Maintaining traceability after cutting steel

A mill test certificate is useful only if the delivered piece can still be linked reliably to the material represented by that certificate.

That link becomes vulnerable when a stockholder or service centre cuts a master plate, beam, pipe or bar into smaller pieces. The original mill marking may remain on only one piece, while the other cut pieces become visually anonymous unless identification is transferred in a controlled way.

This is why traceability after cutting is a process, not merely a copied heat number.

What traceability is trying to preserve

For most steel purchases, the basic chain is:

mill production → original product marking → inspection document → stockholder identity → cut piece → final delivery

The exact identifier can be a heat number, cast number, lot number, product number or a combination defined by the mill and product standard. The important point is that the supplier must be able to demonstrate an unbroken relationship between:

1. the physical master material;
2. the original inspection document;
3. the cutting or processing record; and
4. every piece delivered to the purchaser.

See EN 10204 certificate types 2.1, 2.2, 3.1 and 3.2 for the document framework itself.

A practical controlled-cutting workflow

A robust service-centre procedure normally includes the following stages.

1. Verify the mother material before cutting

Before the first cut, confirm that the physical product marking agrees with the relevant MTC and internal stock record. Typical checks include:

• heat/cast number;
• grade and standard;
• dimensions;
• manufacturer;
• product identification or order reference;
• quantity or length;
• any supplementary requirements such as Z-quality, UT or impact testing.

If the starting identity is uncertain, cutting only spreads the uncertainty.

2. Create a cutting record

The service centre should record which finished pieces came from which master item. Depending on the product and project, this may be a cutting plan, nesting drawing, saw list, production traveller or ERP transaction.

For a plate, for example, the record can show:

mother plate P-102 / heat H4567 → pieces P-102-A, P-102-B, P-102-C

The internal piece IDs do not replace the mill heat number; they provide the bridge from each cut piece back to it.

3. Transfer identification before it is lost

Identification should be transferred while the relationship with the mother material is still physically obvious. Waiting until a pile of pieces has been moved to another bay creates avoidable risk.

Methods can include:

• paint or low-stress marking;
• tags securely attached to the piece or bundle;
• bar coding or QR-linked internal IDs;
• stamping where permitted by the material and specification;
• controlled labels for short pieces.

The permitted marking method is itself specification-dependent. Hard stamping, for example, may be restricted on some materials or applications.

4. Keep the original MTC unchanged

A stockholder should not alter the mill's original certificate to make it look as though the mill produced the final cut size.

The usual documentary package is instead:

• the original mill inspection certificate;
• the stockholder/service-centre delivery document;
• a traceability statement, cutting record or piece list linking the cut product to the original material.

If a project requires a particular form of re-certification or validation, that requirement must be handled explicitly rather than by editing the original MTC.

Multiple heats require stronger controls

A bundle can contain visually identical pieces from different heats. This is one of the highest-risk situations.

Good practice is to avoid mixing unidentified loose pieces from different heats. If mixed-heat bundling is commercially necessary, each piece or clearly segregated sub-bundle needs its own controlled identity.

A single tag on the whole bundle is not enough if it could be removed while individual pieces are distributed.

What about remnants?

Offcuts and remnants often return to stock and may be sold months later. Their traceability must therefore survive storage.

A useful remnant record includes:

• internal stock ID;
• original heat number;
• original product dimensions;
• remaining dimensions;
• original MTC reference;
• date/process of cutting;
• any additional tests performed after the original production.

If a remnant loses its identity, later laboratory testing cannot reconstruct which heat it originally came from.

Retesting cannot repair a broken identity chain

Retesting can demonstrate properties of the sample that was tested. It does not prove that an unidentified piece belongs to a specific original heat or certificate.

This distinction is especially important when using existing stock for demanding projects. Additional UT, Charpy, Z-testing or chemical analysis may be valuable, but only after the material itself has been positively identified. See Using stock material for offshore projects: documentation and retesting risks.

Traceability after further processing

The same principle applies after operations such as:

• beveling;
• threading;
• machining;
• drilling;
• blasting and painting;
• forming;
• fabrication into assemblies.

If original markings will be removed, the processor needs a transfer method before the operation starts.

For threaded micropile tubes, for example, cutting a long mother tube into many short threaded pieces does not reduce the need for traceability. It increases the number of physical items that must remain linked to the original certificate.

What to ask a stockholder

For critical purchases, useful questions are:

• How are mother pieces identified before cutting?
• How is each cut piece linked to the mother material?
• Are heat numbers physically transferred?
• Is there a cutting map or ERP traceability record?
• How are mixed heats segregated?
• How are remnants returned to stock?
• Can the supplier provide the original MTC without alteration?
• If extra testing is performed, how is the test sample linked to the exact piece or heat?
• Is the process available for purchaser or TPI review?

Procurement takeaway

Traceability is not established merely because the supplier can provide an MTC with the same grade written on it.

For cut stock, the real question is:

Can the supplier demonstrate an unbroken and auditable link from the delivered piece back to the original mill material and inspection document?

If that link cannot be demonstrated, the certificate and the physical steel should be treated as disconnected until the identity issue is resolved.

References and verification sources

• ISO 404:2013 — Steel and steel products — General technical delivery requirements
• ISO 10474:2013 — Steel and steel products — Inspection documents
• DIN EN 10204 — Metallic products — Types of inspection documents