Glossary term
Heat Number Traceability
The unbroken chain that links each pressure-retaining part to the steel melt it was made from, through the heat number on the part and its material certificate.
Last reviewed by the OdysseyGPT team
What it is
Heat number traceability is the chain that links each pressure-retaining part to the steel melt it came from. The heat number stamped on the part must match the material certificate, the heat list and the bill of materials. Where a part is cut, the number is transferred so the chain stays unbroken to final tag.
Key Takeaways
- One heat number, one certificate: the part marking, heat list and MTR must agree.
- Transfer the heat number before cutting, not after.
- The chain runs tag → part → heat number → certificate, and back.
- Customers check it in the manufacturing record book.
Why it matters
Steel is made in batches called heats. Each heat gets a heat number, which the mill prints or stamps on the product and reports on the material test report (MTR) with that heat's chemistry and test results. Heat number traceability means you can take any finished part, read its heat number, and find the certificate that proves its material, and go the other way from a certificate to every part made from that heat. The chain runs from the final equipment tag, through the bill of materials and the heat list, to the part marking and the certificate. When material is cut, the heat number is transferred to each piece, usually witnessed by quality, so the chain is not broken. Where a part is marked by hard stamping, low-stress stamps are often required. Specifications for pressure equipment, and the manufacturing record book at handover, depend on this chain.
How OdysseyGPT uses it
The Material Traceability Check (beta) walks the chain from final tag down to certificate, using the bill of materials, certificates, heat list, fabrication records, weld map, tag list and packing list, and reports every unlinked heat number, certificate without a part, conflicting grade or duplicate coverage, with citations. MRB Traceability Verification (beta) checks the same links inside a finished record book.
Evaluation questions
Is a heat number the same as a lot number?
Not always. A heat is one melt. A lot can be a batch of product from one heat that was processed together, for example heat treated in one load. Some certificates give both.
What if a heat number is lost from a part?
Treat it as a nonconformance. Options can include positive material identification and retest, but the customer usually has to agree how the part is handled. Prevention is far cheaper.
Is there software for heat number traceability?
Yes. Stockholder ERPs and fabrication systems record heat numbers as material moves. OdysseyGPT's Material Traceability Check (beta) checks the documents afterwards, linking each heat from tag to certificate with citations.
Frequently asked questions
What is a heat number?
An identifier the mill gives to one batch, or heat, of steel. It appears on the product and on the material test report, so the material can be matched to its chemistry and test results.
How do you read a heat number?
Each mill uses its own format, often letters and digits. You do not decode it; you match it. Find the number on the part marking, then find the same number on the material certificate and in your heat list.
What does a heat number look like?
Usually a short string of letters and numbers, stamped, etched or printed on the material near the grade and size markings, and printed in the heat or cast number field of the certificate.
How do I maintain heat number traceability?
Check the heat number against the certificate at goods-in, record it on a heat list against the bill of materials, transfer it to every cut piece before cutting, and record it on the traveller and weld map so it reaches the final tag.