Does AWS D1.1 require heat-number-level filler metal traceability?

AWS D1.1 does not by default require linking each weld to a specific filler metal heat number. However, the structural steel specification (AISC COSP), the project spec, or the owner's QA program commonly adds this requirement. On seismic and demand-critical weld scopes, AISC 341 requires CVN documentation tied to the specific lot of filler metal used.

What is the difference between a filler metal lot number and a heat number?

A heat number identifies the specific melt batch of the wire or core material. A lot number (or control number) identifies a manufacturing batch, which may span multiple heats. CMTRs are typically issued at the lot level. For seismic applications requiring CVN documentation, the CMTR must be specific enough to cover the lot actually used in production.

How long must filler metal CMTRs be retained?

AWS D1.1 does not specify a retention period for consumable CMTRs, but owner/EOR requirements and AISC certification programs commonly require a minimum of 10 years. For projects subject to building permits, the AHJ retention requirement governs. Best practice is to tie CMTR retention to the structure's design life.

Can I use filler metal without a CMTR on a D1.1 job?

For standard structural work, AWS D1.1 requires the filler metal to conform to an applicable AWS A5 specification — the specification test certificate (typically from the manufacturer's literature) suffices unless the project spec or governing code requires heat-specific CMTRs. For demand-critical welds, a lot-specific CMTR showing CVN data is non-negotiable.

Filler Metal Heat Number Traceability in AWS D1.1

AWS D1.1 filler metal traceability: what heat numbers and lot certs you must keep, how to link them to weld records, and what auditors check first.

At most AWS D1.1 job-site audits, the inspector knows within five minutes whether the fabricator has a real traceability system or a paper trail stitched together retroactively. Filler metal heat numbers — and the Certified Material Test Reports (CMTRs) behind them — are usually the first thing checked, and also the first thing missing.

Why Filler Metal Traceability Matters

Structural welds fail in predictable ways when the wrong filler metal is used: tensile strength mismatch causes premature yield at the joint; hydrogen content above the classified limit causes delayed cracking in high-restraint joints; inadequate CVN toughness causes brittle fracture at low temperature.

All three failure modes are preventable if the filler metal used in production matches the filler metal specified on the WPS — and you can prove it. Traceability is the proof.

AWS D1.1:2025 Clause 4.6 requires that welding consumables conform to the applicable AWS A5 filler metal specification and that they are used within the limits of the WPS. Clause 6.5 extends this to the requirement that the fabricator verify that the filler metal classification matches what the WPS specifies. Neither clause mandates heat-level traceability for routine structural work, but the gap is routinely closed by:

AISC 341 Section A3.4b (seismic filler metal CVN documentation by lot)
AISC Code of Standard Practice Chapter 8.2 (documentation requirements)
Owner or EOR QA programs that require weld logs linked to CMTR numbers
Third-party quality programs (AISC Certification, IAS, etc.) that require consumable records

Rule library based on AWS D1.1:2025; verify against your governing edition.

What a CMTR Must Show

A Certified Material Test Report (CMTR) for a filler metal should include:

Manufacturer name and product identification — electrode classification (e.g., E7018-H4R), trade name, wire diameter.
Heat or lot number — the control number that ties the report to the actual production batch.
Chemical analysis — actual weld metal chemistry for the relevant AWS A5 classification requirements.
Mechanical properties — tensile strength, yield strength, elongation, and (where applicable) CVN impact values at the specified test temperature.
Certifying signature — the manufacturer's authorized signature attesting that the lot meets the classification requirements.

For seismic demand-critical welds, the CMTR must show CVN impact values at −20°F (or as low as −40°F if the project spec requires it for cold-region structures). A generic manufacturer's classification test report from their website does not substitute for a lot-specific CMTR showing actual test values for the material you have in your storage area.

Setting Up a Traceability System

An effective filler metal traceability system has three linked records: receipt, storage/issuance, and weld.

On receipt: When filler metal arrives at the fab shop or job site, record the lot number and heat number (if distinguishable) against the purchase order and the CMTR received with the shipment. Do not accept filler metal shipments without a CMTR if the project requires one. File the CMTR immediately — not when the submittal package is due.

In storage and issuance: Filler metal should be received into a controlled storage area and issued to welders by lot, not by random grab from a bin. An issuance log that records which lot number was issued to which work area on which date gives you the minimum chain of custody to reconstruct traceability after the fact if a weld problem arises.

On the weld record: The weld traveler, fit-up inspection record, or electronic weld log should include a field for the filler metal lot number used. For routine structural work, this is the field that closes the chain. For seismic work, the filler metal lot number must be on the record so the CMTR can be pulled and reviewed against the CVN requirement.

Seismic Scope — The High Bar

On special moment frame (SMF), intermediate moment frame (IMF), or eccentrically braced frame (EBF) work where AISC 341 applies, the traceability requirement is explicit and auditable:

The filler metal used for demand-critical welds must have a CMTR on file showing CVN of ≥20 ft-lb at −20°F.
The weld record must link each demand-critical weld to the filler metal lot used.
The special inspector assigned to the project will verify this chain. A missing or generic CMTR typically results in a required re-weld or at minimum a formal resolution to the record.

See demand-critical weld filler metal selection and AISC 358 prequalified moment connection WPS requirements for the broader qualification context.

Low-Hydrogen Electrode Storage and Lot Identity

For SMAW low-hydrogen electrodes (E7018, E7016, E7028), the electrode lot number is on the carton or container label. Once the container is opened and electrodes are placed in a rod oven, lot identity is only maintained if electrodes from different lots are not mixed in the same oven compartment. On multi-electrode projects, discipline at the oven is the weak link: mark oven compartments, issue by lot, and log the oven temperature daily. The oven log is a secondary traceability document — if a weld is later found defective and hydrogen cracking is suspected, the oven log helps establish whether the electrode was properly conditioned.

See low-hydrogen electrode storage and baking requirements and FCAW electrode storage and moisture control for process-specific conditioning requirements.

What Auditors Check

AISC certification auditors and third-party QA auditors reviewing filler metal traceability will look for:

CMTRs on file for every filler metal lot used in the audit period — missing CMTRs are a nonconformance.
Match between CMTR lot numbers and weld records — if your weld records list lot 2024-1187 but the CMTR on file is for lot 2024-1022, the chain is broken.
CVN values on the CMTR match or exceed the WPS requirement — for demand-critical electrodes, a CMTR showing CVN at 0°F does not satisfy a −20°F requirement even if the number happens to be high.
Issuance log or equivalent control system — how do you ensure that filler metal in production matches what the CMTR covers?
Storage conditions and oven logs for low-hydrogen electrodes — temperature records and electrode exposure tracking.

A robust filler metal traceability system is not complicated, but it requires discipline at receipt, storage, issuance, and documentation. Shops that get this right before the first audit avoid retroactive record reconstruction, which is expensive and unreliable.

Connecting Traceability to WPS Management

Filler metal traceability only works when the WPS itself specifies the filler metal precisely — classification, AWS specification, diameter range, and (for seismic work) the CVN requirement. A WPS that says "E7018" without referencing the AWS A5.1 classification and CVN supplement leaves room for the wrong material to be used without detection. Build the filler metal call-out into the WPS at the classification level, then let your traceability system verify that production matches it.

The weld map that assigns specific WPS numbers to specific joint IDs is the document that ties the weld record, the WPS, and the filler metal CMTR together into a single retrievable package. See weld map and WPS traceability in production for how to structure that map, and welding consumable cert and traceability basics for the A5 specification background. To manage filler metal records, weld logs, and WPS assignments at scale across jobs, see /pricing.