle labels, receiving photographs and warehouse receiving records.

Sixth, traceability helps identify which material was used and the corresponding records. Whether the material is suitable for the application or achieves the expected service life still needs to be evaluated using technical data and operating performance.

An effective traceability chain needs to maintain the connection from the inspection certificate, batch information and incoming material through to each fabricated component. Accurate receiving records, identification transfer before cutting and batch-based document retention help the plant determine material source, inspect quality and address discrepancies that arise during service.